JP6692738B2 - Scheduling apparatus and method - Google Patents

Description

  The present invention relates to a wireless network control technique, and more particularly to a scheduling technique for allocating a wireless resource included in a wireless network by designating an operation content (transmission state) of each antenna in the wireless network.

  With the spread of smartphones, social demands for wireless networks have increased, such as an increase in communication speed and an increase in bandwidth usage. Against the background of such a situation, a wireless network system to which a wireless interface specification of a next-generation mobile communication system called LTE (Long Term Evolution) is applied is becoming widespread. In this LTE, as one of the radio access technologies, CoMP (Coordinated Multi-point transmission / reception: cell) in which a plurality of antennas (TP: base station) cooperatively transmit and receive signals to and from a radio terminal (UE: user radio terminal) Inter-cooperative transmission / reception) is adopted (see Non-Patent Document 1).

  The CoMP technology is one of the important technologies for improving frequency utilization efficiency and cell edge user throughput. For example, in downlink communication (transmission from TP to UE), a plurality of antennas simultaneously transmit to each UE using the same frequency band, so that the utilization efficiency of radio resources can be improved. However, when each antenna transmits to a different UE, for a UE that can receive signals from a plurality of antennas, signals from other antennas interfere with a desired received signal, which rather decreases throughput. There is a fear. Therefore, CoMP is an indispensable technique for improving the communication speed while suppressing such interference.

  Further, in applying CoMP to a wireless network, if the purpose is to maximize the system throughput, priority is given to resource allocation to users with good reception conditions, which causes a problem in fairness among users. Scheduling considering the average rate up to now is considered desirable (see Non-Patent Document 2).

Taoka et al., "MIMO and inter-cell coordinated 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 device specifies a transmission state for each TP, that is, a UE to be a destination or a transmission stop for each TP, as a combination of the TP and the UE having the largest evaluation value. Decide what information to take. In order to determine this combination, the evaluation values of a large number of combinations of TP and UE are calculated, the process of finding the combination with the best evaluation value is performed, and the combination is determined within the scheduling period (for example, within 1 millisecond). Need to be completed.

  A reliable way to obtain the optimal combination is to calculate the evaluation value for each of all possible combinations and find the combination with the highest evaluation value, ie a brute force search. Therefore, as the scale of the wireless network (the number of TPs and UEs included) increases, the search space (the number of possible combinations) becomes enormous. Therefore, in the above-described conventional technique, when the scale of the wireless network becomes large, it takes a long time to find the optimum combination, and it is not possible to determine the optimum combination within the scheduling cycle.

  The present invention is intended to solve such a problem, and an object of the present invention is to provide a scheduling technique capable of shortening the processing time required for determining an optimum combination.

In order to achieve such an object, the scheduling device according to the present invention provides the antenna with an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with the antennas. A scheduling device that determines for each data transmission timing from the wireless terminal to the wireless terminal, and selects, for each data transmission timing, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing. A selection unit, a combination generation unit that sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna, and an evaluation value regarding a combination of the target wireless terminal and the antenna for each combination pattern. Of the combination evaluation unit and the combination pattern, And a optimal combination holding portion for holding the combination pattern value is maximum as the optimum combination pattern, the terminal selecting unit, at a rate of once to a plurality of the data transmission timing, the wireless terminal a plurality of terminal group And sequentially select one of the terminal groups for each of the data transmission timings from these terminal groups, select a wireless terminal included in the selected terminal group as the target wireless terminal, and classify the wireless terminal. In doing so, among the wireless terminals, wireless terminals having low similarity in channel information indicating a radio wave state regarding the antenna are classified into the same terminal group .

Further, the scheduling device according to the present invention transmits an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with these antennas, from the antenna to the wireless terminal. A scheduling device that determines at each timing, and a terminal selection unit that selects a part of the wireless terminal as a target wireless terminal to be transmitted at the data transmission timing for each data transmission timing, and the target wireless terminal. And a combination generation unit that sequentially generates combination pattern candidates indicating the combination of the antenna, a combination evaluation unit that calculates an evaluation value regarding a combination of the target wireless terminal and the antenna for each combination pattern, and the combination Of the patterns, the combination pattern with the highest evaluation value An optimum combination holding unit that holds a code as the optimum combination pattern, wherein the terminal selection unit classifies the wireless terminals into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings. One of the terminal groups is sequentially selected from the terminal groups for each of the data transmission timings, a wireless terminal included in the selected terminal group is selected as the target wireless terminal, and the antenna is used when classifying the wireless terminals. The wireless terminals are classified into the terminal groups based on the magnitude of the temporal fluctuation amount of the channel information indicating the radio wave state regarding, and the terminal group having the largest fluctuation amount is selected from these terminal groups in order .

