Title of Invention	TRANSMISSION DEVICE
Abstract	Provided is a transmission device for allocating a resource block or a distributed resource block includes: means for constituting a first group by a plurality of continuous resource blocks and a second group by one or more resource blocks contained in the plurality of resource blocks constituting the first group and allocating the first group or the second group: means for allocating transmission data to the frequency block or the distributed frequency block in accordance with the allocation; and means for generating control information for a mobile station for which one of the first group and the second group has been allocated.

Title of Invention

TRANSMISSION DEVICE

Abstract

Provided is a transmission device for allocating a resource block or a distributed resource block includes: means for constituting a first group by a plurality of continuous resource blocks and a second group by one or more resource blocks contained in the plurality of resource blocks constituting the first group and allocating the first group or the second group: means for allocating transmission data to the frequency block or the distributed frequency block in accordance with the allocation; and means for generating control information for a mobile station for which one of the first group and the second group has been allocated.

Full Text	DESCRIPTION TRANSMISSION DEVICE TECHNICAL FIELD The present invention generally relates to an LTE (Long Term Evolution) system, and more particularly to a transmission device. BACKGROUND ART As a communication system succeeding the W- CDMA and the HSDPA, an LTE (Long Term Evolution) system is being worked on by the 3GPP (3rd Generation Partnership Project), which is the standardization group for the W-CDMA. In the LTE system, an OFDMA (Orthogonal Frequency Division Multiple Access) system is being considered for the downlink, and an SC-FDMA (Single- Carrier Frequency Division Multiple Access) system is being considered for the uplink. In the OFDMA system, a frequency bandwidth is divided into plural narrower frequency bandwidths (subcarriers), and data are transmitted by being carried on the frequency bandwidths. By contiguously arranging the subcarriers without interfering with each other though the subcarriers may be partially overlapped, it becomes possible to achieve fast transmission and improve the use efficiency of the frequency bandwidths. The SC-FDMA system is a transmission system in which a frequency bandwidth is divided so that plural terminals can transmit using a different frequency bandwidth among the plural terminals to reduce the interference between the terminals. The SC-FDMA system has the characteristics that the variation of the transmitting power becomes small. Therefore, the configuration of the transmitter of the terminal can be relatively simplified. In addition, as the transmission methods in a downlink data channel, there are localized transmission and distributed transmission. In localized transmission, as shown in FIG. 1A, a frequency block is allocated as a unit to each user. For example, in localized transmission, the frequency blocks having good frequency selective fading are allocated. Generally, localized transmission may be effectively used when the size of the transmission data is large and the frequency scheduling effect is required to be enhanced. The frequency block may be called a resource block. In distributed transmission, as shown in FIG. IB, data are spread (distributed) across the entire available bandwidth without relation to the frequency blocks and transmitted. For example, distributed transmission is generally used when the frequency scheduling may not be performed due to fast movement and when the size of the transmission data is small such as the case of VoIP. In the LTE system, it is required for a single system to support various sizes of packets ranging from packets having a larger size used in browsing a Web site or the like to packets having a smaller size used in VoIP or the like in communications with slow users and fast moving users as well. To support both the localized transmission and distributed transmission by a single system, there has been proposed a communication device in which, when distributed transmission is performed at the resource block level, one resource block is divided into plural divided blocks, and the divided blocks are allocated as the resource blocks. This communication device generates control information with respect to a mobile station to which the resource blocks are allocated. For example, the allocated bandwidth is divided into plural parts and identification codes such as identification numbers indicating the physical locations of the thus-divided and generated plural resource blocks are assigned to the plural resource blocks. In this case, a division number of the resource: blocks to be used for distributed transmission among the plural resource blocks is set equal to an allocation unit of the divided resource blocks to be allocated to a mobile station as a unit and is defined as "ND" (where ND is an integer number greater than 0) . Namely, the divided resource blocks are assigned by regarding the resource block as a unit. FIG. 2A shows a case where ND=2. According to FIG. 2A, in a case of ND=2, each of the resource blocks used for distributed transmission is divided into two parts (divided resource blocks), and the two divided resource blocks, namely a pair of the divided resource blocks, becomes a unit to be allocated to a mobile station. In this case, the physical locations of the resource blocks used for distributed transmission are predetermined in accordance with the total number of resource blocks used for distributed transmission. In this case, as shown in FIG. 2B, a specific signaling format for transmitting the allocation information includes each field for an ID (UE-ID) of an allocated mobile station, a transmission type indicating which of localized transmission or distributed transmission is to be performed, and allocation information with respect to each resource block, namely, the resource block used for localized transmission and the resource block for distributed transmission. In the fields for the allocation information with respect to the resource blocks, subfields corresponding to the resource blocks are provided, and information of allocated or non-allocated is assigned to the subfields. An assigning method of the allocation information with respect to the resource blocks is called "bitmap". A base station transmits control bits including such allocation information as many numbers as the number of mobile stations allocated to perform localized transmission and distributed transmission. Non Patent Document 1: R2-062036, "Evolved Universal Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2," Section 16 RF aspects DISCLOSURE OF INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION However, the prior art described above has the following problem. The resource blocks are provided by dividing a system bandwidth, i.e., an allocated bandwidth, into plural parts. The consideration of the size of the resource block is being conducted. When the size of the resource block is 25 subcarriers (375 kHz), there are many transmission data exist that don't require one resource block. Therefore, there has been a proposal in which the size of the resource block is reduced to 12 subcarriers (180 kHz). By adopting this proposal, the size of the resource block becomes smaller and accordingly, the number of resource blocks included in the allocated system bandwidth can be increased, and the degree of freedom of allocating the resource blocks to a user may be increased. However, since the number of resource blocks is increased, the number of signaling bits is increased. More specifically, there is an increase in the number of bits necessary for the allocation information with respect to each resource block described with reference to FIG. 2B. The number of bits necessary for the signaling announcing the allocation of the resource blocks to a user is proportional to the number of the resource blocks. Because of this feature, the number of signaling bits increases in proportion to the increased number cf the resource blocks. For example, when the system bandwidth is 10 MHz, the number of resource blocks is approximately 50. In this case, when a method is applied in which the allocation information is assigned with respect to each resource block using separate coding and bitmap, sixty (60) or more bits per mobile station become necessary. In a transmission device according to an embodiment of the present invention, both of localized transmission and distributed transmission are supported in a single system, and even when the number of resource blocks is increased, the increase of the signaling bits announcing the allocation of the resource blocks to a user can be minimized. MEANS FOR SOLVING THE PROBLEMS According to an aspect of the present invention, a transmission device includes a frequency scheduling unit configured to allocate resource blocks as a unit to each user, the resource blocks being blocks of consecutive frequency subcarriers divided from a system bandwidth, constitute a first group including consecutive plural resource blocks, constitute plural second groups, each including one or more resource blocks of the plural resource blocks constituting each first group, and allocate the resource blocks of either the first group or one or more the second groups; a mapping unit configured to allocate transmission data to the resource blocks in accordance with the allocation; and a control information generating unit configured to generate control information with respect to a mobile station to which either the first group or one or more the second groups are allocated. According to another aspect of the present invention, a transmission device generates distributed- type resource blocks including discretely-distributed frequency subcarriers in the system bandwidth by using the plural resource blocks of the second groups, and the distributed-type resource blocks are allocated as a unit. By having these configurations, it becomes possible to group resource blocks and generate signaling information (control information) by regarding the group as a unit. ADVANTAGEOUS EFFECT OF THE INVENTION According to an embodiment of the present invention, it becomes possible to provide a transmission device in which both of localized transmission and distributed transmission are supported as a single system, and even when the number of resource blocks is increased, the increase of the signaling bits announcing the allocation of the resource blocks to a user can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a drawing showing a localized transmission; FIG. IB is a drawing showing a distributed transmission; FIG. 2A is a drawing showing an example of frequency scheduling; FIG. 2B is a