JP2007180863A - Base station device, priority calculation method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the increase of a transmission-waiting data amount even if the priority of a mobile station device large in communication data amount is lowered. <P>SOLUTION: A base station device 20 which performs communications with a plurality of mobile station devices 10, includes: a transmission data input reception unit 21 which receives an input of data transmitted to each mobile station device 10; a temporary storage unit 22 which temporarily stores data received by the transmission data input reception unit 21; a storage amount decreasing speed calculation unit 241 which calculates a decreasing speed of data stored in the temporary storage unit 22 for each mobile station device 10; and a priority calculation unit 242 which calculates priority based on a storage amount decreasing speed of the mobile station device 10 for at least a part of the mobile station devices 10 when calculating priority at the assignment of communication resources to respective data in order to transmit the data received by the transmission data input unit 21 to each mobile station device 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a base station apparatus, a priority calculation method, and a program.

In packet communication in a mobile communication system, transmission scheduling is performed (for example, Patent Document 1). In this transmission scheduling, the priority is calculated for each mobile station apparatus, and packets are generally transmitted in descending order of the calculated priority.
JP-A-2005-45561

  By the way, in a mobile communication system introducing a packet flat-rate system, communication with a large amount of communication data such as moving picture streaming has been performed. However, since radio resources are limited, when communication with such a large amount of communication data is performed, there is an influence such as a communication rate being slowed on other communication. Therefore, for communication with a large amount of communication data, it may be desired to lower the priority in the transmission scheduling and to preferentially transmit packets related to other communication.

  However, when the priority of a mobile station apparatus with a large amount of communication data decreases in this way, the amount of data waiting for transmission of the mobile station apparatus increases. In this regard, since it is not desirable that the amount of data waiting for transmission increases, it has been desired to suppress an increase in the amount of data waiting for transmission even when the priority of a mobile station apparatus with a large amount of communication data decreases. .

  In this regard, Patent Document 1 describes a technique for calculating priority based on various information, but does not disclose specific control for realizing the above-described problem.

  Accordingly, one of the problems of the present invention is that a base station device, a priority calculation method, and a program that can suppress an increase in the amount of data waiting to be transmitted even if the priority of a mobile station device with a large amount of communication data is lowered. Is to provide.

  A base station apparatus according to the present invention for solving the above-mentioned problems is a base station apparatus that communicates with a plurality of mobile station apparatuses, and transmits transmission data that receives input of data to be transmitted to each of the mobile station apparatuses Input reception means, temporary storage means for temporarily storing data received by the transmission data input reception means, and storage amount reduction speed for calculating a reduction speed of data stored in the temporary storage means for each mobile station device When calculating the priority when allocating communication resources to each data in order to transmit the data accepted by the transmission data input accepting means to the calculating means and each mobile station apparatus, at least a part of the The mobile station apparatus stores the priority calculation means for calculating based on the storage amount decrease rate for the mobile station apparatus and the temporary storage means. In that the data, assigns a sequential communication resources based on said priority, characterized in that it comprises a transmitting means for transmitting to said each mobile station apparatus.

  According to this, since the priority is calculated based on the storage amount decrease rate, even if the priority of the mobile station device with a large amount of communication data is lowered, for example, the storage amount decrease rate does not fall below a predetermined value. It is possible to suppress the increase in the amount of data waiting for transmission.

  The base station apparatus further includes reception speed calculation means for calculating a data reception speed by the transmission data input reception means for each mobile station apparatus, and the priority calculation means sets the storage amount decrease speed to The at least some mobile station devices that calculate the priority based on the determination may be determined based on the reception speed.

  Since the mobile station apparatus with a large reception speed is a mobile station apparatus with a large amount of communication data, according to the base station apparatus, the priority of the mobile station apparatus with a large amount of communication data, for example, the storage amount decrease rate has a predetermined value. It can be calculated to the extent that it does not fall below.