Further, the scheduling device according to the present invention transmits an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with these antennas, from the antenna to the wireless terminal. A scheduling device that determines at each timing, and a terminal selection unit that selects a part of the wireless terminal as a target wireless terminal to be transmitted at the data transmission timing for each data transmission timing, and the target wireless terminal. And a combination generation unit that sequentially generates combination pattern candidates indicating the combination of the antenna, a combination evaluation unit that calculates an evaluation value regarding a combination of the target wireless terminal and the antenna for each combination pattern, and the combination Of the patterns, the combination pattern with the highest evaluation value An optimum combination holding unit that holds a code as the optimum combination pattern, wherein the terminal selection unit classifies the wireless terminals into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings. One of the terminal groups is sequentially selected for each of the data transmission timings from the terminal group, a wireless terminal included in the selected terminal group is selected as the target wireless terminal, and the wireless terminal is classified when the wireless terminal is classified. The wireless terminals are classified into the terminal groups based on the magnitude of the amount of transmission data to be transmitted to the terminals, and the terminal group having the largest amount of transmission data is selected from these terminal groups in order .

Also, the scheduling method according to the present invention transmits an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and wireless terminals to be wirelessly communicated with these antennas, from the antenna to the wireless terminal. A scheduling method used in a scheduling device for each timing, wherein the terminal selection unit selects, for each data transmission timing, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing. And a combination generation step in which the combination generation unit sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna, and a combination evaluation unit, for each combination pattern, the target wireless. Regarding the combination of the terminal and the antenna A combination evaluation step of calculating an evaluation value, and an optimum combination holding unit, an optimum combination holding step of holding the combination pattern having the largest evaluation value among the combination patterns as the optimum combination pattern, the terminal selection In the step, the terminal selection unit classifies the wireless terminals into a plurality of terminal groups at a rate of once for a plurality of the data transmission timings, and selects one of the terminals for each of the data transmission timings from the terminal group. When sequentially selecting groups, selecting a wireless terminal included in the selected terminal group as the target wireless terminal, and classifying the wireless terminals, similarity of channel information indicating the radio wave state of the antenna among the wireless terminals The wireless terminals having low property are classified into the same terminal group .

Also, the scheduling method according to the present invention transmits an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and wireless terminals to be wirelessly communicated with these antennas, from the antenna to the wireless terminal. A scheduling method used in a scheduling device for each timing, wherein the terminal selection unit selects, for each data transmission timing, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing. And a combination generation step in which the combination generation unit sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna, and a combination evaluation unit, for each combination pattern, the target wireless. Regarding the combination of the terminal and the antenna A combination evaluation step of calculating an evaluation value, and an optimum combination holding unit, an optimum combination holding step of holding the combination pattern having the largest evaluation value among the combination patterns as the optimum combination pattern, the terminal selection In the step, the terminal selection unit classifies the wireless terminals into a plurality of terminal groups at a rate of once for a plurality of the data transmission timings, and selects one of the terminals for each of the data transmission timings from the terminal group. A group is sequentially selected, a wireless terminal included in the selected terminal group is selected as the target wireless terminal, and when classifying the wireless terminal, the magnitude of the temporal fluctuation amount of the channel information indicating the radio wave state regarding the antenna is large or small. The wireless terminals are classified into the terminal groups based on To choose from a large terminal groups of momentum.

