JP2013038574A - Wireless communication system, base station device, and wireless resource allocation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance experience quality (QoE) by suppressing frequent and sudden change in a wireless resource allocation amount.SOLUTION: A base station device 16 performs wireless communication with each of a plurality of mobile terminals 14-1 to 14-N. For each of the plurality of mobile terminals 14-1 to 14-N, an index calculation unit 20 calculates an allocation index value M[n] indicating priority of wireless resource allocation for a mobile terminal 14-n according to the past wireless resource allocation amount for the mobile terminal 14-n. A wireless resource allocation unit 30 allocates a wireless resource to each mobile terminal 14 on the basis of the allocation index values M[1] to M[N] calculated for each mobile terminal 14 by the index calculation unit 20.

Description

  The present invention relates to a technique for allocating radio resources to each of a plurality of mobile terminals.

  In a wireless communication system in which a base station apparatus and a plurality of mobile terminals communicate with each other wirelessly, the base station apparatus allocates radio resources to each mobile terminal. Patent Document 1 describes a Max C / that allocates radio resources according to communication quality such as a received signal code power (RSCP) and a signal to noise plus interference power ratio (SINR). I (carrier / interference) technology is disclosed. Patent Document 2 discloses a PF (proportional fairness) algorithm that ensures the fairness of radio resource allocation to each mobile terminal. Patent Document 3 discloses a technique for reducing the amount of radio resources allocated to a mobile terminal having a low reception success rate of packets transmitted from a base station apparatus.

JP 2003-309875 A JP 2010-161598 A JP 2008-011420 A

  However, in the techniques of Patent Literature 1 to Patent Literature 3, there is a possibility that the radio resource allocation amount for each mobile terminal may fluctuate rapidly in a short time. Therefore, there is a problem in that the transmission speed rapidly changes in a short time and the quality of experience (QoE) of the user of each mobile terminal is lowered. In view of the above circumstances, an object of the present invention is to improve the quality of experience by suppressing frequent and rapid fluctuations in the amount of allocated radio resources.

  In order to solve the above-described problem, a base station apparatus of the present invention is a base station apparatus that wirelessly communicates with each of a plurality of mobile terminals, and for each of the plurality of mobile terminals, radio resource allocation to the mobile terminal An index calculation unit that calculates an allocation index value indicating the priority of the mobile terminal according to a past radio resource allocation amount for the mobile terminal, and the allocation index value calculated by the index calculation unit for each mobile terminal A radio resource allocation unit that allocates radio resources to the mobile terminal. For example, the index calculating unit calculates the allocation index value for each of the plurality of mobile terminals so that the radio resource allocation priority indicated by the allocation index value increases as the past radio resource allocation amount increases. To do. In the above configuration, an allocation index value is calculated for each mobile terminal according to the past radio resource allocation amount for each mobile terminal, and radio resource allocation for the mobile terminal is executed according to each allocation index value. Accordingly, it is possible to improve the quality of experience of the user of each mobile terminal by suppressing frequent and rapid fluctuations in the radio resource allocation amount.

  The radio resource is a physical resource for wireless communication between the base station apparatus and the mobile terminal. For example, in time division multiple access (TDMA), it means a time slot, and is an orthogonal frequency division. Multiple access (OFDMA) means resource block (subcarrier), code division multiple access (CDMA) means code, and space division multiple access means antenna. The radio resource allocation amount is the amount of radio resources allocated to the mobile terminal. For example, in time division multiple access, it means the number of time slots per unit time (for example, 1 second) and the total time, and orthogonal frequency division multiple access. Means the number of resource blocks (subcarriers), code division multiple access means the number of codes, and space division multiple access means the number of antennas.

