Title of Invention	WIRELESS COMMUNICATIONDEVICE AND WIRELESS COMMUNICATION METHOD
Abstract	In a wireless communication system, a downstream frequency band includes a plurality of frequency blocks including one or more carrier frequencies, and one or more frequency blocks are used for data transmission to one user. A wireless communication device used in the wireless communication system is provided with a means for measuring a reception signal quality for each frequency block and storing a plurality of reception signal qualities, a means for comparing the reception signal qualities, and a means for transmitting a prescribed number of reception signal qualities by a control channel of an upstream link.

Title of Invention

WIRELESS COMMUNICATIONDEVICE AND WIRELESS COMMUNICATION METHOD

Abstract

In a wireless communication system, a downstream frequency band includes a plurality of frequency blocks including one or more carrier frequencies, and one or more frequency blocks are used for data transmission to one user. A wireless communication device used in the wireless communication system is provided with a means for measuring a reception signal quality for each frequency block and storing a plurality of reception signal qualities, a means for comparing the reception signal qualities, and a means for transmitting a prescribed number of reception signal qualities by a control channel of an upstream link.

Full Text	DESCRIPTION WIRELESS COMMUNICATIONDEVICE AND WIRELESS COMMUNICATION METHOD TECHNICAL FIELD The present invention relates to the technical field of radio communication, and more specifically relates to a radio communication apparatus and a method foruse in a communication system where packet scheduling is carried out on the downlink. BACKGROUND ART In the third generation communication scheme, typically such as IMT-2000 (International Mobile Telecommunications-2000), in particular, a faster and higher-capacity downlink is sought, and for example, the information transmission rate of higher than or equal to 2 Mbps is achieved by using the frequency band of 5 MHz. IMT-2000 adopts the single carrier Wideband-Code Division Multiple Access (W-CDMA) scheme. Alternately, some scheme called High Speed Downlink Packet Access (HSDPA) may be employed. In HSDPA, the Adaptive Modulation and channel Coding (AMC) scheme, MAC layer packet Automatic Repeat Request (ARQ) scheme, fast packet scheduling and others are employed to achieve higher transmission rates and higher quality. For example, AMC is described in non-patent document 1. ARQ is described in non-patent document 2 . FIG. 1 is a schematic view for explaining the AMC scheme. Assuming that transmission power from a base station is fixed, in general, a terminal 11 closer to a base station 10 can receive signals with greater power than a terminal 12 far from the base station 10. Hence, since it is estimated that the terminal 11 has a better 1 channel state, a greater modulation level and a higher coding rate are adopted. On the other hand, the terminal 12 receives signals with less power than the terminal 11. Thus, since it is estimated that the terminal 12 does not have a good channel state, a smaller modulation level and a lower coding rate are adopted. FIG. 2 shows an exemplary combination of different modulation schemes (modulation level) and different channel coding rates. In the illustrated table, the rightmost column represents relative bit rates in the case of the bit rate being "l" under the modulation scheme M of "QPSK" and the channel coding rate R of "1/3". For example, if M="QPSK" and R="l/2", the bit rate of X1.5 is obtained. In general, there is tendency that the higher bit rate is, the less reliability is. More specifically, combinations between different modulation schemes and the coding rates and different amounts indicative of channel states are predefined in a listing table, and the modulation schemes and others are changed depending on the channel state if needed. The amount indicative of the channel state is managed as Channel Quality Indicator (CQI), which is typically SIR (Signal to Interference power Ratio) and SINR of a received signal. FIG. 3 is a schematic view for explaining the ARQ (more accurately, hybrid ARQ) . The hybrid ARQ scheme is a technique derived from a combination of the ARQ scheme of requesting retransmission of packets depending on results of error detection (CRC: Cyclic Redundancy Check) and some error correction coding scheme (also referred to as channel coding) for error correction. As illustrated, a CRC bit is added to a transmission data sequence S1), and the resulting signal is sent after completion of error correction encoding (S2). In 2 response to receipt of the signal, error correction decoding (also referred to as "channel decoding") is carried out (S3) , and error detection is carried out (S4) . If some error is detected, retransmission of the packet is requested to the transmitting side (S5). As illustrated in FIG. 4, there are several methods for such retransmission. In an exemplary method illustrated in FIG. 4A, packet P1 is sent from the transmitting side to the receiving side. If some error is detected at the receiving side, the packet P1 is discarded and then the retransmission is requested. In response to the retransmission request, the transmitting side resends the same packet (represented as "P2") as the packet P1. In an exemplary method illustrated in FIG. 4 B, packet P1 is sent from the transmitting side to the receiving side. If some error is detected at the receiving side, the receiving side keeps the packet P1 without discarding it. In response to the retransmission request, the transmitting side resends the same packet (represented as "P2") as the packet P1. Then, the receiving side generates packet P3 by combining the previously received packet with the currently received packet. Since the packet P3 corresponds to one transmitted with double the power of packet P1, the demodulation accuracy is improved. Also in an exemplary method illustrated in FIG. 4C, packet P1 is sent from the transmitting side to the receiving side. If some error is detected at the receiving side, the receiving side keeps the packet P1 without discarding it. In response to the retransmission request, the transmitting side sends redundancy data derived by performing certain operations on the packet P1 as packet P2 . For example, assume that 3 a sequence of packets such as "P1, P1', P1", ..." has been derived by encoding the packet P1. The derived sequence may differ depending on adopted coding algorithms. In the illustrated example, in response to receipt of a retransmission request, the transmitting side sends P1' as packet P2. The receiving side generates packet P3 by combining the previously received packet with the currently received packet. Since the packet P3 has increased redundancy, the demodulation accuracy will be improved. For example, assuming that the coding rate of the packet P1 is equal to "1/2", the coding rate of the packet P3 becomes equal to "1/4", thereby resulting in improved reliability. Note that the receiving side must already know some information as to what coding algorithm is adopted, what redundancy data are sent (also referred to as "puncture pattern"), and others. Fast packet scheduling scheme is a technique intended to improve frequency utilization efficiency in downlink. In a mobile communication environment, the channel state between a mobile station (user) and a base station varies over time as illustrated in FIG. 5. In this case, even though transmission of a large amount of data to a user with poor channel state is attempted, it is hard to improve the throughput. On the other hand, the higher throughput would be achieved for a user with a good channel state. From such a viewpoint, it is possible to improve the frequency utilization efficiency by determining whether the channel state is good for each user and assigning a shared data packet in favor of the user with the better channel state. FIG. 5 is a schematic diagram for explaining the fast packet scheduling scheme. As illustrated, a shared data packet is assigned to a user with the better channel state (a user associated with greater SINR) in each time 4 slot. Non-patent document 1: T.Ue, S.Aampei, N.Morinaga and K.Hamaguchi, "Symbol Rate and Modulation Level-Controlled Adaptive Modulation/TDMA/TDD System for High-Bit-Rate Wireless Data Transmission", IEEE Trans.VT, pp. 1134-1147, vol. 47, No. 4, Nov. 1998 Non-patent document 2: S.Lin, Costello, Jr.and M.Miller, "Automatic-Repeat-Request Error Control Schemes", IEEE Communication Magazine, vol. 12, No. 12, pp. 5-17, Dec. 1984 DISCLOSURE OF INVENTION [OBJECT TO BE SOLVED BY THE INVENTION] In this technical field, there is a strong need of improved speed and capacity of radio transmission, and in a future communication system, further improved efficiency of radio transmission and further utilization efficiency of a frequency band are desired. One object of the present invention is to provide a radio communication apparatus and a method for use in a communication system where a shared data packet is assigned for a user with a better channel state by priority for further improvement of frequency utilization efficiency. [MEANS FOR SOLVING THE OBJECT] In an embodiment of the present invention, there is provided a radio communication apparatus for use in a communication system where a downlink frequency band includes a plurality of frequency blocks including one or more carrier frequencies and one or more frequency blocks are used for data transmission to a single user. The apparatus includes an evaluation unit evaluating quality of a received signal for each frequency block 5 and storing a plurality of quality evaluations of the received signal, a comparison unit comparing the plurality of quality evaluations of the received signal, and a transmission unit transmitting a predetermined number of quality evaluations of the received signal over an uplink control channel. [ADVANTAGE OF THE INVENTION] According to the embodiment of the present invention, higher frequency utilization efficiency is achieved in a communication system where a shared data packet is assigned for a user with a better channel state by priority. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view for explaining the AMC scheme; FIG. 2 is a diagram illustrating an exemplary combination between modulation schemes and channel coding rates; FIG. 3 is a schematic view for explaining the hybrid ARQ scheme; FIG. 4 is a diagram illustrating an example of retransmission schemes; FIG. 5 is a diagram illustrating quality of receiving varying over time; FIG. 6 is a diagram illustrating an exemplary receiving station in a mobile communication system according to one embodiment; FIG. 7 is a diagram illustrating a transmitting station in a mobile communication system according to one embodiment; FIG. 8 is a diagram illustrating an exemplary method of assigning frequency blocks; 6 FIG. 9 shows an exemplary feedback data generation unit for use in one embodiment; FIG. 10 is a diagram for explaining an exemplary operation according to one embodiment of the present invention; FIG. 11 is a diagram for explaining another exemplary operation according to one embodiment of the present invention; FIG. 12 is a diagram for explaining another exemplary operation according to one embodiment of the present invention; and FIG. 13 is a diagram illustrating an exemplary comparison of amounts of data transmission. LIST OF REFERENCE SYMBOLS 10 : base station 11, 12: terminal 100: transmitting station 100-1: RF receipt circuit 100-2: demodulation and decoding unit 100-3: scheduler 100-4: header information acquisition unit 100-5: packet selection unit 100-6: buffer management unit 100-7: PDU generation unit 100-8: transmission buffer 100-9: selector 100-10: encoding and modulation unit 100-11: RF transmission circuit 200: receiving station 200-1: RF receipt circuit 200-2: subcarrier signal separation unit 200-3: channel estimation unit 200-4: receiving channel state evaluation unit 7 200-5: feedback data generation unit 200-6: encoding and modulation unit 200-7: RF transmission circuit 200-8: demodulation unit 200-9: decoding unit 200-10: parallel to serial conversion unit 200-11: IP packet recovery unit 902: receiving channel state comparison unit 903: reported content determination part 906: control signal generation unit BEST MODE FOR CARRYING OUT THE INVENTION According to one implementation of the present invention, in a communication system where the frequency band of the downlink includes a plurality of frequency blocks including one or more carrier frequencies and one and more frequency blocks are used for data transmission to a single user, the quality of a received signal is evaluated for each frequency block, and the quality evaluations are compared. Then, a predetermined number of quality evaluations of the received signal are sent over a control channel on the uplink. Thus, since only the predetermined number of quality evaluations of the received signal less than the total number of frequency blocks are reported, it is possible to provide feedback on the channel state with a lesser amount of data transmission efficiently. The predetermined number of quality evaluations of a received signal may be obtained through selection of a predetermined number of top ones among a plurality of stored quality evaluations of the received signal. The predetermined number of quality evaluations of a received signal may be quality evaluations of a received signal for one or more frequency blocks reported over a control 8 channel on the downlink. One or more of the predetermined number of received signal quality evaluations may be represented as differences between a reference value and them. Since the differences can be represented in a number of bits smaller than the reference value, it is possible to reduce the number of bits for use in the control channel. The reference value may be an average of received signal quality evaluations throughout the frequency band in the downlink. Also, only differences above a threshold may be provided as feedback. Consequently, it is possible to reduce the number of received signal quality evaluations to be reported. Received signal quality evaluations transmitted over the uplink control channel may be sent in chronological order and in the form of the difference between a current evaluation and the previously transmitted evaluation. Since the difference tends to be a smaller value, it is possible to further reduce the number of bits for use in the control channel. The transmission repetition of the predetermined number of received signal quality evaluations over the uplink control channel may be adjusted depending on Doppler frequency derived from the received signal, delay spreads and other amounts indicative of the communication state . [First Embodiment] In the following embodiment, the case where the OFDM Orthogonal Frequency Division Multiplexing) scheme is adopted in the downlink is described. However, other schemes may be adopted. A broad frequency band in the downlink is divided into a plurality of frequency blocks. In general, although a single frequency block includes 9 one or more carrier frequencies, according to this embodiment, it is supposed that each frequency block includes a plurality of subcarriers. Note that such a frequency block may be referred to as a "chunk". FIG. 6 illustrates a receiving station 200 in a mobile communication system according to one embodiment of the present invention. Although such a receiving station is typically provided in a mobile terminal, it may be provided in some apparatus other than mobile