Also, the scheduling method according to the present invention transmits an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and wireless terminals to be wirelessly communicated with these antennas, from the antenna to the wireless terminal. A scheduling method used in a scheduling device for each timing , wherein the terminal selection unit selects, for each data transmission timing, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing. And a combination generation step in which the combination generation unit sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna, and a combination evaluation unit, for each combination pattern, the target wireless. Regarding the combination of the terminal and the antenna A combination evaluation calculating the evaluation value, the optimal combination holder, among the combination patterns, and a best combination holding step of holding the combination patterns said evaluation value is maximum as the optimum combination pattern, the terminal selection In the step, the terminal selection unit classifies the wireless terminals into a plurality of terminal groups at a rate of once for a plurality of the data transmission timings, and selects one of the terminals for each of the data transmission timings from the terminal group. When selecting groups in sequence, selecting a wireless terminal included in the selected terminal group as the target wireless terminal and classifying the wireless terminals, the wireless terminals are based on the size of the transmission data to be transmitted to the wireless terminals. Are classified into the above-mentioned terminal groups, and among these terminal groups, the terminal group with the large amount of transmission data is From the selection in the order.

  According to the present invention, the number of wireless terminals used in one combination pattern can be reduced, so that the number of combination patterns used as candidates in the search process for the optimum combination pattern is significantly reduced. Therefore, it is possible to significantly reduce the time required to calculate the evaluation value of the combination pattern and further the time required to reach the optimum combination pattern.

It is a block diagram which shows the structure of a scheduling device. It is a sequence diagram which shows the relationship between a terminal group and a scheduling process. It is a flowchart which shows a scheduling process. It is a flow chart which shows terminal group classification processing.

Next, an embodiment of the present invention will be described with reference to the drawings.
[Scheduling device]
First, a scheduling device 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the scheduling device.

  The scheduling apparatus 10 uses, from TP, an optimum combination pattern indicating a combination of a plurality of antennas (hereinafter, referred to as TP) provided in a wireless network and wireless terminals (hereinafter, referred to as UE) that should perform wireless communication with these TPs. It has a function of determining each data transmission timing to the UE.

[Principle of the Invention]
Generally, when determining a UE as a transmission destination of data to be transmitted from each TP, combination patterns of TP and UE are sequentially generated as candidates, and evaluation values of these combination patterns are calculated. Based on a preset search algorithm, this trial is repeatedly executed in accordance with the data transmission timing, and when the data transmission timing arrives, a combination pattern in which the evaluation value obtained up to that point is the maximum, It is determined as the optimum combination pattern used for actual data transmission.

  Here, in such a scheduling process, it is not necessary to assign all UEs to any TP at one data transmission timing. This is because the data transmission timing repeatedly arrives at an extremely short cycle of, for example, 1 millisecond. Therefore, even if an arbitrary UE is not assigned to any TP at a certain data transmission timing, it is assigned at the subsequent data transmission timing. For example, there is no great influence on data transmission.

On the other hand, the number of combination patterns greatly changes depending on the number of UEs assigned by the combination pattern. For example, when the numbers of UEs and TPs are X and Y, respectively, (X + 1) ^Y combination patterns are required to cover all combinations of UEs and TPs. Note that in this trial calculation, the number of cases in which no UE is assigned to the TP is also taken into consideration.

The present invention focuses on the relationship between the data transmission timing and the allocation of the UE to the TP, and selects a plurality of target UEs to be transmitted at the next data transmission timing from all UEs for each data transmission timing. It is something that you choose to.
As a result, the number of UEs used in the combination pattern, that is, the value of M can be reduced, so that the number of combination patterns can be significantly reduced in a power unit of TP. Therefore, the time required for the process of calculating the evaluation value of the combination pattern, and further the time required to reach the optimum combination pattern can be significantly reduced.

[Detailed configuration of the present embodiment]
Next, the configuration of the scheduling device 10 according to the present exemplary embodiment will be described in detail with reference to FIG.
The scheduling device 10 shown in FIG. 1 is provided with a terminal selection unit 11, a combination generation unit 12, a combination evaluation unit 13, and an optimum combination holding unit 14 as main functional units, and these functional units are dedicated. It may be realized by the circuit of, or may be realized by executing a program registered in advance by the CPU.

The terminal selection unit 11 selects, for each data transmission timing, some UEs of all UEs to be scheduled as target UEs to be transmitted at the data transmission timing, and notifies the combination generation unit 12 as a combination generation condition. It has a function to do.
As a method for selecting the target UE, the UE is classified into a plurality of terminal groups at a rate of once for a plurality of data transmission timings, and one of the terminal groups is sequentially selected from the terminal groups for each data transmission timing. There is a method of selecting a UE included in the selected terminal group as a target UE.