drawing showing an example of a signaling format; FIG. 3 is a partial block diagram showing a transmission device according to an embodiment of the present invention; FIG. 4 is a drawing showing frequency scheduling in a transmission device according to an embodiment of the present invention; FIG. 5A is a drawing showing frequency scheduling in a transmission device according to an embodiment of the present invention; FIG. 5B is a drawing showing frequency scheduling in a transmission device according to an embodiment of the present invention; FIG. 6 is a drawing showing a configuration of the resource blocks to be used for localized transmission; FIG. 7 is a drawing showing a configuration of the resource blocks to be used for distributed transmission; FIG. 8 is a drawing showing a configuration of resource blocks to be used for localized transmission and the resource blocks to be used for distributed transmission; FIG. 9 is a drawing showing an example where the resource blocks to be used for localized transmission are allocated to a mobile station; FIG. 10A is a drawing showing an example of signaling format in a transmission device according to an embodiment of the present invention; FIG. 10B is a drawing showing an example of signaling format in a transmission device according to an embodiment of the present invention; FIG. 11 is a drawing showing an example of signaling format in a transmission device according to an embodiment of the present invention; and FIG. 12 is drawing showing an example of correspondence between the allocation information with respect to the resource blocks of a first group and the resource blocks to be allocated. EXPLANATION OF REFERENCES 100 TRANSMISSION DEVICE BEST MODE FOR CARRYING OUT THE INVENTION Next, the best mode for carrying out the invention is described based on the following embodiments with reference to the accompanying drawings. In all the figures, the same reference numerals are commonly used for the elements having the same function, and repeated descriptions of such elements are omitted. A transmission device according to an embodiment is described with reference to FIG. 3. A transmission device 100 according to the embodiment of the present invention performs distributed transmission at the localized transmission level. The transmission device 100 may be incorporated in, for example, a base station. Namely, a resource block used for the localized transmission is divided into plural parts and the thus-divided resource blocks (divided resource blocks) are allocated to a user who uses distributed transmission. As shown in FIG. 4, the transmission device 100 includes a resource block (RB) allocation ratio switching section 102, a frequency scheduling section 104, a control information generating section 106, a transmission data generating section 112, coding rate/data modulation determining sections 108 and 114, and mapping sections 110 and 116. The resource block (RB) allocation ratio switching section 102 inputs information indicating the mobility of each mobile station (UE) and information indicating traffic of the mobile stations such as size and type of transmission data. The frequency scheduling section 104 inputs propagation path information of each mobile station such as the status of the downlink propagation path, the priority information of the mobile station, and the output signal from the resource block allocation ratio switching section 102. The output signal from the frequency scheduling section 104 is input to the control information generating section 106 and the transmission data generating section 112. The output signal from the control information generating section 106 is input to the coding rate/data modulation determining section 108, and the output signal from the transmission data generating section 112 is input to the coding rate/data modulation determining section 114. The mapping section 110 inputs the output signal from the coding rate/data modulation determining section 108 and outputs control information. The mapping section 116 inputs the output signal from the coding rate/data modulation determining section 114 and data and outputs data. The resource block allocation ratio switching section 102 determines mobile stations to perform localized transmission and mobile stations to perform the distributed transmission based on the information indicating the mobility of each mobile station (UE), the information indicating traffic, and the like. The resource block allocation ratio switching section 102 further determines a ratio between the resource blocks to be allocated to the mobile stations that perform localized transmission and the resource blocks to be allocated to the mobile stations that perform distributed transmission, and inputs the determined value of the ratio to the frequency scheduling section 104 as resource block allocation ratio information. The resource block allocation ratio switching section 102 determines that, for example, a mobile station having high mobility and a mobile station transmitting traffic having small data size such as VoIP are the mobile stations which are to perform distributed transmission. Further, upon determining the allocation ratio of the resource blocks, the resource block allocation ratio switching section 102 increases the rate of resource blocks allocated to perform distributed transmission when, for example, there are many mobile stations having high mobility or there are many mobile stations that transmit traffic data having a small data size such as in VoIP. The frequency scheduling section 104 allocates resource blocks to each mobile station based on the input information indicating the propagation path of the mobile stations, priority information indicating priority of the mobile stations, and the resource block allocation ratio information. Herein, the priority information refers to digitized information with respect to each mobile station by considering the items such as whether a retransmission request is included, an elapsed time after packets are transmitted from a transmission terminal, a target transmission rate, actual throughput, and an allowable delay in the packet transmission. For example, the frequency scheduling section 104 adaptively switches the allocation ratio between the resource blocks which are to perform localized transmission and the resource blocks which are to perform distributed transmission at every predetermined cycle such as at every cycle of scheduling based on the status of each mobile station such as a channel status and the resource block allocation ratio information determined in accordance with the traffic. By doing this, the throughput of a data channel may be increased. Further, the frequency scheduling section 104 may switch the allocation ratio between the resource blocks which are to perform localized transmission and the resource blocks which are to perform distributed transmission at a longer period based on the status of each mobile station such as the resource block allocation ratio information determined in accordance with the traffic. By doing this, the control may be performed more easily compared with the case where the switching is performed at every cycle of scheduling. For example, as shown in FIG. 4, the frequency scheduling section 104 allocates the data to be transmitted in localized transmission and the data to be transmitted in distributed transmission by using the resource block as an allocation unit. Namely, the frequency scheduling section 104 allocates distributed- type resource blocks having discretely-distributed frequency subcarriers in a system bandwidth to each user by using the resource blocks that are blocks of consecutive frequency subcarriers divided from the system bandwidth as an allocation unit. By doing this, it becomes possible to eliminate the use of signaling information that is necessary when distributed transmission is to be performed. Further, when distributed transmission is to be performed at the resource block level, the frequency scheduling section 104 divides one resource block into plural parts, for example, "N" divided parts (where N is an integer number greater than 0). Namely, the frequency scheduling section 104 allocates the distributed-type resource blocks as the resource block with respect to a user who uses distributed transmission. Herein, the resource block may also be regarded as a unit for mapping users or, for example, a unit for allocating a certain user. For example, as shown in FIG. 5A, the frequency scheduling section 104 divides one resource block into plural parts such as two parts in the time direction and allocates the resource block with respect to users who use distributed transmission to the mobile stations that perform distributed transmission such as two users. As shown in FIG. 5A, the frequency scheduling section 104 allocates first blocks and second blocks to different users. Further, for example, as shown in FIG. 5B, the frequency scheduling section 104 may divide one resource block into plural parts such as two parts in the frequency direction and allocate the resource blocks with respect to users who use distributed transmission to the mobile stations that perform distributed transmission such as two users. For example, as shown in FIG. 5B, the frequency scheduling section 104 allocates first blocks and second blocks to different users. In FIGS. 5A and 5B, the first two symbols represent pilot and signaling bits, i.e., a pilot channel and an L1/L2 control channel. In distributed transmission at the resource block level, a frequency diversity effect cannot be obtained unless plural resource blocks, namely plural distributed-type resource blocks, with respect to a user who uses distributed transmission are allocated. Because of this feature, in such a case of traffic data whose size is small such as VoIP, all data may be included into one resource block and the frequency diversity effect cannot be obtained. In a case of VoIP, the data size of one packet is, for example, 180 bits. As described above, by dividing a resource block into N parts, it becomes possible to allocate the packet data that can otherwise be included in a single resource block to N distributed-type resource blocks, thereby increasing the frequency diversity effect. The control information generating section 106 generates control information with respect to the mobile stations to which the resource blocks are allocated by the frequency scheduling section 104. The coding rate/data modulation determining section 108 determines a coding rate and a data modulation value that are used when the control information is transmitted. The mapping section 110 performs the data modulation and coding that are determined by the coding rate/data modulation determining section 108 and performs mapping on a physical channel. As a result, the control information is transmitted. The transmission data generating section 112 generates transmission