terminals. The receiving station 200 includes an RF receipt circuit 200-1, a subcarrier signal separation unit 200-2 coupled with the RF receipt circuit 200-1, a channel estimation unit 200-3 coupled with the subcarrier signal separation unit 200-2, one or more receiving channel state evaluation units 200-4 coupled with the subcarrier signal separation unit 200-2 and the channel estimation unit 200-3, a feedback data generation unit 200-5 coupled with the one or more receiving channel state evaluation units 200-4, an encoding and modulation unit 200-6 coupled with the feedback data generation unit 200-5, an RF transmission circuit 200-7 coupled with the encoding and modulation unit 200-6, one or more demodulation units 200-8 coupled with the subcarrier signal separation unit 200-2, one or more decoding units 200-9 coupled with the respective one or more demodulation units 200-8, a parallel to serial conversion unit 200-10 coupled with the one or more decoding units 200-9, and an IP packet recovery unit 200-11 coupled with the parallel to serial conversion unit 200-10. In FIG. 6, a transmitted signal transmitted from a transmitting station (not illustrated) is received at the RF receipt circuit 200-1. The RF receipt circuit 200-1 supplies the received signal to the subcarrier signal separation unit 200-2. The subcarrier signal 10 separation unit 200-2 divides the received signal into signals per subcarrier, and supplies the respective signals to the demodulation units 200-8, the receiving channel state evaluation unit 200-4 and the channel estimation unit 200-3. Each demodulation unit 200-8 demodulates the supplied signals per subcarrier, and supplies the demodulated signals to the respective decoding units 200-9. The number of decoders is variable depending on the decoding algorithm in use (the coding unit used in the algorithm). Each decoding unit 200-9 decodes the supplied respective signal, and supplies the decoded signal to the parallel to serial conversion unit 200-10. The parallel to serial conversion unit 200-10 parallel-to-serial converts the incoming signal, and supplies the resulting signal to the IP packet recovery unit 200-11. The IP packet recovery unit 200-11 recovers the incoming signal. The channel estimation unit 200-3 uses a pilot symbol (pilot channel) for each subcarrier to perform channel estimation, and supplies such a channel estimation value to one or more receiving channel state evaluation units 200-4 for each subcarrier. Each receiving channel state evaluation unit 200-4 evaluates the receiving channel state (ex. SIR) based on the channel estimation and the received signal for each subcarrier, and supplies the evaluation to the feedback data generation unit 200-5. The feedback data generation unit 200-5 generates feedback data (control information) indicative of the receiving channel state of the frequency block based on the evaluation of the incoming receiving channel state, and supplies it to the encoding and demodulation unit 200-6. The SIR included in the feedback data may be SIR per subcarrier just as 11 it is, or may be some converted value such as an average of SIRs throughout a predetermined number of subcarriers included in a frequency block. The latter is why the SIR per frequency block is required in the transmitting side rather than the SIR per subcarrier. The encoding and modulation unit 200-6 encodes and modulates the incoming feedback data, and supplies the resulting signal to the RF transmission circuit 200-7. The RF transmission circuit 200-7 returns the feedback data as control information to the transmitting station 100. FIG. 7 illustrates a transmitting station 100 in a mobile communication system according to one embodiment of the present invention. The transmitting station 100 is typically provided in a base station. However, the transmitting station 100 may be provided in other apparatuses other than base stations. The transmitting station 100 includes an RF receipt circuit 100-1, a demodulation and decoding unit 100-2 coupled with the RF receipt circuit 100-1, a scheduler 100-3 coupled with the demodulation and decoding unit 100-2, a header information acquisition unit 100-4, a packet selection unit 100-5 coupled with the header information acquisition unit 100-4, a buffer management unit 100-6 coupled with the header information acquisition unit 100-4, the packet selection unit 100-5 and the scheduler 100-3, a PDU (Protocol Data Unit) generation unit 100-7 coupled with the packet selection unit 100-5, a transmission buffer 10 0-8 coupled with the PDU generation unit 100-7 and the buffer management unit 100-6, a selector 10 0-9 coupled with the transmission buffer 100-8 and the scheduler 100-3, one or more encoding and modulation units 100-10 coupled with the selector 100-9, and an RF transmission circuit 100-11 coupled with the encoding and modulation units 100-10. 12 As illustrated in the lower-right portion of FIG. 7, a control signal including control information from each receiving station 200 (FIG. 6) is received at the RF receipt circuit 100-1, and the received control signal is supplied to the demodulation and decoding unit 100-2. In the demodulation and decoding unit 100-2, some demodulation and decoding operations are performed on the control signal, and upstream control information of each receiving station (including channel state in the downlink for each frequency block) is reported to the scheduler 100-3. On the other hand, as illustrated in the upper-left portion of FIG. 7, upon receipt of an IP packet from a network, the header information acquisition unit 100-4 obtains packet header information such as a destination address from the received IP packet, reports the obtained packet header information to the buffer management unit 100-6, and supplies the IP packet to the packet selection unit 100-5. The buffer management unit 100-6 specifies a storage location of the packet data to the packet selection unit 100-5 based on the reported packet header information and the state of each queue reported from the transmission buffer 100-8. The buffer management unit 100-6 supplies the destination address and the memory address of a queue corresponding to the destination address to the transmission buffer 100-8. The buffer management unit 100-6 informs the scheduler 100-3 of the packet header information and the state of each queue reported from the transmission buffer 100-8. The packet selection unit 100-5 selects the incoming IP packet based on the storage location for the packet data specified by the buffer management unit 100-6, and supplies selected packets individually to the PDU 13 generation unit 100-7. The PDU generation unit 100-7 converts the incoming packets into PDUs, and supplies the resulting PDUs to the transmission buffer 100-8. The transmission buffer 100-8 configures a distinct queue for each destination address (each receiving station or each user) supplied from the incoming PDUs based on the destination address supplied from the buffer management unit 100-6 and the memory address of the corresponding queue, and informs the buffer management unit 100-6 of the state of each queue. The selector 100-9 extracts data from the queue specified by the scheduler 100-3, and supplies it to the encoding and modulation unit 100-10 associated with the specified frequency block. This frequency block is assigned by the scheduler 100-3. The scheduler 100-3 determines to which user the frequency block should be assigned by priority based on the upstream control information (the channel state per frequency block in the downlink) reported from each receiving station, the packet header information and the state of each queue. The encoding and modulation unit 100-10 performs encoding and modulation on the data supplied from the selector 100-9. The encoded and modulated data are sent to each receiving station by the RF transmission circuit 100-11. Based on the control information returned from the receiving station 200 as feedback, the scheduler 100-3 generates a ranking table where each user is ranked in accordance with the associated priority. The priority is derived for each frequency block based on the quality of the receiving channel state of each user. Then, scheduling is performed for each frequency block. For example, as illustrated in FIG. 8, the downlink frequency band is divided into three frequency blocks 1, 2 and 3. 14 These three frequency blocks are included in any of radio frames (time slots) . For each frame and each frequency block, a user with the best receiving channel state is selected, and then for the selected user, the shared data packet in the downlink is assigned to the frequency block in the frame. In the illustrated example, for the second radio frame from the left, the frequency block 1 is assigned to the user #2, the frequency block 2 is assigned to the user #1, and the frequency block 3 is assigned to the user #4. For the immediately successive radio frame, the frequency blocks 1 and 2 are assigned to the user #2, and the frequency block 3 is assigned to the user #3. On the other hand, in the case where frequency is scheduled in favor of a user with a good receiving channel state, there is a likelihood that more frequency blocks are assigned to some users whereas less frequency blocks are assigned to the other users. In order to maintain fair assignment among users, the number of frequency blocks assigned to a single user within one radio frame may be limited to be less than or equal to a predetermined value K (K is a certain natural number) . In other words, a user to which K frequency blocks are assigned may be deleted from the ranking table for unassigned frequency blocks, and then the unassigned frequency blocks may be assigned to other users. The priority for the frequency blocks may be determined based on the illustratively listed criteria as presented below. (1) Receiving channel state of each frequency block (2) Ratio between time average of the receiving channel states in each frequency block and the receiving channel state for each frequency block in the radio frame (3) Ratio between average the receiving channel 15 state over all subcarriers (included in the frequency block) and the receiving channel state of the target frequency block in the radio frame (4) Ratio between time average over averages of the receiving channel state over all subcarriers (included in the frequency block) and the receiving channel state of the target frequency block in the radio frame In case of the same priority based on the receiving channel state such as a reception SIR, the frequency block is assigned in favor of a user with a greater delay spread, and thereby the peak throughput is improved due to the frequency diversity effect. Alternatively, in case of the same priority based on the receiving channel state such as a reception SIR, the frequency block may be assigned to a user with a smaller delay spread by priority. For a user with a greater delay spread, another frequency block can be assigned to the user because of a small difference of the average receiving channel states between frequency blocks such as difference between the average reception SIRs. [Second Embodiment] As described in the first embodiment, improved frequency utilization efficiency is achieved by dividing the downlink frequency band into a plurality of frequency blocks and assigning one or more frequency blocks to a user with a better channel state by priority. In this case, the receiving channel state of each frequency block must be known to perform frequency scheduling. The receiving channel state may be SIRmeasured at a receiving station (typically a mobile terminal), for example, and may be reported to a transmitting station (typically a base station) over an uplink control channel transmitted from the receiving station. The transmitting station 16 must know the receiving channel state not only for each user but also for each frequency block. As a result, it is a concern that there is a significant increase in the information transmission amount in the control channel for preparing and scheduling a plurality of frequency blocks. In general, the information amount Rup (bit rate) required in an uplink control channel can be represented in the formula as follows; Rup= (Ks+AXNXKa) /T (1) , where Ks represents the number of users to which frequency blocks are actually assigned, A represents the number of bits required to represent SIR (in this embodiment, A=5) , N represents the total number of frequency blocks, Ka represents the number of users to which frequency blocks may be possibly assigned, and T represents the duration of a single packet, which may be referred to as TTI (Transmission Time Interval) . One bit is reserved to report the CRC result (ACK/NACK) of hybrid ARQ. In the above formula, the term "Ks/T" represents the information amount associated the CRC result from each user to which frequency blocks are actually assigned, and does not depend on the number N of frequency blocks. The term " (AXNXKA) /T" represents the information amount required to report SIR per frequency block to each user. For example, assuming that Ks=4, N=8, Ka=20 and T=0.5ms, it holds that Rup=1.61 Mbps. Alternatively, assuming that Ks=8, N=8, Ka=40 and T=0.5ms, it holds that Rup=3.22 Mbps. In this way, the greater the number of frequency blocks is, the significantly more is the information amount transmitted in the control channel. The second embodiment of the present invention is intended to overcome the above-mentioned problem. According to this 17 embodiment, in a communication system where the downlink frequency band is divided into a plurality of frequency blocks and one or more frequency blocks are used for a user with a better receiving channel state by priority, it is possible to provide a radio communication apparatus and method capable of efficiently reporting the channel state with less data transmission amount in the uplink control channel. FIG. 9 illustrates a feedback data generation unit for use in this embodiment. This feedback data generation unit may be used as a feedback data generation unit 200-5 of FIG. 6. The feedback data generation unit 200-5 includes a receiving channel state comparison unit 902, a reported content determination part 904 and a control signal generation unit 906. The receiving channel state comparison unit 902 receives an amount indicative of received channel state, which is SIR in this embodiment, from the receiving channel state evaluation unit 200-4. In case where the received SIR does not correspond to SIR per frequency block, an averaging operation or another suitable operation may be carried out. For example, suppose that SIR is measured for each 1000 subcarriers and a single frequency block includes 100 subcarriers. In this case, every 10 SIRs out of 100 SIRs obtained for each 100 subcarriers are averaged so that 10 SIRs associated with 10 frequency blocks can be derived. The SIRs per subcarrier and/or frequency block are stored in an appropriate memory. The receiving channel state comparison unit 902 compares the SIRs per frequency block with each other, and provides a comparison result. The reported content determination part 904 selects SIRs associated with a predetermined number of frequency blocks, and determines which SIR should be reported to 18 a base station. Such a predetermined number of frequency blocks may be determined as follows. (1) Among a plurality of SIRs stored in the memory, the top L SIRs indicative of better quality may be selected. For example, suppose that if SIR as illustrated in FIG. 10 is obtained the top three SIRs (L=3) are selected. In this case, the three SIRs associated with the frequency blocks "c", "e" and "f" are selected among the