JP6285380B2 - Scheduling apparatus and method - Google Patents

Description

  The present invention relates to a radio network control technique, and more particularly to a scheduling technique for assigning radio resources possessed by a radio network system by designating the operation content (transmission state) of each transmission point in the radio network.

  With the widespread use of smartphones, social demands on wireless networks, such as improved communication speed and increased bandwidth usage, are increasing. Against this background, wireless network systems to which wireless interface specifications of the next generation mobile communication system called LTE (Long Term Evolution) are applied are becoming widespread. In this LTE, as one of radio access technologies, CoMP (Coordinated Multi-point transmission / reception: CoMP) in which a plurality of transmission points (TP: base station) cooperate with each other to transmit / receive signals to / from user terminals (UE: user radio terminals). Inter-cell cooperative transmission / reception is employed (see Non-Patent Document 1).

  The CoMP technique is one of important techniques for improving frequency utilization efficiency and cell edge user throughput. For example, in downlink communication (transmission from TP to UE), the use efficiency of radio resources can be improved by simultaneously transmitting a plurality of TPs to each UE using the same frequency band. However, when each TP is transmitted to a different UE, for UEs that can receive signals from a plurality of TPs, signals from other TPs interfere with the desired received signal, leading to a decrease in throughput. There is a fear. Therefore, CoMP has become an indispensable technology for improving the communication speed while suppressing such interference.

  In addition, when applying CoMP to a wireless network, for the purpose of maximizing system throughput, priority is given to resource allocation to users with good reception conditions, resulting in problems in fairness among users. Scheduling in consideration of the average rate so far is considered desirable (see Non-Patent Document 2).

Taoka et al., “MIMO and inter-cell cooperative transmission / reception technology in LTE-Advanced”, NTT DOCOMO Technical Journal, Vol. 18, No. 2, pp.22-30, July 2010, https: //www.nttdocomo. co.jp/binary/pdf/corporate/technology/rd/technical_journal/bn/vol18_2/vol18_2_022jp.pdf T. Girici, C. Zhu, JR Agre, and A. Ephremides, "Proportional Fair Scheduling Algorithm in OFDMA-Based Wireless Systems with QoS Constraints", Journal of Communications and Networks, Vol. 12, No. 1, pp. 30- 42, February 2010.

  When performing such scheduling in a wireless network system, the scheduling apparatus designates a transmission state for each TP, that is, a UE serving as a transmission destination or a transmission stop for each TP, as a resource allocation pattern having a maximum pattern evaluation value. CoMP processing for determining information is executed. This CoMP process is a process for calculating an evaluation value for each of a large number of resource allocation patterns and finding a resource allocation pattern having the best evaluation value, and needs to be completed within a scheduling period (for example, within a time of 1 ms).

  In such evaluation value calculation, the throughput corresponding to the resource allocation pattern is estimated for each UE, and further, the evaluation value for each UE is obtained from this throughput (for example, the ratio of the throughput to the past average rate is set as the evaluation value for each UE. ). In this throughput estimation calculation, the received SINR (Signal-to-Interference plus Noise power Ratio; the ratio of signal power to the sum of interference power and noise power) of each UE is estimated, and the throughput according to the received SINR is obtained (for example, Draw a table that correlates received SINR and throughput).

  In the above-described estimation calculation of received SINR, received power from each TP is input from the outside (for example, a base station), and these are used as signal power and interference power based on a resource allocation pattern. Each UE measures CQI (Channel Quality Indicator) and notifies the base station through the uplink channel, so that the base station can estimate received power based on the CQI.

  Here, in order to complete the process of finding the resource allocation pattern with the optimum evaluation value within the scheduling period, it is necessary to calculate the evaluation value for each UE at a high speed. The calculation of the evaluation value for each UE for each UE can be accelerated by providing a circuit for each UE and performing parallel processing. However, according to such a configuration, when the scale of the radio network system increases, the number of UEs handled by the scheduling apparatus increases, so that it is necessary to increase the number of circuits for each UE, and the cost of the scheduling apparatus increases. There was a problem.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a scheduling technique that can realize low cost by reducing the circuit scale.

In order to achieve such an object, a scheduling apparatus according to the present invention provides a radio resource for performing radio communication between a transmission point and each user terminal in a wireless network system having a plurality of transmission points. A scheduling apparatus that performs allocation, a pattern generation unit that sequentially creates a resource allocation pattern for designating an operation content indicating a transmission destination user terminal or transmission stop for each transmission point, and each resource allocation pattern A pattern evaluation unit for calculating a pattern evaluation value for evaluating the radio resource allocation based on the resource allocation pattern, and a resource allocation pattern having the best pattern evaluation value among the resource allocation patterns. Radio resource allocation An optimal solution holding unit that selects as an optimal resource allocation pattern to be used, and the pattern evaluation unit stores an evaluation parameter table for each user terminal that stores an evaluation parameter for each user terminal input from the outside, and Based on the user terminal evaluation parameter for the user terminal that is provided for each transmission point and output from the user terminal evaluation parameter table, the transmission point-specific pattern evaluation value for the transmission point A plurality of transmission point-by-transmission pattern evaluation units, and by summing up these transmission point-by-transmission pattern evaluation values, a transmission point-by-transmission point evaluation for calculating a new resource allocation pattern generated by the pattern generation unit A total value unit, and the putter When generating a new resource allocation pattern, the generation unit sequentially creates a resource allocation pattern in which only the operation content at any one transmission point is different from the resource allocation pattern generated immediately before, were sequentially outputs the difference information indicating the pattern evaluation unit is read out from said user terminal based evaluation parameter table-out based on the difference information from the pattern generating unit, for each user terminal evaluation parameters corresponding to the difference Based on the transmission point pattern evaluation unit corresponding to the difference, the user terminal evaluation parameter for the user terminal that is the transmission destination of the transmission point is updated, and the transmission point pattern evaluation value for each transmission point is calculated. Then , the total by the transmission point evaluation value total part A pattern evaluation value relating to a simple resource allocation pattern is calculated.

  Further, in one configuration example relating to the scheduling device according to the present invention, the pattern evaluation unit is provided for each transmission point, and holds a plurality of transmission point evaluation parameters for each transmission point. A transmission point evaluation parameter storage unit corresponding to the difference, and a user terminal evaluation parameter corresponding to the difference read from the user terminal evaluation parameter table. As transmission point-specific evaluation parameters, and based on the transmission point-specific evaluation parameters output from these transmission point-specific evaluation parameter storage units, each transmission point-specific pattern evaluation unit calculates each transmission point-specific pattern evaluation value. It is a thing.

  Also, one configuration example relating to the scheduling device according to the present invention is based on pattern range information in which the pattern generation unit specifies, in advance, the operation content that the transmission point can actually take for each transmission point as an option. The resource allocation pattern is generated for each combination obtained by combining options.

  Also, in one configuration example relating to the scheduling device according to the present invention, the optimum solution holding unit includes a FIFO for storing the difference information sequentially output from the pattern generation unit, and the FIFO in the pattern evaluation unit The delay information is sequentially read out after being delayed by the time required for pattern evaluation value calculation, and the pattern evaluation values corresponding to the pattern evaluation values sequentially output from the pattern evaluation unit are read based on the difference information and the immediately preceding resource allocation pattern. Reproduction resource allocation patterns are sequentially generated, and a reproduction resource allocation pattern having the best pattern evaluation value among these reproduction resource allocation patterns is selected as the optimum resource allocation pattern.

The scheduling method according to the present invention is a scheduling method for assigning radio resources for radio communication between a transmission point and each user terminal to a wireless network system having a plurality of transmission points. , A pattern generation step for sequentially creating a resource allocation pattern for designating operation contents indicating a transmission destination user terminal or transmission stop for each transmission point, and for each resource allocation pattern based on the resource allocation pattern A pattern evaluation step for calculating a pattern evaluation value for evaluating the allocation of the radio resource, and an optimal resource allocation pattern having the best pattern evaluation value among the resource allocation patterns is used for actual radio resource allocation. An optimal solution selection step for selecting as a source allocation pattern, and the pattern evaluation step is provided for each of the transmission points, and stores an evaluation parameter for each user terminal of each user terminal input from the outside. A plurality of transmission point-specific pattern evaluation steps for calculating a transmission point-specific pattern evaluation value for the transmission point based on the user terminal-specific evaluation parameter for the user terminal that is the transmission destination of the transmission point, output from the evaluation parameter table; A pattern evaluation value summation step for each transmission point that calculates a pattern evaluation value for the new resource allocation pattern generated in the pattern generation step by summing the pattern evaluation values for each transmission point, and the pattern generation step Is When a new resource allocation pattern is generated, a resource allocation pattern in which only the operation content at any one transmission point is a difference is sequentially created in comparison with the resource allocation pattern generated immediately before, and difference information indicating the difference the sequentially outputs the pattern evaluation step, read from based-out said another user terminal evaluation parameter table on the difference information from the pattern generation step, based on each user terminal evaluation parameters corresponding to the difference, the Only in the pattern evaluation step by transmission point corresponding to the difference, the evaluation parameter by user terminal regarding the user terminal that is the transmission destination of the transmission point is updated, and the pattern evaluation value by transmission point for each transmission point is calculated and the transmission is performed. In the pattern evaluation value total step for each point By calculating, a pattern evaluation value related to a new resource allocation pattern is calculated.

