Title of Invention	METHOD FOR ESTABLISHING TIME DOMAIN STRUCTURE OF A FRAME IN A HETEROGENEOUS TDD SYSTEMS ENVIRONMENT
Abstract	Disclosed is a method for establishing a time domain structure of a frame in a heterogeneous TDD systems environment. In other words, in a situation of coexisting heterogeneous systems comprising a first system corresponding to an existing TDD system and a second system corresponding to a new system, a method is provided for establishing a time domain structure of a second frame for the second TDD system mode to enable it to coexist with a first frame for the first TDD (Time Division Duplex) system mode, that comprises obtaining information for the first supported system type and a first ratio between the downlink region and the uplink region of the first frame structure, and then, according to the obtained information, establishing a second ratio between the downlink region and the uplink region of the second frame structure for the second system. Further, particular numerology is provided for said method.

Title of Invention

METHOD FOR ESTABLISHING TIME DOMAIN STRUCTURE OF A FRAME IN A HETEROGENEOUS TDD SYSTEMS ENVIRONMENT

Abstract

Disclosed is a method for establishing a time domain structure of a frame in a heterogeneous TDD systems environment. In other words, in a situation of coexisting heterogeneous systems comprising a first system corresponding to an existing TDD system and a second system corresponding to a new system, a method is provided for establishing a time domain structure of a second frame for the second TDD system mode to enable it to coexist with a first frame for the first TDD (Time Division Duplex) system mode, that comprises obtaining information for the first supported system type and a first ratio between the downlink region and the uplink region of the first frame structure, and then, according to the obtained information, establishing a second ratio between the downlink region and the uplink region of the second frame structure for the second system. Further, particular numerology is provided for said method.