FIG. 2 is a sequence diagram showing the relationship between the terminal group and the scheduling process.
In this example, all UEs are classified into two terminal groups Ga and Gb based on the channel information CH that is updated in each update cycle TC having a length from time T1 to time T2. The channel information CH is data indicating the reception intensity of the radio wave from the surrounding TP in each UE, which is periodically measured and notified by each UE, or is estimated periodically.

As shown in FIG. 2, in one update cycle TC, N data transmission timings TT # 1, TT # 2, ..., TT # N are provided, and each of these data transmission timings TT is optimized. Scheduling processes SC # 1, SC # 2, ..., SC # N for determining the combinations P # 1, P # 2, ..., P # N respectively are executed.
The optimum combination P # n determined by the scheduling process SC # n of the data transmission timing TT # n (n is an integer of 1 to N) is the data transmission process TR # n at the next data transmission timing TT # n + 1. Used.

  Therefore, among the N data transmission timings TT provided in the update cycle TC, the UE belonging to the terminal group Ga is selected as the target UE in the scheduling process SC in the first half, and only the target UEs of these terminal groups Ga are used. The combined pattern that has been generated is generated. In the latter half of the scheduling process SC, UEs belonging to the terminal group Gb are selected as target UEs, and a combination pattern using only the target UEs of these terminal groups Ga is generated.

  In addition, although the case where each UE is classified into a terminal group based on channel information has been described in FIG. 2, the present invention is not limited to this, and each UE is based on other data such as the transmission data amount of each UE. May be classified into terminal groups. Further, the number of terminal groups is not limited to two as shown in FIG. 2, and may be classified into three or more terminal groups.

  Further, regarding the allocation of the data transmission timing to the terminal group, it may be allocated equally to each terminal group, or may be allocated based on the number of UEs belonging to the terminal group and the transmission data amount of these UEs. For example, in the example of FIG. 2, when the number of UEs classified into the terminal group Ga is smaller than the upper limit of the number of UEs that can be transmitted at N / 2 data transmission timings, the number of data transmission timings assigned to Ga is reduced, The number of data transmission timings assigned to the group Gb may be increased.

  The combination generation unit 12 has a function of sequentially generating, based on the combination generation condition notified from the terminal selection unit 11, a combination pattern candidate indicating a combination of the target UE and TP specified by the combination generation condition. There is. The combination generation unit 12 may stop the generation of the combination pattern at the time when a predetermined time has elapsed from the time when the generation of the combination pattern is started or when the generation of the predetermined number of combination patterns is finished. A generally known search algorithm is used as the method of generating the pattern combination. For example, in addition to a brute force method that exhaustively generates all combinations, a known approximate solution method of a combinatorial optimization problem such as a hill climbing method and a greedy method can be applied. Further, when the combination pattern is generated, a combination in which the TP is in the transmission stopped state is also generated.

  The combination evaluation unit 13 has a function of calculating an evaluation value regarding a combination of the target UE and TP for each combination pattern generated by the combination generation unit 12. The evaluation value is calculated based on a preset evaluation formula. The parameter used in the evaluation formula is the sum of the wireless throughputs of the TPs, that is, the wireless throughput of the entire system, and the throughput value that is generally used in the wireless network system and that is obtained when transmission is performed with each TP and UE. A value (Proportional Fairness, PF metric) divided by the average throughput value accumulated for a predetermined period may be used.

  The optimum combination holding unit 14 has a function of holding the combination pattern having the maximum evaluation value calculated by the combination evaluation unit 13 as the optimum combination pattern. Specifically, the combination generation unit 12, the combination evaluation unit 13, and the optimum combination holding unit 14 operate in conjunction with each other in pipeline processing, and each time the combination generation unit 12 generates a new combination pattern, a combination is generated. The evaluation unit 13 calculates an evaluation value of a new combination pattern, and the optimum combination holding unit 14 creates a new evaluation value only when the evaluation value of the new combination pattern is larger than the evaluation value of the optimum combination pattern held so far. The combination pattern and its evaluation value are held as the optimum combination pattern.

[Terminal grouping (similar channel information)]
Next, the terminal grouping of the UE in the terminal selection unit 11 will be described in detail.
First, a case where terminal grouping is performed based on UE channel information will be described.
The channel information is data indicating the reception intensity of the radio wave from the surrounding TP in each UE, which is periodically measured and notified by each UE, or is estimated periodically.