data in accordance with the number of resource blocks allocated to each mobile station. For example, the transmission data generating section 112 determines the amount of transmission data. The coding rate/data modulation determining section 114 determines a coding rate and a data modulation value with respect to the data of each mobile station allocated by the frequency scheduling section 104 and the control information. The mapping section 116 performs the data modulation, coding, and mapping on a physical channel. Next, a specific example of the operations of the above-mentioned frequency scheduling section 104 is described in detail. As described above, when the system bandwidth is divided into plural parts, each of the divided bandwidths is called a resource block. In this embodiment of the present invention, the number of resource blocks obtained by dividing an allocated bandwidth is defined as "NPRB" (where NPRB is an integer number greater than 1). The identification codes such as identification numbers are allocated to the resource blocks to identify the resource blocks. In this embodiment of the present invention, for example, a case is described where the allocated bandwidth is divided into 48 parts (NPRB=48) and in the 48 resource blocks, consecutive three (3) resource blocks are grouped (first group) and the same identification number is allocated to those grouped resource blocks. However, this embodiment of the present invention may be applied to cases where the division number is lower than 48 and greater than 48. Further, the above number of resource blocks belonging to the first group is merely an example, and the embodiment of the present invention may be applied to cases where the number is less than 3 and the number is greater than 3. For example, as shown in FIG. 6, when one resource block includes 12 subcarriers (180 kHz), the first group has 36 subcarriers (540 kHz). Further, there are provided other groups as plural second groups each including one or more resource blocks from each first group. For example, from among three consecutive resource blocks in each first group, resource blocks located at the same location in the first groups are grouped, so that second, third, and fourth groups are provided. The resource blocks are allocated to users who use localized transmission by regarding each of the first, the second, the third, and the fourth groups as a unit. In this case, a base station having a transmitter performs downlink frequency scheduling. A mobile station announces the channel status used for the frequency scheduling to the base station. Then, the channel status is announced by using the first group as a unit. The total bandwidth of the resource blocks constituting the first group is substantially equal to the bandwidth used as a measurement unit for receiving channel status. Namely, the mobile station averages the channel status of the resource channels included in the first group (three resource blocks in this embodiment) and announces the averaged result as the channel status of the first group. By doing this, the frequency scheduling may be applied to the allocation of resource blocks of the second through the fourth groups as well while neither measuring at a higher resolution than is necessary nor performing feedback is necessary. Namely, it is not necessary to measure data of the receiving channel in each group nor to perform feedback. To a user who transmits data having small data size, the allocation is performed by using the second through the fourth groups as a unit. When the allocation is performed by using the second though the fourth groups as a unit, the channel status announced from the mobile station has the same value; therefore, the allocation is performed based on another condition. On the other hand, for a user who transmits data having large data size, the allocation is performed by using the first group as a unit. To a user who uses distributed transmission, in accordance with the division number of the resource blocks, the distributed-type resource blocks are allocated using the resource blocks as a unit. Namely, by using the above-mentioned plural resource blocks of the other groups as the second groups, the distributed- type resource blocks including discretely-distributed frequency subcarriers in the system bandwidth are generated. In this case, from among three consecutive resource blocks in the first group, the same number of the distributed-type resource blocks as the division number located at the same locations in the first group are called fifth through seventh groups. For example, when the division number is 2, as shown in FIG. 7, two (2) distributed-type resource blocks are in each of the fifth through the seventh groups. Next, the allocation of the resource blocks to a mobile station that performs the above-mentioned localized transmission and the allocation of the resource blocks to a mobile station that performs distributed transmission are described. The RB allocation ratio switching section 102 determines a necessary number of resource blocks to be used for distributed transmission based on the rate of the mobile stations that perform distributed transmission and traffic amount. Here, the rate of the mobile stations that perform distributed transmission refers to, for example, a ratio of the data size of the mobile station that performs localized transmission to the data size of the mobile station that performs distributed transmission. FIG. 8 shows a case where six (6) resource blocks that are to perform distributed transmission are generated. Namely, the number of distributed-type resource blocks that are to perform distributed transmission is six (6) because the allocation is performed by using the resource block as a unit. Next, the frequency scheduling section 104 allocates resource blocks used for localized transmission to the mobile station. In this case, the resource blocks other than the resource blocks that have been determined to be the resource blocks used for distributed transmission are allocated. As described above, the mobile station announces the channel status by using the first group as a unit. The frequency scheduling section 104 allocates the resource blocks to each mobile station that performs localized transmission as described below. FIG. 9 shows an example where the resource blocks are allocated to the mobile stations that perform localized transmission. The frequency scheduling section 104 allocates the resource blocks to the mobile stations that perform localized transmission based on the channel status such as Channel Quality Indicator (CQI) announced from each mobile station. The frequency scheduling section 104 classifies the mobile stations that perform localized transmission into the mobile stations that transmit larger size data and the mobile stations that transmit smaller size data. For example, the frequency scheduling section 104 sets a threshold value of the data size and classifies the mobile stations based on the threshold value. Next, by using the channel status announced from the mobile stations, the average of the channel status announced from the mobile stations that transmit smaller size data is obtained with respect to each first group. Here, the number of mobile stations is predetermined, the number being used for obtaining the average of the channel status. For example, the number is the same as the number of resource blocks grouped as the first group. Next, in the first group, when the channel status of the mobile station that transmits larger size data is greater than the average of the channel status of the mobile stations that transmit smaller size data, the first group is allocated to the mobile station that transmits larger size data. Here, the mobile station that transmits larger size data refers to the mobile station having the best channel status among the mobile stations that request the transmission of larger size data. On the other hand, the mobile stations that transmit smaller size data refer to the above-mentioned predetermined number of mobile stations that request the transmission of smaller size data. Further, when the channel status of the mobile station that transmits larger size data is less than the average of the channel status of the mobile stations that transmit smaller size data, the first group is divided into plural resource blocks and the divided resource blocks are allocated to the mobile stations that transmit smaller size data. For example, when the number of the mobile stations used for obtaining the average of channel status is the same as the number of resource blocks to be grouped as the first group, each of the resource blocks is allocated to one of the mobile stations. In this embodiment of the present invention, if the number of the mobile stations to be averaged is three (3), those mobile stations can be allocated to three (3) resource blocks constituting the first group. For example, the resource block having 540 kHz bandwidth is divided into three (3) resource blocks having 180 kHz bandwidth and the divided resource blocks are allocated to the mobile stations that transmit smaller size data. Next, the control information generated by control information generating section 106 is described with reference to FIG. 10A. As shown in FIG. 10A, the control information with respect to the mobile stations includes each field for an ID (UE-ID) of an allocated mobile station, a transmission type indicating which of localized transmission or distributed transmission is to be performed, and allocation information with respect to the groups of resource blocks. For the allocation information with respect to the groups of the resource blocks, sixteen (16) sub-fields corresponding to the number of the first, the second, the third, and the fourth groups are provided in this example.. For example, in a case where zero (0) indicating localized transmission is assigned as the transmission type and the information indicating the first, the second, the third, or the fourth group is assigned as the group information of the resource blocks, each sub-field of the allocation information in a group of resource blocks indicates the corresponding first, second, third, or fourth group, and the information indicating whether allocated or non-allocated in each of the first, the second, the third, or the fourth group is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Further, for example, in a case where one (1) indicating distributed transmission is assigned as the transmission type and the information indicating the fifth, sixth, or seventh group is assigned as the group information of the resource blocks, each sub-field of the allocation information in groups of the resource blocks indicates the location where the fifth, sixth, and seventh group, respectively, is allocated, and the information indicating whether allocated or non- allocated in the fifth, the sixth, or the seventh group