  According to the present invention, the number of circuits for calculating evaluation values can be reduced, and the memory scale for storing evaluation parameters for each user terminal can be reduced. As a result, the cost of the scheduling apparatus can be reduced. It becomes possible. In addition, the pattern generation unit and the pattern evaluation unit can be operated at the same time, and the processing speed can be increased up to twice as much by these pipeline processes.

It is a block diagram which shows the structure of the scheduling apparatus concerning 1st Embodiment. It is an example of a structure of the pattern evaluation part of FIG. It is a flowchart which shows the pattern production | generation process concerning 1st Embodiment. It is a generation example of the resource allocation pattern concerning 1st Embodiment. It is a flowchart which shows the pattern production | generation process concerning 2nd Embodiment. It is a generation example of the resource allocation pattern concerning 2nd Embodiment.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, with reference to FIG. 1 and FIG. 2, the scheduling apparatus 10 concerning the 1st Embodiment of this invention is demonstrated. FIG. 1 is a block diagram illustrating a configuration of a scheduling apparatus according to the first embodiment. FIG. 2 is a configuration example of the pattern evaluation unit in FIG.

  The scheduling apparatus 10 is composed of an information processing apparatus such as a server apparatus as a whole, and is provided in a wireless network system with N (N is an integer of 2 or more) transmission points (TP: base) to be controlled. Station), by designating the user terminal (UE: user radio terminal) as a transmission destination and the operation content (transmission state) such as transmission suspension, the optimum resource allocation pattern used for allocation of radio resources possessed by the radio network It has a function to select.

  As shown in FIG. 1, the scheduling device 10 includes a pattern generation unit 11, a pattern evaluation unit 12, and an optimal solution holding unit 13 as main functional units.

The pattern generation unit 11 has a function of sequentially creating a resource allocation pattern for designating an operation content indicating a transmission destination user terminal or transmission stop for each transmission point.
The pattern evaluation unit 12 has a function of calculating a pattern evaluation value for evaluating radio resource allocation based on the resource allocation pattern for each resource allocation pattern.
The optimal solution holding unit 13 has a function of selecting a resource allocation pattern having the best pattern evaluation value from among the resource allocation patterns as an optimal resource allocation pattern used for actual radio resource allocation.

  In this configuration, as shown in FIG. 2, the present embodiment has an evaluation parameter table (UE) for each user terminal that stores, in the pattern evaluation unit 12, an evaluation parameter for each user terminal input from the outside. Separate evaluation parameter table) 22, and the transmission based on the user terminal-specific evaluation parameter relating to the user terminal that is the transmission destination of the transmission point, provided for each transmission point and output from the user terminal-specific evaluation parameter table 22. A plurality of transmission point-specific pattern evaluation units (TP-specific pattern evaluation units) 24 that calculate transmission point-specific pattern evaluation values related to points, and these transmission point-specific pattern evaluation values are summed up to generate the pattern generation unit 11. A transmission poi that calculates pattern evaluation values for new resource allocation patterns It is obtained by a preparative-based evaluation value summing unit 25.

  Then, when the pattern generation unit 11 generates a new resource allocation pattern, it sequentially creates a resource allocation pattern in which only the operation content at any one transmission point becomes a difference as compared with the resource allocation pattern generated immediately before. Then, the difference information indicating the difference is sequentially output, and the pattern evaluation unit 12 evaluates by user terminal corresponding to the difference read from the evaluation parameter table 22 by user terminal based on the difference information from the pattern generation unit 11. Based on the parameter, only the transmission point-specific pattern evaluation value corresponding to the difference is updated, and a new transmission point-specific pattern evaluation value is updated. For the new resource allocation pattern It is obtained so as to calculate the pattern evaluation value.

  As a result, the number of circuits for calculating the evaluation value can be reduced, the memory scale for storing the evaluation parameters for each user terminal can be reduced, and as a result, the cost of the scheduling apparatus 10 can be reduced. Become. In addition, the pattern generation unit 11 and the pattern evaluation unit 12 can be operated at the same time, and the processing speed can be increased up to twice as much by these pipeline processes.

  Next, each configuration of the scheduling apparatus 10 according to the first embodiment will be described in detail with reference to FIGS. 1 and 2.

[Pattern generator]
Based on the resource allocation pattern range setting (pattern range information) input from the outside, the pattern generating unit 11 controls each transmission point TP # i (i = 1... Ntp; Ntp; Corresponding to the transmission state, that is, the number of the destination user equipment UE (1... Nue; Nue is the maximum number of UEs that can be handled by the scheduling apparatus 10) or TP transmission stoppage. A resource allocation pattern T [i] (i = 1... Ntp) representing the value 0 is generated. The resource allocation pattern range setting is a restriction when generating a resource allocation pattern, and is a setting of choices for each TP # i, whether or not transmission stop can be selected and a UE that can be a transmission destination, that is, an option for each TP.

An example of the resource allocation pattern range setting is a format of a list of UE numbers that can be selected as a transmission destination for each TP, and Ns options [i, i,. k] (k = 1... Ns; Ns is the maximum number of options that can be set for each TP) and the number of effective options s [i] (s [i] ≦ Ns) among them.
In addition to the UE that can be the transmission destination for each TP specified as the resource allocation pattern range setting, the pattern generation unit 11 can select transmission stop for each TP. Furthermore, the selection of the transmission stop in each TP is made prior to the selection of the UE included in the resource allocation pattern range setting.

  The pattern generation unit 11 generates a plurality of resource allocation patterns one after another as time elapses. In these generations, the selection is changed for the resource allocation pattern generated immediately before and one TP. Note that the pattern generation unit 11 ends the generation when all the resource allocation patterns within the resource allocation pattern range setting are generated.

  As described above, the pattern generation unit 11 of the scheduling apparatus 10 according to the present embodiment does not generate a resource allocation pattern from all TP # i (i = 1... Ntp) for all UEs in the system as transmission targets. By generating a resource allocation pattern within the resource allocation pattern range setting input from the outside, it is possible to exclude in advance a pattern that is not likely to be an optimal solution or not. The speed can be increased by reducing the number of times the evaluation value is calculated. Note that the degree of speed-up varies depending on the resource allocation pattern range setting. For example, when the choice of each TP is limited to 1/2, the speed can be increased to 2 times the number of TPs.

  Whenever the pattern generation unit 11 generates a resource allocation pattern and compares these patterns with the resource allocation pattern generated immediately before the pattern generation, the transmission destination is different (from the previous pattern to the transmission destination UE). The pattern evaluation unit 12 uses, as difference information, a differential TP number (1... Ntp) that is a TP number and a differential UE number (1... Nue) that is a UE number that is the transmission destination of the TP. Output to. The pattern generation unit 11 does not output the difference TP number and the difference UE number to the pattern evaluation unit 12, but the generated resource allocation pattern T [i] (i = 1... Ntp) is sent to the pattern evaluation unit 12. The pattern evaluation unit 12 can generate a difference TP number and a difference UE number in the pattern evaluation unit 12 by comparing the resource allocation pattern input immediately before and the pattern input this time. is there.

  The pattern generation unit 11 also outputs the difference TP number and the difference UE number (difference information) output to the pattern evaluation unit 12 to the optimum solution holding unit 13 every time a resource allocation pattern is generated. This is because when the pattern evaluation unit 12 outputs an evaluation value for the resource allocation pattern to the optimal solution holding unit 13, and the optimal solution holding unit 13 determines that the evaluation value is the best, the optimal solution holding unit 13 responds. This is because the resource allocation pattern is reproduced using the difference TP number and the difference UE number to be held, and this is retained as the optimum solution. The pattern generation unit 11 does not output the differential TP number and the differential UE number to the optimal solution holding unit 13, but generates the generated resource allocation pattern T [i] (i = 1... Ntp) as the optimal solution holding unit. A configuration of outputting to 13 is also possible.

[Pattern generation processing]
Here, the pattern generation processing in the pattern generation unit 11 will be described with reference to FIG. FIG. 3 is a flowchart showing the pattern generation processing according to the first embodiment.

  The pattern generation unit 11 sets s [i] (s [i] ≦ Ns) that holds the number of options for each TP # i (i = 1... Ntp) as resource allocation pattern range settings, and each TP # i. Option [i, k] (k = 1... S [i]), which is a list of selectable transmission states. In the pattern generation unit 11, an option number [i] (1... S [i]) that represents as a number which option is currently selected by each TP # i is used.

