JP5652193B2 - Allocated radio resource determination method, allocated radio resource determination apparatus, radio communication system, and computer program - Google Patents

Description

  The present invention relates to an allocated radio resource determination method, an allocated radio resource determination apparatus, a radio communication system, and a computer program.

  In order to improve the number of transmission information bits, a general scheduler in a wireless communication system such as LTE of 3GPP calculates an allocation index according to channel quality and allocates radio resources according to the allocation index. In the above, 3GPP is an abbreviation for 3rd Generation Partnership Project, and LTE is an abbreviation for Long Term Evolution. On the other hand, a power saving scheduler for the purpose of reducing power consumption is also being studied. For example, Non-Patent Document 1 discloses a CSDP (Channel State Dependent Packet) scheduler.

  The scheduler described in Non-Patent Document 1 achieves power saving by preferentially allocating resources to a receiver with high channel quality. FIG. 12 is a diagram illustrating a radio resource allocation method in the scheduler described in Non-Patent Document 1. As understood from FIG. 12, the scheduler determines the channel quality of the receiver using the reception signal level Pr of the receiver as an index of the channel quality. When the received signal level Pr is equal to or higher than the threshold value Pth, it is determined as Good State, and when the received signal level Pr is lower than the threshold value Pth, it is determined as Bad State. Then, the scheduler preferentially allocates radio resources to the receiver determined to be Good State. Prioritizing the Good State receiver increases the transmission rate per unit power. As a result, the transmission time can be shortened, so that power saving can be realized.

  However, in the scheduler described in Non-Patent Document 1, when the number of receivers is large, radio resource allocation to the Bad State receiver is not easily performed, so that reception processing is delayed and the request delay of the Bad State receiver is satisfied. It may not be possible. On the other hand, when the number of receivers is small, radio resources are also frequently assigned to Bad State receivers, so the transmission rate per unit power decreases, and as a result, a sufficient power saving effect is obtained. There is a risk that it will not be possible.

  On the other hand, Non-Patent Document 2 proposes a scheduler for maximizing the number of transmission information bits while satisfying the required delay by performing allocation in consideration of the channel quality and the required delay. The scheduler described in Non-Patent Document 2 calculates an allocation index from the channel quality measured in the PHY layer (Physical layer) and the allowance time until the allowable delay measured in the MAC layer (Media Access Control layer), and wirelessly according to the allocation index. Allocate resources.

  Here, a downlink radio resource allocation procedure in LTE using channel quality will be described. A band allocation unit is called an RB (Resource Block). The terminal reports CQI (Channel Quality Indicator) as channel quality information to the base station. In the LTE specification, an RBG (RB Group) composed of a plurality of consecutive RBs is defined, and CQI is reported in units of a plurality of consecutive RBGs. The CQI is obtained by quantizing the channel quality of the data channel, and is defined as a table in the LTE specification (Non-Patent Document 3). The CQI table is provided with a modulation scheme, a coding rate, and transmission efficiency that achieve the target error rate, and the CQI Index is determined in ascending order from the lowest transmission efficiency. Since a modulation scheme and a coding rate are given, it is possible to calculate a channel quality SINR (Signal to Noise plus Interference Ratio) necessary to achieve the target error rate. The terminal measures the channel quality and reports the CQI Index with the highest transmission efficiency to the base station within a range where the target error rate can be achieved.

  The base station determines an RB to be allocated to the terminal from among the assignable RBs, and determines a transmission data size TBS (Transport Block Size) from the determined allocation RB and the reported CQI. The base station notifies the terminal of the allocated RB and the index of MCS (Modulation and Coding Scheme) corresponding to the Index of the TBS table. As described in Non-Patent Document 3, the LTE specification defines the conversion from MCS Index to TBS Index. The base station applies the same modulation scheme and coding rate, that is, the same MCS, to the allocated RBs of the same terminal.

  The MCS index is determined as follows. First, the average channel quality of the allocated RB is calculated using each CQI of the allocated RB. As an average channel quality, SINR is generally used. That is, the average SINR of the allocated RBs is calculated using the required SINR corresponding to the CQI of each RB. The base station has a TBS table for each number of RBs. Similar to the CQI, the table is provided with a modulation scheme, coding rate, transmission efficiency, necessary SINR, and the like for each TBS index. Typically, the base station uses the average SINR to select the maximum TBS that can achieve the required error rate.

P. Bhaqwat, P.A. Bhattacharya, A.B. Krishna, and S.K. K. “Tripathi,“ Enhancing throughput over wireless LANs using channel state dependent dependent packet scheduling, ”IEEE Proc. INFOCOM '98, Vol.3, p.3, p. Y. J. et al. Zhang and S.M. C. Liew, “Link-adaptive large-weighted-throughput-packet packet scheduling for real-time traffics in wireless OFDM networks,” in Proc. IEEE Global Telecommunications Conf. Vol. 5, pp. 5-9, St. Louis, MO, 2005. 3GPP TS 36.213 V8.8.0 (2009-09), 3GPP TSG RAN EUTRAN Physical layer procedures. Pp. 25-33, 47-48

  One of the problems that Non-Patent Document 1 has with the combination technique of combining Non-Patent Document 1 and Non-Patent Document 2 (the request delay of the Bad State receiver cannot be satisfied when the number of receivers is large) Is solved. However, the above combination technique still does not solve the other problem of Non-Patent Document 1 (the power saving effect cannot be sufficiently obtained when the number of receivers is small). The reason is that the above combination technique cannot avoid the phenomenon that radio resources are frequently assigned to Bad State receivers when the number of receivers is small.