  In a preferred aspect of the present invention, the index calculation unit is notified from the mobile terminal for each of the plurality of mobile terminals, and communication quality relating to communication quality of radio communication between the base station apparatus and the mobile terminal. The allocation index value according to the information, reception success / failure information indicating the success / failure of reception of data transmitted from the base station apparatus notified from the mobile terminal, and the past radio resource allocation amount for the mobile terminal. Calculate. For example, the higher the predicted transmission rate specified from the communication quality information or the lower the average transmission rate (effective transmission rate) specified from the reception success / failure information, the higher the priority of the radio resource allocation is. The allocation index value of each mobile terminal is calculated as follows. In the above aspect, since communication quality information and reception success / failure information notified from each mobile terminal are added to the radio resource allocation in addition to the past radio resource allocation amount for the mobile terminal, only the radio resource allocation amount is allocated. Compared with the configuration reflected in the index value, it is possible to appropriately control the radio resource ratio for each mobile terminal.

  The present invention is also realized as a wireless communication system including the base station apparatus of each aspect exemplified above. The wireless communication system of the present invention is a wireless communication system comprising each of a plurality of mobile terminals and a base station apparatus that wirelessly communicates with each of the plurality of mobile terminals, wherein the base station apparatus includes the plurality of mobile terminals. For each mobile terminal, an index calculation unit that calculates an allocation index value indicating the priority of radio resource allocation for the mobile terminal according to a past radio resource allocation amount for the mobile terminal, and the index calculation unit A radio resource allocation unit that allocates radio resources to each mobile terminal based on an allocation index value calculated for the mobile terminal. According to the above configuration, the same operation and effect as the base station apparatus of the present invention are realized. Each of the plurality of mobile terminals receives communication quality information related to communication quality of radio communication between the base station apparatus and the mobile terminal, and reception success / failure of data transmitted from the base station apparatus In the configuration for notifying the success / failure information to the base station apparatus, the index calculation unit of the base station apparatus, for each of the plurality of mobile terminals, an allocation index value indicating a priority of radio resource allocation to the mobile terminal, It is possible to calculate according to the communication quality information and the reception success / failure information notified from the mobile terminal and the past radio resource allocation amount for the mobile terminal.

  The present invention is also realized as a method of allocating radio resources to each of a plurality of mobile terminals (an operation method of the base station apparatus according to each of the above-described embodiments). The radio resource allocation method of the present invention is a method in which a base station apparatus that performs radio communication with each of a plurality of mobile terminals allocates radio resources to each of the mobile terminals, and each of the plurality of mobile terminals is associated with the mobile terminal. An allocation index value indicating the priority of radio resource allocation is calculated according to a past radio resource allocation amount for the mobile terminal, and radio resources are allocated to each mobile terminal based on the allocation index value calculated for each mobile terminal. Assign. According to the above method, the same operation and effect as the base station apparatus of the present invention are realized.

1 is a block diagram of a wireless communication system according to an embodiment of the present invention. It is a block diagram of the base station apparatus in a radio | wireless communications system. It is a block diagram of the unit processing part in a base station apparatus. It is a flowchart of the radio | wireless resource allocation which a base station apparatus performs. It is a data flow figure of radio | wireless resource allocation.

  FIG. 1 is a block diagram of a wireless communication system 100 according to one embodiment of the present invention. The wireless communication system 100 includes a mobile communication network 12 and a plurality of mobile terminals 14 (14-1 to 14-N). The mobile communication network 12 is a communication network that provides each mobile terminal 14 with wireless communication services such as voice calls and data communication, and includes a plurality of base station devices 16. In FIG. 1, only one base station apparatus 16 is shown for convenience.

  The base station apparatus 16 performs radio communication with each mobile terminal 14 by assigning radio resources to the mobile terminals 14 located in the cell formed by the base station apparatus 16. The radio resource is a physical resource necessary for radio communication between the base station apparatus 16 and the mobile terminal 14, which means a time slot in time division multiple access, and a resource block (subcarrier in orthogonal frequency division multiple access). ), Code division multiple access means code, and space division multiple access means antenna. The base station device 16 is an access point for NB (Node B) in UMTS, eNB (evolved Node B) in UMTS (Universal Mobile Telecommunications System) LTE (Long Term Evolution), and WiMAX (Worldwide Interperability for Mictowave Access). obtain.