is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Next, the control information generated by the control information generating section 106 is described with reference to FIG. 10B. Here, the control information is described when plural groups are allocated. As shown in FIG. 10B, the control information with respect to the mobile stations includes each field for an ID (UE-ID) of an allocated mobile station, a transmission type indicating which of localized transmission or distributed transmission is to be performed, the allocation information of the resource blocks in a prescribed group, the information indicating the group of the resource blocks, and the allocation information in the group assigned in the information indicating the group of the resource blocks. For the allocation information of the resource blocks in the prescribed group and the allocation information in the group assigned in the information indicating the group of the resource blocks, sixteen (16) sub-fields corresponding to the number of the first, the second, the third, and the fourth groups are provided. For example, in a case where zero (0) indicating localized transmission is assigned as the transmission type and the information indicating the first, the second, the third, or the fourth group is assigned as the group information of the resource blocks, each sub-field of the allocation information in the group assigned in the information indicating the group of the resource blocks indicates the first, the second, the third, or the fourth group, and the information indicating whether allocated or non-allocated in the first, the second, the third, or the fourth group is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Further, to each sub-field of the allocation information of the resource blocks in a prescribed group, the information indicating whether allocated or non- allocated in a group other than the group assigned by, for example, the group information of resource blocks is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Further, for example, in a case where one (1) indicating distributed transmission is assigned as the transmission type and the information indicating the second, the third, or the fourth group is assigned as the group information of the resource blocks, each sub- field of the allocation information in groups of the resource blocks indicates the allocated location of the fifth, the sixth, and the seventh group that are the groups of the distributed-type resource blocks generated from the second, the third, and the fourth groups, respectively, and the information indicating whether allocated or non-allocated in the fifth, the sixth, and the seventh groups is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Further, to each sub-field of the allocation information of the resource blocks in a prescribed group, the information indicating whether allocated or non-allocated in a group which is, for example, other than the group assigned by the group information of resource blocks is assigned; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. Next, other control information generated by the control information generating section 106 is described with reference to FIGS. 11 and 12. As shown in FIG. 11, the control information with respect to the mobile stations includes each field for an ID (UE-ID) of an allocated mobile station, a transmission type indicating which of localized transmission or distributed transmission is to be performed, the allocation information in the resource blocks of the first group, and the allocation information in the first group. As shown in FIG. 12, to the allocation information in the resource blocks of the first group, the allocation information of the resource blocks constituting the first group is assigned. For example, in response to the allocation information in the resource blocks of the first group, the combination of the resource blocks to be allocated is predetermined. To the allocation information in the first group, the information indicating whether allocated or non-allocated is assigned by using the first group as a unit; for example, one (1) is assigned when allocated and zero (0) is assigned when not allocated. According to an embodiment of the present invention, the consecutive plural resource blocks constitute the first group; the resource blocks located at the same location of the plural resource blocks in the first group constitute the second groups; and either the first group or one or more of the second groups can be allocated. Further, by assigning the identification numbers indicating the groups of the resource blocks, the allocation with respect to each group may be assigned. Therefore, even when the number of the resource blocks is increased, it becomes possible to minimize the increase of the signaling bits announcing the allocation of the resource blocks to a user. In the above description, the present invention is described by being divided into several embodiments. However, it should be noted that the division of the present invention into several embodiments is not an essential element of the present invention. For example, two or more embodiment may be combined on as as-needed basis. To promote an understanding of the present invention, specific values are used as examples throughout the description. However, it should be noted that such specific values are just sample values unless otherwise described, and any other values may be used. The present invention is described by referring to a specific embodiment. However, a person skilled in the art may understand that the above embodiment is described for illustrative purposes only and may think of examples of various modifications, transformations, alterations, changes, and the like. For illustrative purposes, the apparatus according to an embodiment of the present invention is described with reference to the functional block diagrams. However, such an apparatus may be provided by hardware, software, or a combination thereof. The present invention is not limited to the embodiment described above, and various modifications, transformations, alteration, exchanges, and the like may be made without departing from the scope and spirit from the present invention. The present application is based on and claims the benefit of priority of Japanese Patent Application No.2006-225915, filed on August 22, 2006, the entire contents of which are hereby incorporated herein by reference. INDUSTRIAL APPLICABILITY The transmission device according to an embodiment of the present invention may be used in a wireless communications system. CLAIMS 1. A transmission device, comprising: a frequency scheduling unit configured to allocate resource blocks as a unit to each user, the resource blocks being blocks of consecutive frequency subcarriers divided from a system bandwidth, constitute a first group including consecutive plural resource blocks, constitute plural second groups, each including one or more resource blocks of the plural resource blocks constituting the first group, and allocate the resource blocks of either the first group or one or more the second groups; a mapping unit configured to allocate transmission data to the resource blocks in accordance with the allocation; and a control information generating unit configured to generate control information with respect to a mobile station to which either the first group or one or more of the second groups are allocated. 2. The transmission device according to claim 1, further comprising: a distributed-type resource block generating unit configured to generate distributed-type resource blocks including discretely-distributed frequency subcarriers in the system bandwidth by using the plural resource blocks of the second groups. 3. The transmission device according to claim 1, wherein a total bandwidth of the resource blocks constituting the first group is substantially equal to a bandwidth used as a measurement unit of a receiving channel status. 4. The transmission device according to claim 1, wherein the frequency scheduling unit is configured to allocate either the first group or one or more of the second groups based on a channel status measured in the first group from the mobile station. 5. The transmission device according to claim 4, wherein the frequency scheduling unit is configured to allocate either the first group or one or more of the second groups to the mobile station based on a size of data to be transmitted by the mobile station. 6. The transmission device according to claim 5, wherein the frequency scheduling unit is configured to compare the channel status of the mobile station having the best channel status among plural of the mobile stations having the data size to be transmitted in the first group equal to or greater than a predetermined threshold value with an average of the channel status of a predetermined number of the mobile stations among the mobile stations having the data size to be transmitted less than the predetermined threshold value, and allocate, when the channel status of the mobile station having the best channel status is greater, the first group to the mobile station having the best channel status. 7. The transmission device according to claim 6, wherein the frequency scheduling unit is configured to compare the channel status of the mobile station having the best channel status among the mobile stations having the data size to be transmitted in the first group equal to or greater than the predetermined threshold value with an average of the channel status of the predetermined number of mobile stations among the mobile stations having the data size to be transmitted less than the predetermined threshold value, and allocate, when the channel status of the mobile station having the best channel status is lower, the resource blocks constituting the first group to the predetermined number of the mobile stations. 8. The transmission device according to claim 1, wherein the control information generating unit is configured to generate the control information including an ID of the mobile station, information indicating the resource blocks or the distributed-type resource blocks allocated to the mobile station, information indicating the group of the resource blocks, and allocation information in the group of the resource blocks. Provided is a transmission device for allocating a resource block or a distributed resource block includes: means for constituting a first group by a plurality of continuous resource blocks and a second group by one or more resource blocks contained in the plurality of resource blocks constituting the first group and allocating the first group or the second group: means for allocating transmission data to the frequency block or the distributed frequency block in accordance with the allocation; and means for generating control information for a mobile station for which one of the first group and the second group has been allocated.