frequency blocks "a", "b", "c", "d", "e", "f" and "g". It may be determined in advance how many of the top SIRs should be reported. Also, the number may be changed depending on instruction from a base station. (2) Among a plurality of SIRs stored in the memory, SIRs associated with X frequency blocks specified from a base station may be selected. For example, SIR (receiving channel state) as illustrated in FIG. 10 is measured at a radio station, and assuming that downlink data toward the mobile station are transmitted in the frequency blocks "c" and "d". In this case, the base station may instruct the mobile station to report the two SIR associated with the frequency blocks "c" and "d", or may instruct the mobile station to report SIRs associated with other frequency blocks in addition to or instead of those of the frequency blocks "c" and "d". For example, SIRs associated with frequency blocks selected for every two frequency blocks may be reported among a plurality of frequency blocks located on the frequency axis. For example, if SIR as illustrated in FIG. 11 is measured, the three SIRs associated with the frequency blocks "a", "d" and "g" may be selected. (3) Among a plurality of SIRs stored in the memory, one or more SIRs above a predefined threshold may be selected. In other words, only SIRs associated with 19 frequency blocks with relatively better channel states may be reported to a base station among the stored SIRs. The control signal generation unit 906 of FIG. 9 generates a control signal including identification information (ID) of a frequency block selected in the report content determination unit 904 and SIR associated with the frequency block. In other words, the control signal includes a predetermined number of combinations of the IDs of and SIRs associated with the frequency blocks. Also, if any frequency block has been already assigned and downlink data have been received, the control signal also includes information indicative of an error detection result of that data. As stated above, the error detection result information may be represented in one bit to indicate affirmative acknowledge (ACK) or negative acknowledge (NACK). The control signal generated in this manner is provided to the encoding and modulation unit 200-6, where some appropriate operation is subsequently performed, and the feedback is provided to the base station. According to this embodiment, the SIRs to be reported to a base station are selected based on certain criteria, resulting in a decrease in the number of SIRs (the number of frequency blocks) to be reported. Thereby, it is possible to reduce the amount of information transmitted on the uplink control channel while maintaining information necessary to determine frequency blocks with better channel states for each user. [Third Embodiment] In the second embodiment, the number of SIRs (the number of frequency blocks) to be reported to a base station is reduced, but the number of bits to represent 20 SIRs may be reduced. For example, the absolute value of a SIR associated with a certain frequency block may be represented in five bits, and SIRs associated with the other frequency blocks may be represented in form of differences (relative values) between the SIRs and the absolute value. In general, since the difference can be represented in a number of bits smaller than five bits, the transmission amount can be reduced compared to the case of where all SIRs are represented in five bits. The SIR represented as the absolute value may be associated with an arbitrary frequency block. For example, the frequency block including the lowest carrier frequency or the frequency block including the highest carrier frequency may be represented in the form of the absolute value. Alternatively, instead of SIR associated with a frequency block, a predefined different value may be prepared, and each SIR may be represented in the the form of the difference between the SIR and the predefined value. As illustrated in FIG. 12, the average of SIRs over the entire band may be represented in the form of the absolute value, and the SIR associated with each frequency block may be represented in the form of the difference between the SIR and the average. Alternatively, SIR at a certain time point may be represented in the form of the absolute value, and subsequent SIRs may be represented as a temporal variations to the absolute value. Further, SIR at the current time point may be represented as temporal variation to SIR at the immediately previous time point. In general, since the amount of short term variation is smaller than that of long term variation, SIR can be represented with a reduced transmission amount in this manner. However, if an error is detected in a signal received at a mobile station, it is desirable to prevent 21 a chain of inaccurate values by reporting the absolute value and/or ignoring the temporal variation to the immediately previous SIR at the next time. According to this embodiment, SIR to be reported to a base station is represented as some value (relative value) such as the absolute value and/or difference. The reduction in the number of bits required to report SIR makes it possible to reduce the information amount transmitted in the uplink control channel while maintaining information necessary to determine a frequency block with a better channel state for each user. [Fourth Embodiment] In the second and the third embodiments, the data transmission amount required to provide a single feedback is reduced. On the other hand, the feedback may be infrequently provided. For example, the frequency of the feedback may be adjusted based on mobility of a receiving station. Since it is estimated that reception environment of a slow moving receiving station varies less, the frequency of feedback may be decreased. The mobility can be evaluated, for example, based on the maximum Doppler frequency, and the maximum Doppler frequency is small in case of slow movement. On the other hand, since it is estimated that the reception environment of a fast moving receiving station varies relatively more, the frequency of feedback may be increased. In general, since a receiving station more frequently moves at slow speed than fast speed, it is estimated that frequent feedback does not have to be supplied. In addition, the content or the frequency of feedback may be adjusted depending on the delay spread in the downlink. In general, the smaller the delay 22 spread is, the smaller is the channel variation in the frequency range. Thus, since the difference of SIRs between frequency blocks is small for a user with an observed small delay spread, the channel state may be evaluated based on the single average of SIRs over the entire band. Alternatively, the frequency of feedback may be decreased. In addition, only in the case where the level of SIR significantly varies compared to a previously reported SIR (only in the case where the variation amount exceeds a threshold) is the SIR sent to a base station. For example, if the temporal variation of SIR is small, such as in case of a stationary state, the reporting frequency of feedback can be reduced. According to this embodiment, the reduction in the reporting frequency of SIRs makes it possible to decrease the information amount transmitted in the uplink control channel while maintaining information necessary to determine frequency blocks with a better channel state for each user. The schemes described in the different embodiments may be employed by themselves or in any combination thereof. FIG. 13 illustrates an exemplary comparison of data transmission amounts for use in the different embodiments. As stated above, the required information amount Rup bit rate) in an uplink control channel according to the first embodiment can be represented as follows; Rup= (Ks+AXNXKa) /T (1) , where Ks represents the number of users to which frequency blocks are actually assigned, A represents the number of bits required to represent SIR (in this embodiment, A=5), N represents the total number of frequency blocks, Ka represents the number of users to which frequency 23 blocks may be assigned, and T represent the transmission time interval TTI. According to the second embodiment, SIRs associated with N' frequency blocks less than the total number N of frequency blocks are reported to a base station. Thus, the required information amount Rup in an uplink control channel can be represented as follows; Rup= (KS+AXN' XKa) /T (2) . According to the third embodiment, SIRs are represented by an absolute value and values relative to the absolute value. Thus, the required information amount Rup in an uplink control channel can be represented as follows; Rup=(Ks+(AXl + YX (N-l) ) XKa) /T (3). In this formula, the term "AX1" represents the number of bits required to represent a single absolute value, and Y represents the number of bits required to represent a relative value (difference) from the absolute value. Among N frequency blocks, SIR associated with a single frequency block is represented in the form of the absolute value, and SIRs associated with the remaining (N-l) frequency blocks are represented in the form of relative values. In case where the second embodiment scheme is combined with the third embodiment scheme, SIRs are represented as the absolute value and relative values, and only SIRs associated with N' frequency blocks are reported to a base station. Thus, the required information amount Rup in an uplink control channel can be represented as follows; Rup=(Ks+(AXl + YX (N'-l))XKa)/T (4). FIG. 13 illustrates exemplary values of the information amount Rup computed in accordance with the formulae (l)-(4) in the case of the following parameter 24 setting: Ka (the number of users to which frequency blocks may be assigned) = 20 or 40; Ks (the number of users to which frequency blocks are actually assigned) = 4; N (the total number of frequency blocks) = 8; N' (the number of frequency blocks associated with SIRs to be reported to a base station) = 4; A (the number of bits used to represent the absolute value) = 5; Y (the number of bits used to represent differences to the absolute value) = 2; and T (transmission time interval TTI) = 0.5 ms. In this illustration, the values in the column "1st EMBODIMENT" are computed in accordance with the formula (1), the values in the column "2nd EMBODIMENT" are computed in accordance with the formula (2), the values in the column "3rd EMBODIMENT" are computed in accordance with the formula (3), and the values in the column "2nd + 3rd EMBODIMENTS" are computed in accordance with the formula (4). According to the present invention, it is possible to reduce the information amount significantly even in cases of 20 and 40 users. Compared to the first embodiment, the information amount can be reduced to 51 %, 48 % and 28 % according to the second embodiment, the third embodiment and the second and the third embodiments, respectively. In the above description, some preferred embodiments of the present invention have been described. However, the present invention cannot be limited to the exact embodiments but variations and modifications can be made within the sprit of the present invention. For convenience, the present invention has been described through some separate embodiments, but the separation 25 between the embodiments is not essential to the present invention, and one or more embodiments may be used if needed. This international patent application is based on Japanese Priority Application No. 2005-106907 filed on April 1, 2005, the entire contents of which are hereby incorporated by reference. 26 CLAIMS 1. A radio communication apparatus for use in a communication system where a downlink frequency band includes a plurality of frequency blocks including one or more carrier frequencies and one or more of the frequency blocks are used for data transmission to a single user, the apparatus comprising: an evaluation unit evaluating quality of a received signal for each frequency block and storing a plurality of quality evaluations of the received signal; a comparison unit comparing the plurality of quality evaluations of the received signal with each other; and a transmission unit transmitting a predetermined number of the quality evaluations of the received signal over an uplink control channel. 2. A radio communication apparatus as claimed in claim 1, wherein the predetermined number of quality evaluations of the received signal are obtained by selecting a predetermined number of best quality evaluations among the plurality of stored quality evaluations of the received signal. 3. A radio communication apparatus as claimed in claim 1, wherein the predetermined number of quality evaluations of the received signal are quality 27 evaluations associated with the one or more frequency blocks reported over the downlink control channel. 4. A radio communication apparatus as claimed in claim 1, wherein one or more of the predetermined number of quality evaluations of the received signal are represented as differences between the one or more quality evaluations and a reference value. 5. A radio communication apparatus as claimed in claim 4, wherein the reference value is an average of the quality evaluations of the signal received over the downlink frequency band. 6. A radio communication apparatus as claimed in claim 4, wherein the comparison unit compares the differences with a threshold. 7. A radio communication apparatus as claimed in claim 1, wherein the quality evaluations of the received signal transmitted over the uplink control channel are transmitted chronologically and are represented as 28 differences between the quality evaluations and previously transmitted quality evaluations. 8. A radio communication apparatus as claimed in claim 1, wherein a transmission frequency of how often the predetermined number of quality evaluations of the received signal are to be transmitted over the uplink control channel is adjusted depending on a Doppler frequency derived from the received signal. 9. A radio communication apparatus as claimed in claim 1, wherein a transmission frequency of how often the predetermined number of quality evaluations of the received signal are to be transmitted over the uplink control channel is adjusted depending on a delay spread characteristic derived from the received signal. 10. A radio communication method for use in a communication system where a downlink frequency band includes a plurality of frequency blocks including one or more carrier frequencies and one or more of the frequency blocks are used for data transmission to a single user, the method comprising the steps of: receiving a signal from a communication party; evaluating quality of the received signal for each 29 of the frequency blocks and storing a plurality of quality evaluations of the received signal; comparing the plural quality evaluations of the received signal with each other; and transmitting a predetermined number of the quality evaluations of the received signal over an uplink control channel. 30 In a radio communication system, a downlink frequency band includes a plurality of frequency blocks including one or more carrier frequencies, and one or more frequency blocks are used for data transmission to a single user. A radio communication apparatus for use in the communication system has an evaluation unit evaluating the quality of a received signal for each frequency block and storing plurality of stored quality evaluations of the received signal, a comparison unit comparing the plural quality evaluations of the received signal, and a transmission unit transmitting a predetermined number of the quality evaluations of the received signal over an uplink control channel.