  Further, the priority calculation method according to the present invention is a priority calculation method for calculating a priority when transmitting data to each mobile station device from a base station device communicating with a plurality of mobile station devices. A transmission data input receiving step for receiving input of data to be transmitted to each mobile station device; a temporary storage step for temporarily storing data received in the transmission data input receiving step; and the temporary storage step. In order to transmit the data received in the transmission data input reception step to each mobile station device, the storage amount decrease rate calculation step for calculating the reduction rate of the data stored in each mobile station device, When calculating the priority when allocating communication resources to each data, at least a part of the mobile station apparatus A priority calculation step of calculating based on the storage amount decrease rate for the data, and sequentially assigning communication resources to the data stored in the temporary storage step based on the priority, and transmitting the data to each mobile station device And a transmitting step.

  The program according to the present invention is a program for causing a computer to function as a base station apparatus that communicates with a plurality of mobile station apparatuses, and accepts input of data to be transmitted to each of the mobile station apparatuses. Transmission data input reception means, temporary storage means for temporarily storing data received by the transmission data input reception means, storage amount reduction speed for calculating a reduction speed of data stored by the temporary storage means for each mobile station device When calculating the priority when allocating communication resources to each data in order to transmit the data received by the transmission data input receiving means to each mobile station apparatus, at least a part of the mobile For the station device, priority calculation means for calculating based on the storage amount decrease rate for the mobile station device, and The data stored by the temporary storage means, the priority assigned sequentially communication resources based on, characterized in that to further function the computer transmitting means for transmitting, as to the respective mobile station apparatuses.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration of a mobile communication system 1 according to the present embodiment. The mobile communication system 1 performs communication by CDMA2000 1xEV-DO, and includes a base station device 20 and a plurality of mobile station devices 10 as shown in FIG.

  The mobile station apparatus 10 is a computer configured to include a CPU, a memory, and a wireless communication function. The CPU reads out a program stored in the memory and operates according to the program to perform processing described below. Further, wireless communication with the base station apparatus 20 is performed by the wireless communication function.

  The base station apparatus 20 is a computer configured to include a CPU, a memory, a wireless communication function, and a wired communication function. The CPU reads a program stored in the memory and operates in accordance with the program to be described below. I do. In addition, wireless communication with each mobile station apparatus 10 is performed using a wireless communication function, and wired communication with a communication network (not shown) is performed using a wired communication function.

  The base station apparatus 20 and the mobile station apparatus 10 perform radio packet communication by time division multiplexing. That is, the base station apparatus 20 temporarily stores packet data to be transmitted to the mobile station apparatus 10 in a buffer. Then, the packet data stored in this buffer is taken out according to a predetermined reference and assigned to a time slot which is a communication resource of time division multiplex communication. In this way, the base station apparatus 20 transmits packet data to the plurality of mobile station apparatuses 10. In the present embodiment, the calculation of the reference priority for extracting the packet data is performed based on the storage amount decrease rate and the reception rate. Details will be described below.

  FIG. 2 is a diagram illustrating functional blocks of the base station device 20. As shown in the figure, the base station apparatus 20 is functionally configured to include a transmission data input reception unit 21, a temporary storage unit 22, a data transmission unit 23, and a scheduler unit 24. The scheduler unit 24 further calculates reception speed. Unit 240, a storage amount decrease rate calculation unit 241, and a priority calculation unit 242.

  The transmission data input receiving unit 21 receives packet data input from a communication network (not shown). Then, the received packet data is distributed to a plurality of mobile station apparatuses 10 according to the destination. The transmission data input reception unit 21 thus receives input of packet data to be transmitted to each of the plurality of mobile station apparatuses 10 and outputs the packet data to the temporary storage unit 22. The transmission data input receiving unit 21 also performs flow control processing for controlling the amount of packet data received from the communication network so that packet data does not overflow from the temporary storage unit 22.