  Each mobile terminal 14 in FIG. 1 is, for example, a mobile phone (UE (User Equipment) in UMTS LTE), and other communication devices (other mobile terminals 14 and servers) via the base station device 16 of the mobile communication network 12. Device). The wireless communication method between the base station apparatus 16 and the mobile terminal 14 is arbitrary, but for example, OFDMA (Orthogonal Frequency Division Multiple Access) is adopted in the downlink direction, and SC-FDMA (Single -Carrier Frequency Division Multiple Access) is adopted. In the present embodiment, it is assumed for the sake of convenience that N (N is a natural number of 2 or more) mobile terminals 14-1 to 14-N communicate with the base station apparatus 16.

  Each mobile terminal 14 can transmit the communication quality information Q and the reception success / failure information S to the base station apparatus 16. The communication quality information Q is information relating to the communication quality of wireless communication between the base station apparatus 16 and the mobile terminal 14. For example, UMTS or UMTS LTE CQI (Channel Quality Indicator) is preferably used as the communication quality information Q. The reception success / failure information S is information indicating whether or not the mobile terminal 14 has properly received the data transmitted from the base station device 16. For example, ACK or NACK for the mobile terminal 14 to notify the base station apparatus 16 of success or failure of data reception is preferably used as the reception success / failure information S.

  FIG. 2 is a block diagram of elements related to radio resource allocation for each mobile terminal 14 in the base station apparatus 16. As shown in FIG. 2, the base station device 16 includes an index calculation unit 20 and a radio resource allocation unit 30. The index calculation unit 20 and the radio resource allocation unit 30 are functional bodies that are realized by, for example, a CPU (Central Processing Unit) executing a program stored in a storage device.

  The index calculation unit 20 in FIG. 2 generates allocation index values M [1] to M [N] for N mobile terminals 14-1 to 14-N communicating with the base station device 16. The allocation index value M [n] of the mobile terminal 14-n (n = 1 to N) is a scale indicating the priority of radio resource allocation to the mobile terminal 14-n, and is within a range of 0 or more and 1 or less, for example. Is set to be variable. The radio resource allocation unit 30 executes radio resource allocation for the mobile terminal 14-n based on the allocation index values M [1] to M [N] calculated by the index calculation unit 20 for each mobile terminal 14-n. The generation of the allocation index values M [1] to M [N] by the index calculation unit 20 and the radio resource allocation by the radio resource allocation unit 30 are executed, for example, every predetermined time.

  As shown in FIG. 2, the radio resource allocation unit 30 includes an allocation determination unit 32 and an allocation processing unit 34. The allocation determination unit 32 is configured to use one mobile terminal 14 (hereinafter referred to as “allocation target terminal 14”) to which radio resources should be preferentially allocated based on the allocation index values M [1] to M [N] calculated by the index calculation unit 20. And the amount of radio resources allocated to the allocation target terminal 14 is determined. Specifically, out of the N mobile terminals 14-1 to 14-N, the mobile terminal 14-n having the highest priority indicated by the allocation index value M [n] is selected as the allocation target terminal 14, and The allocation amount of radio resources for the allocation target terminal 14 is variably set so that the allocation amount increases as the allocation index value M [n] increases. The allocation determination unit 32 instructs the allocation processing unit 34 about the identifier of the allocation target terminal 14 and the allocation amount of the radio resource. For example, a sequence number given continuously or a terminal identification number (IMEI: International Mobile Equipment Identifier) of the mobile terminal 14 is preferably used as the identifier.

  The allocation processing unit 34 allocates a radio resource having an allocation amount instructed from the allocation determining unit 32 to the allocation target terminal 14 indicated by the identifier instructed from the allocation determining unit 32. Further, the allocation processing unit 34 notifies (feeds back) the allocation information A indicating the allocation result of the radio resource to the allocation target terminal 14 to the index calculation unit 20. The allocation information A specifies, for example, the total number of resource blocks allocated to the allocation target terminal 14.

  The index calculation unit 20 of FIG. 2 includes N unit processing units 22-1 to 22-N corresponding to different mobile terminals 14-n. The nth unit processing unit 22-n calculates the allocation index value M [n] of the mobile terminal 14-n. As shown in FIG. 3, each of the unit processing units 22-1 to 22-N includes a predicted transmission rate specifying unit 42, an average transmission rate specifying unit 44, an allocation rate specifying unit 46, and an arithmetic processing unit 48.