Full Text

DESCRIPTION
WIRELESS COMMUNICATIONDEVICE AND WIRELESS COMMUNICATION METHOD
TECHNICAL FIELD
The present invention relates to the technical
field of radio communication, and more specifically
relates to a radio communication apparatus and a method
foruse in a communication system where packet scheduling
is carried out on the downlink.
BACKGROUND ART
In the third generation communication scheme,
typically such as IMT-2000 (International Mobile
Telecommunications-2000), in particular, a faster and
higher-capacity downlink is sought, and for example, the
information transmission rate of higher than or equal
to 2 Mbps is achieved by using the frequency band of 5
MHz. IMT-2000 adopts the single carrier Wideband-Code
Division Multiple Access (W-CDMA) scheme. Alternately,
some scheme called High Speed Downlink Packet Access
(HSDPA) may be employed. In HSDPA, the Adaptive
Modulation and channel Coding (AMC) scheme, MAC layer
packet Automatic Repeat Request (ARQ) scheme, fast packet
scheduling and others are employed to achieve higher
transmission rates and higher quality. For example, AMC
is described in non-patent document 1. ARQ is described
in non-patent document 2 .
FIG. 1 is a schematic view for explaining the AMC
scheme. Assuming that transmission power from a base
station is fixed, in general, a terminal 11 closer to
a base station 10 can receive signals with greater power
than a terminal 12 far from the base station 10. Hence,
since it is estimated that the terminal 11 has a better
1

channel state, a greater modulation level and a higher
coding rate are adopted. On the other hand, the terminal
12 receives signals with less power than the terminal
11. Thus, since it is estimated that the terminal 12 does
not have a good channel state, a smaller modulation level
and a lower coding rate are adopted.
FIG. 2 shows an exemplary combination of different
modulation schemes (modulation level) and different
channel coding rates. In the illustrated table, the
rightmost column represents relative bit rates in the
case of the bit rate being "l" under the modulation scheme
M of "QPSK" and the channel coding rate R of "1/3". For
example, if M="QPSK" and R="l/2", the bit rate of X1.5
is obtained. In general, there is tendency that the
higher bit rate is, the less reliability is. More
specifically, combinations between different modulation
schemes and the coding rates and different amounts
indicative of channel states are predefined in a listing
table, and the modulation schemes and others are changed
depending on the channel state if needed. The amount
indicative of the channel state is managed as Channel
Quality Indicator (CQI), which is typically SIR (Signal
to Interference power Ratio) and SINR of a received
signal.
FIG. 3 is a schematic view for explaining the ARQ
(more accurately, hybrid ARQ) . The hybrid ARQ scheme is
a technique derived from a combination of the ARQ scheme
of requesting retransmission of packets depending on
results of error detection (CRC: Cyclic Redundancy Check)
and some error correction coding scheme (also referred
to as channel coding) for error correction. As
illustrated, a CRC bit is added to a transmission data
sequence S1), and the resulting signal is sent after
completion of error correction encoding (S2). In
2