Full Text

DESCRIPTION
TRANSMISSION DEVICE
TECHNICAL FIELD
The present invention generally relates to an
LTE (Long Term Evolution) system, and more particularly
to a transmission device.
BACKGROUND ART
As a communication system succeeding the W-
CDMA and the HSDPA, an LTE (Long Term Evolution) system
is being worked on by the 3GPP (3rd Generation
Partnership Project), which is the standardization group
for the W-CDMA. In the LTE system, an OFDMA (Orthogonal
Frequency Division Multiple Access) system is being
considered for the downlink, and an SC-FDMA (Single-
Carrier Frequency Division Multiple Access) system is
being considered for the uplink.
In the OFDMA system, a frequency bandwidth is
divided into plural narrower frequency bandwidths
(subcarriers), and data are transmitted by being carried
on the frequency bandwidths. By contiguously arranging
the subcarriers without interfering with each other
though the subcarriers may be partially overlapped, it
becomes possible to achieve fast transmission and
improve the use efficiency of the frequency bandwidths.
The SC-FDMA system is a transmission system in
which a frequency bandwidth is divided so that plural
terminals can transmit using a different frequency
bandwidth among the plural terminals to reduce the
interference between the terminals. The SC-FDMA system
has the characteristics that the variation of the

transmitting power becomes small. Therefore, the
configuration of the transmitter of the terminal can be
relatively simplified.
In addition, as the transmission methods in a
downlink data channel, there are localized transmission
and distributed transmission.
In localized transmission, as shown in FIG. 1A,
a frequency block is allocated as a unit to each user.
For example, in localized transmission, the frequency
blocks having good frequency selective fading are
allocated. Generally, localized transmission may be
effectively used when the size of the transmission data
is large and the frequency scheduling effect is required
to be enhanced. The frequency block may be called a
resource block.
In distributed transmission, as shown in FIG.
IB, data are spread (distributed) across the entire
available bandwidth without relation to the frequency
blocks and transmitted. For example, distributed
transmission is generally used when the frequency
scheduling may not be performed due to fast movement and
when the size of the transmission data is small such as
the case of VoIP.
In the LTE system, it is required for a single
system to support various sizes of packets ranging from
packets having a larger size used in browsing a Web site
or the like to packets having a smaller size used in
VoIP or the like in communications with slow users and
fast moving users as well.
To support both the localized transmission and
distributed transmission by a single system, there has
been proposed a communication device in which, when
distributed transmission is performed at the resource

block level, one resource block is divided into plural
divided blocks, and the divided blocks are allocated as
the resource blocks.
This communication device generates control
information with respect to a mobile station to which
the resource blocks are allocated. For example, the
allocated bandwidth is divided into plural parts and
identification codes such as identification numbers
indicating the physical locations of the thus-divided
and generated plural resource blocks are assigned to the
plural resource blocks.
In this case, a division number of the
resource: blocks to be used for distributed transmission
among the plural resource blocks is set equal to an
allocation unit of the divided resource blocks to be
allocated to a mobile station as a unit and is defined
as "ND" (where ND is an integer number greater than 0) .
Namely, the divided resource blocks are assigned by
regarding the resource block as a unit. FIG. 2A shows a
case where ND=2. According to FIG. 2A, in a case of ND=2,
each of the resource blocks used for distributed
transmission is divided into two parts (divided resource
blocks), and the two divided resource blocks, namely a
pair of the divided resource blocks, becomes a unit to
be allocated to a mobile station. In this case, the
physical locations of the resource blocks used for
distributed transmission are predetermined in accordance
with the total number of resource blocks used for
distributed transmission.
In this case, as shown in FIG. 2B, a specific
signaling format for transmitting the allocation
information includes each field for an ID (UE-ID) of an
allocated mobile station, a transmission type indicating

which of localized transmission or distributed
transmission is to be performed, and allocation
information with respect to each resource block, namely,
the resource block used for localized transmission and
the resource block for distributed transmission. In the
fields for the allocation information with respect to
the resource blocks, subfields corresponding to the
resource blocks are provided, and information of
allocated or non-allocated is assigned to the subfields.
An assigning method of the allocation information with
respect to the resource blocks is called "bitmap". A
base station transmits control bits including such
allocation information as many numbers as the number of
mobile stations allocated to perform localized
transmission and distributed transmission.
Non Patent Document 1: R2-062036, "Evolved
Universal Radio Access (E-UTRA) and Evolved Universal
Terrestrial Radio Access Network (E-UTRAN); Overall
description; Stage 2," Section 16 RF aspects
DISCLOSURE OF INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
However, the prior art described above has the
following problem.
The resource blocks are provided by dividing a
system bandwidth, i.e., an allocated bandwidth, into
plural parts. The consideration of the size of the
resource block is being conducted.
When the size of the resource block is 25
subcarriers (375 kHz), there are many transmission data
exist that don't require one resource block. Therefore,
there has been a proposal in which the size of the
resource block is reduced to 12 subcarriers (180 kHz).

By adopting this proposal, the size of the
resource block becomes smaller and accordingly, the
number of resource blocks included in the allocated
system bandwidth can be increased, and the degree of
freedom of allocating the resource blocks to a user may
be increased. However, since the number of resource
blocks is increased, the number of signaling bits is
increased. More specifically, there is an increase in
the number of bits necessary for the allocation
information with respect to each resource block
described with reference to FIG. 2B.
The number of bits necessary for the signaling
announcing the allocation of the resource blocks to a
user is proportional to the number of the resource
blocks. Because of this feature, the number of
signaling bits increases in proportion to the increased
number cf the resource blocks.
For example, when the system bandwidth is 10
MHz, the number of resource blocks is approximately 50.
In this case, when a method is applied in which the
allocation information is assigned with respect to each
resource block using separate coding and bitmap, sixty
(60) or more bits per mobile station become necessary.
In a transmission device according to an
embodiment of the present invention, both of localized
transmission and distributed transmission are supported
in a single system, and even when the number of resource
blocks is increased, the increase of the signaling bits
announcing the allocation of the resource blocks to a
user can be minimized.
MEANS FOR SOLVING THE PROBLEMS
According to an aspect of the present

invention, a transmission device includes
a frequency scheduling unit configured to
allocate resource blocks as a unit to each user,
the resource blocks being blocks of consecutive
frequency subcarriers divided from a system bandwidth,
constitute a first group including consecutive
plural resource blocks,
constitute plural second groups, each including one
or more resource blocks of the plural resource blocks
constituting each first group, and
allocate the resource blocks of either the first
group or one or more the second groups;
a mapping unit configured to allocate
transmission data to the resource blocks in accordance
with the allocation; and
a control information generating unit
configured to generate control information with respect
to a mobile station to which either the first group or
one or more the second groups are allocated.
According to another aspect of the present
invention, a transmission device generates distributed-
type resource blocks including discretely-distributed
frequency subcarriers in the system bandwidth by using
the plural resource blocks of the second groups, and the
distributed-type resource blocks are allocated as a unit.
By having these configurations, it becomes
possible to group resource blocks and generate signaling
information (control information) by regarding the group
as a unit.
ADVANTAGEOUS EFFECT OF THE INVENTION
According to an embodiment of the present
invention, it becomes possible to provide a transmission

device in which both of localized transmission and
distributed transmission are supported as a single
system, and even when the number of resource blocks is
increased, the increase of the signaling bits announcing
the allocation of the resource blocks to a user can be
minimized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a drawing showing a localized
transmission;
FIG. IB is a drawing showing a distributed
transmission;
FIG. 2A is a drawing showing an example of
frequency scheduling;
FIG. 2B is a drawing showing an example of a
signaling format;
FIG. 3 is a partial block diagram showing a
transmission device according to an embodiment of the
present invention;
FIG. 4 is a drawing showing frequency
scheduling in a transmission device according to an
embodiment of the present invention;
FIG. 5A is a drawing showing frequency
scheduling in a transmission device according to an
embodiment of the present invention;
FIG. 5B is a drawing showing frequency
scheduling in a transmission device according to an
embodiment of the present invention;
FIG. 6 is a drawing showing a configuration of
the resource blocks to be used for localized
transmission;
FIG. 7 is a drawing showing a configuration of
the resource blocks to be used for distributed

transmission;
FIG. 8 is a drawing showing a configuration of
resource blocks to be used for localized transmission
and the resource blocks to be used for distributed
transmission;
FIG. 9 is a drawing showing an example where
the resource blocks to be used for localized
transmission are allocated to a mobile station;
FIG. 10A is a drawing showing an example of
signaling format in a transmission device according to
an embodiment of the present invention;
FIG. 10B is a drawing showing an example of
signaling format in a transmission device according to
an embodiment of the present invention;
FIG. 11 is a drawing showing an example of
signaling format in a transmission device according to
an embodiment of the present invention; and
FIG. 12 is drawing showing an example of
correspondence between the allocation information with
respect to the resource blocks of a first group and the
resource blocks to be allocated.
EXPLANATION OF REFERENCES
100 TRANSMISSION DEVICE
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the best mode for carrying out the
invention is described based on the following
embodiments with reference to the accompanying drawings.
In all the figures, the same reference
numerals are commonly used for the elements having the
same function, and repeated descriptions of such
elements are omitted.