  Here, when the channel information regarding different UEs shows the same reception intensity with respect to the radio wave from the same TP, it is considered that these UEs are located near each other. Therefore, when transmitting transmission data to these UEs at the same data transmission timing, it is highly possible that these UEs are assigned to the same TP, and in such a case, traffic concentration on the TP occurs, and The possibility of communication failure due to interference also increases.

  For this reason, in the present embodiment, when classifying each UE, the terminal selecting unit 11 classifies, among the UEs, UEs having low similarity in channel information indicating a radio wave state regarding TP into the same terminal group. You may do it. As a result, UEs that are close to each other in location are classified into different groups, and thus these UEs are included in different combination patterns. Therefore, the possibility that these UEs are assigned to the same TP at the same data transmission timing can be avoided, the concentration of traffic on the TP and the occurrence of communication failure due to radio wave interference can be suppressed, and a good wireless service can be provided. Becomes

[Terminal grouping (channel information fluctuation amount)]
On the other hand, the fluctuation amount of the reception intensity obtained at the UE per unit time is greatly influenced by the moving speed of the UE. This is because the greater the moving speed of the UE, the greater the change in the distance from the TP, and therefore the more the change in the radio wave transmitted from the TP.
Therefore, when the fluctuation amount of the channel information is large, the radio environment of the UE is likely to change in a short time from the time when the channel information is obtained, and the accuracy of the channel information is likely to deteriorate. On the other hand, when the fluctuation amount of the channel information is small, the radio environment of the UE is unlikely to change even after a certain amount of time has elapsed since the channel information was obtained, and the accuracy of the channel information is less likely to deteriorate.

  Therefore, in the present embodiment, when the terminal selection unit 11 classifies each UE, the UE is classified into a terminal group based on the magnitude of the temporal fluctuation amount of the channel information indicating the radio wave state regarding TP, You may make it select from a terminal group with a big fluctuation | variation amount among these terminal groups in order. As a result, the UE whose channel information accuracy is likely to deteriorate is selected first to generate the combination pattern, and the TP is assigned to these UEs with priority from the data transmission timing located at the beginning of the update period. Therefore, it is possible to minimize the allocation error between the UE and the TP caused by the deterioration of the accuracy of the channel information, reduce the transmission error due to this, and provide a good wireless service.

[Terminal grouping (data transmission amount)]
Also, when the amount of transmission data to be transmitted from the UE is large, the time required to complete the transmission of these transmission data is relatively long, so the radio environment of the UE is likely to change until the transmission is completed, and the channel information Accuracy is likely to deteriorate. On the other hand, when the amount of transmission data is small, the time required to complete the transmission of these transmission data is relatively short, so the radio environment of the UE is unlikely to change before the transmission is completed, and the accuracy of the channel information deteriorates. Hateful.

  Therefore, in the present embodiment, when the terminal selection unit 11 classifies each UE, the UE is classified into a terminal group based on the size of the transmission data amount of each UE, and the transmission data among these terminal groups is classified. You may make it select from a terminal group with a large amount in order. As a result, the UE whose channel information accuracy is likely to deteriorate is selected first to generate the combination pattern, and the TP is assigned to these UEs with priority from the data transmission timing located at the beginning of the update period. Therefore, it is possible to minimize the allocation error between the UE and the TP caused by the deterioration of the accuracy of the channel information, reduce the transmission error due to this, and provide a good wireless service.

  The grouping of these UEs may be applied individually or in combination. For example, a UE having a large amount of variation in channel information and a large amount of transmission data is classified into a first terminal group, the others are classified into a second terminal group, and TPs are sequentially assigned from UEs belonging to the first terminal group. You may hit. As a result, the UE whose radio environment is likely to change can be preferentially selected as the target UE, and a good radio service can be provided as a whole.

[Operation of this Embodiment]
Next, the operation of the scheduling device 10 according to the present exemplary embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the scheduling process. FIG. 4 is a flowchart showing the terminal group classification process.