  The predicted transmission rate specifying unit 42 specifies the predicted transmission rate V1 based on the communication quality information Q notified from each mobile terminal 14-n. The predicted transmission rate V1 means a theoretical transmission rate estimated from the communication quality information Q. Although the method for specifying the predicted transmission rate V1 from the communication quality information Q is arbitrary, for example, the method for calculating the predicted transmission rate V1 from the coding rate, the size of the transmission packet, etc., or the CQI table specified in 3GPP TS 25.214 A method of obtaining the predicted transmission rate V1 from a table prepared in advance as described above is preferable.

  The average transmission rate identification unit 44 is a period of a predetermined length (hereinafter referred to as “unit period”) based on the reception success / failure information S notified from each mobile terminal 14-n and the allocation information A notified from the radio resource allocation unit 30. The actual average transmission rate (effective transmission rate) V2 at (1) is specified and held. The average transmission rate V2 means the amount of data successfully transmitted from the base station apparatus 16 to the mobile terminal 14 within the unit period. For example, the number of bits appropriately transmitted from the base station device 16 to the mobile terminal 14 per second is calculated as the average transmission rate V2. The average transmission rate specifying unit 44 of the unit processing unit 22-n calculates an average transmission rate V2 every time radio resources are allocated to the mobile terminal 14-n corresponding to the unit processing unit 22-n.

  The allocation rate specifying unit 46 specifies and holds the radio resource allocation rate R in the unit period based on the allocation information A notified from the radio resource allocation unit 30. The radio resource allocation rate R is an index indicating the degree of radio resource allocation for the mobile terminal 14-n. For example, the total number of resource blocks allocated to the mobile terminal 14-n per second is calculated as the radio resource allocation rate R. The allocation rate specifying unit 46 of the unit processing unit 22-n calculates a radio resource allocation rate R each time radio resource allocation is performed for the mobile terminal 14-n corresponding to the unit processing unit 22-n.

  The arithmetic processing unit 48 in FIG. 3 includes the predicted transmission rate V1 specified by the predicted transmission rate specifying unit 42, the average transmission rate V2 held by the average transmission rate specifying unit 44, and the radio resource allocation held by the allocation rate specifying unit 46. Based on the rate R, the allocation index value M [n] of the mobile terminal 14-n is calculated. Specifically, the arithmetic processing unit 48 increases the rate of reception failure indicated by the reception success / failure information S as the predicted transmission rate V1 is higher (the communication quality indicated by the communication quality information Q is higher) and the average transmission rate V2 is lower. The allocation index value M [n] is calculated such that the higher the radio resource allocation rate R is, the higher the radio resource allocation priority indicated by the allocation index value M [n] is. For example, the arithmetic processing unit 48 divides the predicted transmission rate V1 by the average transmission rate V2 and multiplies the radio resource allocation rate R (corrects the predicted transmission rate V1 by the average transmission rate V2 and the radio resource allocation rate R). To calculate the allocation index value M [n] (M [n] = (V1 / V2) · R). However, the specific method of calculating the allocation index value M [n] can be changed as appropriate.

  FIG. 4 is a flowchart of radio resource allocation executed by the base station apparatus 16, and FIG. 5 is a data flow diagram of the entire radio communication system 100. Processes corresponding to each other in FIGS. 4 and 5 are denoted by common reference numerals. The process of FIG. 4 is executed every predetermined time with an interrupt instruction periodically generated.

  When the radio resource allocation is started, the base station device 16 transmits the communication quality information Q generated by the communication quality measurement (SA10) by the mobile terminal 14-n from each of the N mobile terminals 14-1 to 14-N. Obtain (SB10). The predicted transmission rate specifying unit 42 of each unit processing unit 22-n specifies the predicted transmission rate V1 according to the communication quality information Q acquired from the mobile terminal 14-n in step SB10 (SB11).