  Furthermore, when the above combination technique is applied to, for example, an LTE downlink, there is a problem that the number of transmission information bits per band is reduced, and a sufficient power saving effect cannot be obtained. The reason why the number of transmission information bits per band decreases will be described. FIG. 13 is a diagram for explaining a problem of the scheduler when Non-Patent Document 1 and Non-Patent Document 2 are combined. Specifically, FIG. 13 is a diagram illustrating a relationship between assigned RBG candidates and channel quality. is there. In FIG. 13, the horizontal axis indicates the frequency (band of each RBG candidate), and the vertical axis indicates the channel quality. The scheduler performs allocation in units of RBGs. In FIG. 13, black circles indicate the channel quality of each RBG. In the scheduler, resource allocation candidates are determined so that the transmission data size per unit time is maximized. Therefore, allocation including an RBG having a relatively low channel quality relative to an RBG having a high channel quality is performed. May be done. For example, as shown in FIG. 13, allocation including RBG2 and RBG5 having low communication channel quality among the assignable RBG1-7 is performed. Here, in LTE, when a plurality of RBGs are allocated to the same terminal, the MCS is determined using the average channel quality of the allocated RBGs. Therefore, if the allocated band includes RBGs with low channel quality (for example, RBG2 and RBG5 in FIG. 13), it is not possible to select an MCS with high transmission efficiency. As a result, the number of transmission information bits per band decreases.

  An object of the present invention is to provide a radio resource allocation method, a radio resource allocation device, a radio communication system, and a computer program capable of realizing power saving while increasing the number of transmission information bits.

  An allocated radio resource determination method according to the present invention is an allocated radio resource determination method used for performing radio communication between a receiver and a transmitter, wherein radio channel quality between the transmitter and the receiver is determined. Calculating a quality index value from the first resource block, a first selection process for selecting a resource block having a large number of transmission information bits from the predetermined resource block group as an allocation candidate using the quality index value, and a predetermined resource block A step of determining a resource block for performing the wireless communication by executing, in a predetermined order, a second selection process for selecting a resource block having a high wireless channel quality from among a group as an allocation candidate. And one of the first selection process and the second selection process performs the selection process on the other selection result. That.

  An allocated radio resource determination apparatus according to the present invention is an allocated radio resource determination apparatus used for performing radio communication between a receiver and a transmitter, wherein the radio channel quality between the transmitter and the receiver Calculating means for calculating a quality index value from a first resource, a first selection process for selecting a resource block having a large number of transmission information bits from among a predetermined resource block group as an allocation candidate using the quality index value, and a predetermined resource A second selection process for selecting a resource block having a high wireless channel quality from among the block group as an allocation candidate is executed in a predetermined order to determine an allocation resource block for performing the wireless communication. Determining means, wherein one of the first selection process and the second selection process is the result of the selection of the other. To run the selection process for.

  The wireless communication system of the present invention includes a receiver, a transmitter, and an allocated radio resource determination device that determines an allocated radio resource used to perform wireless communication between the receiver and the transmitter, The allocated radio resource determination device uses a calculation means for calculating a quality index value from quality of a radio channel between the transmitter and the receiver, and transmits the quality index value from a predetermined resource block group. A first selection process for selecting a resource block having a large number of information bits as an allocation candidate; and a second selection process for selecting a resource block having a high radio channel quality as an allocation candidate from a predetermined resource block group. Determining means for determining an allocation resource block for performing the wireless communication by executing in a predetermined order, In the first selection process and one of the second selection process, it performs the selection processing for the other selection result.

  The computer program according to the present invention allows a computer of an apparatus for determining an assigned radio resource to be used for performing wireless communication between a receiver and a transmitter, from a wireless channel quality between the transmitter and the receiver. A function for calculating a quality index value; a first selection process for selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; and a predetermined resource block group A function of determining a resource block for performing the wireless communication by executing a second selection process for selecting a resource block having a high wireless communication channel quality as an allocation candidate from a predetermined order in a predetermined order; One of the first selection process and the second selection process performs a selection process on the other selection result To the execution.

  According to the present invention, it is possible to realize power saving while increasing the number of transmission information bits.