  Further, when the selection of each TP # i (i = 1... Ntp) is updated, the update amount [i] (selective update) is a value indicating whether the option number [i] is incremented (+) or decremented (−). Sometimes the value added to option number [i] is used. In the selective update of TP # i, the update amount [i] is 1 when incrementing the option number [i], and the update amount [i] is -1 when decrementing. The update direction [i] may be used instead of the update amount [i]. Thus, when the update direction [i] is 1, the option number [i] is incremented, and when the update direction [i] is 0, the option number [i] is defined to be decremented. On the other hand, it can be expressed using a 1-bit update direction [i].

  Furthermore, in order to determine the TP number having a difference between the resource allocation pattern generated last time and the resource allocation pattern to be generated next, that is, the difference TP number, the TP number is sequentially tried from 1 to Ntp which is the number of TPs. Using the variable Itp. That is, Itp is used as a candidate for the differential TP number. However, when the pattern generation unit 11 is implemented as a circuit, trials from TP numbers 1 to Ntp can be performed simultaneously. In this case, the variable Itp is not used, and the flowchart shown in FIG. It is not necessary to operate according to this procedure, and it is only necessary that an equivalent operation is possible.

Hereinafter, the flowchart shown in FIG. 3 will be described in detail.
First, after starting the operation, the pattern generation unit 11 initializes the pattern generation unit 11 by selecting the top of the TP options for all TPs (step 100). Here, a process of setting 1 as the value of the option number [i] corresponding to each TP [i] and a process of setting 1 as the value of the update amount [i] are performed. Thereby, an initial pattern is generated.

  Next, the pattern generation unit 11 outputs the initial pattern generated in this way to the pattern evaluation unit 12 based on the difference information. Therefore, for each TP, the number of the TP is set as the difference TP number, and the first option of the TP is selected. Is output to the pattern evaluation unit 12 as a differential UE number (step 101). That is, for each TP number i when the TP number i is changed in the order of 1 to Ntp, i is output to the pattern evaluation unit 12 as i as the difference TP number and option [i, 1] as the difference UE number. As a result, the pattern generation unit 11 passes the resource allocation pattern to be generated first to the pattern evaluation unit 12.

Thereafter, in order to generate the next pattern, the pattern generation unit 11 initializes Itp by setting 1 to Itp (step 102). Itp is a candidate for a differential TP number.
Subsequently, the pattern generation unit 11 determines whether Itp becomes the differential TP number, that is, whether the option can be changed for TP # Itp (step 103).

Specifically, when the value obtained by adding the update amount [Itp] to the option number [Itp] is 1 or more and s [Itp] (number of options) or less, that is, the updated option number is within a normal range. If it is, it is determined that the option can be changed for TP # Itp.
When using a variable that represents the difference in the update direction instead of the update amount, if the value of this variable represents increment, the option number [Itp] <s [Itp] is determined, and the value of this variable represents decrement. Then, the option number [Itp]> 1 is determined.

  Here, when the current Itp is not the difference TP number (step 103: NO), the pattern generation unit 11 obtains a new candidate for the difference TP number by updating (incrementing) Itp. Return to the state where the first option is selected for the current TP # Itp (step 104). However, instead of returning to the first option (setting option number [Itp] to 1), the current selection is made the first option by reversing only the update direction. That is, the update amount [Itp] is changed from 1 to −1 and from −1 to 1. As a result, it is possible to prevent two or more differences from occurring in the resource allocation pattern, so that only one differential TP number can be generated per generation of the resource allocation pattern.

  Thereafter, the pattern generation unit 11 determines whether Itp is the last TP number, that is, Itp == Ntp, in order to determine whether all patterns have been generated (operation end) (step 105). . Here, when Itp is the last TP number (step 105: YES), the pattern generation unit 11 ends a series of pattern generation processing.

  If Itp is not the last TP number (step 105: NO), the pattern generation unit 11 updates Itp by incrementing Itp (adding 1 to Itp) (step 106). To determine whether the new Itp is the differential TP number, the process returns to step 103.

On the other hand, when the current Itp is the differential TP number in step 103 (step 103: YES), the pattern generation unit 11 updates the option by changing the current selection of TP # Itp to the next option. (Step 107). This step is a process of adding the update amount [Itp] to the option number [Itp].
When a variable expressing the difference in update direction is used instead of the update amount, if the value of this variable represents increment, this is a process of adding 1 to the option number [Itp], and the value of this variable represents decrement. Then, 1 is subtracted from the option number [Itp].

  Thereby, the pattern generation unit 11 completes the update for the next pattern and outputs the difference TP number, the difference UE number, etc. corresponding to the update, so that Itp is the difference TP number and the updated option is the difference. It outputs as a UE number (step 108). Specifically, the difference TP number = Itp, the difference UE number = option [Itp, option number [Itp]], and these are output to the pattern evaluation unit 12. Thereafter, the process returns to step 102 to generate the next resource allocation pattern.

  As described above, the pattern generation unit 11 finds the TP # Itp having the smallest number among the TPs from which the next option can be selected, sets this Itp as the differential TP number, and sets the next option after the TP # Itp as the differential UE number. And For the TP with a number smaller than Itp, the sign of the update amount is inverted (the update direction is reversed). Thereby, it is possible to generate a resource allocation pattern having different options for at least one TP from a resource allocation pattern generated in the past. Further, it is guaranteed that the generated resource allocation pattern is different from the previously generated pattern only for one TP (the TP indicated by the differential TP number), and for each generation of one resource allocation pattern, One differential TP number and a differential UE number can be output.

FIG. 4 is a generation example of the resource allocation pattern according to the first embodiment, FIG. 4A is an example of resource allocation pattern range setting, FIG. 4B is an example of the generated resource allocation pattern, FIG. 4C shows an example of difference information for each resource allocation pattern.
As shown in FIG. 4, for each generation of one resource allocation pattern, there is one differential TP number and one differential UE number.

[Pattern evaluation section]
The pattern evaluation unit 12 calculates an evaluation value for each resource allocation pattern and outputs the obtained evaluation value toward the optimum solution holding unit 13. This evaluation value is an index representing the goodness of scheduling adopting the resource allocation pattern. For example, the evaluation value is a value obtained by summing the throughput of each UE for all UEs, or the throughput of the past average rate for each UE. There is a method that considers fairness among users (see Non-Patent Document 2) by obtaining a ratio and summing this value for all UEs as an evaluation value.

  In calculating this evaluation value, it is necessary to estimate the throughput of each UE. First, estimate the received SINR (Signal-to-Interference plus Noise power Ratio: the ratio of signal power to the sum of interference power and noise power) of each UE. Further, the throughput corresponding to the received SINR is obtained (for example, a table that associates the received SINR with the throughput is drawn). Since the calculation of the received SINR requires interference power and signal power values for each UE, the received power when the UE receives a signal transmitted by each TP is measured based on these values. Estimate from the value and resource allocation pattern. Note that the measured value is not a received power value measured by the UE, but a value obtained by converting a CQI (Channel Quality Indicator) notified by the UE to the base station through an uplink channel into a received power value, or an uplink signal transmitted by the UE. It is also possible to use a value estimated from the received power value when the TP is received.

  In this manner, the pattern evaluation unit 12 calculates the evaluation value for each UE (throughput, the ratio of the throughput to the average rate, etc.) for each UE, and calculates the evaluation value by a method of summing the evaluation values for each UE. . In addition, the evaluation value for each UE includes the evaluation parameters for each UE (the average rate of each UE, the number of each TP that can be received by each UE, the value of received power when receiving a TP signal, etc.). Necessary and input from outside such as base station.

  As shown in FIG. 2, the pattern evaluation unit 12 includes, as main circuit units, a transmission state generation unit 21, a UE-specific evaluation parameter table (user terminal-specific evaluation parameter table) 22, a TP-specific evaluation parameter holding unit [i. ] (I = 1... Ntp) (evaluation parameter holding unit by transmission point) 23, pattern evaluation unit by TP [i] (i = 1... Ntp) (evaluation unit by transmission point) 24, and evaluation value summation unit by TP (Evaluation value total part by transmission point) 25 is provided.

  The transmission status generation unit 21 sends a differential TP number (the number of the TP whose transmission destination UE has been changed when compared with the previous resource allocation pattern) and the differential UE number (the transmission of the TP indicated by the differential TP number) from the pattern generation unit 11 Each time the number of the previous UE is input, but when the TP stops transmission, the value 0) that is not used as the UE number is input, that is, each time the pattern generation unit 11 generates a resource allocation pattern, each TP Transmission flag [i] (i = 1... Ntp, a bit indicating that TP # i is being transmitted when the value is 1) is generated, and each TP-specific evaluation parameter evaluation unit [i ] (I = 1... Ntp).