Full Text	[SPECIFICATION] [Title of the Invention] THE METHOD FOR ESTABLISHING TIME DOMAIN STRUCTURE OF A FRAME IN A HETEROGENEOUS TDD SYSTEMS ENVIRONMENT [Field of the Invention] The following description of the present invention relates to a method of establishing a time domain structure of a frame in an environment where heterogeneous TDD systems co- exist. [Field Background] In case of wideband telecommunications systems, in order to maximize the efficiency of limited wireless (or radio) resources, a number of more effective transmitting and receiving methods in time, space, and frequency domains and the respective application methods have been proposed. Particularly, the multi carrier OFDM method has the advantages of reducing the complexity of a receiving end in a frequency selective fading environment that occurs in a wideband channel and, also, of maximizing spectral efficiency through selective scheduling in a frequency domain by applying different channel characteristics (or attributes) of a subcarrier. Furthermore, by allocating (or assigning) different subcarriers to multiple users, the OFDM method is extendable to an orthogonal frequency division multiple access (OFDMA) method, thereby being capable of enhancing the efficiency of the wireless resource in the frequency domain. As the WirelessMAN-OFDMA standard adopting the typical OFDMA, IEEE 802.1.6-2004 and the amended standard IEEE 802.16e- 2005 (hereinafter referred to as IEEE 802.16e) have been completed. FIG. 1 shows a logical frame structure of the IEEE 802.16e system. As shown in FIG. 1, the logical frame structure of the IEEE 802.16e system consists of a preamble (101), an FCH (frame control header) (102), control signal blocks of DL/UL-MAP (103, 104), and data bursts. Also, the data transmission of each user is defined by different subcarrier allocation methods (e.g., PUSC, (O)-FUSC, TUSC, AMC, etc.) depending upon the method of configuring the subcarrier. Herein, various permutation zones may be configured in one frame. In the frame of the IEEE 802.16e system, as shown in FIG. 1, the reception of an initial preamble (101), an FCH (102), and control information on the DL/UL-MAP (103, 104) is required. And, the role of each field is as follows: Preamble (101) : performing synchronization, channel estimation, cell ID acquisition, etc. FCH (102) : providing channel allocation information and channel code information associated with the DL-MAP (103) - DL/UL-MAP (103, 104) : providing channel allocation information of a data burst in an downlink (DL)/uplink (UL) Among the above-described control fields, with the exception of the preamble (101), the logical frame structure may be diversely configured (or established) in accordance with a subchannel allocation method (PUSC, (O)-FUSC, TUSC, AMC, etc.) selected by taking into consideration factors such as frequency diversity gain, scheduling gain, convenience in adopting a pilot overhead or multi/adaptive antenna. Meanwhile, discussions of an enhanced version (or system) of the above-described IEEE 802.16e system is in progress, and such system will be regulated as the IEEE 802.16m standard. Accordingly, reference may be made to "IEEE 802.16m-07/002r4 - TGM System Requirements Document" (hereinafter referred to as "SRD") for the requirements that the IEEE 802.16m system should satisfy. Referring to the above-described SRD of the IEEE 802.16m system, it is mentioned that co-existence with the TD-SCMA, 3GPP LTE TDD should be supported in the IEEE 802.16m TDD mode. However, in case of the IEEE 802.16m system, an accurate frame structure has not yet been decided, and, accordingly, discussions on the uplink/downlink ratio and time domain structure of a frame within the IEEE 802.16m system for the co-existence with the heterogeneous TDD system is required to be made. [Detailed description of the invention] [Technical objects] In order to resolve the above-described problems, the present invention proposes a method of determining a downlink (DL)/uplink (CJL) ratio and a method of establishing a time domain structure of other frames so as to prevent collision with a heterogeneous time division duplex (TDD) network when designing the frame structure from occurring, in the aspect of a specific system design. [Technical solutions] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, according to an embodiment of the present invention, in a situation of coexisting heterogeneous systems including a first system and a second system, in a method of establishing a time domain structure of a second frame used for a Time Division Duplex (TDD) mode of the second system, so that the second frame can coexist with a first frame for a TDD mode of the first system, the method of establishing a time domain structure of a frame includes an information acquiring step for acquiring type information of the first system being supported and information on a first ratio, wherein the first ratio corresponds to a ratio between an uplink section and a downlink section in the first frame structure; a second frame structure establishing step for establishing a second frame structure for the second system based upon the acquired information; and a ratio determining step for determining a second ratio, wherein the second ratio corresponds to a ratio between an uplink section and a downlink section in the second frame structure. At this point, the determining step may further include a set-up step of excluding a predetermined number of OFDM symbols from transmission so that a sum of the downlink section and a transmit transition gap (TTG) of the second frame can be equal to or greater than a sum of the downlink section and a downlink pilot time slot (DwPTS) of the first frame. Also, the determining step may further include a step of establishing a frame offset from a starting point of the first frame of the second frame. In a more specific embodiment of the present invention, the first system may correspond to an LCR-TDD (low^-chip-rate time division duplex) system, and the second system may correspond to an IEEE 802.16m system, and a cyclic prefix (CP) length of the second frame may be equal to 1/8 valid OFDM symbol time (Tu) . And, in this case, the second ratio may be set to 7:1 when the first ratio is set to 6:1. The second ratio may also be set to 6:2 when the first ratio is set to 5:2. The second ratio may also be set to 5:3 when the first ratio is set to 4:3. Herein, x:y corresponds to (a downlink section length):(an uplink section length). And, this is identically applied to the following cases. Also, in the same situation, among the second frame structure, 1 OFDM symbol may be excluded from the transmission when the first ratio is 6:1, and 2 OFDM symbols may be excluded from the transmission when the first ratio is 5:2, and 3 OFDM symbols may be excluded from the transmission when the first ratio is 4:3. In another more specific embodiment of the present invention, the first system may correspond to a 3GPP LTE TDD system, and the second system may correspond to an IEEE 802.16m system, and a cyclic prefix (CP) length of the second frame may be equal to 1/8 valid OFDM symbol time (Tu) . And, in this case, the information acquiring step may include a step of additionally acquiring CP length information of the first frame and configuration index information of the first frame in the 3GPP LTE TDD system. In this embodiment, when it is assumed that the CP length of the first frame corresponds to a normal CP and that the first ratio is 1:3, the second ratio may be set to 2:6 or 3:5 when the configuration index of the first frame is 0, the second ratio may be set to 3:5 when the configuration index of the first.frame is 1, the second ratio may be set to 3:5 when the configuration index of the first frame is 2, the second ratio may be set to 3:5 when the configuration index of the first frame is 3, the second ratio may be set to 3;5 when the configuration index of the first frame is 4, the second ratio may be set to 2:6 or 3:5 when the configuration index of the first frame is 5, the second ratio may be set to 3:5 when the configuration index of the first frame is 6, the second ratio may be set to 3:5 when the configuration index of the first frame is 7, and the second ratio may be set to 3:5 when the configuration index of the first frame is 8. Also, when it is assumed that the CP length of the first frame corresponds to a normal CP and that the first ratio is 2:2, the second ratio may be set to 4:4 when the configuration index of the first frame is 0, the second ratio may be set to 5:3 when the configuration index of the first frame is 1, the second ratio may be set to 5:3 when the configuration index of the first frame is 2, the second ratio may be set to 5:3 when the configuration index of the first frame is 3, the second ratio may be set to 5:3 when the configuration index of the first frame is 4, the second ratio may be set to 4:4 when the configuration index of the first frame is 5, the second ratio may be set to 5:3 when the configuration index of the first frame is 6, the second ratio may be set to 5:3 when the configuration index of the first frame is 7, and the second ratio may be set to 5:3 when the configuration index of the first frame is 8. Also, when it is assumed that the CP length of the. first frame corresponds to a normal CP and that the first ratio is 3:1, the second ratio may be set to 6:2 when the configuration index of the first frame is 0, the second ratio may be set to 6:2 when the configuration index of the first frame is 1, the second ratio may be set to 6:2 when the configuration index of the first frame is 2, the second ratio may be set to 7:1 when the configuration index of the first frame is 3, the second ratio may be set to 7:1 when the configuration index of the first frame is 4, the second ratio may be set to 6:2 when the configuration index of the first frame is 5, the second ratio may be set to 6:2 when the configuration index of the first frame is 6, the second ratio may be set to 7:1 or 6:2 when the configuration index of the first frame is 7, and the second ratio may be set to 7:1 when the configuration index of the first frame is 8. In such cases, when the configuration index of the first frame is 7 and when the second ratio is 6:2, the second frame may be set-up to be delayed for a predetermined time starting from the starting point of the first frame within a receive transition gap (RTG) range. Meanwhile, when it is assumed that the CP length of the first frame corresponds to an extended CP and that the first ratio is 1:3, the second ratio may be set to 3:5 when the configuration index of the first frame is any one of 0 to 6. Also, when it is assumed that the CP length of the first frame corresponds to an extended CP and that the first ratio is 2:2, the second ratio may be set to 4:4 when the configuration index of the first frame is 0 or 6, and the second ratio may be set to 5:3 when the configuration index of the first frame is any one of 1, 2, 3, 5, and 6. Furthermore, when it is assumed that the CP length of the first frame corresponds to an extended CP and that the first ratio is 3:1, the second ratio may be set to 6:2 or 7:1 when the configuration index of the first frame is 0, the second ratio may be set to 6:2 or 7:1 when the configuration index of the first frame is 1, the second ratio may be set to 7:1 when the configuration index of the first frame is 2, the second ratio may be set to 7:1 when -the configuration index of the first frame is 3, the second ratio may be set to 6:2 when the configuration index of the first frame is 4, the second ratio may be set to 6:2 when the configuration index of the first frame is 5, and the second ratio.may be set to 7:1 when the configuration index of the first frame is 6. [Advantageous effects] When carrying out the above-described embodiments of the present invention, in the aspect of the design of a specific system, the DL/UL ratio of a frame structure and the establishment of other time domains may be determined (or set- up) so as to prevent (or minimize) the occurrence of a collision with a heterogeneous time division . duplex (TDD) network. [Brief description of the drawings] FIG. 1 illustrates a logical frame structure of an IEEE 802.16e system. FIG. 2 illustrates a flow chart introducing a method of establishing a DL/UL ratio of a new system and a method of establishing the time domain of other frames according to an embodiment of the present invention. FIG. 3 illustrates a frame structure having a CP length of 1/8 Tu, which is proposed for a legacy support mode of the IEEE 802.16m according to an embodiment of the present invention. FIG. 4 illustrates a frame structure according to an exemplary DL/UL ratio of an LCR-TDD system. FIG. 5 illustrates a drawing describing the DL/UL ratio available in the LCR-TDD system. FIG. 6 illustrates a positional relation between a case wherein the DL/UL ratio of the LCR-TDD system shown in FIG. 5 corresponds to 4:3 and the IEEE 802.16m system having the structure shown in Table 2 according to an embodiment of the present invention. FIG. 7 illustrates a frame structure (Type 2 frame structure) supporting the TDD mode in a 3GPP LTE system. FIG. 8 to FIG. 13 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio of Table 4 according to an embodiment of the present invention corresponds to 1:3, and when configuration 0 to configuration 5 are used. FIG. 14 to FIG. 17 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio of Table 4 according to an embodiment of the present invention corresponds to 2:2. FIG. 18 to FIG. 26 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio, of Table 4 according to an embodiment of the present invention corresponds to 3:1, and when configuration 0 to configuration 8 are used. FIG. 27 illustrates a method of establishing an IEEE 802.16m frame by delaying.the IEEE 802.16m frame within an RTG range so as to be aligned, with the heterogeneous TDD system according to a preferred embodiment of the present invention. [Best mode for carrying out.the invention] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The purpose of the following disclosure of the detailed description of the .' present invention with reference to the accompanying drawings is to provide exemplary descriptions of the embodiments of the present invention, and not .to provide the sole and unique embodiments that can be carried out according to the present invention. The following detailed description of the present invention includes detailed specifications in order to provide a full understanding of the present invention. However, it is apparent to anyone skilled in the art that the present invention may be carried out without such detailed specifications. Meanwhile, in some cases, in order to avoid any ambiguity in the concept of the present invention, the disclosure of some structures and devices may be omitted, or such structures and devices may be illustrated in the form of a single block based upon the essential functions of each structure and device. Furthermore, the same reference numerals will be used for the same elements of the present invention throughout the description of the present invention. The following description of the present invention will mainly focus on the method of determining a downlink (DL)/uplink (UL) ratio and the method of establishing a time domain structure of other frames, so as to prevent collision with a heterogeneous time division duplex (TDD) network, e.g., TD-SCMA system or 3GPP LTE TDD system from occurring, when designing the frame structure, in the aspect of a specific system design. However, the basic principle for supporting the TDD system without any collision with a heterogeneous TDD system may also be applied in other systems by using the same method. In order to maintain the DL/UL switch-point according to the DL/UL ratio of the heterogeneous system supporting the TDD mode, it is preferable that the DL/UL alignment according to the DL/UL ratio of a newly designed system matches with (or is identical to) the aligned state (or alignment) of the conventional heterogeneous system. If the time domain alignment with the conventional heterogeneous system is not identical (or does not match) , an interference may occur between the systems, thereby causing a deterioration in the performance of the systems. In order to avoid such problems, an idle OFDM symbol sections that does not transmit any OFDM symbols may be assigned. Also, an excessive number of such idle OFDM symbols may cause damage in the overall performance of the system. In order to minimize such disadvantages, an adequate Dl/UL ratio is required to be set-up (or determined) in a newly designed system according to the DL/UL ratio in the conventional heterogeneous TDD system. FIG. 2 illustrates a flow chart introducing a method of establishing a DL/UL ratio of a new system and a method of establishing the time domain of other frames according to an embodiment of the present invention. As shown in FIG. 2, in a coexisting situation with the conventional heterogeneous TDD system, when establishing a frame structure for the TDD mode of the new system, type information of the conventional heterogeneous TDD system and information of the DL/UL ratio within the frame of the conventional TDD system are required to be acquired (S201) . The conventional TDD system that is to coexist with the newly designed system is pre-decided when installing the newly designed system, so as to be stored in advance in each subject (e.g., base station, mobile station, etc.) of the new system. However, depending upon the situation, since each subject may be set-up in different environments, it is preferable to determine such information as upper-layer (or higher-layer) information that can be acquired based upon a specific cycle period or when a change occurs. For example, the base station or user equipment supporting the IEEE 802.16mmay acquire information on whether the conventional heterogeneous TDD system corresponds to an LCR-TDD (low-chip-rate time division duplex) system respective to a: TD-SCDMA system or whether the conventional heterogeneous TDD system corresponds to a 3GPP LTE TDD system. Also, information on what the DL/UL ratio is in the frame structure according to each system may also be acquired. Furthermore, as described below, in case of the 3GPP LTE TDD system, since different TDD frames are used in accordance with the type of cyclic prefix (hereinafter referred to as "CP") within each frame and the frame structure index, the respective information should be acquired so that the time domain frame structure of the new system (IEEE 802.16m) can be established without any collision with the conventional system. After acquiring such information on the conventional system, the DL/UL ratio of the new frame and the time domain alignment of other frames may be set-up (or determined) in accordance with such acquired information (S202). According to an embodiment of the present invention, apart from the set- up of the DL/UL ratio of each frame, a frame offset is proposed as the time domain alignment that is to be established. More specifically, in some particular cases, the frame of the new system may be established so that specific information can be delayed in comparison with the conventional system without any collision with the conventional the conventional heterogeneous TDD system. More particularly, in order ' to provide support without causing any collision between the conventional heterogeneous TDD system and the new system, the sum (or added value) of the downlink section of the new system frame and the transmit transition gap (TTG) is required to be set-up so" as to be greater than or equal to the sum (or added value) of downlink section of the conventional TDD system frame and a downlink pilot time slot (DwPTS). If a first location corresponding to the sum (or added value) of the downlink section of the new system frame and the transmit transition gap (TTG) is later than (or comes after) a second location corresponding to the sum (or added value) of downlink section of. the conventional TDD system frame and a downlink pilot time slot (DwPTS), the OFDM symbols corresponding to the first location to the second location cannot be used for transmission in the new system frame. Under such assumption, in the above-described embodiment of the present invention, by delaying the new system frame by a predetermined interval in comparison with the starting point of the conventional TDD system, the first location may be set to be positioned at the same location as the second location or at a location after the second position. And, in this case, the last portion of the frame in the tome domain may use the receive transition gap (RTG). More specific details will be described in the following detailed description of the exemplary embodiment of each system. Meanwhile, as described above, for the coexistence with the conventional heterogeneous TDD system, consideration is required to be made as to how the frame structure of the IEEE 802.16m system will be established. More specifically, in case of the IEEE 802.16m, it is very likely to support CP lengths having diverse sizes. Since there in a difference in OFDM symbols that can be used in accordance with the CP length, this may influence the DL/UL ratio according to the present invention. Therefore, hereinafter, the CP length of the IEEE 802.16m system will now be described in detail. First of all, the basic OFDM value regulation in the conventional IEEE 802.16e system is as follows. Table 1 shows the basic OFDM value regulation on the transmission bandwidth, sampling frequency, FFT size, and sub- carrier spacing, and so on, in the conventional IEEE 802.16e system. Table 1 also shows the available CP lengths and the respective number of OFDM symbols per frame and idle time. Herein, "Tu" indicates the valid OFDM symbol length, and this may be defined as 1/(sub-carrier spacing). Among the CP lengths 1/4 Tu, 1/8 Tu, 1/16 Tu, and 1/32 Tu regulated in the conventional IEEE 802.16e, as shown in Table 1, the CP length required to be supported in the legacy- mode of the new system corresponds to the CP length 1/8 Tu, and this is marked in bold font in Table 1 (see IEEE 802.16m- 07/02r4 - TGm System Requirements Document (SRD)). Also, in the following description of the present invention, the "legacy support mode" or "legacy mode" indicates the mode supporting the communications method regulated as a fundamental standard in the IEEE 802.16e system required in the SRD. As described above, when using the 1/8 Tu CP length, as shown in Table 1, 48 OFDM symbols and an idle time of 64.64 us are included in a 5 msec frame. Therefore, in case of a new frame structure coexisting with the new mode, and, more particularly, in case of a frame structure supporting the legacy mode, a new frame structure is required to be proposed under the conditions of the basic values. Accordingly, in the following description, it will be assumed that the CP length of the IEEE 802.16m system corresponds to 1/8 Tu. FIG. 3 illustrates a frame structure having a CP length of 1/8 Tu, which is proposed for a legacy support mode of the IEEE 802.16m according to an embodiment of the present invention. As shown in FIG. 3, in the frame structure for the legacy support mode of the IEEE 802.16m, a basic sub-frame consists of 6 OFDM symbols, and one frame is configured of 48 OFDM symbols and an idle time of 64.64 us. In this structure, by configuring the TTG and RTG by using one OFDM symbol and the idle time of the DL region, the TDD mode may be supported. Hereinafter, it is assumed that the new system corresponds to the IEEE 802.16m system based upon the above- described structure, and an example of establishing a frame enabling the LCR-TDD system and the 3GPP LTE TDD system to be supported without any collision will also be described. Coexistence with the LCR-TDD system FIG. 4 illustrates a frame structure, according to an exemplary DL/UL ratio of an LCR-TDD system. As shown in FIG. 4, one. radio (or wireless) frame in the LCR-TDD system consists of 7 traffic slots (TSO ~ TS6), and the length of each traffic slot is 0.675 ms. The DwPTS, GP, and UpPTS are sequentially configured between TSO and TSl, and these are used for the UL and. DL synchronization and the guard period. The DwPTS, the GP, and the OpPTS have the length