It is a block diagram which shows the structural example of the radio | wireless communications system of the 1st Embodiment of this invention. It is a flowchart which shows the example of an operation | movement procedure of the allocation part in the 1st Embodiment of this invention. It is a figure for demonstrating the specific example of selection operation | movement of the allocation RBG candidate in the allocation part of the 1st Embodiment of this invention. It is a flowchart which shows the example of an operation | movement procedure of the allocation part in the 2nd Embodiment of this invention. It is a figure for demonstrating the specific example of selection operation | movement of the allocation RBG candidate in the allocation part of the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the radio | wireless communications system of the 3rd Embodiment of this invention. It is a flowchart which shows the example of an operation | movement procedure of the allocation part in the 3rd Embodiment of this invention. It is a figure for demonstrating the specific example of the operation | movement of selection of the allocation RBG candidate in the allocation part of the 3rd Embodiment of this invention. It is a block diagram which shows the structural example of the radio | wireless communications system of the 4th Embodiment of this invention. It is a flowchart which shows the example of an operation | movement procedure of the allocation part in the 4th Embodiment of this invention. It is a block diagram which shows the structural example of the radio | wireless resource allocation apparatus of the 5th Embodiment of this invention. It is a figure explaining the radio | wireless resource allocation method in the scheduler described in the nonpatent literature 1. FIG. It is a figure for demonstrating the subject of the scheduler at the time of combining a nonpatent literature 1 and a nonpatent literature 2, and is a figure which shows the relationship between the RBG candidate allocated and communication path quality in detail.

[First Embodiment]
In this embodiment, an LTE downlink will be described as an example. Also, since the radio access scheme in the case of downlink is OFDMA (Orthogonal Frequency Division Multiple Access), RBs that are not adjacent to each other can be assigned. In the present embodiment, the allocation unit is RBG.

  FIG. 1 is a block diagram illustrating a configuration example of a wireless communication system according to the first embodiment of the present invention. The wireless communication system includes a base station 100 and a terminal 200. In the downlink, the base station 100 functions as a transmitter, and the terminal 200 functions as a receiver. Base station 100 and terminal 200 are connected via a wireless line. Base station 100 can be connected to a terminal (not shown) other than terminal 200. The base station 100 is connected to other base stations (not shown) via a network (not shown).

  Base station 100 includes transmission / reception section 101, reference signal generation section 102, and allocation section 103.

  The transceiver unit 101 has a function equivalent to that of a general base station transceiver unit. Further, in the present embodiment, the transmission / reception unit 101 performs data transmission to the terminal 200 based on the radio resource allocation information notified from the allocation unit 103. Further, the transmission / reception unit 101 performs transmission of the reference signal generated by the reference signal generation unit 102 to the terminal 200, notification of the channel quality information notified from the terminal 200 to the allocation unit 103, and the like. In the present embodiment, a preset fixed value is assigned as the transmission power for each RB. In the present embodiment, CQI is used as an example of channel quality information.

  The reference signal generation unit 102 generates a reference signal at a predetermined timing and transmits the generated reference signal to the transmission / reception unit 101.

  The allocation unit 103 selects an RBG allocated to the terminal 200 based on the CQI notified from the transmission / reception unit 101, and transmits radio resource allocation information including information about the selected allocation RBG to the transmission / reception unit 101.

  The allocation unit 103 includes an allocation determination unit 104, a first allocation candidate selection unit 105, and a second allocation candidate selection unit 106.

  The allocation determination unit 104 calculates a quality index from the CQI received from the terminal 200 via the transmission / reception unit 101. The allocation determination unit 104 sends the calculated quality index and the allocation RBG candidate (in this case, the allocation RBG before update to the first allocation candidate selection unit 105 or, for example, updated by the second allocation candidate selection unit 106 It may be an assigned RBG candidate). The allocation determination unit 104 receives the updated allocation RBG candidate from the first allocation candidate selection unit 105. Also, the assignment determination unit 104 sends the second assignment candidate selection unit 106 to the CQI and the assignment RBG candidate (in this case, the assignment RBG candidate before update may be used, or, for example, updated by the first assignment candidate selection unit 105 It may be an assigned RBG candidate). The allocation determination unit 104 receives the updated allocation RBG candidate from the second allocation candidate selection unit 106. Then, allocation determination section 104 selects the allocation RBG candidate updated by both first allocation candidate selection section 105 and second allocation candidate selection section 106 as the allocation RBG to terminal 200. Allocation determining section 104 inputs radio resource allocation information including allocation RBG and MCS Index to transmission / reception section 101.

  The first allocation candidate selection unit 105 selects an RBG candidate having a high transmission information bit number from the allocation RBG candidates input from the allocation determination unit 104 based on the quality index, and allocates the selected RBG candidate to the allocation determination unit 104. To notify. In the present embodiment, TBS is used as the number of transmission information bits.

  The second allocation candidate selection unit 106 has a function of setting the RBG number deletion rate R_RbgReduce. The second allocation candidate selection unit 106 selects and selects an RBG candidate having a high transmission bit index per band from the allocation RBG candidates input from the allocation determination unit 104 using the RBG count deletion rate R_RbgReduce and CQI It has a function of notifying the allocation determining unit 104 of RBG candidates. In this embodiment, the number of transmission information bits per band (TBS / RBG number) is used as a transmission bit index per band.

  The terminal 200 includes a transmission / reception unit 201 and a communication path quality measurement unit 202.

  The transmission / reception unit 201 has a function equivalent to that of a general terminal transmission / reception unit. In the present embodiment, the transmission / reception unit 201 notifies the communication channel quality measurement unit 202 of the reference signal received from the base station 100 and the communication channel quality information notified from the communication channel quality measurement unit 202 to the base station 100. Make reports.