response to receipt of the signal, error correction
decoding (also referred to as "channel decoding") is
carried out (S3) , and error detection is carried out (S4) .
If some error is detected, retransmission of the packet
is requested to the transmitting side (S5). As
illustrated in FIG. 4, there are several methods for such
retransmission.
In an exemplary method illustrated in FIG. 4A,
packet P1 is sent from the transmitting side to the
receiving side. If some error is detected at the
receiving side, the packet P1 is discarded and then the
retransmission is requested. In response to the
retransmission request, the transmitting side resends
the same packet (represented as "P2") as the packet P1.
In an exemplary method illustrated in FIG. 4 B,
packet P1 is sent from the transmitting side to the
receiving side. If some error is detected at the
receiving side, the receiving side keeps the packet P1
without discarding it. In response to the
retransmission request, the transmitting side resends
the same packet (represented as "P2") as the packet P1.
Then, the receiving side generates packet P3 by combining
the previously received packet with the currently
received packet. Since the packet P3 corresponds to one
transmitted with double the power of packet P1, the
demodulation accuracy is improved.
Also in an exemplary method illustrated in FIG. 4C,
packet P1 is sent from the transmitting side to the
receiving side. If some error is detected at the
receiving side, the receiving side keeps the packet P1
without discarding it. In response to the
retransmission request, the transmitting side sends
redundancy data derived by performing certain operations
on the packet P1 as packet P2 . For example, assume that
3

a sequence of packets such as "P1, P1', P1", ..." has been
derived by encoding the packet P1. The derived sequence
may differ depending on adopted coding algorithms. In
the illustrated example, in response to receipt of a
retransmission request, the transmitting side sends P1'
as packet P2. The receiving side generates packet P3 by
combining the previously received packet with the
currently received packet. Since the packet P3 has
increased redundancy, the demodulation accuracy will be
improved. For example, assuming that the coding rate of
the packet P1 is equal to "1/2", the coding rate of the
packet P3 becomes equal to "1/4", thereby resulting in
improved reliability. Note that the receiving side must
already know some information as to what coding algorithm
is adopted, what redundancy data are sent (also referred
to as "puncture pattern"), and others.
Fast packet scheduling scheme is a technique
intended to improve frequency utilization efficiency in
downlink. In a mobile communication environment, the
channel state between a mobile station (user) and a base
station varies over time as illustrated in FIG. 5. In
this case, even though transmission of a large amount
of data to a user with poor channel state is attempted,
it is hard to improve the throughput. On the other hand,
the higher throughput would be achieved for a user with
a good channel state. From such a viewpoint, it is
possible to improve the frequency utilization efficiency
by determining whether the channel state is good for each
user and assigning a shared data packet in favor of the
user with the better channel state.
FIG. 5 is a schematic diagram for explaining the
fast packet scheduling scheme. As illustrated, a shared
data packet is assigned to a user with the better channel
state (a user associated with greater SINR) in each time
4

slot.
Non-patent document 1: T.Ue, S.Aampei, N.Morinaga
and K.Hamaguchi, "Symbol Rate and Modulation
Level-Controlled Adaptive Modulation/TDMA/TDD System
for High-Bit-Rate Wireless Data Transmission", IEEE
Trans.VT, pp. 1134-1147, vol. 47, No. 4, Nov. 1998
Non-patent document 2: S.Lin, Costello, Jr.and
M.Miller, "Automatic-Repeat-Request Error Control
Schemes", IEEE Communication Magazine, vol. 12, No. 12,
pp. 5-17, Dec. 1984
DISCLOSURE OF INVENTION
[OBJECT TO BE SOLVED BY THE INVENTION]
In this technical field, there is a strong need of
improved speed and capacity of radio transmission, and
in a future communication system, further improved
efficiency of radio transmission and further utilization
efficiency of a frequency band are desired.
One object of the present invention is to provide
a radio communication apparatus and a method for use in
a communication system where a shared data packet is
assigned for a user with a better channel state by
priority for further improvement of frequency
utilization efficiency.
[MEANS FOR SOLVING THE OBJECT]
In an embodiment of the present invention, there
is provided a radio communication apparatus for use in
a communication system where a downlink frequency band
includes a plurality of frequency blocks including one
or more carrier frequencies and one or more frequency
blocks are used for data transmission to a single user.
The apparatus includes an evaluation unit evaluating
quality of a received signal for each frequency block
5

and storing a plurality of quality evaluations of the
received signal, a comparison unit comparing the
plurality of quality evaluations of the received signal,
and a transmission unit transmitting a predetermined
number of quality evaluations of the received signal over
an uplink control channel.
[ADVANTAGE OF THE INVENTION]
According to the embodiment of the present
invention, higher frequency utilization efficiency is
achieved in a communication system where a shared data
packet is assigned for a user with a better channel state
by priority.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic view for explaining the AMC
scheme;
FIG. 2 is a diagram illustrating an exemplary
combination between modulation schemes and channel
coding rates;
FIG. 3 is a schematic view for explaining the hybrid
ARQ scheme;
FIG. 4 is a diagram illustrating an example of
retransmission schemes;
FIG. 5 is a diagram illustrating quality of
receiving varying over time;
FIG. 6 is a diagram illustrating an exemplary
receiving station in a mobile communication system
according to one embodiment;
FIG. 7 is a diagram illustrating a transmitting
station in a mobile communication system according to
one embodiment;
FIG. 8 is a diagram illustrating an exemplary method
of assigning frequency blocks;
6

FIG. 9 shows an exemplary feedback data generation
unit for use in one embodiment;
FIG. 10 is a diagram for explaining an exemplary
operation according to one embodiment of the present
invention;
FIG. 11 is a diagram for explaining another
exemplary operation according to one embodiment of the
present invention;
FIG. 12 is a diagram for explaining another
exemplary operation according to one embodiment of the
present invention; and
FIG. 13 is a diagram illustrating an exemplary
comparison of amounts of data transmission.
LIST OF REFERENCE SYMBOLS
10 : base station
11, 12: terminal
100: transmitting station
100-1: RF receipt circuit
100-2: demodulation and decoding unit
100-3: scheduler
100-4: header information acquisition unit
100-5: packet selection unit
100-6: buffer management unit
100-7: PDU generation unit
100-8: transmission buffer
100-9: selector
100-10: encoding and modulation unit
100-11: RF transmission circuit
200: receiving station
200-1: RF receipt circuit
200-2: subcarrier signal separation unit
200-3: channel estimation unit
200-4: receiving channel state evaluation unit
7

200-5: feedback data generation unit
200-6: encoding and modulation unit
200-7: RF transmission circuit
200-8: demodulation unit
200-9: decoding unit
200-10: parallel to serial conversion unit
200-11: IP packet recovery unit
902: receiving channel state comparison unit
903: reported content determination part
906: control signal generation unit
BEST MODE FOR CARRYING OUT THE INVENTION
According to one implementation of the present
invention, in a communication system where the frequency
band of the downlink includes a plurality of frequency
blocks including one or more carrier frequencies and one
and more frequency blocks are used for data transmission
to a single user, the quality of a received signal is
evaluated for each frequency block, and the quality
evaluations are compared. Then, a predetermined number
of quality evaluations of the received signal are sent
over a control channel on the uplink. Thus, since only
the predetermined number of quality evaluations of the
received signal less than the total number of frequency
blocks are reported, it is possible to provide feedback
on the channel state with a lesser amount of data
transmission efficiently.
The predetermined number of quality evaluations of
a received signal may be obtained through selection of
a predetermined number of top ones among a plurality of
stored quality evaluations of the received signal. The
predetermined number of quality evaluations of a received
signal may be quality evaluations of a received signal
for one or more frequency blocks reported over a control
8

channel on the downlink.
One or more of the predetermined number of received
signal quality evaluations may be represented as
differences between a reference value and them. Since
the differences can be represented in a number of bits
smaller than the reference value, it is possible to reduce
the number of bits for use in the control channel. The
reference value may be an average of received signal
quality evaluations throughout the frequency band in the
downlink. Also, only differences above a threshold may
be provided as feedback. Consequently, it is possible
to reduce the number of received signal quality
evaluations to be reported.
Received signal quality evaluations transmitted
over the uplink control channel may be sent in
chronological order and in the form of the difference
between a current evaluation and the previously
transmitted evaluation. Since the difference tends to
be a smaller value, it is possible to further reduce the
number of bits for use in the control channel.
The transmission repetition of the predetermined
number of received signal quality evaluations over the
uplink control channel may be adjusted depending on
Doppler frequency derived from the received signal, delay
spreads and other amounts indicative of the communication
state .
[First Embodiment]
In the following embodiment, the case where the OFDM
Orthogonal Frequency Division Multiplexing) scheme is
adopted in the downlink is described. However, other
schemes may be adopted. A broad frequency band in the
downlink is divided into a plurality of frequency blocks.
In general, although a single frequency block includes
9