[Scheduling process]
First, the scheduling process according to the present embodiment will be described with reference to FIG. The scheduling device 10 executes the scheduling process of FIG. 3 in synchronization with the channel information updated every update period TC.
In the scheduling process of FIG. 3, first, the terminal selection unit 11 classifies all UEs to be scheduled into a plurality of terminal groups by executing a target UE selection process of FIG. 4 described later (step 100).

  Subsequently, the terminal selection unit 11 selects, for each of the plurality of data transmission timings TT provided in the update cycle TC, an arbitrary terminal group from the terminal groups obtained in the above classification, for example, a variation amount of channel information. Target UEs to be transmitted at the data transmission timing by selecting one from the one with the largest transmission data or from the one with the largest transmission data amount (step 101), and listing the terminal IDs of the UEs belonging to the selected terminal group. (Step 102). As a result, the search process for the optimum combination pattern used at the next data transmission timing is started based on this combination generation condition.

In the search process, first, the combination generation unit 12 generates one candidate of a new combination pattern indicating a combination of the target UE and TP specified by the combination generation condition from the terminal selection unit 11 according to a predetermined search algorithm. (Step 103). When the combination pattern is generated, a combination in which each TP is in the transmission stop state is also generated.
Subsequently, the combination evaluation unit 13 calculates a new evaluation value for the combination of the target UE and TP for the new combination pattern generated by the combination generation unit 12 (step 104).

  After that, the optimum combination holding unit 14 compares the new evaluation value of the new combination pattern calculated by the combination evaluation unit 13 with the held evaluation value of the held combination pattern held so far (step 105). Here, when the new evaluation value is higher than the held evaluation value and indicates the maximum value of the combination patterns that have been generated so far (step 105: YES), the new combination pattern and the new evaluation value are updated and held (step 105: YES). Step 106).

Next, the optimum combination holding unit 14 determines whether or not to end the search process when it is confirmed that the search process currently being executed has converged or when the next data transmission timing arrives (step 107) If not completed (step 107: NO), the process returns to step 103 to generate and evaluate a new combination pattern.
If the new evaluation value is equal to or less than the held evaluation value in step 105 (step 105: NO), the process similarly returns to step 103 to start generation / evaluation of a new combination pattern.

  On the other hand, when the search processing is completed (step 107: YES), the optimum combination holding unit 14 outputs the held combination pattern finally held in the search processing up to that time as the optimum combination pattern (step 108). As a result, the combination of the UE and TP at the next data transmission timing is set based on this optimum combination pattern.

After that, the terminal selection unit 11 confirms whether or not the update period TC of the channel information CH has ended (step 109), and if it has not ended (step 109: NO), returns to step 101 and sets new data. The terminal group selection and search processing for the transmission timing TT is started.
When the update period TC ends (step 109: YES), the process returns to step 100 and the terminal group classification process based on the new channel information is started.

[Terminal group classification processing]
Next, the terminal group classification process according to the present embodiment will be described with reference to FIG. The terminal selecting unit 11 executes the terminal group classification process shown in FIG. 4 in step 100 of FIG. Here, a case will be described as an example where these UEs are classified into two terminal groups Ga and Gb based on the channel information and the transmission data amount of each UE. Of these, Ga is a group of UEs to which TP is assigned prior to Gb.

In the terminal group classification process of FIG. 4, first, the terminal selection unit 11 acquires channel information about all UEs to be scheduled (step 200), and calculates a variation amount from the previously acquired channel information for each UE (step 200). Step 201).
Next, the terminal selection unit 11 acquires the data amount relating to the UE-destined data accumulated in, for example, a frame buffer (not shown), so that the transmission data amount (transmitted data amount to be transmitted by each UE at the next data transmission timing ( The maximum value) is acquired (step 202).

  After that, the terminal selection unit 11 selects one unclassified UE from each UE (step 210), and determines the variation amount of the selected UE obtained in step 201 and the variation amount threshold value set in advance. The comparison is made (step 211). Here, when the channel variation amount of the selected UE exceeds the variation amount threshold value (step 211: YES), the terminal selection unit 11 is preset with the transmission data amount of the selected UE obtained in step 202. The transmission amount threshold value is compared (step 212).