  Therefore, the transmission state generation unit 21 holds the transmission flag [i] (i = 1... Ntp) of each TP, and sets the value of the transmission flag [differential TP number] of the TP indicated by the input differential TP number as the difference. Update based on UE number. Specifically, if the differential UE number is a value 0 indicating that transmission is stopped, a value 0 indicating that transmission is not being performed is set in the transmission flag [differential TP number]. In the case of representing a valid UE number), a value 1 representing that transmission is in progress is set in the transmission flag [difference TP number].

  Note that the values of the transmission flags [i] (i = 1... Ntp, i ≠ difference TP number) of each TP other than the difference TP number are not changed and the values so far are held. With respect to these TP transmission flags [i] (i = 1... Ntp), each TP-specific pattern evaluation unit [i] (i = 1... Ntp) calculates the reception SINR of the UE that is the transmission destination of TP # i. Is used to calculate the interference power that is the sum of the received power from each TP being transmitted other than TP # i.

  Instead of generating the transmission flag [i] (i = 1... Ntp) of each TP based on the differential TP number and the differential UE number, the resource allocation pattern T [i] (i = 1) is generated from the pattern generation unit 11. ... Ntp, the number of the UE that is the destination of TP # i or a value 0) indicating transmission stop can be input and generated based on whether T [i] is a value indicating transmission stop. is there. Further, it is possible to adopt a configuration having the transmission state generation unit 21 in the pattern generation unit 11 instead of the configuration having the transmission state generation unit 21 in the pattern evaluation unit 12. In this configuration, the pattern generation unit 11 is a pattern evaluation unit. The transmission flag [i] (i = 1... Ntp) of each TP is output toward the terminal 12.

  The UE-specific evaluation parameter table 22 includes a UE-specific evaluation parameter [j] (UE-specific evaluation value) for each UE # j (j = 1... Nue; Nue is the maximum number of UEs that can be handled by the scheduling apparatus 10). A set of numerical values necessary for calculation) is stored. The stored value can be set and updated by external access. When the pattern evaluation unit 12 inputs the differential UE number J and the differential TP number I, which are valid UE numbers, the UE-specific evaluation parameter table 22 indicates the UE # J-specific UE pointed to by the stored differential UE number J. The evaluation parameter [J] is output to the TP-specific evaluation parameter holding unit 23 together with the difference TP number I.

  In the circuit implementation of the evaluation parameter table 22 for each UE, an SRAM (Static Random Access Memory) can be used. The number of words in the SRAM is set to Nue (maximum value of the number of UEs that can be handled by the scheduling apparatus 10), the evaluation parameter for each UE of each UE is stored in each word, and the UE of UE # J from the input differential UE number J By converting the address of the word in which the separate evaluation parameter [J] is stored (for example, address = difference UE number J-1) and performing read access to the SRAM, the read data of the SRAM is changed to the evaluation parameter [J] by UE. Become.

  Since the UE-specific evaluation parameter table 22 does not need to output the UE-specific evaluation parameters of a plurality of UEs simultaneously to the TP-specific evaluation parameter holding unit 23, the number of words that can be read simultaneously is limited as in the SRAM. However, it is possible to use a small-area and large-capacity memory composed of memory cells having a small area per bit.

That is, the scheduling apparatus 10 according to the present embodiment needs to store received power from each TP (evaluation parameter for each UE) necessary for calculating the evaluation value for each UE, but calculates the evaluation value for each UE. The circuit area of the memory used for storage can be reduced because it is stored as a table (evaluation table for each UE) instead of being distributed and stored for each circuit to be performed.
Therefore, the scheduling apparatus 10 according to the present embodiment can effectively use a circuit having a complicated access mechanism but a small area per bit, like an SRAM, by providing the UE-specific evaluation parameters of each UE as a table. .

  On the other hand, in the configuration in which the UE-specific evaluation parameters are distributed and stored for each circuit that calculates the UE-specific evaluation value, it is possible to adopt SRAM, but for each circuit that calculates the UE-specific evaluation value, Since a circuit for realizing the access mechanism is required, the entire circuit area increases. Even when a flip-flop that does not require an access mechanism is employed, the area per bit is larger than that of an SRAM, so that the entire circuit area increases. According to this Embodiment, the area of the memory which memorize | stores the evaluation parameter according to UE becomes small, and the cost of the scheduling apparatus 10 can be reduced.

  Each TP-specific evaluation parameter holding unit [i] (i = 1... Ntp) holds the UE-specific evaluation parameter [j] of the UE # j that is the transmission destination of TP # i as the TP-specific evaluation parameter [i]. The TP-specific evaluation parameter [i] is output to the TP-specific pattern evaluation unit [i].

  At this time, the UE-specific evaluation parameter [J] corresponding to the differential UE number J input by the pattern evaluation unit 12 and the differential TP number I input by the pattern evaluation unit 12 together with the differential UE number J are used as the UE-specific evaluation parameter table 22. Is output by the evaluation parameter holding unit [I] for each TP of the TP # I pointed to by the differential TP number I by using the evaluation parameter [I] for each TP held so far by the evaluation parameter [J] for each UE. Update to the value of.

  That is, for updating the TP-specific evaluation parameter [I] held by the TP-specific evaluation parameter holding unit [I], the pattern evaluation unit 12 inputs the differential TP number I and the differential UE number J that is a valid UE number, This is performed when the UE-specific evaluation parameter [J] is output by the UE-specific evaluation parameter table 22. In addition, when the value of the differential UE number J is 0 indicating transmission stop, or the evaluation parameter holding unit for each TP corresponding to the TP number i (i = 1... Ntp, i ≠ I) excluding the differential TP number I [i ] Does not update the evaluation parameter [I] for each TP and continues to hold it.

  Each TP-specific pattern evaluation unit [i] (i = 1... Ntp) corresponds to the difference TP number I input from the pattern generation unit 11 and corresponds to the difference UE number J of each TP generated by the transmission state generation unit 21. A transmission flag [i] indicating presence / absence of transmission (i = 1... Ntp, a bit indicating that TP # i is being transmitted when the value is 1) is input, and further, an evaluation parameter holding unit for each TP [i TP-specific evaluation parameters [i] (in this case, the TP-specific evaluation parameters [I] have been updated to the same values as the UE-specific evaluation parameters [J] stored in the UE-specific evaluation parameter table 22). Based on this, the evaluation value for each UE of the UE #j that is the transmission destination of TP # i is calculated and output to the evaluation value for each TP summation unit 25 as the evaluation value for each TP [i].

  Thus, the scheduling apparatus 10 according to the present embodiment does not include a circuit that calculates the evaluation value for each UE for each UE, but performs pattern evaluation for each TP as a circuit that calculates the evaluation value for each UE. The unit 24 is provided. Usually, the number of UEs in the radio network system is larger than the number of TPs in the radio network system. This is because one TP can generally connect to a plurality of UEs at the same time (for example, frequency multiplexing that assigns different frequency bands to each UE and time multiplexing that changes the transmission time to each UE can be performed). Therefore, according to the present embodiment, the number of circuits for calculating evaluation values can be reduced as compared with a scheduling apparatus provided with circuits for the number of UEs, so that the cost of the scheduling apparatus can be reduced.

  In addition, in the scheduling apparatus 10 according to the present embodiment, the resource allocation pattern generated in the pattern generation unit 11 is only for one UE that is the transmission destination for one TP from the pattern generated last time. Since a resource allocation pattern that is guaranteed to be changed is generated, every time one resource allocation pattern is generated, the UE-specific evaluation parameter is obtained from the UE-specific evaluation parameter table 22 for a maximum of one UE. (If the transmission is changed to stop transmission, it is not necessary to obtain the UE-specific evaluation parameter from the UE-specific evaluation parameter table 22 for the resource allocation pattern).

  This characteristic is that when the evaluation parameter table 22 for each UE is implemented using an SRAM that has a limitation that simultaneous reading of different words cannot be performed, an adverse effect due to such limitation (for example, for each resource allocation pattern, for each UE). By obtaining the UE-specific evaluation parameters a plurality of times from the evaluation parameter table 22, the time required for the acquisition becomes longer, and the number of resource allocation patterns that can be evaluated per unit time is reduced).

The TP-specific evaluation value summation unit 25 sums the TP-specific evaluation values [i] output by the TP-specific pattern evaluation units [i] (i = 1... Ntp), and uses this as an evaluation value to the optimum solution holding unit 13. Output.
In the configuration in which the pattern evaluation unit 12 holds the input of the next difference TP number and the difference UE number from the input of the difference TP number and the difference UE number to the output of the evaluation value, this delay is a unit time. Since the number of resource allocation patterns that can be evaluated per second is constrained, the pattern evaluation unit 12 is pipelined, and within the time from when the differential TP number and differential UE number are input to when the evaluation value is output, The input of the difference TP number and the difference UE number can be continued.