A transmission device according to an
embodiment is described with reference to FIG. 3.
A transmission device 100 according to the
embodiment of the present invention performs distributed
transmission at the localized transmission level. The
transmission device 100 may be incorporated in, for
example, a base station. Namely, a resource block used
for the localized transmission is divided into plural
parts and the thus-divided resource blocks (divided
resource blocks) are allocated to a user who uses
distributed transmission.
As shown in FIG. 4, the transmission device
100 includes a resource block (RB) allocation ratio
switching section 102, a frequency scheduling section
104, a control information generating section 106, a
transmission data generating section 112, coding
rate/data modulation determining sections 108 and 114,
and mapping sections 110 and 116. The resource block
(RB) allocation ratio switching section 102 inputs
information indicating the mobility of each mobile
station (UE) and information indicating traffic of the
mobile stations such as size and type of transmission
data. The frequency scheduling section 104 inputs
propagation path information of each mobile station such
as the status of the downlink propagation path, the
priority information of the mobile station, and the
output signal from the resource block allocation ratio
switching section 102. The output signal from the
frequency scheduling section 104 is input to the control
information generating section 106 and the transmission
data generating section 112. The output signal from the
control information generating section 106 is input to
the coding rate/data modulation determining section 108,

and the output signal from the transmission data
generating section 112 is input to the coding rate/data
modulation determining section 114. The mapping section
110 inputs the output signal from the coding rate/data
modulation determining section 108 and outputs control
information. The mapping section 116 inputs the output
signal from the coding rate/data modulation determining
section 114 and data and outputs data.
The resource block allocation ratio switching
section 102 determines mobile stations to perform
localized transmission and mobile stations to perform
the distributed transmission based on the information
indicating the mobility of each mobile station (UE), the
information indicating traffic, and the like. The
resource block allocation ratio switching section 102
further determines a ratio between the resource blocks
to be allocated to the mobile stations that perform
localized transmission and the resource blocks to be
allocated to the mobile stations that perform
distributed transmission, and inputs the determined
value of the ratio to the frequency scheduling section
104 as resource block allocation ratio information.
The resource block allocation ratio switching
section 102 determines that, for example, a mobile
station having high mobility and a mobile station
transmitting traffic having small data size such as VoIP
are the mobile stations which are to perform distributed
transmission. Further, upon determining the allocation
ratio of the resource blocks, the resource block
allocation ratio switching section 102 increases the
rate of resource blocks allocated to perform distributed
transmission when, for example, there are many mobile
stations having high mobility or there are many mobile

stations that transmit traffic data having a small data
size such as in VoIP.
The frequency scheduling section 104 allocates
resource blocks to each mobile station based on the
input information indicating the propagation path of the
mobile stations, priority information indicating
priority of the mobile stations, and the resource block
allocation ratio information. Herein, the priority
information refers to digitized information with respect
to each mobile station by considering the items such as
whether a retransmission request is included, an elapsed
time after packets are transmitted from a transmission
terminal, a target transmission rate, actual throughput,
and an allowable delay in the packet transmission.
For example, the frequency scheduling section
104 adaptively switches the allocation ratio between the
resource blocks which are to perform localized
transmission and the resource blocks which are to
perform distributed transmission at every predetermined
cycle such as at every cycle of scheduling based on the
status of each mobile station such as a channel status
and the resource block allocation ratio information
determined in accordance with the traffic. By doing
this, the throughput of a data channel may be increased.
Further, the frequency scheduling section 104 may
switch the allocation ratio between the resource blocks
which are to perform localized transmission and the
resource blocks which are to perform distributed
transmission at a longer period based on the status of
each mobile station such as the resource block
allocation ratio information determined in accordance
with the traffic. By doing this, the control may be
performed more easily compared with the case where the

switching is performed at every cycle of scheduling.
For example, as shown in FIG. 4, the frequency
scheduling section 104 allocates the data to be
transmitted in localized transmission and the data to be
transmitted in distributed transmission by using the
resource block as an allocation unit. Namely, the
frequency scheduling section 104 allocates distributed-
type resource blocks having discretely-distributed
frequency subcarriers in a system bandwidth to each user
by using the resource blocks that are blocks of
consecutive frequency subcarriers divided from the
system bandwidth as an allocation unit. By doing this,
it becomes possible to eliminate the use of signaling
information that is necessary when distributed
transmission is to be performed.
Further, when distributed transmission is to
be performed at the resource block level, the frequency
scheduling section 104 divides one resource block into
plural parts, for example, "N" divided parts (where N is
an integer number greater than 0). Namely, the
frequency scheduling section 104 allocates the
distributed-type resource blocks as the resource block
with respect to a user who uses distributed transmission.
Herein, the resource block may also be regarded as a
unit for mapping users or, for example, a unit for
allocating a certain user.
For example, as shown in FIG. 5A, the
frequency scheduling section 104 divides one resource
block into plural parts such as two parts in the time
direction and allocates the resource block with respect
to users who use distributed transmission to the mobile
stations that perform distributed transmission such as
two users. As shown in FIG. 5A, the frequency

scheduling section 104 allocates first blocks and second
blocks to different users.
Further, for example, as shown in FIG. 5B, the
frequency scheduling section 104 may divide one resource
block into plural parts such as two parts in the
frequency direction and allocate the resource blocks
with respect to users who use distributed transmission
to the mobile stations that perform distributed
transmission such as two users. For example, as shown
in FIG. 5B, the frequency scheduling section 104
allocates first blocks and second blocks to different
users.
In FIGS. 5A and 5B, the first two symbols
represent pilot and signaling bits, i.e., a pilot
channel and an L1/L2 control channel.
In distributed transmission at the resource
block level, a frequency diversity effect cannot be
obtained unless plural resource blocks, namely plural
distributed-type resource blocks, with respect to a user
who uses distributed transmission are allocated.
Because of this feature, in such a case of traffic data
whose size is small such as VoIP, all data may be
included into one resource block and the frequency
diversity effect cannot be obtained. In a case of VoIP,
the data size of one packet is, for example, 180 bits.
As described above, by dividing a resource
block into N parts, it becomes possible to allocate the
packet data that can otherwise be included in a single
resource block to N distributed-type resource blocks,
thereby increasing the frequency diversity effect.
The control information generating section 106
generates control information with respect to the mobile
stations to which the resource blocks are allocated by

the frequency scheduling section 104.
The coding rate/data modulation determining
section 108 determines a coding rate and a data
modulation value that are used when the control
information is transmitted.
The mapping section 110 performs the data
modulation and coding that are determined by the coding
rate/data modulation determining section 108 and
performs mapping on a physical channel. As a result,
the control information is transmitted.
The transmission data generating section 112
generates transmission data in accordance with the
number of resource blocks allocated to each mobile
station. For example, the transmission data generating
section 112 determines the amount of transmission data.
The coding rate/data modulation determining
section 114 determines a coding rate and a data
modulation value with respect to the data of each mobile
station allocated by the frequency scheduling section
104 and the control information.
The mapping section 116 performs the data
modulation, coding, and mapping on a physical channel.
Next, a specific example of the operations of
the above-mentioned frequency scheduling section 104 is
described in detail.
As described above, when the system bandwidth
is divided into plural parts, each of the divided
bandwidths is called a resource block. In this
embodiment of the present invention, the number of
resource blocks obtained by dividing an allocated
bandwidth is defined as "NPRB" (where NPRB is an integer
number greater than 1). The identification codes such
as identification numbers are allocated to the resource

blocks to identify the resource blocks. In this
embodiment of the present invention, for example, a case
is described where the allocated bandwidth is divided
into 48 parts (NPRB=48) and in the 48 resource blocks,
consecutive three (3) resource blocks are grouped (first
group) and the same identification number is allocated
to those grouped resource blocks. However, this
embodiment of the present invention may be applied to
cases where the division number is lower than 48 and
greater than 48. Further, the above number of resource
blocks belonging to the first group is merely an example,
and the embodiment of the present invention may be
applied to cases where the number is less than 3 and the
number is greater than 3.
For example, as shown in FIG. 6, when one
resource block includes 12 subcarriers (180 kHz), the
first group has 36 subcarriers (540 kHz).
Further, there are provided other groups as
plural second groups each including one or more resource
blocks from each first group. For example, from among
three consecutive resource blocks in each first group,
resource blocks located at the same location in the
first groups are grouped, so that second, third, and
fourth groups are provided.
The resource blocks are allocated to users who
use localized transmission by regarding each of the
first, the second, the third, and the fourth groups as a
unit.
In this case, a base station having a
transmitter performs downlink frequency scheduling. A
mobile station announces the channel status used for the
frequency scheduling to the base station. Then, the
channel status is announced by using the first group as