one or more carrier frequencies, according to this
embodiment, it is supposed that each frequency block
includes a plurality of subcarriers. Note that such a
frequency block may be referred to as a "chunk".
FIG. 6 illustrates a receiving station 200 in a
mobile communication system according to one embodiment
of the present invention. Although such a receiving
station is typically provided in a mobile terminal, it
may be provided in some apparatus other than mobile
terminals. The receiving station 200 includes an RF
receipt circuit 200-1, a subcarrier signal separation
unit 200-2 coupled with the RF receipt circuit 200-1,
a channel estimation unit 200-3 coupled with the
subcarrier signal separation unit 200-2, one or more
receiving channel state evaluation units 200-4 coupled
with the subcarrier signal separation unit 200-2 and the
channel estimation unit 200-3, a feedback data generation
unit 200-5 coupled with the one or more receiving channel
state evaluation units 200-4, an encoding and modulation
unit 200-6 coupled with the feedback data generation unit
200-5, an RF transmission circuit 200-7 coupled with the
encoding and modulation unit 200-6, one or more
demodulation units 200-8 coupled with the subcarrier
signal separation unit 200-2, one or more decoding units
200-9 coupled with the respective one or more
demodulation units 200-8, a parallel to serial conversion
unit 200-10 coupled with the one or more decoding units
200-9, and an IP packet recovery unit 200-11 coupled with
the parallel to serial conversion unit 200-10.
In FIG. 6, a transmitted signal transmitted from
a transmitting station (not illustrated) is received at
the RF receipt circuit 200-1. The RF receipt circuit
200-1 supplies the received signal to the subcarrier
signal separation unit 200-2. The subcarrier signal
10

separation unit 200-2 divides the received signal into
signals per subcarrier, and supplies the respective
signals to the demodulation units 200-8, the receiving
channel state evaluation unit 200-4 and the channel
estimation unit 200-3.
Each demodulation unit 200-8 demodulates the
supplied signals per subcarrier, and supplies the
demodulated signals to the respective decoding units
200-9. The number of decoders is variable depending on
the decoding algorithm in use (the coding unit used in
the algorithm). Each decoding unit 200-9 decodes the
supplied respective signal, and supplies the decoded
signal to the parallel to serial conversion unit 200-10.
The parallel to serial conversion unit 200-10
parallel-to-serial converts the incoming signal, and
supplies the resulting signal to the IP packet recovery
unit 200-11. The IP packet recovery unit 200-11 recovers
the incoming signal.
The channel estimation unit 200-3 uses a pilot
symbol (pilot channel) for each subcarrier to perform
channel estimation, and supplies such a channel
estimation value to one or more receiving channel state
evaluation units 200-4 for each subcarrier.
Each receiving channel state evaluation unit 200-4
evaluates the receiving channel state (ex. SIR) based
on the channel estimation and the received signal for
each subcarrier, and supplies the evaluation to the
feedback data generation unit 200-5. The feedback data
generation unit 200-5 generates feedback data (control
information) indicative of the receiving channel state
of the frequency block based on the evaluation of the
incoming receiving channel state, and supplies it to the
encoding and demodulation unit 200-6. The SIR included
in the feedback data may be SIR per subcarrier just as
11

it is, or may be some converted value such as an average
of SIRs throughout a predetermined number of subcarriers
included in a frequency block. The latter is why the SIR
per frequency block is required in the transmitting side
rather than the SIR per subcarrier. The encoding and
modulation unit 200-6 encodes and modulates the incoming
feedback data, and supplies the resulting signal to the
RF transmission circuit 200-7. The RF transmission
circuit 200-7 returns the feedback data as control
information to the transmitting station 100.
FIG. 7 illustrates a transmitting station 100 in
a mobile communication system according to one embodiment
of the present invention. The transmitting station 100
is typically provided in a base station. However, the
transmitting station 100 may be provided in other
apparatuses other than base stations. The transmitting
station 100 includes an RF receipt circuit 100-1, a
demodulation and decoding unit 100-2 coupled with the
RF receipt circuit 100-1, a scheduler 100-3 coupled with
the demodulation and decoding unit 100-2, a header
information acquisition unit 100-4, a packet selection
unit 100-5 coupled with the header information
acquisition unit 100-4, a buffer management unit 100-6
coupled with the header information acquisition unit
100-4, the packet selection unit 100-5 and the scheduler
100-3, a PDU (Protocol Data Unit) generation unit 100-7
coupled with the packet selection unit 100-5, a
transmission buffer 10 0-8 coupled with the PDU generation
unit 100-7 and the buffer management unit 100-6, a
selector 10 0-9 coupled with the transmission buffer 100-8
and the scheduler 100-3, one or more encoding and
modulation units 100-10 coupled with the selector 100-9,
and an RF transmission circuit 100-11 coupled with the
encoding and modulation units 100-10.
12

As illustrated in the lower-right portion of FIG.
7, a control signal including control information from
each receiving station 200 (FIG. 6) is received at the
RF receipt circuit 100-1, and the received control signal
is supplied to the demodulation and decoding unit 100-2.
In the demodulation and decoding unit 100-2, some
demodulation and decoding operations are performed on
the control signal, and upstream control information of
each receiving station (including channel state in the
downlink for each frequency block) is reported to the
scheduler 100-3.
On the other hand, as illustrated in the upper-left
portion of FIG. 7, upon receipt of an IP packet from a
network, the header information acquisition unit 100-4
obtains packet header information such as a destination
address from the received IP packet, reports the obtained
packet header information to the buffer management unit
100-6, and supplies the IP packet to the packet selection
unit 100-5.
The buffer management unit 100-6 specifies a
storage location of the packet data to the packet
selection unit 100-5 based on the reported packet header
information and the state of each queue reported from
the transmission buffer 100-8. The buffer management
unit 100-6 supplies the destination address and the
memory address of a queue corresponding to the
destination address to the transmission buffer 100-8.
The buffer management unit 100-6 informs the scheduler
100-3 of the packet header information and the state of
each queue reported from the transmission buffer 100-8.
The packet selection unit 100-5 selects the
incoming IP packet based on the storage location for the
packet data specified by the buffer management unit 100-6,
and supplies selected packets individually to the PDU
13

generation unit 100-7. The PDU generation unit 100-7
converts the incoming packets into PDUs, and supplies
the resulting PDUs to the transmission buffer 100-8.
The transmission buffer 100-8 configures a distinct
queue for each destination address (each receiving
station or each user) supplied from the incoming PDUs
based on the destination address supplied from the buffer
management unit 100-6 and the memory address of the
corresponding queue, and informs the buffer management
unit 100-6 of the state of each queue.
The selector 100-9 extracts data from the queue
specified by the scheduler 100-3, and supplies it to the
encoding and modulation unit 100-10 associated with the
specified frequency block. This frequency block is
assigned by the scheduler 100-3. The scheduler 100-3
determines to which user the frequency block should be
assigned by priority based on the upstream control
information (the channel state per frequency block in
the downlink) reported from each receiving station, the
packet header information and the state of each queue.
The encoding and modulation unit 100-10 performs
encoding and modulation on the data supplied from the
selector 100-9. The encoded and modulated data are sent
to each receiving station by the RF transmission circuit
100-11.
Based on the control information returned from the
receiving station 200 as feedback, the scheduler 100-3
generates a ranking table where each user is ranked in
accordance with the associated priority. The priority
is derived for each frequency block based on the quality
of the receiving channel state of each user. Then,
scheduling is performed for each frequency block. For
example, as illustrated in FIG. 8, the downlink frequency
band is divided into three frequency blocks 1, 2 and 3.
14

These three frequency blocks are included in any of radio
frames (time slots) . For each frame and each frequency
block, a user with the best receiving channel state is
selected, and then for the selected user, the shared data
packet in the downlink is assigned to the frequency block
in the frame. In the illustrated example, for the second
radio frame from the left, the frequency block 1 is
assigned to the user #2, the frequency block 2 is assigned
to the user #1, and the frequency block 3 is assigned
to the user #4. For the immediately successive radio
frame, the frequency blocks 1 and 2 are assigned to the
user #2, and the frequency block 3 is assigned to the
user #3.
On the other hand, in the case where frequency is
scheduled in favor of a user with a good receiving channel
state, there is a likelihood that more frequency blocks
are assigned to some users whereas less frequency blocks
are assigned to the other users. In order to maintain
fair assignment among users, the number of frequency
blocks assigned to a single user within one radio frame
may be limited to be less than or equal to a predetermined
value K (K is a certain natural number) . In other words,
a user to which K frequency blocks are assigned may be
deleted from the ranking table for unassigned frequency
blocks, and then the unassigned frequency blocks may be
assigned to other users.
The priority for the frequency blocks may be
determined based on the illustratively listed criteria
as presented below.
(1) Receiving channel state of each frequency block
(2) Ratio between time average of the receiving
channel states in each frequency block and the receiving
channel state for each frequency block in the radio frame
(3) Ratio between average the receiving channel
15

state over all subcarriers (included in the frequency
block) and the receiving channel state of the target
frequency block in the radio frame
(4) Ratio between time average over averages of the
receiving channel state over all subcarriers (included
in the frequency block) and the receiving channel state
of the target frequency block in the radio frame
In case of the same priority based on the receiving
channel state such as a reception SIR, the frequency block
is assigned in favor of a user with a greater delay spread,
and thereby the peak throughput is improved due to the
frequency diversity effect. Alternatively, in case of
the same priority based on the receiving channel state
such as a reception SIR, the frequency block may be
assigned to a user with a smaller delay spread by priority.
For a user with a greater delay spread, another frequency
block can be assigned to the user because of a small
difference of the average receiving channel states
between frequency blocks such as difference between the
average reception SIRs.
[Second Embodiment]
As described in the first embodiment, improved
frequency utilization efficiency is achieved by dividing
the downlink frequency band into a plurality of frequency
blocks and assigning one or more frequency blocks to a
user with a better channel state by priority. In this
case, the receiving channel state of each frequency block
must be known to perform frequency scheduling. The
receiving channel state may be SIRmeasured at a receiving
station (typically a mobile terminal), for example, and
may be reported to a transmitting station (typically a
base station) over an uplink control channel transmitted
from the receiving station. The transmitting station
16