  The communication channel quality measuring unit 202 has a function of measuring the communication channel quality of the reference signal and reporting it to the transmission / reception unit 201 as communication channel quality information. CQI is reported as channel quality information.

  FIG. 2 is a flowchart illustrating an example of an operation procedure of the assignment unit 103 according to the first embodiment.

First, the assignment determination unit 104 selects a terminal having the maximum average value AveMet (k, t) of the quality indicators Met (k, i, t) of each RBG as an assigned terminal (step S11). k represents a terminal number, i represents an RBG number, and t represents a time. AveMet (k, t) can be calculated using the following equation (1).

A method for calculating the quality index will be described. In this embodiment, a metric of a PF (Proportional Fairness) scheduler is used as the quality index Met (k, i, t). The PF scheduler is a scheduler that realizes throughput improvement while considering fairness by using propagation path quality. Met (k, i, t) can be calculated using the following equation (2).

Here, TBS_RBG (k, i, t) indicates a TBS that can be transmitted at time t and RBGi. TBS_Ave (k, t) indicates an average TBS at time t. TBS_RBG (k, i, t) is obtained from a TBS Index that is uniquely calculated using the CQI and the number of RBs (details will be described in the background art). TBS_Ave (k, t) can be calculated using the following equation (3).

  Here, δ (t) indicates an assignment indicator at time t, and is 1 when transmitting data, and 0 otherwise. W represents a smoothing weighting coefficient. TBS_Inst (t) indicates the TBS of the RBG allocated at time t. If no assignment is made, TBS_Inst (t) is zero.

  Returning to the description of FIG. 2, the allocation determination unit 104 selects the RBG having the highest quality index of the allocated terminal as an allocated RBG candidate for all RBGs that can be allocated (step S12).

  The first allocation candidate selection unit 105 searches for an RBG combination having the maximum TBS from the allocation RBG candidates input from the allocation determination unit 104, selects the RBG combination as an allocation RBG candidate, and sets the updated allocation RBG candidate as It outputs to the allocation determination part 104 (step S13).

The second allocation candidate selection unit 106 uses the allocation RBG candidate notified from the allocation determination unit 104 (for example, the allocation candidate RBG updated by the first allocation candidate selection unit 105) and the RBG number reduction rate R_RbgReduce. The number N of RBGs to be calculated is calculated using the following equation (4) (step S14).

  In Expression (4), N_RbgCand represents the number of allocation candidate RBGs input from the allocation determination unit 104. Floor (x) is a function that returns a maximum integer that does not exceed x.

  The second allocation candidate selection unit 106 selects an RBG candidate in which N RBGs are deleted from the allocation RBG candidates notified from the allocation determination unit 104 in ascending order of quality index as an updated allocation RBG candidate. It outputs to 104 (step S15).

  The allocation determination unit 104 allocates the allocation RBG candidate updated by both the first allocation candidate selection unit 105 and the second allocation candidate selection unit 106 to the terminal selected in Step S11 (Step S16).

  FIG. 3 is a diagram for describing a specific example of an operation for selecting an allocation RBG candidate in the allocation unit 103 according to the first embodiment. Specifically, FIG. 3 shows the final assigned RBG candidate after the RBG having the highest quality index is selected as the assigned RBG candidate (after the processing of S12 in FIG. 2) in the assigning unit 103 of the present embodiment. A specific example of the operation until the selection is completed (after the process of step S15 in FIG. 2) is shown. In this specific example, the RBG number deletion rate R_RbgReduce is set to 0.5. As a result, since the number of assigned RBs is halved at the maximum, the transmission delay time is doubled at the maximum. In FIG. 3, a large square indicated by a thick broken line indicates each of the first to third assigned RBG candidates, each number in a small square indicated by a solid line indicates a CQI Index of each RBG, and a number next to the small square indicates an RBG number Indicates. In the lower part of FIG. 3, the number of RBGs of each allocation candidate, the MCS Index and TBS that can be selected in each allocation RBG candidate, and the transmission bit index per band are shown. In the present embodiment, the transmission bit index per band is TBS per RBG (TBS / RBG number). As the transmission bit index per band is higher, the total number of RBGs required for transmission of a predetermined data size can be reduced, so that the power saving effect is increased.

  First, in FIG. 3, the assigned RBG candidate after the process of step 12 (that is, the assigned RBG candidate whose assigned terminal quality index is the highest RBG) is defined as the first assigned RBG candidate. As a result of calculation by the method shown in the background art, it is assumed that the MCS Index of the first assigned RBG candidate is 14 and the TBS is 450 bits.

  As illustrated in FIG. 3, by executing the process of step S <b> 13, the second assigned RBG candidate that maximizes the TBS is selected from the first assigned RBG candidates. As a result, RBG # 4 with the lowest CQI is deleted from the candidates, thereby increasing the average channel quality of the candidates. Accordingly, the second allocation RBG candidate can select an MCS Index (= 15) that is larger than the first allocation RBG candidate.