of 75 us, 75 us, and 125 us, respectively. The available DL/UL ratios using 7 symbols within the frame according to the LCR-TDD system are 6:1, 5:2, and 4:3. The concept of each DL/UL ratio is as shown in FIG. 5. FIG. 5 illustrates a drawing describing the DL/UL ratio available in the LCR-TDD system. And, the portion marked in dark shading specifies the DL/UL ratio by indicating a DL and UL pair. When considering the coexistence of the above-described LCR-TDD system and the IEEE 802.16m TDD system, it is preferable that, in the IEEE 802.16m TDD mode, the DL/UL ratio of the IEEE 802.16m is decided based upon the DL/UL ratio of the LCR-TDD. At least one or more IEEE 802.16m DL/UL ratio may be determined with respect to one DL/UL ratio of the LCR- TDD. If non-conformity in the time alignment occurs between the two systems, a specific OFDM symbol may not be used in the transmission. According to the embodiment of the present invention, in order to minimize the number of OFDM symbols that cannot be used in the transmission, a method of determining (or setting-up) the DL/UL ratio of the IEEE 802.16m frame based upon each of the DL/UL ratios of the conventional LCR-TDD system may be proposed as shown below. In Table 2, it is assumed that each of the DwPTS, the GP, and the UpPTS respectively corresponds to 75 us, 75 us, and 125 us. As shown in Table 2, when the DL/UL ratio of the LCR-TDD system is 6:1, and when considering the situation wherein the DL(us) or the DL+TTG(us) of the IEEE 802.16m TDD should be equal to or greater than the DL+DwPTS (us) of the LCR-TDD, when the ratio of the IEEE 802.16m is 7:1, the configuration may be made without transmitting a maximum of only 1 OFDM symbol. In all of the cases shown below, the basic condition that the DL(us) or the DL+TTG(us) of the 16m TDD is "equal to or greater than the DL+DwPTS (us) of another TDD system. When considering another ratio of the 16m, a situation where at least one or more OFDM symbols are not transmitted may occur. Therefore, when the ratio of the LCR-TDD is 6:1, 7:1 becomes the optimal ratio of the 16m. Based upon the same principle, with respect to the other ratios of the LCR-TDD, when considerations are made outside of the range of ratios mentioned in Table 2, a larger number of OFDM symbols may not be used. FIG. 6 illustrates a positional relation between a case wherein the DL/UL ratio of the LCR-TDD system shown in FIG. 5 corresponds to 4:3 and the IEEE 802.16m system having the structure shown in Table 2 according to an embodiment of the present invention. As shown in FIG. 4, when the DL/UL ratio of the LCR-TDD is 4:3, the positional relation of the 16m may be indicated in accordance with Table 2. Also, in case of other DL/UL ratios of the LCR-TDD, such as 5:2 and 6:1, the respective positional relation may be indicated by using the same method shown in FIG. 6. Herein, each ratio may have the respective relation shown in Table 2. Coexistence with the 3GPP LTE TDD system FIG. 7 illustrates a frame structure (Type 2 frame structure) supporting the TDD mode in a 3GPP LTE system. The frame structure shown in FIG. 7 corresponds to a case where the frame structure has a 5 ms switch-point cycle period, and reference may be made to 3GPP TS 36.211 for the corresponding details. As shown in FIG. 7, in the 3GPP LTE system, a radio (or wireless) frame has the length of 10 ms. One radio frame is configured of 2 half-frames. Herein, one half-frame is equal to 5ms, and each half-frame is configured of 5 sub-frames each having the length of 1 ms. One sub-frame includes one switch- point. This corresponds to when the cycle period of the switch-point is 5 ms. Herein, the cycle period of the. switch- point may also be equal to 10 is. ~ In this embodiment of the present invention, the. case where the cycle period of the switch-point is 5 ms is first considered. As shown in Table 3 below, the frame configuration of the 3GPP LTE TDD mode may respectively have 9 different configurations or 7 different configurations in two different modes, wherein one corresponds to using a normal CP and the other corresponds to using an extended CP. In this embodiment of the present invention, a method of establishing DL/UL ratios of the frame for the IEEE 802.16m TDD system and establishing the time domain structure of a frame based upon the 3GPP LTE TDD frame structure shown in FIG. 7 and each configuration index of Table 3 is provided. According to the embodiment of the present invention, the details shown in Table 3 with respect to the 3GPP LTE TDD system propose the regulations for establishing the DL/UL ratios of the IEEE 802.16m and the time domain of a frame in Table 4a, Table 4B, and Table 5 shown below with respect to the case of using a normal CP and an extended CP. First of all, the case of using a normal CP in the 3GPP LTE system will now be described. Table 4a and Table 4b respectively show the method of determining the DL/UL ratio of the IEEE 802.16m frame according to each configuration index, when the 3GPP LTE TDD system uses the general CP. As shown in Table 4a and Table 4b, 2 or more DL/UL ratios may be available under the same condition. Along with the Dl/UL ratio of the 16m frame, Table 4a and Table 4b show the number of OFDM symbols that cannot be used due to the non-conformity of the two systems. When the DL/UL ratio of the 3GPP LTE TDD is 1:3, the 16m does not have a separate frame offset. And, the configurations 0 and 5 of Table 4 may configure 2 different ratios 2:6 and 3:5, with respect to the DL/UL ratio 1:3 of the LTE TDD system, without any separate symbol puncturing (i.e., the act of not transmitting specific symbols from a sub-frame of a 6 OFDM symbol unit) . In the remaining cases,, only one ratio 3:5 is optimal for the DL/UL ratio 1:3 of the LTE TDD system. With the exception of this ratio, when other ratios are being considered, the occurrence of the above-described symbol puncturing should be taken into consideration. When the DL/UL ratio of the LTE TDD system is 2:2, the frame offset of the 16m becomes the sub-frame unit 4000 us, and only one ratio may be available for all configurations of Table 4. In this case, as described above, the number of symbols processed with puncturing starts from one to a maximum number of two symbols. When the DL/UL ratio of the LTE TDD system is 3:1, the frame offset of the 16m becomes the sub-frame unit 3000 us, and only one ratio may be available for all configurations of Table 4 with the exception of configuration 7. In this case, the number of puncturing symbols ranges from a minimum of 3 symbols and a maximum of 4 symbols. Herein, since the case of configuration 7 corresponds to a particular case, the description of the same will be given in the following description. FIG. 8 to FIG. 13 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio of Table 4 according to an embodiment of the present invention corresponds to 1:3, and when configuration 0 to configuration 5 are used. The maximum portion that can be occupied by the DL portion of the 16m frame is up to the length of DL 1 symbol + DwPTS + GP of the LTE TDD. When the 16m frame exceeds this region, a particular situation of having to perform puncturing on the corresponding symbol occurs. However, when configuration is made as shown in Table 4 according to the embodiment of the present invention, the situation wherein the symbol puncturing is to be performed may not be occurred when the LTE TDD DL/UL ratio corresponds to 1:3. FIG. 8 to FIG. 13 all correspond to cases where the DL/UL ratio of the LTE TDD frame is 1:3. Most particularly, FIG. 8 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 2:6 and 3:5 with respect to LTE TDD configuration 0. FIG. 9 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to LTE TDD configuration 1. FIG. 10 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to LTE TDD configuration 2. FIG. 11 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to LTE TDD configuration 3. Also, FIG. 12 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to LTE TDD configuration 4. And, finally, FIG. 13 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to LTE TDD configuration 5. Furthermore, the LTE TDD configurations 6 to 8 that have not been illustrated may also be illustrated as shown in FIG. 8 to FIG. 13 in accordance with Table 4. FIG. 14 to FIG. 17 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio of Table 4 according to an embodiment of the present invention corresponds to 2:2. The same principles as those of FIG. 8 to FIG. 13 are applied in FIG. 14 to FIG. 17. More specifically, the maximum portion that can be occupied by the DL portion of the 16m frame is up to the length of DL 1 symbol + DwPTS + GP of the LTE TDD, and when the 16m frame exceeds this region, a particular situation of having to perform puncturing on the corresponding symbol occurs. According to the embodiment of the present invention, when the LTE TDD DL/UL ratio is 2:2, optimization may be performed at a level of puncturing 1~2 OFDM symbols. The frame offset for all LTE TDD configurations (configuration 0 to configuration 8) is equally set to 4000 us. FIG. 14 to FIG. 17 all correspond to cases where the DL/UL ratio of the LTE TDD frame is 2:2. Most particularly, FIG. 14 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 4:4 with respect to LTE TDD configuration 0. FIG. 15 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 5:3 with respect to LTE TDD configuration 1. FIG. 16 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 4:4 with respect to LTE TDD configuration 5. FIG. 17 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 5:3 with respect to LTE TDD configuration 6. Furthermore, the situations that have not been illustrated may also be illustrated as shown in FIG. 14 to FIG. 17 in accordance with Table 4. More specifically, configurations 2, 3, and 4 are all identical to configuration 1 of FIG. 14. Also, configurations 7 and 8 may be applied identically as the situation of configuration 6. FIG. 18 to FIG. 26 illustrate the relation with an IEEE 802.16m frame, when the LTE TDD DL/UL ratio of Table 4 according to an embodiment of the present invention corresponds to 3:1, and when configuration 0 to configuration 8 are used. According to the embodiment of the present invention, the number of OFDM symbols that ate punctured when the LTE TDD DL/UL ratio is 3:1 may be set to be equal to or less that 3-4 OFDM symbols. Furthermore, the frame offset for all cases (or situations) is equally set to 3000 us. *FIG. 18 to FIG. 26 all correspond to cases where the DL/UL ratio of the LTE TDD frame is 3:1. Most particularly, FIG. 18 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to LTE TDD configuration 0. FIG. 19 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to LTE TDD configuration 1. Also, FIG. 20 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to LTE TDD configuration 2. FIG. 21 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 7:1 with respect to LTE TDD configuration 3. Also, FIG. 22 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 7:1 with respect to LTE TDD configuration 4. FIG. 23 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to LTE TDD configuration 5. Additionally, FIG. 24 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to LTE TDD configuration 6. FIG. 25 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 7:1 with respect to LTE TDD configuration 7. And, finally, FIG. 26 illustrates a situation where the DL/UL ratio of the 16m TDD frame is set to 7:1 with respect to LTE TDD configuration 8. Meanwhile, Table 5 shown below indicates the optimization of the 16m frame structure using the same method as that of Table 4 upon reference to Table 3, when the LTE TDD system uses the extended CP. As shown in Table 5, when the LTE TDD DL/UL ratio is 1:3, the 16m frame may be optimized by eliminating the puncturing symbols so that the DL/UL ratio can become 3:5. When the LTE TDD DL/UL ratio is 2:2, puncturing symbols may occur, and the ratio for minimizing the number of puncturing symbols is indicated in Table 5. And, the figures marked in bold fonts in Table 5 indicate the number of symbols. When the LTE TDD DL/UL ratio is 3:1, with the exception of configuration 6, the ratio of the 16m may be determined so that there are no puncturing symbols. Although the frame offset is not mentioned in Table 5, the frame offset may have the same value in accordance with the 3 different DL/UL ratios of the LTE TDD system, as shown in Table 4. Hereinafter, as a preferred embodiment of the present invention, a method of determining the 16m frame by delaying the 16m frame within the RTG range, so as to minimize the puncturing caused by a non-conformity between the conventional system and the time domain, will be described in detail. FIG. 27 illustrates a method of establishing an IEEE 802.16m frame by delaying the IEEE 802.16m frame within an RTG range so as to be aligned with the heterogeneous TDD system according to a preferred embodiment of the present invention. Most particularly, among the details specified in Table 4, FIG. 27 illustrates the case of configuration 7 when the LTE TDD DL/UL ratio is 3:1. As described above, in accordance with Table 4, the LTE TDD system should puncture 4 symbols, when using configuration 7 with respect to the DL/UL ratio of 3:1, and when using the 16m frame DL/UL ratio of 7:1 (42:6). However, in the same situation, by using the 16m frame DL/UL ratio of 6:2 (36:12), and by delaying the 16m frame to a predetermined degree, as shown in FIG. 27, settings may be made so that there are no punctured symbols. In principle, when the LTE TDD system uses configuration 7 so that the DL/UL ratio can become 3:1, even when the 16m frame DL/UL ratio of 6:2 is used, a collision may occur between the two frames, as shown in the mid-portion of FIG. 27. Therefore, according to the embodiment of the present invention, as shown in the lower portion of FIG. 27, in order to prevent collision in the UL Portion of the 16m, the present invention proposes a method of delaying the 16m frame within the RTG length range. At this point, the degree of delay may be acquired within a range satisfying the following equation. As described above, by delaying the 16m frame, a frame may be designed so that there is no puncturing (or so that the puncturing can be minimized) in the 16m frame. As described above, the detailed description of the disclosed preferred embodiments of the present invention is provided so that anyone skilled in the art can realize and carry out the present invention. In the above description, although the present invention is described with reference to the preferred embodiments of the present invention, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Therefore, the present invention is not intended to limit the present invention to the embodiments presented herein. Instead, it is intended that the present invention grants a broadest range matching the principles and new characteristics disclosed herein. [Industrial Applicability] As described above, in each embodiment of the present invention, a TD-SCDMA (LCR-TDD) system or 3GPP LTE TDD system is given as an example of the conventional heterogeneous TDD system, and an IEEE 802.16m system is given as an example of the new system, and the descriptions of the same are given in detail. However, the present invention is not required to be limited to the given example. And, the present invention may be used as a method of efficiently establishing a frame based upon the same principles in an arbitrary telecommunications system. [What is claimed is] 1. In a situation of coexisting heterogeneous systems including a first system and a second system, in a method of establishing a time domain structure of a second frame used for a Time Division Duplex (TDD) mode of the second system, so that the second frame can coexist with a first frame for a TDD mode of the first system, the method of establishing a time domain structure of a frame comprises: an information acquiring step for acquiring type information of the first system being supported and information on a first ratio, wherein the first ratio corresponds to a ratio between an uplink section and a downlink section in the first frame structure; a second frame structure establishing step for establishing a second frame structure for the second system based upon the acquired information; and a ratio determining step for determining a second ratio, wherein the second ratio corresponds to a ratio between an uplink section and a downlink section in the second frame structure. 2. The method of claim 1, wherein the ratio determining step comprises a step of setting-up a sum of the downlink section and a transmit transition gap (TTG) of the second frame or a sum of the downlink section, TTG, and a receive transition gap (RTG) of the second frame, so that the sum can be equal to or greater than a sum of the downlink section and a downlink pilot time slot (DwPTS) of the first frame. 3. The method of claim 1, wherein, in the ratio determining step, when a sum of the receive transition gap (RTG), downlink section, and transmit transition gap (TTG) of the second frame is greater than a sum of the downlink section, downlink piloting time slot (DwPTS), and guard period (GP) of the first frame, a predetermined number of OFDM symbols are excluded from a transmission. 4. The method of claim 1, wherein the ratio determining step further comprises: a step of establishing a frame offset from a starting point of the first frame of the second frame. 5. The method of claim 4, wherein the first system corresponds to an LCR-TDD (low-chip-rate time division duplex) system, wherein the second system corresponds to an IEEE 802.16m system, and wherein a cyclic prefix (CP) length of the second frame is equal to 1/8 valid OFDM symbol time (Tu), and wherein the second ratio is set to 7:1 when the first ratio is set to 6:1, wherein the second ratio is set to 6:2 when the first ratio is set to 5:2, wherein the second ratio is set to 5:3 when the first ratio is set to 4:3. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 6. The method of claim 5, wherein among the second frame structure, 1 OFDM symbol is excluded from the transmission when the first ratio is 6:1, wherein 2 OFDM symbols are excluded from the transmission when the first ratio is 5:2, and wherein 3 OFDM symbols are excluded from the transmission when the first ratio is 4:3. 7. The method of claim 1, wherein the first system corresponds to a 3GPP LTE TDD system, wherein the second system corresponds to an IEEE 802.16m system, and wherein a cyclic prefix (CP) length of the second frame is equal to 1/8 valid OFDM symbol time (Tu), and wherein the information acquiring step comprises a step of additionally acquiring CP length information of the first frame and configuration index information of the first frame in the 3GPP LTE TDD system. 8. The method of claim 7, wherein, when the CP length of the first frame corresponds to a normal CP and when the first ratio is 1:3, the second ratio is set to 2:6 or 3:5 when the configuration index of the first frame is 0, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 1, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 2, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 3, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 4, wherein the second ratio is set to 2:6 or 3:5 when the configuration index of the first frame is 5, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 6, wherein the second ratio is set to 3:5 when the configuration index of the first frame is 7, and wherein the second ratio is set to 3:5 when the configuration index of the first frame is 8. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 9. The method of claim 7, wherein,, when the CP length of the first frame corresponds, to a normal CP and when the first ratio is 2:2, the second ratio is set to 4:4 when the configuration index of the first frame is 0, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 1, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 2, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 3, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 4, wherein the second ratio is set to 4:4 when the configuration index of the first frame is 5, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 6, wherein the second ratio is set to 5:3 when the configuration index of the first frame is 7, and wherein the second ratio is set to 5:3 when the configuration index of the first frame is 8. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 10. The method of claim 7, wherein, when the CP length of the first frame corresponds to a normal CP and when the first ratio is 3:1, the second ratio is set to 6:2 when the configuration index of the first frame is 0, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 1, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 2, wherein the second ratio is set to 7:1 when the configuration index of the first frame is 3, wherein the second ratio is set to 7:1 when the configuration index of the first frame is 4, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 5, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 6, wherein the second ratio is set to 7:1 or 6:2 when the configuration index of the first frame is 7, and wherein the second ratio is set to 7:1 when the configuration index of the first frame is 8. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 11. The method of claim 10, wherein the second frame is set-up to have a frame offset of 300 us from a starting point of the first frame. 12. The method of claim 11, wherein, when the configuration index of the first frame is 7 and when the second ratio is 6:2, the second frame is set-up to be delayed for a predetermined time starting from a point corresponding to the frame offset at the starting point of the first frame within a receive transition gap (RTG) range of the second frame. 13. The method of claim 7, wherein, when the CP length of the first frame corresponds to an extended CP and when the first ratio is 1:3, the second ratio is set to 3:5 when the configuration index of the first frame is any one of 0 to 6. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 14. The method of claim 7, wherein, when the CP length of the first frame corresponds to an extended CP and when the first ratio is 2:2, the second ratio is set to 4:4 when the configuration index of the first frame is 0 or 6, and wherein the second ratio is set to 5:3 when the configuration index of the first frame is any one of 1, 2, 3, 5, and 6. (Herein, x:y corresponds to (a downlink section length):(an uplink section length).) 15. The method of claim 7, wherein, when the CP length of the first frame corresponds to an extended CP and when the first ratio is 3:1, the second ratio is set to 6:2 or 7:1 when the configuration index of the first frame is 0, wherein the second ratio is set to 6:2 or 7:1 when the configuration index of the first frame is 1, wherein the second ratio is set to 7:1 when the configuration index of the first frame is 2, wherein the second ratio is set to 7:1 when the configuration index of the first frame is 3, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 4, wherein the second ratio is set to 6:2 when the configuration index of the first frame is 5, and wherein the second ratio is set to 7:1 when the configuration index of the first frame is 6. (Herein, x:y corresponds to (a downlink section length) : (an uplink section length).) Disclosed is a method for establishing a time domain structure of a frame in a heterogeneous TDD systems environment. In other words, in a situation of coexisting heterogeneous systems comprising a first system corresponding to an existing TDD system and a second system corresponding to a new system, a method is provided for establishing a time domain structure of a second frame for the second TDD system mode to enable it to coexist with a first frame for the first TDD (Time Division Duplex) system mode, that comprises obtaining information for the first supported system type and a first ratio between the downlink region and the uplink region of the first frame structure, and then, according to the obtained information, establishing a second ratio between the downlink region and the uplink region of the second frame structure for the second system. Further, particular numerology is provided for said method.