Here, when the transmission data amount of the selected UE exceeds the transmission amount threshold value (step 212: YES), the terminal selection unit 11 classifies the selected UE into the terminal group Ga (step 213).
On the other hand, in step 211, if the variation amount of the selected UE is less than or equal to the variation amount threshold value (step 211: NO), and in step 212, the transmission data amount of the selected UE is less than or equal to the transmission threshold value (step 212: NO), the terminal selection unit 11 classifies the selected UE into the terminal group Gb (step 214).

After that, the terminal selection unit 11 confirms whether or not the classification of all UEs has been completed (step 215), and if there is an unclassified UE (step 215: NO), returns to step 210 and starts a new UE. The classification process of is started.
On the other hand, when the classification is completed for all UEs (step 215: YES), the series of terminal group classification processing is ended.

As for the fluctuation amount of any UE calculated in step 202 of FIG. 4, an average value of fluctuation amounts of reception intensity of radio waves from the UE and each TP may be used, and the reception intensity is the best for the UE. Alternatively, the variation amount regarding only TP may be used.
Further, in the example of FIG. 4, an example in which the UE is classified using the channel information and the transmission data amount is shown, but the example of the UE classification is not limited to this. For example, it may be classified into a plurality of terminal groups using only the channel information and its variation amount. Also, the UE may be classified using only the amount of transmission data.

  Also, UEs having low channel information similarity may be classified into the same terminal group. At this time, first, each UE is classified into a TP group based on the TP having the best reception sensitivity in each UE, and each UE is selected to generate a terminal group so that UEs in the same TP group are not selected. May be. As a result, UEs having low channel information similarity can be classified into the same terminal group.

[Effects of this Embodiment]
As described above, in this embodiment, the terminal selection unit 11 selects, for each data transmission timing TT, a part of the UEs as a target UE to be transmitted at the data transmission timing TT.
More specifically, the terminal selecting unit 11 classifies the UE into a plurality of terminal groups at a rate of once for a plurality of data transmission timings, and selects one of the terminal groups for each data transmission timing TT. The terminal groups are sequentially selected, and UEs included in the selected terminal groups are selected as target UEs.

  As a result, the number of UEs used in one combination pattern can be reduced, so that the number of combination patterns used as candidates in the search process for the optimum combination pattern is significantly reduced. Therefore, it is possible to significantly reduce the time required to calculate the evaluation value of the combination pattern and further the time required to reach the optimum combination pattern.

[Expansion of Embodiment]
Although the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above exemplary 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. Further, the respective embodiments can be implemented in any combination within a range that does not contradict.

  10 ... Scheduling device, 11 ... Terminal selection part, 12 ... Combination generation part, 13 ... Combination evaluation part, 14 ... Optimal combination holding part.

Claims (6)