  The arithmetic processing unit 48 of each unit processing unit 22-n includes the predicted transmission rate V1 specified in step SB11, the average transmission rate V2 held by the average transmission rate specification unit 44 (average transmission rate V2 after the last update), and Then, the allocation index value M [n] is calculated from the radio resource allocation rate R (radio resource allocation rate R immediately after update) held by the allocation rate specifying unit 46 (SB12).

  The radio resource allocation unit 30 selects one mobile terminal 14-1 as the allocation target terminal 14 based on the allocation index values M [1] to M [N] calculated in step SB12, and allocates the allocation index value M [ 1] is allocated to the allocation target terminal 14-1 (SB13). In step SB13, the allocation rate specifying unit 46 of the unit processing unit 22-1 corresponding to the allocation target terminal 14-1 to which radio resources are allocated is assigned information A (current allocation amount) notified from the radio resource allocation unit 30. ) And a default (after the last update) radio resource allocation rate R held at this stage, a new radio resource allocation rate R is calculated, and the default radio resource allocation rate R is calculated as a new radio resource allocation rate R. (SB14).

  On the other hand, the allocation target terminal 14-1 to which the radio resource is allocated determines whether or not the data transmitted from the base station apparatus 16 is successfully received (SA11). The base station device 16 receives the reception success / failure information S (ACK / NACK) indicating the result of the determination in step SA11 from the allocation target terminal 14-1 (SB15). The average transmission rate specifying unit 44 of the unit processing unit 22-1 corresponding to the allocation target terminal 14-1 is based on the reception success / failure information S received in step SB15 and the allocation information A notified from the radio resource allocation unit 30. A new average transmission rate V2 is calculated taking into account the allocation of radio resources, and the default (after the last update) average transmission rate V2 held at this stage is updated to the new average transmission rate V2 (SB16). .

  The radio resource allocation described above is repeated at predetermined intervals. That is, in each radio resource allocation, for each of the N mobile terminals 14-1 to 14-N, the current communication quality information Q notified from the mobile terminal 14-n and the mobile terminal 14-n are notified. Allocation index according to the past reception success / failure information S (average transmission rate V2 after the last update) and the past radio resource allocation amount (radio resource allocation rate R after the last update) for the mobile terminal 14-n. The value M [n] is calculated.

  As described above, in this embodiment, radio resource allocation for each of the N mobile terminals 14-1 to 14-N is controlled according to the past radio resource allocation amount for each mobile terminal 14-n. . Specifically, radio resources are preferentially allocated to the mobile terminal 14 having a large past radio resource allocation amount. Therefore, compared with the configuration in which the allocation target terminal 14 is selected without taking into account the past allocation amount of radio resources, frequent and sudden fluctuations in radio resource allocation amount (transmission rate fluctuations) are suppressed, and consequently It is possible to improve the quality of experience of the user of each mobile terminal 14.

  In the present embodiment, in addition to the past allocation amount of radio resources, the predicted transmission rate V1 corresponding to the communication quality indicated by the communication quality information Q and the past average transmission rate V2 indicated by the reception success / failure information S are the radio resources. Reflected in the allocation. Therefore, it is possible to appropriately allocate radio resources to each mobile terminal 14 as compared with the configuration in which only the past radio resource allocation amount is added to the radio resource allocation.

<Modification>
Various modifications are added to the above embodiment. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following examples can be appropriately combined as long as they do not contradict each other.

(1) In the above embodiment, one mobile terminal 14 is assigned as the assignment target terminal 14 in the radio resource assignment (step SB13) of FIG. 4, but the mobile terminal selected as the assignment target terminal 14 is used. The total number of 14 is arbitrary. For example, a predetermined number (plural) of mobile terminals 14 positioned in descending order of allocation index values M [1] to M [N] are selected as allocation target terminals 14, and the allocation index is assigned to each allocation target terminal 14. It is also possible to allocate a variable amount of radio resources according to the value M [n] (for example, a larger amount of radio resources as the allocation index value M [n] is larger). In the above-described embodiment, the amount of radio resources allocated to the allocation target terminal 14 is changed according to the allocation index value M [n], but the allocation target terminal 14 selected according to the allocation index value M [n]. A configuration in which a predetermined amount of radio resources are allocated to (i.e., a configuration in which one allocation amount is fixed) may be employed.