Full Text

[SPECIFICATION]
[Title of the Invention]
THE METHOD FOR ESTABLISHING TIME DOMAIN STRUCTURE OF A FRAME
IN A HETEROGENEOUS TDD SYSTEMS ENVIRONMENT
[Field of the Invention]
The following description of the present invention
relates to a method of establishing a time domain structure of
a frame in an environment where heterogeneous TDD systems co-
exist.
[Field Background]
In case of wideband telecommunications systems, in order
to maximize the efficiency of limited wireless (or radio)
resources, a number of more effective transmitting and
receiving methods in time, space, and frequency domains and
the respective application methods have been proposed.
Particularly, the multi carrier OFDM method has the advantages
of reducing the complexity of a receiving end in a frequency
selective fading environment that occurs in a wideband channel
and, also, of maximizing spectral efficiency through selective
scheduling in a frequency domain by applying different channel
characteristics (or attributes) of a subcarrier. Furthermore,
by allocating (or assigning) different subcarriers to multiple
users, the OFDM method is extendable to an orthogonal
frequency division multiple access (OFDMA) method, thereby
being capable of enhancing the efficiency of the wireless

resource in the frequency domain.
As the WirelessMAN-OFDMA standard adopting the typical
OFDMA, IEEE 802.1.6-2004 and the amended standard IEEE 802.16e-
2005 (hereinafter referred to as IEEE 802.16e) have been
completed.
FIG. 1 shows a logical frame structure of the IEEE
802.16e system. As shown in FIG. 1, the logical frame
structure of the IEEE 802.16e system consists of a preamble
(101), an FCH (frame control header) (102), control signal
blocks of DL/UL-MAP (103, 104), and data bursts. Also, the
data transmission of each user is defined by different
subcarrier allocation methods (e.g., PUSC, (O)-FUSC, TUSC, AMC,
etc.) depending upon the method of configuring the subcarrier.
Herein, various permutation zones may be configured in one
frame.
In the frame of the IEEE 802.16e system, as shown in FIG.
1, the reception of an initial preamble (101), an FCH (102),
and control information on the DL/UL-MAP (103, 104) is
required. And, the role of each field is as follows:
Preamble (101) : performing synchronization, channel
estimation, cell ID acquisition, etc.
FCH (102) : providing channel allocation information and
channel code information associated with the DL-MAP (103)
- DL/UL-MAP (103, 104) : providing channel allocation
information of a data burst in an downlink (DL)/uplink