must know the receiving channel state not only for each
user but also for each frequency block. As a result, it
is a concern that there is a significant increase in the
information transmission amount in the control channel
for preparing and scheduling a plurality of frequency
blocks.
In general, the information amount Rup (bit rate)
required in an uplink control channel can be represented
in the formula as follows;
Rup= (Ks+AXNXKa) /T (1) ,
where Ks represents the number of users to which frequency
blocks are actually assigned, A represents the number
of bits required to represent SIR (in this embodiment,
A=5) , N represents the total number of frequency blocks,
Ka represents the number of users to which frequency
blocks may be possibly assigned, and T represents the
duration of a single packet, which may be referred to
as TTI (Transmission Time Interval) . One bit is reserved
to report the CRC result (ACK/NACK) of hybrid ARQ. In
the above formula, the term "Ks/T" represents the
information amount associated the CRC result from each
user to which frequency blocks are actually assigned,
and does not depend on the number N of frequency blocks.
The term " (AXNXKA) /T" represents the information amount
required to report SIR per frequency block to each user.
For example, assuming that Ks=4, N=8, Ka=20 and
T=0.5ms, it holds that Rup=1.61 Mbps.
Alternatively, assuming that Ks=8, N=8, Ka=40 and
T=0.5ms, it holds that Rup=3.22 Mbps.
In this way, the greater the number of frequency
blocks is, the significantly more is the information
amount transmitted in the control channel. The second
embodiment of the present invention is intended to
overcome the above-mentioned problem. According to this
17

embodiment, in a communication system where the downlink
frequency band is divided into a plurality of frequency
blocks and one or more frequency blocks are used for a
user with a better receiving channel state by priority,
it is possible to provide a radio communication apparatus
and method capable of efficiently reporting the channel
state with less data transmission amount in the uplink
control channel.
FIG. 9 illustrates a feedback data generation unit
for use in this embodiment. This feedback data
generation unit may be used as a feedback data generation
unit 200-5 of FIG. 6. The feedback data generation unit
200-5 includes a receiving channel state comparison unit
902, a reported content determination part 904 and a
control signal generation unit 906.
The receiving channel state comparison unit 902
receives an amount indicative of received channel state,
which is SIR in this embodiment, from the receiving
channel state evaluation unit 200-4. In case where the
received SIR does not correspond to SIR per frequency
block, an averaging operation or another suitable
operation may be carried out. For example, suppose that
SIR is measured for each 1000 subcarriers and a single
frequency block includes 100 subcarriers. In this case,
every 10 SIRs out of 100 SIRs obtained for each 100
subcarriers are averaged so that 10 SIRs associated with
10 frequency blocks can be derived. The SIRs per
subcarrier and/or frequency block are stored in an
appropriate memory. The receiving channel state
comparison unit 902 compares the SIRs per frequency block
with each other, and provides a comparison result.
The reported content determination part 904 selects
SIRs associated with a predetermined number of frequency
blocks, and determines which SIR should be reported to
18

a base station. Such a predetermined number of frequency
blocks may be determined as follows.
(1) Among a plurality of SIRs stored in the memory,
the top L SIRs indicative of better quality may be
selected. For example, suppose that if SIR as
illustrated in FIG. 10 is obtained the top three SIRs
(L=3) are selected. In this case, the three SIRs
associated with the frequency blocks "c", "e" and "f"
are selected among the frequency blocks "a", "b", "c",
"d", "e", "f" and "g". It may be determined in advance
how many of the top SIRs should be reported. Also, the
number may be changed depending on instruction from a
base station.
(2) Among a plurality of SIRs stored in the memory,
SIRs associated with X frequency blocks specified from
a base station may be selected. For example, SIR
(receiving channel state) as illustrated in FIG. 10 is
measured at a radio station, and assuming that downlink
data toward the mobile station are transmitted in the
frequency blocks "c" and "d". In this case, the base
station may instruct the mobile station to report the
two SIR associated with the frequency blocks "c" and "d",
or may instruct the mobile station to report SIRs
associated with other frequency blocks in addition to
or instead of those of the frequency blocks "c" and "d".
For example, SIRs associated with frequency blocks
selected for every two frequency blocks may be reported
among a plurality of frequency blocks located on the
frequency axis. For example, if SIR as illustrated in
FIG. 11 is measured, the three SIRs associated with the
frequency blocks "a", "d" and "g" may be selected.
(3) Among a plurality of SIRs stored in the memory,
one or more SIRs above a predefined threshold may be
selected. In other words, only SIRs associated with
19

frequency blocks with relatively better channel states
may be reported to a base station among the stored SIRs.
The control signal generation unit 906
of FIG. 9 generates a control signal including
identification information (ID) of a frequency block
selected in the report content determination unit 904
and SIR associated with the frequency block. In other
words, the control signal includes a predetermined number
of combinations of the IDs of and SIRs associated with
the frequency blocks. Also, if any frequency block has
been already assigned and downlink data have been
received, the control signal also includes information
indicative of an error detection result of that data.
As stated above, the error detection result information
may be represented in one bit to indicate affirmative
acknowledge (ACK) or negative acknowledge (NACK). The
control signal generated in this manner is provided to
the encoding and modulation unit 200-6, where some
appropriate operation is subsequently performed, and the
feedback is provided to the base station.
According to this embodiment, the SIRs to be
reported to a base station are selected based on certain
criteria, resulting in a decrease in the number of SIRs
(the number of frequency blocks) to be reported. Thereby,
it is possible to reduce the amount of information
transmitted on the uplink control channel while
maintaining information necessary to determine
frequency blocks with better channel states for each
user.
[Third Embodiment]
In the second embodiment, the number of SIRs (the
number of frequency blocks) to be reported to a base
station is reduced, but the number of bits to represent
20

SIRs may be reduced. For example, the absolute value of
a SIR associated with a certain frequency block may be
represented in five bits, and SIRs associated with the
other frequency blocks may be represented in form of
differences (relative values) between the SIRs and the
absolute value. In general, since the difference can be
represented in a number of bits smaller than five bits,
the transmission amount can be reduced compared to the
case of where all SIRs are represented in five bits. The
SIR represented as the absolute value may be associated
with an arbitrary frequency block. For example, the
frequency block including the lowest carrier frequency
or the frequency block including the highest carrier
frequency may be represented in the form of the absolute
value. Alternatively, instead of SIR associated with a
frequency block, a predefined different value may be
prepared, and each SIR may be represented in the the form
of the difference between the SIR and the predefined value.
As illustrated in FIG. 12, the average of SIRs over the
entire band may be represented in the form of the absolute
value, and the SIR associated with each frequency block
may be represented in the form of the difference between
the SIR and the average.
Alternatively, SIR at a certain time point may be
represented in the form of the absolute value, and
subsequent SIRs may be represented as a temporal
variations to the absolute value. Further, SIR at the
current time point may be represented as temporal
variation to SIR at the immediately previous time point.
In general, since the amount of short term variation is
smaller than that of long term variation, SIR can be
represented with a reduced transmission amount in this
manner. However, if an error is detected in a signal
received at a mobile station, it is desirable to prevent
21

a chain of inaccurate values by reporting the absolute
value and/or ignoring the temporal variation to the
immediately previous SIR at the next time.
According to this embodiment, SIR to be reported
to a base station is represented as some value (relative
value) such as the absolute value and/or difference. The
reduction in the number of bits required to report SIR
makes it possible to reduce the information amount
transmitted in the uplink control channel while
maintaining information necessary to determine a
frequency block with a better channel state for each user.
[Fourth Embodiment]
In the second and the third embodiments, the data
transmission amount required to provide a single feedback
is reduced. On the other hand, the feedback may be
infrequently provided. For example, the frequency of
the feedback may be adjusted based on mobility of a
receiving station. Since it is estimated that reception
environment of a slow moving receiving station varies
less, the frequency of feedback may be decreased. The
mobility can be evaluated, for example, based on the
maximum Doppler frequency, and the maximum Doppler
frequency is small in case of slow movement. On the other
hand, since it is estimated that the reception
environment of a fast moving receiving station varies
relatively more, the frequency of feedback may be
increased. In general, since a receiving station more
frequently moves at slow speed than fast speed, it is
estimated that frequent feedback does not have to be
supplied.
In addition, the content or the frequency of
feedback may be adjusted depending on the delay spread
in the downlink. In general, the smaller the delay
22

spread is, the smaller is the channel variation in the
frequency range. Thus, since the difference of SIRs
between frequency blocks is small for a user with an
observed small delay spread, the channel state may be
evaluated based on the single average of SIRs over the
entire band. Alternatively, the frequency of feedback
may be decreased.
In addition, only in the case where the level of
SIR significantly varies compared to a previously
reported SIR (only in the case where the variation amount
exceeds a threshold) is the SIR sent to a base station.
For example, if the temporal variation of SIR is small,
such as in case of a stationary state, the reporting
frequency of feedback can be reduced.
According to this embodiment, the reduction in the
reporting frequency of SIRs makes it possible to decrease
the information amount transmitted in the uplink control
channel while maintaining information necessary to
determine frequency blocks with a better channel state
for each user.
The schemes described in the different embodiments
may be employed by themselves or in any combination
thereof.
FIG. 13 illustrates an exemplary comparison of data
transmission amounts for use in the different embodiments.
As stated above, the required information amount Rup bit
rate) in an uplink control channel according to the first
embodiment can be represented as follows;
Rup= (Ks+AXNXKa) /T (1) ,
where Ks represents the number of users to which frequency
blocks are actually assigned, A represents the number
of bits required to represent SIR (in this embodiment,
A=5), N represents the total number of frequency blocks,
Ka represents the number of users to which frequency
23