  Next, although not shown in FIG. 3, the number N of RBGs to be deleted is calculated as floor (6 * 0.5) = 3 by executing the process of step S14. Then, as shown in FIG. 3, by executing the process of step S15, the third assigned RBG candidate from which the three lower quality RBGs are deleted is selected from the second assigned RBG candidates. In the same tendency as in step S13, the average channel quality of the candidate is increased by deleting the RBG having a low CQI. As a result, the third assigned RBG candidate is larger than the second assigned RBG candidate. Index (= 17) can be selected.

  As is clear from this specific example, in the third assigned RBG candidate, the transmission bit index per band is improved from 83 to 133 of the second assigned RBG candidate that maximizes the TBS.

  According to the first embodiment described above, since the allocated RBG candidate is selected in consideration of TBS, RBG selection considering the number of transmission information bits can be performed. Furthermore, in the first embodiment, RBGs with low channel quality are deleted from the assigned RBG candidates, so that MCS with high transmission efficiency can be selected, and as a result, the total number of RBGs necessary for transmission can be reduced. Power saving can be realized. That is, according to the first embodiment described above, it is possible to realize power saving while increasing the number of transmission information bits.

[Second Embodiment]
The difference of the second embodiment from the first embodiment is that the operation of the assigning unit 103 shown in FIG. 1 is different, and the configuration in this embodiment is the same as that of the first embodiment (FIG. 1). Therefore, description of the configuration is omitted, and only the difference in operation will be described below.

  FIG. 4 is a flowchart illustrating an example of an operation procedure of the assigning unit 103 in the present embodiment. In the case of the operation procedure example of the present embodiment shown in FIG. 4, the process of step S13 is executed after the processes of step S14 and step S15 are executed with respect to the operation procedure example of the first embodiment shown in FIG. Is different. That is, the processing order is different between the first embodiment and the second embodiment. Note that the processing contents themselves of steps S11 to S16 in FIG. 4 are the same as those in the first embodiment (the flowchart shown in FIG. 2), and thus description thereof is omitted here.

  FIG. 5 is a diagram for explaining a specific example of an operation for selecting an allocation RBG candidate in the allocation unit 103 according to the second embodiment. Specifically, FIG. 5 shows the final assigned RBG candidate after the RBG having the highest quality index is selected as the assigned RBG candidate (after the processing of S12 in FIG. 4) in the assigning unit 103 of the present embodiment. A specific example of the operation until the selection is completed (after the process of step S13 in FIG. 4) is shown. In the second embodiment, the RBG number deletion rate R_RbgReduce is set to 0.5 as in the first embodiment. Also, in FIG. 5, the assigned RBG candidate after the processing in step 12 (that is, the assigned RBG candidate whose assigned terminal quality index is the highest RBG) is defined as the first assigned RBG candidate.

  First, although not shown in FIG. 5, the number N of RBGs to be deleted is calculated as follows from the number of RBGs of the first allocation candidate and R_RbgReduce by executing the process of step S <b> 14. Calculated. Then, as shown in FIG. 5, by executing the process of step S <b> 15, the second assigned RBG candidate from which the three lower quality RBGs are deleted is selected from the first assigned RBG candidate. Next, as shown in FIG. 5, by executing the process of step S <b> 13, the third assigned RBG candidate that maximizes the TBS is selected from the second assigned RBG candidates.

  According to the second embodiment described above, it is possible to select an allocation RBG candidate that maximizes the number of transmission information bits while reducing the number of RBGs by a certain value.

[Third Embodiment]
FIG. 6 is a block diagram illustrating a configuration example of a wireless communication system according to the third embodiment of the present invention. The difference from the wireless communication system of the first embodiment shown in FIG. 1 is the configuration of the assigning unit 103A. The allocating unit 103A includes a third allocation candidate selecting unit 107 instead of the second allocation candidate selecting unit 106 configuring the allocating unit 103 shown in FIG.

  The third allocation candidate selection unit 107 has a function of setting a target value TE_target of a transmission bit index per band and a function of calculating a transmission bit index TE per band. Further, the third allocation candidate selection unit 107 selects and selects an RBG candidate having a high transmission bit index per band from the allocation RBG candidates input from the allocation determination unit 104 using TE_target, TE, and CQI. A function of notifying the allocation determining unit 104 of the RBG candidates that have been processed.

  FIG. 7 is a flowchart illustrating an example of an operation procedure of the assignment unit 103 in the present embodiment. Compared with the operation procedure of the first embodiment shown in FIG. 2, in FIG. 7, steps S21 to S25 are executed instead of steps S14 and S15 in FIG. Since the other processes (steps S11 to S13 and S16) in FIG. 7 are the same as those in the first embodiment, the description thereof will be omitted below.

  The third allocation candidate selection unit 107 transmits the allocation RBG candidate (for example, the allocation candidate RBG updated by the first allocation candidate selection unit 105) notified from the allocation determination unit 104 after step S13 is executed per band. A bit index TE0 is calculated (step S21). In this embodiment, the number of transmission information bits per band (TBS / RBG number) is used as a transmission bit index per band.

Next, the third allocation candidate selection unit 107 calculates the target value TE_Target of the transmission bit index per band by the following equation (5) using the calculated TE0 (step S22).