(UL)
Among the above-described control fields, with the
exception of the preamble (101), the logical frame structure
may be diversely configured (or established) in accordance
with a subchannel allocation method (PUSC, (O)-FUSC, TUSC, AMC,
etc.) selected by taking into consideration factors such as
frequency diversity gain, scheduling gain, convenience in
adopting a pilot overhead or multi/adaptive antenna.
Meanwhile, discussions of an enhanced version (or
system) of the above-described IEEE 802.16e system is in
progress, and such system will be regulated as the IEEE
802.16m standard. Accordingly, reference may be made to "IEEE
802.16m-07/002r4 - TGM System Requirements Document"
(hereinafter referred to as "SRD") for the requirements that
the IEEE 802.16m system should satisfy.
Referring to the above-described SRD of the IEEE 802.16m
system, it is mentioned that co-existence with the TD-SCMA,
3GPP LTE TDD should be supported in the IEEE 802.16m TDD mode.
However, in case of the IEEE 802.16m system, an accurate frame
structure has not yet been decided, and, accordingly,
discussions on the uplink/downlink ratio and time domain
structure of a frame within the IEEE 802.16m system for the
co-existence with the heterogeneous TDD system is required to
be made.
[Detailed description of the invention]

[Technical objects]
In order to resolve the above-described problems, the
present invention proposes a method of determining a downlink
(DL)/uplink (CJL) ratio and a method of establishing a time
domain structure of other frames so as to prevent collision
with a heterogeneous time division duplex (TDD) network when
designing the frame structure from occurring, in the aspect of
a specific system design.
[Technical solutions]
To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, according to an embodiment of the
present invention, in a situation of coexisting heterogeneous
systems including a first system and a second system, in a
method of establishing a time domain structure of a second
frame used for a Time Division Duplex (TDD) mode of the second
system, so that the second frame can coexist with a first
frame for a TDD mode of the first system, the method of
establishing a time domain structure of a frame includes an
information acquiring step for acquiring type information of
the first system being supported and information on a first
ratio, wherein the first ratio corresponds to a ratio between
an uplink section and a downlink section in the first frame
structure; a second frame structure establishing step for
establishing a second frame structure for the second system

based upon the acquired information; and a ratio determining
step for determining a second ratio, wherein the second ratio
corresponds to a ratio between an uplink section and a
downlink section in the second frame structure.
At this point, the determining step may further include
a set-up step of excluding a predetermined number of OFDM
symbols from transmission so that a sum of the downlink
section and a transmit transition gap (TTG) of the second
frame can be equal to or greater than a sum of the downlink
section and a downlink pilot time slot (DwPTS) of the first
frame.
Also, the determining step may further include a step of
establishing a frame offset from a starting point of the first
frame of the second frame.
In a more specific embodiment of the present invention,
the first system may correspond to an LCR-TDD (low^-chip-rate
time division duplex) system, and the second system may
correspond to an IEEE 802.16m system, and a cyclic prefix (CP)
length of the second frame may be equal to 1/8 valid OFDM
symbol time (Tu) . And, in this case, the second ratio may be
set to 7:1 when the first ratio is set to 6:1. The second
ratio may also be set to 6:2 when the first ratio is set to
5:2. The second ratio may also be set to 5:3 when the first
ratio is set to 4:3. Herein, x:y corresponds to (a downlink
section length):(an uplink section length). And, this is

identically applied to the following cases.
Also, in the same situation, among the second frame
structure, 1 OFDM symbol may be excluded from the transmission
when the first ratio is 6:1, and 2 OFDM symbols may be
excluded from the transmission when the first ratio is 5:2,
and 3 OFDM symbols may be excluded from the transmission when
the first ratio is 4:3.
In another more specific embodiment of the present
invention, the first system may correspond to a 3GPP LTE TDD
system, and the second system may correspond to an IEEE
802.16m system, and a cyclic prefix (CP) length of the second
frame may be equal to 1/8 valid OFDM symbol time (Tu) . And,
in this case, the information acquiring step may include a
step of additionally acquiring CP length information of the
first frame and configuration index information of the first
frame in the 3GPP LTE TDD system.
In this embodiment, when it is assumed that the CP
length of the first frame corresponds to a normal CP and that
the first ratio is 1:3, the second ratio may be set to 2:6 or
3:5 when the configuration index of the first frame is 0, the
second ratio may be set to 3:5 when the configuration index of
the first.frame is 1, the second ratio may be set to 3:5 when
the configuration index of the first frame is 2, the second
ratio may be set to 3:5 when the configuration index of the
first frame is 3, the second ratio may be set to 3;5 when the

configuration index of the first frame is 4, the second ratio
may be set to 2:6 or 3:5 when the configuration index of the
first frame is 5, the second ratio may be set to 3:5 when the
configuration index of the first frame is 6, the second ratio
may be set to 3:5 when the configuration index of the first
frame is 7, and the second ratio may be set to 3:5 when the
configuration index of the first frame is 8.
Also, when it is assumed that the CP length of the first
frame corresponds to a normal CP and that the first ratio is
2:2, the second ratio may be set to 4:4 when the configuration
index of the first frame is 0, the second ratio may be set to
5:3 when the configuration index of the first frame is 1, the
second ratio may be set to 5:3 when the configuration index of
the first frame is 2, the second ratio may be set to 5:3 when
the configuration index of the first frame is 3, the second
ratio may be set to 5:3 when the configuration index of the
first frame is 4, the second ratio may be set to 4:4 when the
configuration index of the first frame is 5, the second ratio
may be set to 5:3 when the configuration index of the first
frame is 6, the second ratio may be set to 5:3 when the
configuration index of the first frame is 7, and the second
ratio may be set to 5:3 when the configuration index of the
first frame is 8.
Also, when it is assumed that the CP length of the. first
frame corresponds to a normal CP and that the first ratio is

3:1, the second ratio may be set to 6:2 when the configuration
index of the first frame is 0, the second ratio may be set to
6:2 when the configuration index of the first frame is 1, the
second ratio may be set to 6:2 when the configuration index of
the first frame is 2, the second ratio may be set to 7:1 when
the configuration index of the first frame is 3, the second
ratio may be set to 7:1 when the configuration index of the
first frame is 4, the second ratio may be set to 6:2 when the
configuration index of the first frame is 5, the second ratio
may be set to 6:2 when the configuration index of the first
frame is 6, the second ratio may be set to 7:1 or 6:2 when the
configuration index of the first frame is 7, and the second
ratio may be set to 7:1 when the configuration index of the
first frame is 8.
In such cases, when the configuration index of the first
frame is 7 and when the second ratio is 6:2, the second frame
may be set-up to be delayed for a predetermined time starting
from the starting point of the first frame within a receive
transition gap (RTG) range.
Meanwhile, when it is assumed that the CP length of the
first frame corresponds to an extended CP and that the first
ratio is 1:3, the second ratio may be set to 3:5 when the
configuration index of the first frame is any one of 0 to 6.
Also, when it is assumed that the CP length of the first
frame corresponds to an extended CP and that the first ratio

is 2:2, the second ratio may be set to 4:4 when the
configuration index of the first frame is 0 or 6, and the
second ratio may be set to 5:3 when the configuration index of
the first frame is any one of 1, 2, 3, 5, and 6.
Furthermore, when it is assumed that the CP length of
the first frame corresponds to an extended CP and that the
first ratio is 3:1, the second ratio may be set to 6:2 or 7:1
when the configuration index of the first frame is 0, the
second ratio may be set to 6:2 or 7:1 when the configuration
index of the first frame is 1, the second ratio may be set to
7:1 when the configuration index of the first frame is 2, the
second ratio may be set to 7:1 when -the configuration index of
the first frame is 3, the second ratio may be set to 6:2 when
the configuration index of the first frame is 4, the second
ratio may be set to 6:2 when the configuration index of the
first frame is 5, and the second ratio.may be set to 7:1 when
the configuration index of the first frame is 6.
[Advantageous effects]
When carrying out the above-described embodiments of the
present invention, in the aspect of the design of a specific
system, the DL/UL ratio of a frame structure and the
establishment of other time domains may be determined (or set-
up) so as to prevent (or minimize) the occurrence of a
collision with a heterogeneous time division . duplex (TDD)
network.

[Brief description of the drawings]
FIG. 1 illustrates a logical frame structure of an IEEE
802.16e system.
FIG. 2 illustrates a flow chart introducing a method of
establishing a DL/UL ratio of a new system and a method of
establishing the time domain of other frames according to an
embodiment of the present invention.
FIG. 3 illustrates a frame structure having a CP length
of 1/8 Tu, which is proposed for a legacy support mode of the
IEEE 802.16m according to an embodiment of the present
invention.
FIG. 4 illustrates a frame structure according to an
exemplary DL/UL ratio of an LCR-TDD system.
FIG. 5 illustrates a drawing describing the DL/UL ratio
available in the LCR-TDD system.
FIG. 6 illustrates a positional relation between a case
wherein the DL/UL ratio of the LCR-TDD system shown in FIG. 5
corresponds to 4:3 and the IEEE 802.16m system having the
structure shown in Table 2 according to an embodiment of the
present invention.
FIG. 7 illustrates a frame structure (Type 2 frame
structure) supporting the TDD mode in a 3GPP LTE system.
FIG. 8 to FIG. 13 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio of Table 4
according to an embodiment of the present invention

corresponds to 1:3, and when configuration 0 to configuration
5 are used.
FIG. 14 to FIG. 17 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio of Table 4
according to an embodiment of the present invention
corresponds to 2:2.
FIG. 18 to FIG. 26 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio, of Table 4
according to an embodiment of the present invention
corresponds to 3:1, and when configuration 0 to configuration
8 are used.
FIG. 27 illustrates a method of establishing an IEEE
802.16m frame by delaying.the IEEE 802.16m frame within an RTG
range so as to be aligned, with the heterogeneous TDD system
according to a preferred embodiment of the present invention.
[Best mode for carrying out.the invention]
Hereinafter, the preferred embodiments of the present
invention will be described in detail with reference to the
accompanying drawings. The purpose of the following
disclosure of the detailed description of the .' present
invention with reference to the accompanying drawings is to
provide exemplary descriptions of the embodiments of the
present invention, and not .to provide the sole and unique
embodiments that can be carried out according to the present
invention. The following detailed description of the present