[Optimal solution holding unit]
The optimum solution holding unit 13 optimizes the resource allocation pattern when the evaluation value calculated by the pattern evaluation unit 12 based on the resource allocation pattern is the best among the plurality of resource allocation patterns generated by the pattern generation unit 11 Output as a resource allocation pattern. The optimal solution holding unit 13 uses the resource allocation pattern and the evaluation value calculated by the pattern evaluation unit 12 based on the pattern when the best evaluation value is obtained after the pattern generation unit 11 starts generating the resource allocation pattern. And hold as the optimal solution.

  That is, every time a resource allocation pattern is generated, the evaluation value calculated by the pattern evaluation unit 12 based on the resource allocation pattern is compared with the evaluation value held by the optimal solution holding unit 13, and the former is better. If it is determined, the former resource allocation pattern is adopted as the optimal resource allocation pattern, and if it is determined that the latter is better, the optimal resource allocation pattern is not updated. As a result, the scheduling device 10 performs the optimal resource allocation held by the optimal solution holding unit 13 when the processing is completed for all the resource allocation patterns within the resource allocation pattern range setting or when the scheduling cycle time has elapsed. Output the pattern. It is also possible to output the evaluation value held by the optimum solution holding unit 13 together with the optimum resource allocation pattern.

  The optimal solution holding unit 13 is not the resource allocation pattern from the pattern generation unit 11, but the differential TP number (the TP number to which the destination UE has been changed when compared with the previous resource allocation pattern) and the differential UE number (the differential TP). Enter the number of the UE that is the transmission destination of the TP indicated by the number, but the value 0) that is not used as the UE number when the transmission is stopped.

  For this reason, the optimal solution holding unit 13 holds the UE number that is the transmission destination of TP # i (i = 1... Ntp) for all TPs as the reproduction resource allocation pattern R [i], and the input differential TP number. Based on I and the differential UE number J, the reproduction resource allocation pattern R [I] is changed to the value of the differential UE number J, and the TP number i excluding the differential TP number I (i = 1... Ntp, i ≠ I) The corresponding reproduction resource allocation pattern R [i] is continuously held, so that the same pattern as the resource allocation pattern generated by the pattern generation unit 11 is reproduced in the optimum solution holding unit 13. The pattern generation unit 11 does not output the differential TP number and the differential UE number to the optimal solution holding unit 13, but generates the generated resource allocation pattern T [i] (i = 1... Ntp) as the optimal solution holding unit. A configuration of outputting to 13 is also possible.

  Moreover, since there is a delay between the pattern evaluation unit 12 inputting the differential TP number and the differential UE number from the pattern generation unit 11 and outputting the evaluation value, the evaluation value calculated by the pattern evaluation unit 12 is the best. When the optimum solution holding unit 13 can determine, the optimum solution holding unit 13 needs to acquire a resource allocation pattern corresponding to the evaluation value. In particular, in the configuration in which the pattern evaluation unit 12 is pipelined, it is necessary to acquire resource allocation patterns generated by the pattern generation unit 11 before the number of resource allocation patterns that can be processed by the pattern evaluation unit 12 within the delay time. There is.

  For this reason, the optimal solution holding unit 13 accumulates the pair of the differential TP number and the differential UE number input from the pattern generation unit 11 in a FIFO (First-In First-Out) buffer, and the pattern evaluation unit 12 stores the differential TP number. A delay corresponding to the time from the input of the differential UE number to the output of the evaluation value is given to the differential TP number and the differential UE number, and playback is performed using the differential TP number and the differential UE number extracted from the FIFO buffer. Generate a resource allocation pattern.

  Thereby, the memory amount of the FIFO buffer can be reduced as compared with the configuration in which the reproduction resource allocation pattern is stored in the FIFO buffer. For example, for holding one reproduction resource allocation pattern, there is a memory that stores a number obtained by multiplying the number of bits w_ue required to represent one UE number by the number of TPs, that is, Ntp × w_ue. Necessary. On the other hand, for holding one set of the differential TP number and the differential UE number, the number of bits w_tp necessary to express one TP number and the number of bits necessary to express one UE number A memory for storing the number of bits corresponding to the sum of w_ue is required. In general, since Ntp <Nue (the number of UEs is larger than the number of TPs), the number of bits necessary to express each number is also w_tp ≦ w_ue, so the differential TP number and the differential UE number are retained. This configuration requires less memory.

[Second Embodiment]
Next, the scheduling device 10 according to the second exemplary embodiment of the present invention will be described. In the present embodiment, the content of the pattern generation processing in the pattern generation unit 11 is different from that in the first embodiment, so the processing in each circuit unit is slightly different according to this, but the overall circuit configuration is The same as FIG. 1 and FIG.

  Next, with reference to FIG. 1 and FIG. 2, each structure of the scheduling apparatus 10 concerning 2nd Embodiment is demonstrated in detail.

[Pattern generator]
Based on the resource allocation pattern range setting (pattern range information) input from the outside, the pattern generating unit 11 controls each transmission point TP # i (i = 1... Ntp; Ntp; Corresponding to the transmission state, that is, the number of the destination user equipment UE (1... Nue; Nue is the maximum number of UEs that can be handled by the scheduling apparatus 10) or TP transmission stoppage. A resource allocation pattern T [i] (i = 1... Ntp) representing the value 0 is generated. The resource allocation pattern range setting is a restriction when generating a resource allocation pattern, and is a setting of choices for each TP # i, whether or not transmission stop can be selected and a UE that can be a transmission destination, that is, an option for each TP.

An example of the resource allocation pattern range setting is a format of a list of UE numbers that can be selected as a transmission destination for each TP, and Ns options [i, i,. k] (k = 1... Ns; Ns is the maximum number of options that can be set for each TP) and the number of effective options s [i] (s [i] ≦ Ns) among them.
In addition to the UE that can be the transmission destination for each TP specified as the resource allocation pattern range setting, the pattern generation unit 11 can select transmission stop for each TP. Furthermore, the selection of the transmission stop in each TP is made prior to the selection of the UE included in the resource allocation pattern range setting.

  The pattern generation unit 11 generates a plurality of resource allocation patterns one after another as time elapses. In these generations, the selection is changed for the resource allocation pattern generated immediately before and one TP. Note that the pattern generation unit 11 ends the generation when all the resource allocation patterns within the resource allocation pattern range setting are generated.

  As described above, the pattern generation unit 11 of the scheduling apparatus 10 according to the present embodiment does not generate a resource allocation pattern from all TP # i (i = 1... Ntp) for all UEs in the system as transmission targets. By generating a resource allocation pattern within the resource allocation pattern range setting input from the outside, it is possible to exclude in advance a pattern that is not likely to be an optimal solution or not. The speed can be increased by reducing the number of times the evaluation value is calculated. Note that the degree of speed-up varies depending on the resource allocation pattern range setting. For example, when the choice of each TP is limited to 1/2, the speed can be increased to 2 times the number of TPs.

  Every time the resource generation pattern is generated, the pattern generation unit 11 compares these patterns with the resource allocation pattern generated immediately before the pattern generation, except for the TP that is changed to stop transmission. Are different TP numbers (1... Ntp) that are different TP numbers (the destination UE has changed from the previous pattern) and differential UE numbers (1... Nue) that are the numbers of UEs that are the destination of the TP. ) Is output to the pattern evaluation unit 12 as difference information. The pattern generation unit 11 does not output the difference TP number and the difference UE number to the pattern evaluation unit 12, but the generated resource allocation pattern T [i] (i = 1... Ntp) is sent to the pattern evaluation unit 12. The pattern evaluation unit 12 can generate a difference TP number and a difference UE number in the pattern evaluation unit 12 by comparing the resource allocation pattern input immediately before and the pattern input this time. is there.

  The pattern generation unit 11 also outputs the difference TP number and the difference UE number (difference information) output to the pattern evaluation unit 12 to the optimum solution holding unit 13 every time a resource allocation pattern is generated. This is because when the pattern evaluation unit 12 outputs an evaluation value for the resource allocation pattern to the optimal solution holding unit 13, and the optimal solution holding unit 13 determines that the evaluation value is the best, the optimal solution holding unit 13 responds. This is because the resource allocation pattern is reproduced using the difference TP number and the difference UE number to be held, and this is retained as the optimum solution. The pattern generation unit 11 does not output the differential TP number and the differential UE number to the optimal solution holding unit 13, but generates the generated resource allocation pattern T [i] (i = 1... Ntp) as the optimal solution holding unit. A configuration of outputting to 13 is also possible.

[Pattern generation processing]
Here, the pattern generation processing in the pattern generation unit 11 will be described with reference to FIG. FIG. 5 is a flowchart showing a pattern generation process according to the second embodiment.