  Here, a is a coefficient indicating the improvement rate and is a positive value. For example, when a = 1.2, the improvement rate with respect to TE0 is 20%.

  Next, the third allocation candidate selection unit 107 calculates a transmission bit index TE per band of a candidate obtained by deleting the RBG having the lowest quality index from the allocation RBG candidates (step S23). The third allocation candidate selection unit 107 compares TE and TE_target (step S24). When TE is less than TE_Target (No determination in step S24), the third allocation candidate selection unit 107 updates the candidate at that time as an allocation RBG candidate (step S25), and executes step S23 again. On the other hand, when TE is equal to or greater than TE_Target (Yes in step S24), third allocation candidate selection section 107 returns the candidate at that time as an output to allocation determination section 104. The allocation determination unit 104 allocates the allocation RBG candidate updated by the third allocation candidate selection unit 107 to the selected terminal (step S16).

  FIG. 8 is a diagram for explaining a specific example of the operation for selecting an allocation RBG candidate in the allocation unit 103A according to the third embodiment. Specifically, FIG. 8 shows the final assigned RBG candidate after the RBG having the highest quality index is selected as the assigned RBG candidate (after the processing of S12 in FIG. 7) in the assigning unit 103A of the present embodiment. A specific example of the operation until the selection is completed (after the process of step S24 in FIG. 7) is shown. In this specific example, the coefficient a indicating the improvement rate of Equation (5) is 1.2. Also, in FIG. 8, the assigned RBG candidate after the processing in step 12 (that is, the assigned RBG candidate whose assigned terminal quality index is the highest RBG) is defined as the first assigned RBG candidate.

  First, by executing the process of step S13, a second assigned RBG candidate having the maximum TBS is selected from the first assigned RBG candidates. By executing step S21, the transmission bit index TE0 per band of the second assigned RBG candidate is calculated as 500/6 = 83. By executing step S22, the target value TE_Target of the transmission bit index per band of the second assigned RBG candidate is calculated as 83 * 1.2 = 99.6. By executing step S23, the transmission bit index TE per band of the third assigned RBG candidate obtained by deleting the lower quality RBG # 7 from the second assigned RBG candidate is calculated as 450/5 = 90. In step S24, since it is determined that TE (= 90) is less than TE_Target (= 99.6), the third allocation RBG candidate is updated as an allocation candidate, and the process is executed again from step S23. By executing step S23 again, the transmission bit index TE per band of the fourth assigned RBG candidate obtained by deleting the lower quality RBG # 5 from the third assigned RBG candidate is further calculated as 420/4 = 105. The In this case, since it is determined in step S24 that TE (= 105) is equal to or higher than TE_Target (= 99.6), the fourth assigned RBG candidate is selected as the final assigned RBG candidate.

  According to the third embodiment described above, similarly to the first embodiment, since the allocated RBG candidate is selected in consideration of TBS, RBG selection considering the number of transmission information bits can be performed. Furthermore, in the third embodiment, RBGs with low channel quality are deleted from the assigned RBG candidates, and resource blocks whose transmission bit index per band is equal to or higher than a reference value are selected as assignment candidates. Therefore, an MCS with high transmission efficiency can be selected, and as a result, the total number of RBGs necessary for transmission can be reduced, so that power saving can be realized.

[Fourth Embodiment]
FIG. 9 is a block diagram illustrating a configuration example of a wireless communication system according to the fourth embodiment of this invention. The present embodiment is a configuration example in which the first embodiment is applied to the uplink. In the uplink, the terminal functions as a transmitter and the base station functions as a receiver. In the allocation unit 103B of the base station 300 in FIG. 9, a fourth allocation candidate selection unit 108 is provided instead of the first allocation candidate selection unit 105 shown in FIG. Also, as shown in FIG. 9, in the wireless communication system of this embodiment, a channel quality measurement unit 202 that exists in the terminal 200 in FIG. 1 is provided in the base station 300. On the other hand, in the wireless communication system of the present embodiment, a reference signal generation unit 102 present in the base station 100 in FIG.

  In the present embodiment, the transmission / reception unit 201 configuring the terminal 400 transmits the reference signal generated by the reference signal generation unit 102 to the base station 300 or to the base station 300 according to the scheduling information notified from the base station 300. Send data.

  In the present embodiment, the uplink radio access scheme is SC-FDMA (Single Carrier FDMA), and a continuous RB group is allocated. In this embodiment, the allocation unit is RB.

  FIG. 10 is a flowchart illustrating an example of an operation procedure of the assignment unit 103B in the present embodiment. Compared to the operation procedure example of the first embodiment shown in FIG. 2, in FIG. 10, step S31 is executed instead of step S12 in FIG. The allocation unit is an RB unit. Since the other processes (steps S11 and S13 to S16) in FIG. 10 are the same as those in the first embodiment, the description thereof will be omitted below.

  For all allocable RBs, fourth allocation candidate selection section 108 selects an RB group having the highest quality index of the allocated terminal as an RB candidate among consecutive RBs (step S31).

  According to the fourth embodiment described above, it is possible to realize power saving while increasing the number of transmission information bits in the uplink in the radio communication system as in the first embodiment.