invention includes detailed specifications in order to provide
a full understanding of the present invention. However, it is
apparent to anyone skilled in the art that the present
invention may be carried out without such detailed
specifications.
Meanwhile, in some cases, in order to avoid any
ambiguity in the concept of the present invention, the
disclosure of some structures and devices may be omitted, or
such structures and devices may be illustrated in the form of
a single block based upon the essential functions of each
structure and device. Furthermore, the same reference
numerals will be used for the same elements of the present
invention throughout the description of the present invention.
The following description of the present invention will
mainly focus on the method of determining a downlink
(DL)/uplink (UL) ratio and the method of establishing a time
domain structure of other frames, so as to prevent collision
with a heterogeneous time division duplex (TDD) network, e.g.,
TD-SCMA system or 3GPP LTE TDD system from occurring, when
designing the frame structure, in the aspect of a specific
system design. However, the basic principle for supporting
the TDD system without any collision with a heterogeneous TDD
system may also be applied in other systems by using the same
method.
In order to maintain the DL/UL switch-point according to

the DL/UL ratio of the heterogeneous system supporting the TDD
mode, it is preferable that the DL/UL alignment according to
the DL/UL ratio of a newly designed system matches with (or is
identical to) the aligned state (or alignment) of the
conventional heterogeneous system. If the time domain
alignment with the conventional heterogeneous system is not
identical (or does not match) , an interference may occur
between the systems, thereby causing a deterioration in the
performance of the systems. In order to avoid such problems,
an idle OFDM symbol sections that does not transmit any OFDM
symbols may be assigned. Also, an excessive number of such
idle OFDM symbols may cause damage in the overall performance
of the system.
In order to minimize such disadvantages, an adequate
Dl/UL ratio is required to be set-up (or determined) in a
newly designed system according to the DL/UL ratio in the
conventional heterogeneous TDD system.
FIG. 2 illustrates a flow chart introducing a method of
establishing a DL/UL ratio of a new system and a method of
establishing the time domain of other frames according to an
embodiment of the present invention.
As shown in FIG. 2, in a coexisting situation with the
conventional heterogeneous TDD system, when establishing a
frame structure for the TDD mode of the new system, type
information of the conventional heterogeneous TDD system and

information of the DL/UL ratio within the frame of the
conventional TDD system are required to be acquired (S201) .
The conventional TDD system that is to coexist with the newly
designed system is pre-decided when installing the newly
designed system, so as to be stored in advance in each subject
(e.g., base station, mobile station, etc.) of the new system.
However, depending upon the situation, since each subject may
be set-up in different environments, it is preferable to
determine such information as upper-layer (or higher-layer)
information that can be acquired based upon a specific cycle
period or when a change occurs.
For example, the base station or user equipment
supporting the IEEE 802.16mmay acquire information on whether
the conventional heterogeneous TDD system corresponds to an
LCR-TDD (low-chip-rate time division duplex) system respective
to a: TD-SCDMA system or whether the conventional heterogeneous
TDD system corresponds to a 3GPP LTE TDD system. Also,
information on what the DL/UL ratio is in the frame structure
according to each system may also be acquired. Furthermore,
as described below, in case of the 3GPP LTE TDD system, since
different TDD frames are used in accordance with the type of
cyclic prefix (hereinafter referred to as "CP") within each
frame and the frame structure index, the respective
information should be acquired so that the time domain frame
structure of the new system (IEEE 802.16m) can be established

without any collision with the conventional system.
After acquiring such information on the conventional
system, the DL/UL ratio of the new frame and the time domain
alignment of other frames may be set-up (or determined) in
accordance with such acquired information (S202). According
to an embodiment of the present invention, apart from the set-
up of the DL/UL ratio of each frame, a frame offset is
proposed as the time domain alignment that is to be
established. More specifically, in some particular cases, the
frame of the new system may be established so that specific
information can be delayed in comparison with the conventional
system without any collision with the conventional the
conventional heterogeneous TDD system.
More particularly, in order ' to provide support without
causing any collision between the conventional heterogeneous
TDD system and the new system, the sum (or added value) of the
downlink section of the new system frame and the transmit
transition gap (TTG) is required to be set-up so" as to be
greater than or equal to the sum (or added value) of downlink
section of the conventional TDD system frame and a downlink
pilot time slot (DwPTS). If a first location corresponding to
the sum (or added value) of the downlink section of the new
system frame and the transmit transition gap (TTG) is later
than (or comes after) a second location corresponding to the
sum (or added value) of downlink section of. the conventional

TDD system frame and a downlink pilot time slot (DwPTS), the
OFDM symbols corresponding to the first location to the second
location cannot be used for transmission in the new system
frame. Under such assumption, in the above-described
embodiment of the present invention, by delaying the new
system frame by a predetermined interval in comparison with
the starting point of the conventional TDD system, the first
location may be set to be positioned at the same location as
the second location or at a location after the second position.
And, in this case, the last portion of the frame in the tome
domain may use the receive transition gap (RTG). More
specific details will be described in the following detailed
description of the exemplary embodiment of each system.
Meanwhile, as described above, for the coexistence with
the conventional heterogeneous TDD system, consideration is
required to be made as to how the frame structure of the IEEE
802.16m system will be established. More specifically, in
case of the IEEE 802.16m, it is very likely to support CP
lengths having diverse sizes. Since there in a difference in
OFDM symbols that can be used in accordance with the CP length,
this may influence the DL/UL ratio according to the present
invention.
Therefore, hereinafter, the CP length of the IEEE
802.16m system will now be described in detail.
First of all, the basic OFDM value regulation in the

conventional IEEE 802.16e system is as follows.

Table 1 shows the basic OFDM value regulation on the
transmission bandwidth, sampling frequency, FFT size, and sub-
carrier spacing, and so on, in the conventional IEEE 802.16e
system. Table 1 also shows the available CP lengths and the
respective number of OFDM symbols per frame and idle time.
Herein, "Tu" indicates the valid OFDM symbol length, and this

may be defined as 1/(sub-carrier spacing).
Among the CP lengths 1/4 Tu, 1/8 Tu, 1/16 Tu, and 1/32
Tu regulated in the conventional IEEE 802.16e, as shown in
Table 1, the CP length required to be supported in the legacy-
mode of the new system corresponds to the CP length 1/8 Tu,
and this is marked in bold font in Table 1 (see IEEE 802.16m-
07/02r4 - TGm System Requirements Document (SRD)). Also, in
the following description of the present invention, the
"legacy support mode" or "legacy mode" indicates the mode
supporting the communications method regulated as a
fundamental standard in the IEEE 802.16e system required in
the SRD.
As described above, when using the 1/8 Tu CP length, as
shown in Table 1, 48 OFDM symbols and an idle time of 64.64 us
are included in a 5 msec frame. Therefore, in case of a new
frame structure coexisting with the new mode, and, more
particularly, in case of a frame structure supporting the
legacy mode, a new frame structure is required to be proposed
under the conditions of the basic values.
Accordingly, in the following description, it will be
assumed that the CP length of the IEEE 802.16m system
corresponds to 1/8 Tu.
FIG. 3 illustrates a frame structure having a CP length
of 1/8 Tu, which is proposed for a legacy support mode of the
IEEE 802.16m according to an embodiment of the present

invention.
As shown in FIG. 3, in the frame structure for the
legacy support mode of the IEEE 802.16m, a basic sub-frame
consists of 6 OFDM symbols, and one frame is configured of 48
OFDM symbols and an idle time of 64.64 us. In this structure,
by configuring the TTG and RTG by using one OFDM symbol and
the idle time of the DL region, the TDD mode may be supported.
Hereinafter, it is assumed that the new system
corresponds to the IEEE 802.16m system based upon the above-
described structure, and an example of establishing a frame
enabling the LCR-TDD system and the 3GPP LTE TDD system to be
supported without any collision will also be described.
Coexistence with the LCR-TDD system
FIG. 4 illustrates a frame structure, according to an
exemplary DL/UL ratio of an LCR-TDD system.
As shown in FIG. 4, one. radio (or wireless) frame in the
LCR-TDD system consists of 7 traffic slots (TSO ~ TS6), and
the length of each traffic slot is 0.675 ms. The DwPTS, GP,
and UpPTS are sequentially configured between TSO and TSl, and
these are used for the UL and. DL synchronization and the guard
period. The DwPTS, the GP, and the OpPTS have the length of
75 us, 75 us, and 125 us, respectively.
The available DL/UL ratios using 7 symbols within the
frame according to the LCR-TDD system are 6:1, 5:2, and 4:3.

The concept of each DL/UL ratio is as shown in FIG. 5. FIG. 5
illustrates a drawing describing the DL/UL ratio available in
the LCR-TDD system. And, the portion marked in dark shading
specifies the DL/UL ratio by indicating a DL and UL pair.
When considering the coexistence of the above-described
LCR-TDD system and the IEEE 802.16m TDD system, it is
preferable that, in the IEEE 802.16m TDD mode, the DL/UL ratio
of the IEEE 802.16m is decided based upon the DL/UL ratio of
the LCR-TDD. At least one or more IEEE 802.16m DL/UL ratio
may be determined with respect to one DL/UL ratio of the LCR-
TDD. If non-conformity in the time alignment occurs between
the two systems, a specific OFDM symbol may not be used in the
transmission. According to the embodiment of the present
invention, in order to minimize the number of OFDM symbols
that cannot be used in the transmission, a method of
determining (or setting-up) the DL/UL ratio of the IEEE
802.16m frame based upon each of the DL/UL ratios of the
conventional LCR-TDD system may be proposed as shown below.

In Table 2, it is assumed that each of the DwPTS, the GP,
and the UpPTS respectively corresponds to 75 us, 75 us, and
125 us.
As shown in Table 2, when the DL/UL ratio of the LCR-TDD
system is 6:1, and when considering the situation wherein the
DL(us) or the DL+TTG(us) of the IEEE 802.16m TDD should be
equal to or greater than the DL+DwPTS (us) of the LCR-TDD,
when the ratio of the IEEE 802.16m is 7:1, the configuration
may be made without transmitting a maximum of only 1 OFDM
symbol. In all of the cases shown below, the basic condition
that the DL(us) or the DL+TTG(us) of the 16m TDD is "equal to
or greater than the DL+DwPTS (us) of another TDD system. When
considering another ratio of the 16m, a situation where at
least one or more OFDM symbols are not transmitted may occur.
Therefore, when the ratio of the LCR-TDD is 6:1, 7:1 becomes

the optimal ratio of the 16m. Based upon the same principle,
with respect to the other ratios of the LCR-TDD, when
considerations are made outside of the range of ratios
mentioned in Table 2, a larger number of OFDM symbols may not
be used.
FIG. 6 illustrates a positional relation between a case
wherein the DL/UL ratio of the LCR-TDD system shown in FIG. 5
corresponds to 4:3 and the IEEE 802.16m system having the
structure shown in Table 2 according to an embodiment of the
present invention.
As shown in FIG. 4, when the DL/UL ratio of the LCR-TDD
is 4:3, the positional relation of the 16m may be indicated in
accordance with Table 2. Also, in case of other DL/UL ratios
of the LCR-TDD, such as 5:2 and 6:1, the respective positional
relation may be indicated by using the same method shown in
FIG. 6. Herein, each ratio may have the respective relation
shown in Table 2.
Coexistence with the 3GPP LTE TDD system
FIG. 7 illustrates a frame structure (Type 2 frame
structure) supporting the TDD mode in a 3GPP LTE system.
The frame structure shown in FIG. 7 corresponds to a
case where the frame structure has a 5 ms switch-point cycle
period, and reference may be made to 3GPP TS 36.211 for the

corresponding details.
As shown in FIG. 7, in the 3GPP LTE system, a radio (or
wireless) frame has the length of 10 ms. One radio frame is
configured of 2 half-frames. Herein, one half-frame is equal
to 5ms, and each half-frame is configured of 5 sub-frames each
having the length of 1 ms. One sub-frame includes one switch-
point. This corresponds to when the cycle period of the
switch-point is 5 ms. Herein, the cycle period of the. switch-
point may also be equal to 10 is. ~
In this embodiment of the present invention, the. case
where the cycle period of the switch-point is 5 ms is first
considered. As shown in Table 3 below, the frame
configuration of the 3GPP LTE TDD mode may respectively have 9
different configurations or 7 different configurations in two
different modes, wherein one corresponds to using a normal CP
and the other corresponds to using an extended CP.