  The pattern generation unit 11 sets s [i] (s [i] ≦ Ns) that holds the number of options for each TP # i (i = 1... Ntp) as resource allocation pattern range settings, and each TP # i. Option [i, k] (k = 1... S [i]), which is a list of selectable transmission states. In the pattern generation unit 11, an option number [i] (1... S [i], which indicates which option is currently selected by each TP # i is selected as a value 0. Represent).

  Furthermore, in order to determine the TP number having a difference between the resource allocation pattern generated last time and the resource allocation pattern to be generated next, that is, the difference TP number, the TP number is sequentially tried from 1 to Ntp which is the number of TPs. Using the variable Itp. That is, Itp is used as a candidate for the differential TP number. However, when the pattern generation unit 11 is implemented as a circuit, it is possible to simultaneously perform trials from TP numbers 1 to Ntp. In this case, the variable Itp is not used and the flowchart shown in FIG. It is not necessary to operate according to this procedure, and it is only necessary that an equivalent operation is possible.

Hereinafter, the flowchart shown in FIG. 5 will be described in detail.
First, after starting the operation, the pattern generation unit 11 initializes the pattern generation unit 11 by selecting the top of the TP options for all TPs (step 200). Here, a process of setting 0 as a value of option number [i] corresponding to each TP [i] (a process of setting all TPs to stop transmission) is performed.

Next, in order to generate the first pattern, the pattern generation unit 11 initializes Itp by setting 1 to Itp (step 201). Itp is a candidate for a differential TP number.
Subsequently, the pattern generation unit 11 determines whether Itp becomes the differential TP number, that is, whether the option can be changed for TP # Itp (step 202). Specifically, when the value obtained by adding 1 to the option number [Itp] is equal to or less than s [Itp] (number of options), that is, when the updated option number is within a normal range, TP # Itp It is determined that the option can be changed.

  Here, when the current Itp is not the difference TP number (step 202: NO), the pattern generation unit 11 obtains a new candidate for the difference TP number by updating (incrementing) Itp. Return to the state where the first option is selected for the current TP # Itp (step 203). That is, 1 is set to the option number [Itp]. As a result, the TP having a number smaller than the differential TP number is changed back to the first option, but the transmission destination is not changed to UE but is changed to transmission stop. The TP whose destination UE is changed can be only one TP indicated by the differential TP number.

  Thereafter, the pattern generation unit 11 determines whether Itp is the last TP number, that is, whether Itp == Ntp, in order to determine whether all patterns have been generated (operation end) (step 204). . Here, if Itp is the last TP number (step 204: YES), the pattern generation unit 11 ends the series of pattern generation processing.

  If Itp is not the last TP number (step 204: NO), the pattern generation unit 11 updates Itp by incrementing Itp (adding 1 to Itp) (step 205). To determine whether the new Itp is the differential TP number, the process returns to step 103.

  On the other hand, when the current Itp is the differential TP number in step 202 (step 202: YES), the pattern generation unit 11 updates the option by changing the current selection of TP # Itp to the next option. (Step 206). Here, the process is to add 1 to the option number [Itp].

  Thereby, the pattern generation unit 11 completes the update for the next pattern and outputs the difference TP number, the difference UE number, etc. corresponding to the update, so that Itp is the difference TP number and the updated option is the difference. It outputs as a UE number (step 207). Specifically, the difference TP number = Itp, the difference UE number = option [Itp, option number [Itp]], and these are output to the pattern evaluation unit 12. Thereafter, the process returns to step 201 to generate the next resource allocation pattern.

  As described above, the pattern generation unit 11 finds the TP # Itp having the smallest number among the TPs from which the next option can be selected, sets this Itp as the differential TP number, and sets the next option after the TP # Itp as the differential UE number. And For the TP having a number smaller than Itp, the transmission is returned to the first option, ie, transmission stop. Thereby, it is possible to generate a resource allocation pattern having different options for at least one TP from a resource allocation pattern generated in the past. Furthermore, the generated resource allocation pattern is a pattern generated last time, and only one TP (TP indicated by the differential TP number) has its options changed and transmitted to the UE (UE indicated by the differential UE number). (Change from transmission stop to transmission to UE or change destination to another UE). Therefore, each generation of one resource allocation pattern can be output as one differential TP number and one differential UE number.

FIG. 6 is a generation example of the resource allocation pattern according to the second embodiment, FIG. 6A is an example of resource allocation pattern range setting, FIG. 6B is an example of the generated resource allocation pattern, FIG. 6C shows an example of difference information for each resource allocation pattern.
As shown in FIG. 6, for each generation of one resource allocation pattern, there is one differential TP number and one differential UE number.

[Pattern evaluation section]
The pattern evaluation unit 12 calculates an evaluation value for each resource allocation pattern and outputs the obtained evaluation value toward the optimum solution holding unit 13. This evaluation value is an index representing the goodness of scheduling adopting the resource allocation pattern. For example, the evaluation value is a value obtained by summing the throughput of each UE for all UEs, or the throughput of the past average rate for each UE. There is a method that considers fairness among users (see Non-Patent Document 2) by obtaining a ratio and summing this value for all UEs as an evaluation value.

  In calculating this evaluation value, it is necessary to estimate the throughput of each UE. First, estimate the received SINR (Signal-to-Interference plus Noise power Ratio: the ratio of signal power to the sum of interference power and noise power) of each UE. Further, the throughput corresponding to the received SINR is obtained (for example, a table that associates the received SINR with the throughput is drawn). Since the calculation of the received SINR requires interference power and signal power values for each UE, the received power when the UE receives a signal transmitted by each TP is measured based on these values. Estimate from the value and resource allocation pattern. Note that the measured value is not a received power value measured by the UE, but a value obtained by converting a CQI (Channel Quality Indicator) notified by the UE to the base station through an uplink channel into a received power value, or an uplink signal transmitted by the UE. It is also possible to use a value estimated from the received power value when the TP is received.

  In this manner, the pattern evaluation unit 12 calculates the evaluation value for each UE (throughput, the ratio of the throughput to the average rate, etc.) for each UE, and calculates the evaluation value by a method of summing the evaluation values for each UE. . In addition, the evaluation value for each UE includes the evaluation parameters for each UE (the average rate of each UE, the number of each TP that can be received by each UE, the value of received power when receiving a TP signal, etc.). Necessary and input from outside such as base station.

  As shown in FIG. 2, the pattern evaluation unit 12 includes, as main circuit units, a transmission state generation unit 21, a UE-specific evaluation parameter table 22, a TP-specific evaluation parameter holding unit [i] (i = 1... Ntp). 23, a TP-specific pattern evaluation unit [i] (i = 1... Ntp) 24, and a TP-specific evaluation value summation unit 25 are provided.

  The transmission status generation unit 21 sends a differential TP number (the number of the TP whose transmission destination UE has been changed when compared with the previous resource allocation pattern) and the differential UE number (the transmission of the TP indicated by the differential TP number) from the pattern generation unit 11. Transmission flag [i] (i = 1... Ntp, value indicating the presence / absence of transmission of each TP, every time a previous UE number) is input, that is, each time the pattern generation unit 11 generates a resource allocation pattern. 1 is a bit indicating that TP # i is being transmitted), and outputs it to each TP-specific evaluation parameter evaluation unit [i] (i = 1... Ntp).

  Therefore, the transmission state generation unit 21 holds the transmission flag [i] (i = 1... Ntp) of each TP, and sets the value of the transmission flag [differential TP number] of the TP indicated by the input differential TP number as the difference. Update based on UE number. Specifically, if the differential UE number is a value 0 indicating that transmission is stopped, a value 0 indicating that transmission is not being performed is set in the transmission flag [differential TP number]. In the case of representing a valid UE number), a value 1 representing that transmission is in progress is set in the transmission flag [difference TP number].

  Note that the values of the transmission flags [i] (i = 1... Ntp, i ≠ difference TP number) of each TP other than the difference TP number are not changed and the values so far are held. With respect to these TP transmission flags [i] (i = 1... Ntp), each TP-specific pattern evaluation unit [i] (i = 1... Ntp) calculates the reception SINR of the UE that is the transmission destination of TP # i. Is used to calculate the interference power that is the sum of the received power from each TP being transmitted other than TP # i.

  Instead of generating the transmission flag [i] (i = 1... Ntp) of each TP based on the differential TP number and the differential UE number, the resource allocation pattern T [i] (i = 1) is generated from the pattern generation unit 11. ... Ntp, the number of the UE that is the destination of TP # i or a value 0) indicating transmission stop can be input and generated based on whether T [i] is a value indicating transmission stop. is there. Further, it is possible to adopt a configuration having the transmission state generation unit 21 in the pattern generation unit 11 instead of the configuration having the transmission state generation unit 21 in the pattern evaluation unit 12. In this configuration, the pattern generation unit 11 is a pattern evaluation unit. The transmission flag [i] (i = 1... Ntp) of each TP is output toward the terminal 12.