[Fifth Embodiment]
FIG. 11 is a block diagram illustrating a configuration example of a radio resource allocation device 500 according to the fifth embodiment of this invention. The radio resource allocation device 500 is a device that allocates radio resources to be used for performing radio communication between the receiver and the transmitter. The radio resource allocation device 500 includes a calculation unit 502 (calculation unit) and a determination unit 504 (determination unit).

  The calculation unit 502 calculates a quality index value from the quality of the wireless channel between the transmitter and the receiver.

  The determination unit 504 executes the first selection process and the second selection process in a predetermined order, and determines an allocation resource block for performing wireless communication. In the first selection process, a resource block having a large number of transmission bits is selected as an allocation candidate from the predetermined resource block group using the quality index value. In the second selection process, a resource block having a high wireless channel quality is selected as an allocation candidate from a predetermined resource block group. In the determination unit 504, one of the first selection process and the second selection process performs the selection process on the other selection result.

  With the configuration of the fifth embodiment described above, it is possible to realize power saving while increasing the number of transmission information bits.

[Other Embodiments]
As mentioned above, although several embodiment was described about this invention, this invention is not limited to the said embodiment.

  For example, in the third embodiment, the number of transmission information bits per band (number of TBS / RBG) is used as the transmission bit index per band, but the present invention is not limited to this. The transmission bit index per band can be, for example, TBS Index or MCS Index.

  Further, as a method for updating the allocation RBG candidate in the third allocation candidate unit 107 of the third embodiment, a candidate at the time when the transmission bit index per band first reaches the target value of the transmission bit index per band is allocated RBG Although it selected as a candidate, it is not limited to this. For example, the transmission bit index per band for all combinations may be calculated, and the combination having the highest transmission bit index per band may be selected as the assigned RBG candidate.

  According to the first to fourth and other embodiments described above, a resource block having the maximum transmission bit index per band can be selected as an allocation candidate, so that an MCS with high transmission efficiency can be selected. As a result, since the total number of RBGs required for transmission can be reduced, power saving can be realized.

  The first to fifth embodiments described above and other embodiments can be embodied as predetermined hardware, for example, a circuit.

  The first to fifth embodiments described above and the other embodiments can be controlled and operated by a computer circuit (for example, a CPU (Central Processing Unit)) (not shown) based on a control program. In this case, these control programs are stored, for example, in an allocation device, a base station, a storage medium inside the wireless communication system, or an external storage medium, and read and executed by the computer circuit. Examples of the internal storage medium include a ROM (Read Only Memory) and a hard disk. Moreover, examples of the external storage medium include a removable medium and a removable disk.

(Appendix 1)
An allocated radio resource determination method according to another embodiment of the present invention is an allocated radio resource determination method used to perform radio communication between a receiver and a transmitter, between the transmitter and the receiver. Calculating a quality index value from the quality of the wireless channel, and a first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; An allocation resource for performing the radio communication by executing, in a predetermined order, a second selection process of selecting a resource block having a high radio channel quality from a predetermined resource block group as an allocation candidate. Determining a block, wherein one of the first selection process and the second selection process is performed on the other selection result. To run-option process.

(Appendix 2)
In the allocated radio resource determination method according to attachment 1, the second selection process is executed on a selection result of the first selection process.

(Appendix 3)
In the allocated radio resource determination method according to attachment 1, the first selection process is executed on a selection result of the second selection process.

(Appendix 4)
In the allocation radio resource determination method according to any one of attachments 1 to 3, the second selection process selects a predetermined number of resource blocks as allocation candidates.

(Appendix 5)
In the allocated radio resource determination method according to attachment 4, the predetermined number of resource blocks is obtained as a result of deleting resource blocks with low channel quality.

(Appendix 6)
The allocated radio resource determination method according to any one of appendices 1 to 3, wherein the second selection process calculates a transmission bit index per band, and the transmission bit index per band is equal to or greater than a predetermined reference value. Select a block as an allocation candidate.

(Appendix 7)
The allocation radio resource determination method according to any one of attachments 1 to 3, wherein the second selection process calculates a transmission bit index per band and allocates a resource block that maximizes the transmission bit index per band. Select as a candidate.

(Appendix 8)
An allocated radio resource determination apparatus according to another embodiment of the present invention is an allocated radio resource determination apparatus used for performing radio communication between a receiver and a transmitter, and includes an allocation between the transmitter and the receiver. Calculating means for calculating a quality index value from the wireless channel quality between the first and second resource blocks having a large number of transmission information bits among the predetermined resource block group using the quality index value as a candidate for allocation Performing the wireless communication by executing a process and a second selection process for selecting, as a candidate for allocation, a resource block having a high wireless channel quality from a predetermined group of resource blocks in a predetermined order. Determining means for determining an allocation resource block, wherein in the determining means, one of the first selection process and the second selection process , It performs the selection processing for the other selection result.