In this embodiment of the present invention, a method of
establishing DL/UL ratios of the frame for the IEEE 802.16m
TDD system and establishing the time domain structure of a
frame based upon the 3GPP LTE TDD frame structure shown in FIG.
7 and each configuration index of Table 3 is provided.
According to the embodiment of the present invention, the
details shown in Table 3 with respect to the 3GPP LTE TDD
system propose the regulations for establishing the DL/UL
ratios of the IEEE 802.16m and the time domain of a frame in
Table 4a, Table 4B, and Table 5 shown below with respect to
the case of using a normal CP and an extended CP.
First of all, the case of using a normal CP in the 3GPP
LTE system will now be described.

Table 4a and Table 4b respectively show the method of
determining the DL/UL ratio of the IEEE 802.16m frame
according to each configuration index, when the 3GPP LTE TDD
system uses the general CP. As shown in Table 4a and Table 4b,
2 or more DL/UL ratios may be available under the same
condition. Along with the Dl/UL ratio of the 16m frame, Table
4a and Table 4b show the number of OFDM symbols that cannot be
used due to the non-conformity of the two systems.
When the DL/UL ratio of the 3GPP LTE TDD is 1:3, the 16m
does not have a separate frame offset. And, the
configurations 0 and 5 of Table 4 may configure 2 different
ratios 2:6 and 3:5, with respect to the DL/UL ratio 1:3 of the
LTE TDD system, without any separate symbol puncturing (i.e.,
the act of not transmitting specific symbols from a sub-frame
of a 6 OFDM symbol unit) . In the remaining cases,, only one
ratio 3:5 is optimal for the DL/UL ratio 1:3 of the LTE TDD
system. With the exception of this ratio, when other ratios
are being considered, the occurrence of the above-described
symbol puncturing should be taken into consideration.
When the DL/UL ratio of the LTE TDD system is 2:2, the
frame offset of the 16m becomes the sub-frame unit 4000 us,

and only one ratio may be available for all configurations of
Table 4. In this case, as described above, the number of
symbols processed with puncturing starts from one to a maximum
number of two symbols.
When the DL/UL ratio of the LTE TDD system is 3:1, the
frame offset of the 16m becomes the sub-frame unit 3000 us,
and only one ratio may be available for all configurations of
Table 4 with the exception of configuration 7. In this case,
the number of puncturing symbols ranges from a minimum of 3
symbols and a maximum of 4 symbols. Herein, since the case of
configuration 7 corresponds to a particular case, the
description of the same will be given in the following
description.
FIG. 8 to FIG. 13 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio of Table 4
according to an embodiment of the present invention
corresponds to 1:3, and when configuration 0 to configuration
5 are used.
The maximum portion that can be occupied by the DL
portion of the 16m frame is up to the length of DL 1 symbol +
DwPTS + GP of the LTE TDD. When the 16m frame exceeds this
region, a particular situation of having to perform puncturing
on the corresponding symbol occurs. However, when
configuration is made as shown in Table 4 according to the

embodiment of the present invention, the situation wherein the
symbol puncturing is to be performed may not be occurred when
the LTE TDD DL/UL ratio corresponds to 1:3.
FIG. 8 to FIG. 13 all correspond to cases where the
DL/UL ratio of the LTE TDD frame is 1:3. Most particularly,
FIG. 8 illustrates a situation where the DL/UL ratio of the
16m TDD frame is set to 2:6 and 3:5 with respect to LTE TDD
configuration 0. FIG. 9 illustrates a situation where the
DL/UL ratio of the 16m TDD frame is set to 3:5 with respect to
LTE TDD configuration 1. FIG. 10 illustrates a situation
where the DL/UL ratio of the 16m TDD frame is set to 3:5 with
respect to LTE TDD configuration 2. FIG. 11 illustrates a
situation where the DL/UL ratio of the 16m TDD frame is set to
3:5 with respect to LTE TDD configuration 3. Also, FIG. 12
illustrates a situation where the DL/UL ratio of the 16m TDD
frame is set to 3:5 with respect to LTE TDD configuration 4.
And, finally, FIG. 13 illustrates a situation where the DL/UL
ratio of the 16m TDD frame is set to 3:5 with respect to LTE
TDD configuration 5. Furthermore, the LTE TDD configurations
6 to 8 that have not been illustrated may also be illustrated
as shown in FIG. 8 to FIG. 13 in accordance with Table 4.
FIG. 14 to FIG. 17 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio of Table 4
according to an embodiment of the present invention
corresponds to 2:2.

The same principles as those of FIG. 8 to FIG. 13 are
applied in FIG. 14 to FIG. 17. More specifically, the maximum
portion that can be occupied by the DL portion of the 16m
frame is up to the length of DL 1 symbol + DwPTS + GP of the
LTE TDD, and when the 16m frame exceeds this region, a
particular situation of having to perform puncturing on the
corresponding symbol occurs. According to the embodiment of
the present invention, when the LTE TDD DL/UL ratio is 2:2,
optimization may be performed at a level of puncturing 1~2
OFDM symbols. The frame offset for all LTE TDD configurations
(configuration 0 to configuration 8) is equally set to 4000 us.
FIG. 14 to FIG. 17 all correspond to cases where the
DL/UL ratio of the LTE TDD frame is 2:2. Most particularly,
FIG. 14 illustrates a situation where the DL/UL ratio of the
16m TDD frame is set to 4:4 with respect to LTE TDD
configuration 0. FIG. 15 illustrates a situation where the
DL/UL ratio of the 16m TDD frame is set to 5:3 with respect to
LTE TDD configuration 1. FIG. 16 illustrates a situation
where the DL/UL ratio of the 16m TDD frame is set to 4:4 with
respect to LTE TDD configuration 5. FIG. 17 illustrates a
situation where the DL/UL ratio of the 16m TDD frame is set to
5:3 with respect to LTE TDD configuration 6.
Furthermore, the situations that have not been
illustrated may also be illustrated as shown in FIG. 14 to FIG.
17 in accordance with Table 4. More specifically,

configurations 2, 3, and 4 are all identical to configuration
1 of FIG. 14. Also, configurations 7 and 8 may be applied
identically as the situation of configuration 6.
FIG. 18 to FIG. 26 illustrate the relation with an IEEE
802.16m frame, when the LTE TDD DL/UL ratio of Table 4
according to an embodiment of the present invention
corresponds to 3:1, and when configuration 0 to configuration
8 are used.
According to the embodiment of the present invention,
the number of OFDM symbols that ate punctured when the LTE TDD
DL/UL ratio is 3:1 may be set to be equal to or less that 3-4
OFDM symbols. Furthermore, the frame offset for all cases (or
situations) is equally set to 3000 us.
*FIG. 18 to FIG. 26 all correspond to cases where the
DL/UL ratio of the LTE TDD frame is 3:1. Most particularly,
FIG. 18 illustrates a situation where the DL/UL ratio of the
16m TDD frame is set to 6:2 with respect to LTE TDD
configuration 0. FIG. 19 illustrates a situation where the
DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to
LTE TDD configuration 1. Also, FIG. 20 illustrates a
situation where the DL/UL ratio of the 16m TDD frame is set to
6:2 with respect to LTE TDD configuration 2. FIG. 21
illustrates a situation where the DL/UL ratio of the 16m TDD
frame is set to 7:1 with respect to LTE TDD configuration 3.
Also, FIG. 22 illustrates a situation where the DL/UL ratio of

the 16m TDD frame is set to 7:1 with respect to LTE TDD
configuration 4. FIG. 23 illustrates a situation where the
DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to
LTE TDD configuration 5.
Additionally, FIG. 24 illustrates a situation where the
DL/UL ratio of the 16m TDD frame is set to 6:2 with respect to
LTE TDD configuration 6. FIG. 25 illustrates a situation
where the DL/UL ratio of the 16m TDD frame is set to 7:1 with
respect to LTE TDD configuration 7. And, finally, FIG. 26
illustrates a situation where the DL/UL ratio of the 16m TDD
frame is set to 7:1 with respect to LTE TDD configuration 8.
Meanwhile, Table 5 shown below indicates the
optimization of the 16m frame structure using the same method
as that of Table 4 upon reference to Table 3, when the LTE TDD
system uses the extended CP.

As shown in Table 5, when the LTE TDD DL/UL ratio is 1:3,
the 16m frame may be optimized by eliminating the puncturing
symbols so that the DL/UL ratio can become 3:5. When the LTE
TDD DL/UL ratio is 2:2, puncturing symbols may occur, and the
ratio for minimizing the number of puncturing symbols is
indicated in Table 5. And, the figures marked in bold fonts
in Table 5 indicate the number of symbols. When the LTE TDD
DL/UL ratio is 3:1, with the exception of configuration 6, the
ratio of the 16m may be determined so that there are no
puncturing symbols.
Although the frame offset is not mentioned in Table 5,
the frame offset may have the same value in accordance with
the 3 different DL/UL ratios of the LTE TDD system, as shown
in Table 4.
Hereinafter, as a preferred embodiment of the present
invention, a method of determining the 16m frame by delaying
the 16m frame within the RTG range, so as to minimize the
puncturing caused by a non-conformity between the conventional
system and the time domain, will be described in detail.

FIG. 27 illustrates a method of establishing an IEEE
802.16m frame by delaying the IEEE 802.16m frame within an RTG
range so as to be aligned with the heterogeneous TDD system
according to a preferred embodiment of the present invention.
Most particularly, among the details specified in Table
4, FIG. 27 illustrates the case of configuration 7 when the
LTE TDD DL/UL ratio is 3:1. As described above, in accordance
with Table 4, the LTE TDD system should puncture 4 symbols,
when using configuration 7 with respect to the DL/UL ratio of
3:1, and when using the 16m frame DL/UL ratio of 7:1 (42:6).
However, in the same situation, by using the 16m frame DL/UL
ratio of 6:2 (36:12), and by delaying the 16m frame to a
predetermined degree, as shown in FIG. 27, settings may be
made so that there are no punctured symbols.
In principle, when the LTE TDD system uses configuration
7 so that the DL/UL ratio can become 3:1, even when the 16m
frame DL/UL ratio of 6:2 is used, a collision may occur
between the two frames, as shown in the mid-portion of FIG. 27.
Therefore, according to the embodiment of the present
invention, as shown in the lower portion of FIG. 27, in order
to prevent collision in the UL Portion of the 16m, the present
invention proposes a method of delaying the 16m frame within
the RTG length range.
At this point, the degree of delay may be acquired
within a range satisfying the following equation.