  The UE-specific evaluation parameter table 22 includes a UE-specific evaluation parameter [j] (UE-specific evaluation value) for each UE # j (j = 1... Nue; Nue is the maximum number of UEs that can be handled by the scheduling apparatus 10). A set of numerical values necessary for calculation) is stored. The stored value can be set and updated by external access. When the pattern evaluation unit 12 inputs the differential UE number J and the differential TP number I, which are valid UE numbers, the UE-specific evaluation parameter table 22 indicates the UE # J-specific UE pointed to by the stored differential UE number J. The evaluation parameter [J] is output to the TP-specific evaluation parameter holding unit 23 together with the difference TP number I.

  In the circuit implementation of the evaluation parameter table 22 for each UE, an SRAM (Static Random Access Memory) can be used. The number of words in the SRAM is set to Nue (maximum value of the number of UEs that can be handled by the scheduling apparatus 10), the evaluation parameter for each UE of each UE is stored in each word, and the UE of UE # J from the input differential UE number J By converting the address of the word in which the separate evaluation parameter [J] is stored (for example, address = difference UE number J-1) and performing read access to the SRAM, the read data of the SRAM is changed to the evaluation parameter [J] by UE. Become.

  Since the UE-specific evaluation parameter table 22 does not need to output the UE-specific evaluation parameters of a plurality of UEs simultaneously to the TP-specific evaluation parameter holding unit 23, the number of words that can be read simultaneously is limited as in the SRAM. However, it is possible to use a small-area and large-capacity memory composed of memory cells having a small area per bit.

That is, the scheduling apparatus 10 according to the present embodiment needs to store received power from each TP (evaluation parameter for each UE) necessary for calculating the evaluation value for each UE, but calculates the evaluation value for each UE. The circuit area of the memory used for storage can be reduced because it is stored as a table (evaluation table for each UE) instead of being distributed and stored for each circuit to be performed.
Therefore, the scheduling apparatus 10 according to the present embodiment can effectively use a circuit having a complicated access mechanism but a small area per bit, like an SRAM, by providing the UE-specific evaluation parameters of each UE as a table. .

  On the other hand, in the configuration in which the UE-specific evaluation parameters are distributed and stored for each circuit that calculates the UE-specific evaluation value, it is possible to adopt SRAM, but for each circuit that calculates the UE-specific evaluation value, Since a circuit for realizing the access mechanism is required, the entire circuit area increases. Even when a flip-flop that does not require an access mechanism is employed, the area per bit is larger than that of an SRAM, so that the entire circuit area increases. According to this Embodiment, the area of the memory which memorize | stores the evaluation parameter according to UE becomes small, and the cost of the scheduling apparatus 10 can be reduced.

  Each TP-specific evaluation parameter holding unit [i] (i = 1... Ntp) holds the UE-specific evaluation parameter [j] of the UE # j that is the transmission destination of TP # i as the TP-specific evaluation parameter [i]. The TP-specific evaluation parameter [i] is output to the TP-specific pattern evaluation unit [i].

  At this time, the UE-specific evaluation parameter [J] corresponding to the differential UE number J input by the pattern evaluation unit 12 and the differential TP number I input by the pattern evaluation unit 12 together with the differential UE number J are used as the UE-specific evaluation parameter table 22. Is output by the evaluation parameter holding unit [I] for each TP of the TP # I pointed to by the differential TP number I by using the evaluation parameter [I] for each TP held so far by the evaluation parameter [J] for each UE. Update to the value of.

  That is, for updating the TP-specific evaluation parameter [I] held by the TP-specific evaluation parameter holding unit [I], the pattern evaluation unit 12 inputs the differential TP number I and the differential UE number J that is a valid UE number, This is performed when the UE-specific evaluation parameter [J] is output by the UE-specific evaluation parameter table 22. In addition, when the value of the differential UE number J is 0 indicating transmission stop, or the evaluation parameter holding unit for each TP corresponding to the TP number i (i = 1... Ntp, i ≠ I) excluding the differential TP number I [i ] Does not update the evaluation parameter [I] for each TP and continues to hold it.

  Each TP-specific pattern evaluation unit [i] (i = 1... Ntp) corresponds to the difference TP number I input from the pattern generation unit 11 and corresponds to the difference UE number J of each TP generated by the transmission state generation unit 21. A transmission flag [i] indicating presence / absence of transmission (i = 1... Ntp, a bit indicating that TP # i is being transmitted when the value is 1) is input, and further, an evaluation parameter holding unit for each TP [i TP-specific evaluation parameters [i] (in this case, the TP-specific evaluation parameters [I] have been updated to the same values as the UE-specific evaluation parameters [J] stored in the UE-specific evaluation parameter table 22). Based on this, the evaluation value for each UE of the UE #j that is the transmission destination of TP # i is calculated and output to the evaluation value for each TP summation unit 25 as the evaluation value for each TP [i].

  Thus, the scheduling apparatus 10 according to the present embodiment does not include a circuit that calculates the evaluation value for each UE for each UE, but performs pattern evaluation for each TP as a circuit that calculates the evaluation value for each UE. The unit 24 is provided. Usually, the number of UEs in the radio network system is larger than the number of TPs in the radio network system. This is because one TP can generally connect to a plurality of UEs at the same time (for example, frequency multiplexing that assigns different frequency bands to each UE and time multiplexing that changes the transmission time to each UE can be performed). Therefore, according to the present embodiment, the number of circuits for calculating evaluation values can be reduced as compared with a scheduling apparatus provided with circuits for the number of UEs, so that the cost of the scheduling apparatus 10 can be reduced.

  In addition, in the scheduling apparatus 10 according to the present embodiment, the resource allocation pattern generated in the pattern generation unit 11 is only for one UE that is the transmission destination for one TP from the pattern generated last time. Since a resource allocation pattern that is guaranteed to be changed is generated, every time one resource allocation pattern is generated, the UE-specific evaluation parameter is obtained from the UE-specific evaluation parameter table 22 for a maximum of one UE. (If the transmission is changed to stop transmission, it is not necessary to obtain the UE-specific evaluation parameter from the UE-specific evaluation parameter table 22 for the resource allocation pattern).

  This characteristic is that when the evaluation parameter table 22 for each UE is implemented using an SRAM that has a limitation that simultaneous reading of different words cannot be performed, an adverse effect due to such limitation (for example, for each resource allocation pattern, for each UE). By performing the UE-specific evaluation parameter acquisition a plurality of times from the evaluation parameter table 22, the time required for acquisition becomes longer and the number of resource allocation patterns that can be evaluated per unit time is reduced).

The TP-specific evaluation value summation unit 25 sums the TP-specific evaluation values [i] output by the TP-specific pattern evaluation units [i] (i = 1... Ntp), and uses this as an evaluation value to the optimum solution holding unit 13. Output.
In the configuration in which the pattern evaluation unit 12 holds the input of the next difference TP number and the difference UE number from the input of the difference TP number and the difference UE number to the output of the evaluation value, this delay is a unit time. Since the number of resource allocation patterns that can be evaluated per second is constrained, the pattern evaluation unit 12 is pipelined, and within the time from when the differential TP number and differential UE number are input to when the evaluation value is output, The input of the difference TP number and the difference UE number can be continued.

[Optimal solution holding unit]
The optimum solution holding unit 13 optimizes the resource allocation pattern when the evaluation value calculated by the pattern evaluation unit 12 based on the resource allocation pattern is the best among the plurality of resource allocation patterns generated by the pattern generation unit 11 Output as a resource allocation pattern. The optimal solution holding unit 13 uses the resource allocation pattern and the evaluation value calculated by the pattern evaluation unit 12 based on the pattern when the best evaluation value is obtained after the pattern generation unit 11 starts generating the resource allocation pattern. And hold as the optimal solution.

  That is, every time a resource allocation pattern is generated, the evaluation value calculated by the pattern evaluation unit 12 based on the resource allocation pattern is compared with the evaluation value held by the optimal solution holding unit 13, and the former is better. If it is determined, the former resource allocation pattern is adopted as the optimal resource allocation pattern, and if it is determined that the latter is better, the optimal resource allocation pattern is not updated. As a result, the scheduling device 10 performs the optimal resource allocation held by the optimal solution holding unit 13 when the processing is completed for all the resource allocation patterns within the resource allocation pattern range setting or when the scheduling cycle time has elapsed. Output the pattern. It is also possible to output the evaluation value held by the optimum solution holding unit 13 together with the optimum resource allocation pattern.