A scheduling device that determines an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with these antennas for each data transmission timing from the antenna to the wireless terminal. ,
For each of the data transmission timing, a terminal selection unit that selects a part of the wireless terminal as a target wireless terminal to be transmitted at the data transmission timing,
A combination generating unit that sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
For each of the combination patterns, a combination evaluation unit that calculates an evaluation value related to the combination of the target wireless terminal and the antenna,
Among the combination patterns, an optimum combination holding unit that holds the combination pattern having the largest evaluation value as the optimum combination pattern ,
The terminal selection unit,
The wireless terminal is classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
A scheduling device , wherein when classifying the wireless terminals, wireless terminals having low similarity in channel information indicating a radio wave state regarding the antenna among the wireless terminals are classified into the same terminal group . A scheduling device that determines an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with these antennas for each data transmission timing from the antenna to the wireless terminal. ,
For each of the data transmission timing, a terminal selection unit that selects a part of the wireless terminal as a target wireless terminal to be transmitted at the data transmission timing,
A combination generating unit that sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
For each combination pattern, a combination evaluation unit that calculates an evaluation value for the combination of the target wireless terminal and the antenna,
Among the combination patterns, an optimum combination holding unit that holds the combination pattern having the largest evaluation value as the optimum combination pattern,
Equipped with
The terminal selection unit,
The wireless terminals are classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
When classifying the wireless terminals, the wireless terminals are classified into the terminal groups based on the magnitude of the temporal variation of the channel information indicating the radio wave state related to the antenna, and the variation of the terminal groups is large. A scheduling device characterized by selecting from a terminal group in order . A scheduling device that determines an optimum combination pattern indicating a combination of a plurality of antennas provided in a wireless network and a wireless terminal to be wirelessly communicated with these antennas for each data transmission timing from the antenna to the wireless terminal. ,
For each of the data transmission timing, a terminal selection unit that selects a part of the wireless terminal as a target wireless terminal to be transmitted at the data transmission timing,
A combination generating unit that sequentially generates candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
For each of the combination patterns, a combination evaluation unit that calculates an evaluation value related to the combination of the target wireless terminal and the antenna,
Among the combination patterns, an optimum combination holding unit that holds the combination pattern having the largest evaluation value as the optimum combination pattern,
Equipped with
The terminal selection unit,
The wireless terminal is classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
When classifying the wireless terminals, the wireless terminals are classified into the terminal groups based on the magnitude of the amount of transmission data to be transmitted to the wireless terminals, and the terminal groups with the largest amount of transmission data are selected from these terminal groups in order . A scheduling device characterized by the above. Used by a scheduling device that determines, for each data transmission timing from the antenna to the wireless terminal, an optimum combination pattern indicating a combination of a plurality of antennas provided in the wireless network and wireless terminals that should perform wireless communication with these antennas. A scheduling method,
A terminal selection step in which the terminal selection unit selects, for each of the data transmission timings, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing,
A combination generation step, a combination generation step of sequentially generating candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
A combination evaluation unit, for each of the combination patterns, a combination evaluation step of calculating an evaluation value regarding a combination of the target wireless terminal and the antenna,
An optimum combination holding step of the optimum combination holding unit holding the combination pattern having the largest evaluation value among the combination patterns as the optimum combination pattern;
Equipped with
In the terminal selection step, the terminal selection unit,
The wireless terminal is classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
When classifying the wireless terminals, the scheduling method is characterized in that, among the wireless terminals, wireless terminals having low similarity in channel information indicating a radio wave state regarding the antenna are classified into the same terminal group. Used by a scheduling device that determines, for each data transmission timing from the antenna to the wireless terminal, an optimum combination pattern indicating a combination of a plurality of antennas provided in the wireless network and wireless terminals that should perform wireless communication with these antennas. A scheduling method,
A terminal selection step in which the terminal selection unit selects, for each of the data transmission timings, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing,
A combination generation step, a combination generation step of sequentially generating candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
A combination evaluation unit, for each of the combination patterns, a combination evaluation step of calculating an evaluation value regarding a combination of the target wireless terminal and the antenna,
An optimum combination holding step of the optimum combination holding unit holding the combination pattern having the largest evaluation value among the combination patterns as the optimum combination pattern;
Equipped with
In the terminal selection step, the terminal selection unit,
The wireless terminal is classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
When classifying the wireless terminals, the wireless terminals are classified into the terminal groups based on the magnitude of the temporal fluctuation amount of the channel information indicating the radio wave state related to the antenna, and the fluctuation amount of the terminal groups is large. A scheduling method characterized by selecting from a terminal group in order. Used by a scheduling device that determines, for each data transmission timing from the antenna to the wireless terminal, an optimum combination pattern indicating a combination of a plurality of antennas provided in the wireless network and wireless terminals that should perform wireless communication with these antennas. A scheduling method,
A terminal selection step in which the terminal selection unit selects, for each of the data transmission timings, a part of the wireless terminals as a target wireless terminal to be transmitted at the data transmission timing,
A combination generation step, a combination generation step of sequentially generating candidates for a combination pattern indicating a combination of the target wireless terminal and the antenna,
A combination evaluation unit, for each of the combination patterns, a combination evaluation step of calculating an evaluation value regarding a combination of the target wireless terminal and the antenna,
An optimum combination holding unit, which holds, as the optimum combination pattern, a combination pattern having the largest evaluation value among the combination patterns ,
In the terminal selection step, the terminal selection unit,
The wireless terminal is classified into a plurality of terminal groups at a rate of once for each of the plurality of data transmission timings, and one of the terminal groups is sequentially selected for each of the data transmission timings, and the selected one is selected. Select a wireless terminal included in the terminal group as the target wireless terminal,
When classifying the wireless terminals, the wireless terminals are classified into the terminal groups based on the magnitude of the amount of transmission data to be transmitted to the wireless terminals, and the terminal groups with the largest amount of transmission data are selected from these terminal groups in order. A scheduling method characterized by the above.

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