As described above, by delaying the 16m frame, a frame
may be designed so that there is no puncturing (or so that the
puncturing can be minimized) in the 16m frame.
As described above, the detailed description of the
disclosed preferred embodiments of the present invention is
provided so that anyone skilled in the art can realize and
carry out the present invention. In the above description,
although the present invention is described with reference to
the preferred embodiments of the present invention, it will be
apparent to those skilled in the art that various
modifications and variations can be made in the present
invention without departing from the spirit or scope of the
inventions. Therefore, the present invention is not intended
to limit the present invention to the embodiments presented
herein. Instead, it is intended that the present invention
grants a broadest range matching the principles and new
characteristics disclosed herein.
[Industrial Applicability]
As described above, in each embodiment of the present
invention, a TD-SCDMA (LCR-TDD) system or 3GPP LTE TDD system
is given as an example of the conventional heterogeneous TDD
system, and an IEEE 802.16m system is given as an example of

the new system, and the descriptions of the same are given in
detail. However, the present invention is not required to be
limited to the given example. And, the present invention may
be used as a method of efficiently establishing a frame based
upon the same principles in an arbitrary telecommunications
system.

[What is claimed is]
1. In a situation of coexisting heterogeneous systems
including a first system and a second system, in a method of
establishing a time domain structure of a second frame used
for a Time Division Duplex (TDD) mode of the second system, so
that the second frame can coexist with a first frame for a TDD
mode of the first system, the method of establishing a time
domain structure of a frame comprises:
an information acquiring step for acquiring type
information of the first system being supported and
information on a first ratio, wherein the first ratio
corresponds to a ratio between an uplink section and a
downlink section in the first frame structure;
a second frame structure establishing step for
establishing a second frame structure for the second system
based upon the acquired information; and
a ratio determining step for determining a second ratio,
wherein the second ratio corresponds to a ratio between an
uplink section and a downlink section in the second frame
structure.
2. The method of claim 1, wherein the ratio determining
step comprises a step of setting-up a sum of the downlink
section and a transmit transition gap (TTG) of the second

frame or a sum of the downlink section, TTG, and a receive
transition gap (RTG) of the second frame, so that the sum can
be equal to or greater than a sum of the downlink section and
a downlink pilot time slot (DwPTS) of the first frame.
3. The method of claim 1, wherein, in the ratio
determining step, when a sum of the receive transition gap
(RTG), downlink section, and transmit transition gap (TTG) of
the second frame is greater than a sum of the downlink section,
downlink piloting time slot (DwPTS), and guard period (GP) of
the first frame, a predetermined number of OFDM symbols are
excluded from a transmission.
4. The method of claim 1, wherein the ratio determining
step further comprises:
a step of establishing a frame offset from a starting
point of the first frame of the second frame.
5. The method of claim 4, wherein the first system
corresponds to an LCR-TDD (low-chip-rate time division duplex)
system, wherein the second system corresponds to an IEEE
802.16m system, and wherein a cyclic prefix (CP) length of the
second frame is equal to 1/8 valid OFDM symbol time (Tu), and
wherein the second ratio is set to 7:1 when the first
ratio is set to 6:1, wherein the second ratio is set to 6:2

when the first ratio is set to 5:2, wherein the second ratio
is set to 5:3 when the first ratio is set to 4:3.
(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
6. The method of claim 5, wherein among the second frame
structure, 1 OFDM symbol is excluded from the transmission
when the first ratio is 6:1, wherein 2 OFDM symbols are
excluded from the transmission when the first ratio is 5:2,
and wherein 3 OFDM symbols are excluded from the transmission
when the first ratio is 4:3.
7. The method of claim 1, wherein the first system
corresponds to a 3GPP LTE TDD system, wherein the second
system corresponds to an IEEE 802.16m system, and wherein a
cyclic prefix (CP) length of the second frame is equal to 1/8
valid OFDM symbol time (Tu), and
wherein the information acquiring step comprises a step
of additionally acquiring CP length information of the first
frame and configuration index information of the first frame
in the 3GPP LTE TDD system.
8. The method of claim 7, wherein, when the CP length of
the first frame corresponds to a normal CP and when the first
ratio is 1:3,

the second ratio is set to 2:6 or 3:5 when the
configuration index of the first frame is 0, wherein the
second ratio is set to 3:5 when the configuration index of the
first frame is 1, wherein the second ratio is set to 3:5 when
the configuration index of the first frame is 2, wherein the
second ratio is set to 3:5 when the configuration index of the
first frame is 3, wherein the second ratio is set to 3:5 when
the configuration index of the first frame is 4, wherein the
second ratio is set to 2:6 or 3:5 when the configuration index
of the first frame is 5, wherein the second ratio is set to
3:5 when the configuration index of the first frame is 6,
wherein the second ratio is set to 3:5 when the configuration
index of the first frame is 7, and wherein the second ratio is
set to 3:5 when the configuration index of the first frame is
8.
(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
9. The method of claim 7, wherein,, when the CP length of
the first frame corresponds, to a normal CP and when the first
ratio is 2:2,
the second ratio is set to 4:4 when the configuration
index of the first frame is 0, wherein the second ratio is set
to 5:3 when the configuration index of the first frame is 1,
wherein the second ratio is set to 5:3 when the configuration

index of the first frame is 2, wherein the second ratio is set
to 5:3 when the configuration index of the first frame is 3,
wherein the second ratio is set to 5:3 when the configuration
index of the first frame is 4, wherein the second ratio is set
to 4:4 when the configuration index of the first frame is 5,
wherein the second ratio is set to 5:3 when the configuration
index of the first frame is 6, wherein the second ratio is set
to 5:3 when the configuration index of the first frame is 7,
and wherein the second ratio is set to 5:3 when the
configuration index of the first frame is 8.
(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
10. The method of claim 7, wherein, when the CP length
of the first frame corresponds to a normal CP and when the
first ratio is 3:1,
the second ratio is set to 6:2 when the configuration
index of the first frame is 0, wherein the second ratio is set
to 6:2 when the configuration index of the first frame is 1,
wherein the second ratio is set to 6:2 when the configuration
index of the first frame is 2, wherein the second ratio is set
to 7:1 when the configuration index of the first frame is 3,
wherein the second ratio is set to 7:1 when the configuration
index of the first frame is 4, wherein the second ratio is set
to 6:2 when the configuration index of the first frame is 5,

wherein the second ratio is set to 6:2 when the configuration
index of the first frame is 6, wherein the second ratio is set
to 7:1 or 6:2 when the configuration index of the first frame
is 7, and wherein the second ratio is set to 7:1 when the
configuration index of the first frame is 8.
(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
11. The method of claim 10, wherein the second frame is
set-up to have a frame offset of 300 us from a starting point
of the first frame.
12. The method of claim 11, wherein, when the
configuration index of the first frame is 7 and when the
second ratio is 6:2, the second frame is set-up to be delayed
for a predetermined time starting from a point corresponding
to the frame offset at the starting point of the first frame
within a receive transition gap (RTG) range of the second
frame.
13. The method of claim 7, wherein, when the CP length
of the first frame corresponds to an extended CP and when the
first ratio is 1:3,
the second ratio is set to 3:5 when the configuration
index of the first frame is any one of 0 to 6.

(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
14. The method of claim 7, wherein, when the CP length
of the first frame corresponds to an extended CP and when the
first ratio is 2:2,
the second ratio is set to 4:4 when the configuration
index of the first frame is 0 or 6, and wherein the second
ratio is set to 5:3 when the configuration index of the first
frame is any one of 1, 2, 3, 5, and 6.
(Herein, x:y corresponds to (a downlink section
length):(an uplink section length).)
15. The method of claim 7, wherein, when the CP length
of the first frame corresponds to an extended CP and when the
first ratio is 3:1,
the second ratio is set to 6:2 or 7:1 when the
configuration index of the first frame is 0, wherein the
second ratio is set to 6:2 or 7:1 when the configuration index
of the first frame is 1, wherein the second ratio is set to
7:1 when the configuration index of the first frame is 2,
wherein the second ratio is set to 7:1 when the configuration
index of the first frame is 3, wherein the second ratio is set
to 6:2 when the configuration index of the first frame is 4,
wherein the second ratio is set to 6:2 when the configuration

index of the first frame is 5, and wherein the second ratio is
set to 7:1 when the configuration index of the first frame is
6.
(Herein, x:y corresponds to (a downlink section
length) : (an uplink section length).)

Disclosed is a method for establishing a time domain
structure of a frame in a heterogeneous TDD systems environment. In other
words, in a situation of coexisting heterogeneous systems comprising a
first system corresponding to an existing TDD system and a second system
corresponding to a new system, a method is provided for establishing
a time domain structure of a second frame for the second TDD system
mode to enable it to coexist with a first frame for the first TDD (Time Division
Duplex) system mode, that comprises obtaining information for the
first supported system type and a first ratio between the downlink region
and the uplink region of the first frame structure, and then, according to
the obtained information, establishing a second ratio between the downlink
region and the uplink region of the second frame structure for the second
system. Further, particular numerology is provided for said method.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=nBSr5ZRzfcGtIL2yPtOUDw==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

271467

Indian Patent Application Number

2489/KOLNP/2010

PG Journal Number

09/2016

Publication Date

26-Feb-2016

Grant Date

23-Feb-2016

Date of Filing

08-Jul-2010

Name of Patentee

LG ELECTRONICS INC.

Applicant Address

20 YEOUIDO-DONG YEONGDEUNGPO-GU SEOUL 150-721 REPUBLIC OF KOREA

Inventors:

#	Inventor's Name	Inventor's Address
1	KWON, YEONG HYEON	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
2	KWAK, JIN SAM	LG INSTITUTE #533 HOGYE-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
3	NOH, MIN SEOK	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
4	KIM, DONG CHEOL	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
5	MOON, SUNG HO	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
6	HAN, SEUNG HEE	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA
7	LEE, HYUN WOO	LG INSTITUTE HOGYE 1(IL)-DONG DONGAN-GU ANYANG-SI GYEONGGI-DO 431-080 REPUBLIC OF KOREA

PCT International Classification Number

H04B 7/212

PCT International Application Number

PCT/KR2009/000368

PCT International Filing date

2009-01-23

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	61/022,824	2008-01-23	U.S.A.
2	10-2008-0041124	2008-05-02	U.S.A.