  The optimal solution holding unit 13 is not the resource allocation pattern from the pattern generation unit 11, but the differential TP number (the TP number to which the destination UE has been changed when compared with the previous resource allocation pattern) and the differential UE number (the differential TP). Enter the number of the UE that is the transmission destination of the TP indicated by the number, but the value 0) that is not used as the UE number when the corresponding TP stops transmission.

  For this reason, the optimal solution holding unit 13 holds the UE number that is the transmission destination of TP # i (i = 1... Ntp) for all TPs as the reproduction resource allocation pattern R [i], and the input differential TP number. The reproduction resource allocation pattern R [I] is changed to the value of the difference UE number J based on I and the difference UE number J, and corresponds to the TP number i (i = 1... Ntp, i ≠ I) excluding the difference TP number I. The reproduction resource allocation pattern R [i] to be reproduced is retained in the optimum solution retaining unit 13 by continuing to retain the same resource allocation pattern generated by the pattern generating unit 11. The pattern generation unit 11 does not output the differential TP number and the differential UE number to the optimal solution holding unit 13, but generates the generated resource allocation pattern T [i] (i = 1... Ntp) as the optimal solution holding unit. A configuration of outputting to 13 is also possible.

  Moreover, since there is a delay between the pattern evaluation unit 12 inputting the differential TP number and the differential UE number from the pattern generation unit 11 and outputting the evaluation value, the evaluation value calculated by the pattern evaluation unit 12 is the best. When the optimum solution holding unit 13 can determine, the optimum solution holding unit 13 needs to acquire a resource allocation pattern corresponding to the evaluation value. In particular, in the configuration in which the pattern evaluation unit 12 is pipelined, it is necessary to acquire resource allocation patterns generated by the pattern generation unit 11 before the number of resource allocation patterns that can be processed by the pattern evaluation unit 12 within the delay time. There is.

  For this reason, the optimal solution holding unit 13 accumulates the pair of the differential TP number and the differential UE number input from the pattern generation unit 11 in a FIFO (First-In First-Out) buffer, and the pattern evaluation unit 12 stores the differential TP number. A delay corresponding to the time from the input of the differential UE number to the output of the evaluation value is given to the differential TP number and the differential UE number, and playback is performed using the differential TP number and the differential UE number extracted from the FIFO buffer. Generate a resource allocation pattern.

  Thereby, the memory amount of the FIFO buffer can be reduced as compared with the configuration in which the reproduction resource allocation pattern is stored in the FIFO buffer. For example, for holding one reproduction resource allocation pattern, there is a memory that stores a number obtained by multiplying the number of bits w_ue required to represent one UE number by the number of TPs, that is, Ntp × w_ue. Necessary. On the other hand, for holding one set of the differential TP number and the differential UE number, the number of bits w_tp necessary to express one TP number and the number of bits necessary to express one UE number A memory for storing the number of bits corresponding to the sum of w_ue is required. In general, since Ntp <Nue (the number of UEs is larger than the number of TPs), the number of bits necessary to express each number is also w_tp ≦ w_ue, so the differential TP number and the differential UE number are retained. This configuration requires less memory.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 10 ... Scheduling apparatus, 11 ... Pattern production | generation part, 12 ... Pattern evaluation part, 13 ... Optimal solution holding part, 21 ... Transmission state production | generation part, 22 ... Evaluation parameter table classified by user terminal (evaluation parameter table classified by UE), 23 ... Transmission Point-by-point evaluation parameter holding unit (TP-by-TP evaluation parameter holding unit), 24 ... Transmission point-by-point evaluation unit (TP-by-TP evaluation unit), 25 ... Transmission point-by-point evaluation value summation unit (TP-by-TP evaluation value summation unit)

Claims (5)

A scheduling device that performs radio resource allocation for performing radio communication between a transmission point and each user terminal with respect to a wireless network system having a plurality of transmission points,
For each transmission point, a pattern generation unit that sequentially creates a resource allocation pattern for designating operation content indicating a user terminal or transmission stop as a transmission destination;
For each resource allocation pattern, a pattern evaluation unit that calculates a pattern evaluation value for evaluating the radio resource allocation based on the resource allocation pattern;
An optimal solution holding unit that selects a resource allocation pattern having the best pattern evaluation value among the resource allocation patterns as an optimal resource allocation pattern used for actual radio resource allocation;
The pattern evaluation unit
An evaluation parameter table for each user terminal that stores an evaluation parameter for each user terminal input from the outside, and an evaluation parameter table for each user terminal;
Based on the user terminal evaluation parameter for the user terminal that is provided for each transmission point and output from the user terminal evaluation parameter table, the pattern evaluation by transmission point for the transmission point is performed. A plurality of pattern evaluation units for each transmission point for calculating values;
By summing these pattern evaluation values for each transmission point, the transmission point evaluation value totaling unit for calculating a pattern evaluation value for the new resource allocation pattern generated by the pattern generation unit,
When generating a new resource allocation pattern, the pattern generation unit sequentially creates a resource allocation pattern in which only the operation content at any one transmission point is a difference compared to the resource allocation pattern generated immediately before, The difference information indicating the difference is sequentially output,
The pattern evaluation unit, wherein from the pattern generation unit read out from the user terminal based evaluation parameter table-out based on the difference information, based on each user terminal evaluation parameters corresponding to the difference corresponds to the difference a Only the transmission point pattern evaluation unit updates the user terminal evaluation parameter for the user terminal that is the transmission destination of the transmission point, calculates the transmission point pattern evaluation value for each transmission point, and the transmission point evaluation value total And calculating a pattern evaluation value related to a new resource allocation pattern by performing summation in each section. The scheduling apparatus according to claim 1, wherein
The pattern evaluation unit is further provided for each transmission point, and further includes a plurality of transmission point-specific evaluation parameter holding units that hold transmission point-specific evaluation parameters related to the transmission point. The transmission point-specific evaluation parameter holding unit corresponding to the difference holds the user terminal evaluation parameter corresponding to the difference read from the user terminal-specific evaluation parameter table as a transmission point-specific evaluation parameter. A scheduling apparatus characterized in that each pattern evaluation unit for each transmission point calculates a pattern evaluation value for each transmission point based on the evaluation parameter for each transmission point output from the parameter holding unit. In the scheduling apparatus according to claim 1 or 2,
The pattern generation unit generates, for each transmission point, the resource allocation pattern for each combination obtained by combining these options based on pattern range information in which the operation content that the transmission point can actually take is specified in advance. A scheduling apparatus characterized by: In the scheduling apparatus in any one of Claims 1-3,
The optimum solution holding unit includes a FIFO for storing the difference information sequentially output from the pattern generation unit, and the difference information is delayed by a time required for pattern evaluation value calculation in the pattern evaluation unit by the FIFO. Are sequentially read out, and based on the difference information and the immediately preceding resource allocation pattern, playback resource allocation patterns corresponding to the pattern evaluation values sequentially output from the pattern evaluation unit are sequentially generated. A scheduling apparatus characterized by selecting a reproduction resource allocation pattern having the best pattern evaluation value as the optimum resource allocation pattern. A scheduling method for assigning radio resources for radio communication between a transmission point and each user terminal for a radio network system having a plurality of transmission points,
A pattern generation step for sequentially creating a resource allocation pattern for designating an operation content indicating a transmission destination user terminal or transmission stop for each transmission point;
For each resource allocation pattern, a pattern evaluation step for calculating a pattern evaluation value for evaluating the radio resource allocation based on the resource allocation pattern;
An optimal solution selection step of selecting a resource allocation pattern having the best pattern evaluation value among the resource allocation patterns as an optimal resource allocation pattern used for actual radio resource allocation,
The pattern evaluation step includes
A user related to a user terminal serving as a transmission destination of the transmission point, which is provided for each transmission point and is output from an evaluation parameter table for each user terminal that is input from the outside and stores an evaluation parameter for each user terminal. A plurality of transmission point-specific pattern evaluation steps for calculating a transmission point-specific pattern evaluation value related to the transmission point based on the terminal-specific evaluation parameters;
A pattern evaluation value summation step for each transmission point that calculates a pattern evaluation value related to the new resource allocation pattern generated in the pattern generation step by summing the pattern evaluation values for each transmission point, and
In the pattern generation step, when generating a new resource allocation pattern, in comparison with the resource allocation pattern generated immediately before, a resource allocation pattern in which only the operation content at any one transmission point becomes a difference is sequentially generated, The difference information indicating the difference is sequentially output,
The pattern evaluation step, the pattern read from based-out the user terminal based evaluation parameter table on the difference information from the generating step, based on the user terminal based evaluation parameters corresponding to the difference corresponds to the difference a Update the evaluation parameter for each user terminal related to the user terminal that is the transmission destination of the transmission point only in the pattern evaluation step for each transmission point, calculate the pattern evaluation value for each transmission point and calculate the pattern evaluation value for each transmission point A scheduling method characterized by calculating a pattern evaluation value related to a new resource allocation pattern by summing in a summation step.

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