blocks may be assigned, and T represent the transmission
time interval TTI.
According to the second embodiment, SIRs associated
with N' frequency blocks less than the total number N
of frequency blocks are reported to a base station. Thus,
the required information amount Rup in an uplink control
channel can be represented as follows;
Rup= (KS+AXN' XKa) /T (2) .
According to the third embodiment, SIRs are
represented by an absolute value and values relative to
the absolute value. Thus, the required information
amount Rup in an uplink control channel can be represented
as follows;
Rup=(Ks+(AXl + YX (N-l) ) XKa) /T (3).
In this formula, the term "AX1" represents the
number of bits required to represent a single absolute
value, and Y represents the number of bits required to
represent a relative value (difference) from the absolute
value. Among N frequency blocks, SIR associated with a
single frequency block is represented in the form of the
absolute value, and SIRs associated with the remaining
(N-l) frequency blocks are represented in the form of
relative values.
In case where the second embodiment scheme is
combined with the third embodiment scheme, SIRs are
represented as the absolute value and relative values,
and only SIRs associated with N' frequency blocks are
reported to a base station. Thus, the required
information amount Rup in an uplink control channel can
be represented as follows;
Rup=(Ks+(AXl + YX (N'-l))XKa)/T (4).
FIG. 13 illustrates exemplary values of the
information amount Rup computed in accordance with the
formulae (l)-(4) in the case of the following parameter
24

setting:
Ka (the number of users to which frequency blocks
may be assigned) = 20 or 40;
Ks (the number of users to which frequency blocks
are actually assigned) = 4;
N (the total number of frequency blocks) = 8;
N' (the number of frequency blocks associated with
SIRs to be reported to a base station) = 4;
A (the number of bits used to represent the absolute
value) = 5;
Y (the number of bits used to represent differences
to the absolute value) = 2; and
T (transmission time interval TTI) = 0.5 ms.
In this illustration, the values in the column "1st
EMBODIMENT" are computed in accordance with the formula
(1), the values in the column "2nd EMBODIMENT" are
computed in accordance with the formula (2), the values
in the column "3rd EMBODIMENT" are computed in accordance
with the formula (3), and the values in the column "2nd
+ 3rd EMBODIMENTS" are computed in accordance with the
formula (4). According to the present invention, it is
possible to reduce the information amount significantly
even in cases of 20 and 40 users. Compared to the first
embodiment, the information amount can be reduced to 51 %,
48 % and 28 % according to the second embodiment, the
third embodiment and the second and the third embodiments,
respectively.
In the above description, some preferred
embodiments of the present invention have been described.
However, the present invention cannot be limited to the
exact embodiments but variations and modifications can
be made within the sprit of the present invention. For
convenience, the present invention has been described
through some separate embodiments, but the separation
25

between the embodiments is not essential to the present
invention, and one or more embodiments may be used if
needed.
This international patent application is based on
Japanese Priority Application No. 2005-106907 filed on
April 1, 2005, the entire contents of which are hereby
incorporated by reference.
26

CLAIMS
1. A radio communication apparatus for use in a
communication system where a downlink frequency band
includes a plurality of frequency blocks including one
or more carrier frequencies and one or more of the
frequency blocks are used for data transmission to a
single user, the apparatus comprising:
an evaluation unit evaluating quality of a received
signal for each frequency block and storing a plurality
of quality evaluations of the received signal;
a comparison unit comparing the plurality of
quality evaluations of the received signal with each
other; and
a transmission unit transmitting a predetermined
number of the quality evaluations of the received signal
over an uplink control channel.
2. A radio communication apparatus as claimed in
claim 1, wherein the predetermined number of quality
evaluations of the received signal are obtained by
selecting a predetermined number of best quality
evaluations among the plurality of stored quality
evaluations of the received signal.
3. A radio communication apparatus as claimed in
claim 1, wherein the predetermined number of quality
evaluations of the received signal are quality
27

evaluations associated with the one or more frequency
blocks reported over the downlink control channel.
4. A radio communication apparatus as claimed in
claim 1, wherein one or more of the predetermined number
of quality evaluations of the received signal are
represented as differences between the one or more
quality evaluations and a reference value.
5. A radio communication apparatus as claimed in
claim 4, wherein the reference value is an average of
the quality evaluations of the signal received over the
downlink frequency band.
6. A radio communication apparatus as claimed in
claim 4, wherein the comparison unit compares the
differences with a threshold.
7. A radio communication apparatus as claimed in
claim 1, wherein the quality evaluations of the received
signal transmitted over the uplink control channel are
transmitted chronologically and are represented as
28

differences between the quality evaluations and
previously transmitted quality evaluations.
8. A radio communication apparatus as claimed in
claim 1, wherein a transmission frequency of how often
the predetermined number of quality evaluations of the
received signal are to be transmitted over the uplink
control channel is adjusted depending on a Doppler
frequency derived from the received signal.
9. A radio communication apparatus as claimed in
claim 1, wherein a transmission frequency of how often
the predetermined number of quality evaluations of the
received signal are to be transmitted over the uplink
control channel is adjusted depending on a delay spread
characteristic derived from the received signal.
10. A radio communication method for use in a
communication system where a downlink frequency band
includes a plurality of frequency blocks including one
or more carrier frequencies and one or more of the
frequency blocks are used for data transmission to a
single user, the method comprising the steps of:
receiving a signal from a communication party;
evaluating quality of the received signal for each
29

of the frequency blocks and storing a plurality of quality
evaluations of the received signal;
comparing the plural quality evaluations of the
received signal with each other; and
transmitting a predetermined number of the quality
evaluations of the received signal over an uplink control
channel.
30

In a radio communication system, a downlink
frequency band includes a plurality of frequency blocks
including one or more carrier frequencies, and one or
more frequency blocks are used for data transmission to
a single user. A radio communication apparatus for use
in the communication system has an evaluation unit
evaluating the quality of a received signal for each
frequency block and storing plurality of stored quality
evaluations of the received signal, a comparison unit
comparing the plural quality evaluations of the received
signal, and a transmission unit transmitting a
predetermined number of the quality evaluations of the
received signal over an uplink control channel.

Documents:

03632-kolnp-2007-abstract.pdf

03632-kolnp-2007-claims.pdf

03632-kolnp-2007-correspondence others.pdf

03632-kolnp-2007-description complete.pdf

03632-kolnp-2007-drawings.pdf

03632-kolnp-2007-form 1.pdf

03632-kolnp-2007-form 3.pdf

03632-kolnp-2007-form 5.pdf

03632-kolnp-2007-gpa.pdf

03632-kolnp-2007-international publication.pdf

03632-kolnp-2007-international search report.pdf

03632-kolnp-2007-pct priority document notification.pdf

03632-kolnp-2007-pct request form.pdf

3632-KOLNP-2007-(16-01-2015)-CLAIMS.pdf

3632-KOLNP-2007-(16-01-2015)-CORRESPONDENCE.pdf

3632-KOLNP-2007-(19-02-2014)-CORRESPONDENCE.pdf

3632-KOLNP-2007-(23-07-2014)-ABSTRACT.pdf

3632-KOLNP-2007-(23-07-2014)-ANNEXURE TO FORM 3.pdf

3632-KOLNP-2007-(23-07-2014)-CLAIMS.pdf

3632-KOLNP-2007-(23-07-2014)-CORRESPONDENCE.pdf

3632-KOLNP-2007-(23-07-2014)-FORM-2.pdf

3632-KOLNP-2007-(23-07-2014)-OTHER.1.pdf

3632-KOLNP-2007-(23-07-2014)-OTHER.2.pdf

3632-KOLNP-2007-(23-07-2014)-OTHER.3.pdf

3632-KOLNP-2007-(23-07-2014)-OTHERS.pdf

3632-KOLNP-2007-(23-07-2014)-PA.pdf

3632-KOLNP-2007-(23-07-2014)-PETITION UNDER RULE 137.pdf

3632-KOLNP-2007-(24-07-2014)-CORRESPONDENCE.pdf

3632-KOLNP-2007-(24-07-2014)-DRAWINGS.pdf

3632-KOLNP-2007-(25-07-2013)-CLAIMS.pdf

3632-KOLNP-2007-(25-07-2013)-CORRESPONDENCE.pdf

3632-KOLNP-2007-(25-07-2013)-FORM-13.pdf

3632-KOLNP-2007-AMANDED CLAIMS.pdf

3632-KOLNP-2007-CORRESPONDENCE.pdf

3632-KOLNP-2007-ENGLISH TRANSLATION.pdf

3632-KOLNP-2007-FORM 13.pdf

3632-KOLNP-2007-GRANTED-FORM 1.pdf

3632-KOLNP-2007-GRANTED-SPECIFICATION-COMPLETE.pdf

3632-KOLNP-2007-OTHERS.pdf

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Patent Number

265513

Indian Patent Application Number

3632/KOLNP/2007

PG Journal Number

10/2015

Publication Date

06-Mar-2015

Grant Date

26-Feb-2015

Date of Filing

26-Sep-2007

Name of Patentee

NTT DOCOMO INC

Applicant Address

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

Inventors:

#	Inventor's Name	Inventor's Address
1	TANNO MOTOHIRO	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC. SANNO PARK TOWER, 11-1 NAGATACHO 2-CHOME,, CHIYODA-KU, TOKYO 100-6150
2	HIGUCHI KENICHI	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC. SANNO PARK TOWER, 11-1 NAGATACHO 2-CHOME,, CHIYODA-KU, TOKYO 100-6150
3	SAWAHASHI MAMORU	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC. SANNO PARK TOWER, 11-1 NAGATACHO 2-CHOME,, CHIYODA-KU, TOKYO 100-6150
4	ATARASHI HIROYUKI	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC. SANNO PARK TOWER, 11-1 NAGATACHO 2-CHOME,, CHIYODA-KU, TOKYO 100-6150

PCT International Classification Number

H04Q 7/38

PCT International Application Number

PCT/JP2006/305497

PCT International Filing date

2006-03-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005-106907	2005-04-01	Japan