a unit. The total bandwidth of the resource blocks
constituting the first group is substantially equal to
the bandwidth used as a measurement unit for receiving
channel status. Namely, the mobile station averages the
channel status of the resource channels included in the
first group (three resource blocks in this embodiment)
and announces the averaged result as the channel status
of the first group. By doing this, the frequency
scheduling may be applied to the allocation of resource
blocks of the second through the fourth groups as well
while neither measuring at a higher resolution than is
necessary nor performing feedback is necessary. Namely,
it is not necessary to measure data of the receiving
channel in each group nor to perform feedback.
To a user who transmits data having small data
size, the allocation is performed by using the second
through the fourth groups as a unit. When the
allocation is performed by using the second though the
fourth groups as a unit, the channel status announced
from the mobile station has the same value; therefore,
the allocation is performed based on another condition.
On the other hand, for a user who transmits data having
large data size, the allocation is performed by using
the first group as a unit.
To a user who uses distributed transmission,
in accordance with the division number of the resource
blocks, the distributed-type resource blocks are
allocated using the resource blocks as a unit. Namely,
by using the above-mentioned plural resource blocks of
the other groups as the second groups, the distributed-
type resource blocks including discretely-distributed
frequency subcarriers in the system bandwidth are
generated. In this case, from among three consecutive

resource blocks in the first group, the same number of
the distributed-type resource blocks as the division
number located at the same locations in the first group
are called fifth through seventh groups. For example,
when the division number is 2, as shown in FIG. 7, two
(2) distributed-type resource blocks are in each of the
fifth through the seventh groups.
Next, the allocation of the resource blocks to
a mobile station that performs the above-mentioned
localized transmission and the allocation of the
resource blocks to a mobile station that performs
distributed transmission are described.
The RB allocation ratio switching section 102
determines a necessary number of resource blocks to be
used for distributed transmission based on the rate of
the mobile stations that perform distributed
transmission and traffic amount. Here, the rate of the
mobile stations that perform distributed transmission
refers to, for example, a ratio of the data size of the
mobile station that performs localized transmission to
the data size of the mobile station that performs
distributed transmission. FIG. 8 shows a case where six
(6) resource blocks that are to perform distributed
transmission are generated. Namely, the number of
distributed-type resource blocks that are to perform
distributed transmission is six (6) because the
allocation is performed by using the resource block as a
unit.
Next, the frequency scheduling section 104
allocates resource blocks used for localized
transmission to the mobile station. In this case, the
resource blocks other than the resource blocks that have
been determined to be the resource blocks used for

distributed transmission are allocated.
As described above, the mobile station
announces the channel status by using the first group as
a unit. The frequency scheduling section 104 allocates
the resource blocks to each mobile station that performs
localized transmission as described below.
FIG. 9 shows an example where the resource
blocks are allocated to the mobile stations that perform
localized transmission.
The frequency scheduling section 104 allocates
the resource blocks to the mobile stations that perform
localized transmission based on the channel status such
as Channel Quality Indicator (CQI) announced from each
mobile station.
The frequency scheduling section 104
classifies the mobile stations that perform localized
transmission into the mobile stations that transmit
larger size data and the mobile stations that transmit
smaller size data. For example, the frequency
scheduling section 104 sets a threshold value of the
data size and classifies the mobile stations based on
the threshold value.
Next, by using the channel status announced
from the mobile stations, the average of the channel
status announced from the mobile stations that transmit
smaller size data is obtained with respect to each first
group. Here, the number of mobile stations is
predetermined, the number being used for obtaining the
average of the channel status. For example, the number
is the same as the number of resource blocks grouped as
the first group.
Next, in the first group, when the channel
status of the mobile station that transmits larger size

data is greater than the average of the channel status
of the mobile stations that transmit smaller size data,
the first group is allocated to the mobile station that
transmits larger size data. Here, the mobile station
that transmits larger size data refers to the mobile
station having the best channel status among the mobile
stations that request the transmission of larger size
data. On the other hand, the mobile stations that
transmit smaller size data refer to the above-mentioned
predetermined number of mobile stations that request the
transmission of smaller size data.
Further, when the channel status of the mobile
station that transmits larger size data is less than the
average of the channel status of the mobile stations
that transmit smaller size data, the first group is
divided into plural resource blocks and the divided
resource blocks are allocated to the mobile stations
that transmit smaller size data. For example, when the
number of the mobile stations used for obtaining the
average of channel status is the same as the number of
resource blocks to be grouped as the first group, each
of the resource blocks is allocated to one of the mobile
stations. In this embodiment of the present invention,
if the number of the mobile stations to be averaged is
three (3), those mobile stations can be allocated to
three (3) resource blocks constituting the first group.
For example, the resource block having 540 kHz bandwidth
is divided into three (3) resource blocks having 180 kHz
bandwidth and the divided resource blocks are allocated
to the mobile stations that transmit smaller size data.
Next, the control information generated by
control information generating section 106 is described
with reference to FIG. 10A.

As shown in FIG. 10A, the control information
with respect to the mobile stations includes each field
for an ID (UE-ID) of an allocated mobile station, a
transmission type indicating which of localized
transmission or distributed transmission is to be
performed, and allocation information with respect to
the groups of resource blocks. For the allocation
information with respect to the groups of the resource
blocks, sixteen (16) sub-fields corresponding to the
number of the first, the second, the third, and the
fourth groups are provided in this example..
For example, in a case where zero (0)
indicating localized transmission is assigned as the
transmission type and the information indicating the
first, the second, the third, or the fourth group is
assigned as the group information of the resource blocks,
each sub-field of the allocation information in a group
of resource blocks indicates the corresponding first,
second, third, or fourth group, and the information
indicating whether allocated or non-allocated in each of
the first, the second, the third, or the fourth group is
assigned; for example, one (1) is assigned when
allocated and zero (0) is assigned when not allocated.
Further, for example, in a case where one (1)
indicating distributed transmission is assigned as the
transmission type and the information indicating the
fifth, sixth, or seventh group is assigned as the group
information of the resource blocks, each sub-field of
the allocation information in groups of the resource
blocks indicates the location where the fifth, sixth,
and seventh group, respectively, is allocated, and the
information indicating whether allocated or non-
allocated in the fifth, the sixth, or the seventh group

is assigned; for example, one (1) is assigned when
allocated and zero (0) is assigned when not allocated.
Next, the control information generated by the
control information generating section 106 is described
with reference to FIG. 10B. Here, the control
information is described when plural groups are
allocated.
As shown in FIG. 10B, the control information
with respect to the mobile stations includes each field
for an ID (UE-ID) of an allocated mobile station, a
transmission type indicating which of localized
transmission or distributed transmission is to be
performed, the allocation information of the resource
blocks in a prescribed group, the information indicating
the group of the resource blocks, and the allocation
information in the group assigned in the information
indicating the group of the resource blocks. For the
allocation information of the resource blocks in the
prescribed group and the allocation information in the
group assigned in the information indicating the group
of the resource blocks, sixteen (16) sub-fields
corresponding to the number of the first, the second,
the third, and the fourth groups are provided.
For example, in a case where zero (0)
indicating localized transmission is assigned as the
transmission type and the information indicating the
first, the second, the third, or the fourth group is
assigned as the group information of the resource blocks,
each sub-field of the allocation information in the
group assigned in the information indicating the group
of the resource blocks indicates the first, the second,
the third, or the fourth group, and the information
indicating whether allocated or non-allocated in the