(Appendix 9)
A radio communication system according to another embodiment of the present invention includes a receiver, a transmitter, and an allocated radio resource determination that determines an allocated radio resource to be used for performing radio communication between the receiver and the transmitter. And the allocated radio resource determination device includes: a calculating unit that calculates a quality index value from a quality of a radio channel between the transmitter and the receiver; and the quality from a predetermined group of resource blocks. A first selection process for selecting a resource block having a large number of transmission information bits as an allocation candidate using an index value; and Determining means for determining the allocated resource block for performing the wireless communication by performing the selection process of 2 in a predetermined order; Comprising, in the determination unit, wherein the first selection process and one of the second selection process, performs the selection processing for the other selection result.

(Appendix 10)
A computer program according to another embodiment of the present invention provides a computer program for determining an assigned radio resource to be used for wireless communication between a receiver and a transmitter between the transmitter and the receiver. A function of calculating a quality index value from the quality of the wireless communication channel, and a first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; An allocation resource for performing the radio communication by executing, in a predetermined order, a second selection process of selecting a resource block having a high radio channel quality from a predetermined resource block group as an allocation candidate. One of the function for determining a block and the first selection process and the second selection process is selected for the other selection result And the ability to run a sense, to the execution.

(Appendix 11)
In the allocation radio resource determination method according to attachment 1, the transmitter is a base station and the receiver is a terminal.

(Appendix 12)
In the allocation radio resource determination method according to attachment 1, the transmitter is a terminal and the receiver is a base station.

(Appendix 13)
In the allocation radio resource determination method according to attachment 6 or 7, the transmission bit index per band is a transmission data size.

(Appendix 14)
In the allocated radio resource determination method according to attachment 6 or 7, the transmission bit index per band is MCS Index.

(Appendix 15)
In the allocated radio resource determination method according to attachment 6 or 7, the transmission bit index per band is TBS Index.

100, 300 Base station 101 Transmission / reception unit 102 Reference signal generation unit 103, 103A, 103B Allocation unit 104 Allocation determination unit 105 First allocation candidate selection unit 106 Second allocation candidate selection unit 107 Third allocation candidate selection unit 108 Fourth allocation candidate Selection unit 200, 400 Terminal 201 Transmission / reception unit 202 Channel quality measurement unit 500 Radio resource allocation device 502 Calculation unit 504 Determination unit

Claims (10)

An allocated radio resource determination method used to perform radio communication between a receiver and a transmitter,
Calculating a quality index value from the quality of the radio channel between the transmitter and the receiver;
A first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; and the wireless channel quality from the predetermined resource block group Performing a second selection process of selecting a high resource block as an allocation candidate in a predetermined order to determine an allocation resource block for performing the wireless communication;
With
One of the first selection process and the second selection process performs a selection process on the other selection result, and an assigned radio resource determination method, characterized in that:   The allocated radio resource determination method according to claim 1, wherein the second selection process is executed on a selection result of the first selection process.   The allocated radio resource determination method according to claim 1, wherein the first selection process is executed on a selection result of the second selection process.   The allocated radio resource determination method according to claim 1, wherein the second selection process selects a predetermined number of resource blocks as allocation candidates.   5. The allocated radio resource determination method according to claim 4, wherein the predetermined number of resource blocks are obtained as a result of deleting resource blocks having low channel quality.   The second selection process calculates a transmission bit index per band, and selects a resource block having a transmission bit index per band equal to or greater than a predetermined reference value as an allocation candidate. The allocated radio resource determination method according to any one of the above.   4. The method according to claim 1, wherein the second selection process calculates a transmission bit index per band and selects a resource block having a maximum transmission bit index per band as an allocation candidate. 2. The allocated radio resource determination method according to item 1. An allocated radio resource determination device used to perform radio communication between a receiver and a transmitter,
Calculating means for calculating a quality index value from the quality of the radio channel between the transmitter and the receiver;
A first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; and the wireless channel quality from the predetermined resource block group Determining means for determining a resource block for performing the wireless communication by executing a second selection process for selecting a high resource block as an allocation candidate in a predetermined order;
With
In the determining means, one of the first selection process and the second selection process performs a selection process on the other selection result, and an assigned radio resource determination apparatus, A receiver,
A transmitter,
An allocated radio resource determination device for determining an allocated radio resource used for performing radio communication between the receiver and the transmitter;
With
The allocated radio resource determination device includes:
Calculating means for calculating a quality index value from the quality of the radio channel between the transmitter and the receiver;
A first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; and the wireless channel quality from the predetermined resource block group Determining means for determining a resource block for performing the wireless communication by executing a second selection process for selecting a high resource block as an allocation candidate in a predetermined order;
With
In the determining means, one of the first selection process and the second selection process executes a selection process on the other selection result. A computer of an apparatus for determining an assigned radio resource to be used for wireless communication between a receiver and a transmitter;
A function of calculating a quality index value from the quality of a wireless channel between the transmitter and the receiver;
A first selection process of selecting a resource block having a large number of transmission information bits as an allocation candidate from the predetermined resource block group using the quality index value; and the wireless channel quality from the predetermined resource block group A function of executing a second selection process of selecting a high resource block as an allocation candidate in a predetermined order, and determining an allocation resource block for performing the wireless communication;
One of the first selection process and the second selection process is a computer program for executing a function of executing a selection process on the other selection result.

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