(2) In the above-described embodiment, the communication quality information Q and the reception success / failure information S are added to the radio resource allocation in addition to the past radio resource allocation amount, but the configuration in which the communication quality information Q is reflected in the radio resource allocation ( The configuration (the average transmission rate specifying unit 44) for reflecting the predicted transmission rate specifying unit 42) and the reception success / failure information S in the radio resource allocation may be omitted. That is, the index calculation unit 20 is an element that specifies the allocation index values M [1] to M [N] of each mobile terminal 14 according to the past radio resource allocation amount (radio resource allocation rate R) for each mobile terminal 14. It is included as

(3) The order of each process illustrated in FIG. 4 is changed as appropriate. For example, the radio resource allocation rate R can be updated (SB14) after the acquisition success / failure information S is acquired (SB15) and the average transmission rate V2 is updated (SB16).

(4) In the above-described embodiment, each element of the base station device 16 is realized by the CPU executing the program. However, all or a part of the base station device 16 may be replaced with dedicated hardware or an FPGA (Field Programmable). It can also be realized by a programmable logic device such as a gate array (DSP) and a digital signal processor (DSP). Further, a configuration in which each element of the base station device 16 is distributed to a plurality of devices may be employed.

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system, 12 ... Mobile communication network, 14 (14-1-14-N) ... Mobile terminal, 16 ... Base station apparatus, 20 ... Index calculation part, 22 (22-1-22) -N) ... unit processing unit, 30 ... radio resource allocation unit, 32 ... allocation determination unit, 34 ... allocation processing unit, 42 ... predicted transmission rate specification unit, 44 ... average transmission rate specification unit, 46 ... Allocation rate specifying unit, 48 ... Calculation processing unit.

Claims (5)

A wireless communication system comprising each of a plurality of mobile terminals and a base station device that wirelessly communicates with each of the plurality of mobile terminals,
Each of the plurality of mobile terminals includes communication quality information regarding communication quality of radio communication between the base station apparatus and the mobile terminal, and reception success / failure information indicating success or failure of reception of data transmitted from the base station apparatus To the base station device,
The base station device
For each of the plurality of mobile terminals, an allocation index value indicating the priority of radio resource allocation to the mobile terminal, the communication quality information and the reception success / failure information notified from the mobile terminal, and the past for the mobile terminal An index calculation unit for calculating according to the radio resource allocation amount;
A radio resource allocation unit that allocates radio resources to each mobile terminal based on an allocation index value calculated by the index calculation unit for each mobile terminal.
A wireless communication system. A base station apparatus that wirelessly communicates with each of a plurality of mobile terminals,
For each of the plurality of mobile terminals, an index calculation unit that calculates an allocation index value indicating a priority of radio resource allocation for the mobile terminal according to a past radio resource allocation amount for the mobile terminal;
A base station apparatus, comprising: a radio resource allocation unit that allocates radio resources to each mobile terminal based on an allocation index value calculated by the index calculation unit for each mobile terminal. The index calculation unit calculates the allocation index value for each of the plurality of mobile terminals so that the radio resource allocation priority indicated by the allocation index value increases as the past radio resource allocation amount increases. The base station apparatus according to claim 2. The index calculation unit is notified from the mobile terminal for each of the plurality of mobile terminals, and is notified from the mobile terminal of communication quality information related to communication quality of wireless communication between the base station apparatus and the mobile terminal. The allocation index value is calculated according to reception success / failure information indicating success / failure of reception of data transmitted from the base station apparatus and a past radio resource allocation amount for the mobile terminal. Item 4. The base station apparatus according to Item 2 or Claim 3. A base station apparatus that wirelessly communicates with each of a plurality of mobile terminals allocates radio resources to each of the mobile terminals,
For each of the plurality of mobile terminals, an allocation index value indicating a priority of radio resource allocation to the mobile terminal is calculated according to a past radio resource allocation amount for the mobile terminal,
A radio resource allocating method, wherein a radio resource is allocated to each mobile terminal based on an allocation index value calculated for each mobile terminal.

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