first, the second, the third, or the fourth group is
assigned; for example, one (1) is assigned when
allocated and zero (0) is assigned when not allocated.
Further, to each sub-field of the allocation information
of the resource blocks in a prescribed group, the
information indicating whether allocated or non-
allocated in a group other than the group assigned by,
for example, the group information of resource blocks is
assigned; for example, one (1) is assigned when
allocated and zero (0) is assigned when not allocated.
Further, for example, in a case where one (1)
indicating distributed transmission is assigned as the
transmission type and the information indicating the
second, the third, or the fourth group is assigned as
the group information of the resource blocks, each sub-
field of the allocation information in groups of the
resource blocks indicates the allocated location of the
fifth, the sixth, and the seventh group that are the
groups of the distributed-type resource blocks generated
from the second, the third, and the fourth groups,
respectively, and the information indicating whether
allocated or non-allocated in the fifth, the sixth, and
the seventh groups is assigned; for example, one (1) is
assigned when allocated and zero (0) is assigned when
not allocated. Further, to each sub-field of the
allocation information of the resource blocks in a
prescribed group, the information indicating whether
allocated or non-allocated in a group which is, for
example, other than the group assigned by the group
information of resource blocks is assigned; for example,
one (1) is assigned when allocated and zero (0) is
assigned when not allocated.
Next, other control information generated by

the control information generating section 106 is
described with reference to FIGS. 11 and 12.
As shown in FIG. 11, the control information
with respect to the mobile stations includes each field
for an ID (UE-ID) of an allocated mobile station, a
transmission type indicating which of localized
transmission or distributed transmission is to be
performed, the allocation information in the resource
blocks of the first group, and the allocation
information in the first group.
As shown in FIG. 12, to the allocation
information in the resource blocks of the first group,
the allocation information of the resource blocks
constituting the first group is assigned. For example,
in response to the allocation information in the
resource blocks of the first group, the combination of
the resource blocks to be allocated is predetermined.
To the allocation information in the first
group, the information indicating whether allocated or
non-allocated is assigned by using the first group as a
unit; for example, one (1) is assigned when allocated
and zero (0) is assigned when not allocated.
According to an embodiment of the present
invention, the consecutive plural resource blocks
constitute the first group; the resource blocks located
at the same location of the plural resource blocks in
the first group constitute the second groups; and either
the first group or one or more of the second groups can
be allocated. Further, by assigning the identification
numbers indicating the groups of the resource blocks,
the allocation with respect to each group may be
assigned. Therefore, even when the number of the
resource blocks is increased, it becomes possible to

minimize the increase of the signaling bits announcing
the allocation of the resource blocks to a user.
In the above description, the present
invention is described by being divided into several
embodiments. However, it should be noted that the
division of the present invention into several
embodiments is not an essential element of the present
invention. For example, two or more embodiment may be
combined on as as-needed basis. To promote an
understanding of the present invention, specific values
are used as examples throughout the description.
However, it should be noted that such specific values
are just sample values unless otherwise described, and
any other values may be used.
The present invention is described by
referring to a specific embodiment. However, a person
skilled in the art may understand that the above
embodiment is described for illustrative purposes only
and may think of examples of various modifications,
transformations, alterations, changes, and the like.
For illustrative purposes, the apparatus according to an
embodiment of the present invention is described with
reference to the functional block diagrams. However,
such an apparatus may be provided by hardware, software,
or a combination thereof. The present invention is not
limited to the embodiment described above, and various
modifications, transformations, alteration, exchanges,
and the like may be made without departing from the
scope and spirit from the present invention.
The present application is based on and claims
the benefit of priority of Japanese Patent Application
No.2006-225915, filed on August 22, 2006, the entire
contents of which are hereby incorporated herein by

reference.
INDUSTRIAL APPLICABILITY
The transmission device according to an
embodiment of the present invention may be used in a
wireless communications system.

CLAIMS
1. A transmission device, comprising:
a frequency scheduling unit configured to
allocate resource blocks as a unit to each user,
the resource blocks being blocks of consecutive
frequency subcarriers divided from a system bandwidth,
constitute a first group including consecutive
plural resource blocks,
constitute plural second groups, each including one
or more resource blocks of the plural resource blocks
constituting the first group, and
allocate the resource blocks of either the first
group or one or more the second groups;
a mapping unit configured to allocate
transmission data to the resource blocks in accordance
with the allocation; and
a control information generating unit
configured to generate control information with respect
to a mobile station to which either the first group or
one or more of the second groups are allocated.
2. The transmission device according to claim
1, further comprising:
a distributed-type resource block generating
unit configured to generate distributed-type resource
blocks including discretely-distributed frequency
subcarriers in the system bandwidth by using the plural
resource blocks of the second groups.

3. The transmission device according to claim
1, wherein
a total bandwidth of the resource blocks
constituting the first group is substantially equal to a
bandwidth used as a measurement unit of a receiving
channel status.
4. The transmission device according to claim
1, wherein
the frequency scheduling unit is configured to
allocate either the first group or one or more of the
second groups based on a channel status measured in the
first group from the mobile station.
5. The transmission device according to claim
4, wherein
the frequency scheduling unit is configured to
allocate either the first group or one or more of the
second groups to the mobile station based on a size of
data to be transmitted by the mobile station.
6. The transmission device according to claim
5, wherein
the frequency scheduling unit is configured to
compare the channel status of the mobile station
having the best channel status among plural of the
mobile stations having the data size to be transmitted
in the first group equal to or greater than a
predetermined threshold value with an average of the
channel status of a predetermined number of the mobile

stations among the mobile stations having the data size
to be transmitted less than the predetermined threshold
value, and
allocate, when the channel status of the mobile
station having the best channel status is greater, the
first group to the mobile station having the best
channel status.
7. The transmission device according to claim
6, wherein
the frequency scheduling unit is configured to
compare the channel status of the mobile station
having the best channel status among the mobile stations
having the data size to be transmitted in the first
group equal to or greater than the predetermined
threshold value with an average of the channel status of
the predetermined number of mobile stations among the
mobile stations having the data size to be transmitted
less than the predetermined threshold value, and
allocate, when the channel status of the mobile
station having the best channel status is lower, the
resource blocks constituting the first group to the
predetermined number of the mobile stations.
8. The transmission device according to claim
1, wherein
the control information generating unit is
configured to generate the control information including
an ID of the mobile station, information indicating the
resource blocks or the distributed-type resource blocks
allocated to the mobile station, information indicating

the group of the resource blocks, and allocation
information in the group of the resource blocks.

Provided is a transmission device for allocating a resource block or a distributed resource block includes: means
for constituting a first group by a plurality of continuous resource blocks and a second group by one or more resource blocks contained
in the plurality of resource blocks constituting the first group and allocating the first group or the second group: means for
allocating transmission data to the frequency block or the distributed frequency block in accordance with the allocation; and means
for generating control information for a mobile station for which one of the first group and the second group has been allocated.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=S2jJ/1s6c0Wad6NaMyyX+w==&loc=wDBSZCsAt7zoiVrqcFJsRw==

« Previous Patent

Next Patent »

Patent Number

279417

Indian Patent Application Number

624/KOLNP/2009

PG Journal Number

04/2017

Publication Date

27-Jan-2017

Grant Date

20-Jan-2017

Date of Filing

17-Feb-2009

Name of Patentee

NTT DOCOMO, INC.

Applicant Address

11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO

Inventors:

#	Inventor's Name	Inventor's Address
1	NAGATA, SATOSHI	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC., SANNO PARK TOWER, 11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO 1006150
2	HIGUCHI, KENICHI	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC., SANNO PARK TOWER, 11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO 1006150
3	SAWAHASHI, MAMORU	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC., SANNO PARK TOWER, 11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO 1006150
4	OFUJI, YOSHIAKI	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC., SANNO PARK TOWER, 11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO 1006150

PCT International Classification Number

H04J 11/00,H04Q 7/36

PCT International Application Number

PCT/JP2007/065819

PCT International Filing date

2007-08-13

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2006-225915	2006-08-22	Japan