  The temporary storage unit 22 functions as a buffer for temporarily storing packet data input from the transmission data input receiving unit 21. Here, FIG. 3 is an explanatory diagram of communication resource allocation according to the present embodiment. As shown in the figure, the temporary storage unit 22 stores a predetermined amount of transmission data to be transmitted to each mobile station apparatus 10. When the communication rate differs for each mobile station apparatus 10, this predetermined amount is preferably determined according to the communication rate for each mobile station apparatus 10. This is because the amount of data that can be allocated to one time slot differs depending on the communication rate.

  The data transmission unit 23 sequentially assigns communication resources to the packet data stored in the temporary storage unit 22 according to the determination of the scheduler unit 24 and transmits the packet resources to each mobile station apparatus 10.

  The scheduler unit 24 determines an allocation order when the data transmission unit 23 allocates communication resources to packet data. Details will be described below.

  The reception speed calculation unit 240 calculates a speed (acceptance speed) at which the transmission data input reception unit 21 receives input of packet data for each mobile station device 10. The storage amount decrease rate calculation unit 241 calculates the decrease rate (storage amount decrease rate) of the packet data stored in the temporary storage unit 22 for each mobile station device 10.

  The priority calculation unit 242 calculates, for example, a priority when allocating communication resources to each packet data in order to transmit the packet data received by the transmission data input reception unit 21 by the method described in Patent Document 1. ing. When calculating the priority in this way, the priority calculation unit 242 further calculates the priority for at least some of the mobile station apparatuses 10 based on the storage amount decrease rate for the mobile station apparatus 10. The priority calculation unit 242 determines the mobile station apparatus 10 that calculates the priority based on the storage amount decrease speed based on the reception speed.

  FIG. 4 is an explanatory diagram for explaining the reception speed and the storage amount decrease speed. In the figure, for a certain mobile station device 10 (referred to as a mobile station device 10-1), (a) shows the amount of packet data (transmission waiting data) stored in the temporary storage unit 22, and (b) shows the transmission amount. The data amount (transmission data amount) of the packet data received by the data input receiving unit 21 is shown. As shown in FIG. 4, the reception speed is the data amount of the packet data received by the transmission data input reception unit 21 per unit time, and the storage amount decrease speed is the rate of change of the transmission waiting data amount.

  FIG. 4 shows an example in which the mobile station device 10-1 starts streaming video at time T. In general, when streaming viewing of a moving image is started, the amount of transmission data increases. That is, the data amount (acceptance speed) of packet data received by the transmission data input acceptance unit 21 per unit time increases.

  By the way, there is a case where the amount of data waiting for transmission decreases even when the reception speed is relatively high (when the storage amount reduction speed> 0). FIG. 4A shows such an example. Such an example may occur, for example, when the priority calculated by the method described in Patent Document 1 is high. In such a case, the priority calculation unit 242 can suppress an increase in the amount of data waiting to be transmitted even if the priority of the mobile station apparatus having a relatively high reception speed is lowered. The priority for the mobile station apparatus 10 whose reception speed is equal to or higher than a predetermined value is calculated based on the storage amount decrease speed at the time of priority calculation. Specifically, the priority calculation unit 242 calculates the priority of the mobile station apparatus whose reception speed exceeds a predetermined value so that the storage amount decrease speed does not fall below a predetermined value.

More specifically, the priority calculation unit 242 calculates the priority by the following expressions (1) and (2). Here, D _i is the amount of data waiting to be transmitted by the mobile station apparatus 10-i, S _i is the priority of the mobile station apparatus 10-i, and -d D _i / dt indicates the storage amount decrease rate. Α is a priority calculated based on CIR (Carrier to Interference Ratio) and DRC (Data Rate Control, required rate), which are parameters used in, for example, 1xEV-DO.

When the memory decrease rate> 0, S _i = α × D _i / (− dD _i / dt) (1)

When the memory amount decrease rate ≦ 0, S _i = α × (dD _i / dt) (2)

Expression (1) is an expression that is applied to the mobile station apparatus 10 in which the amount of data waiting for transmission is decreasing. By making the priority inversely proportional to the rate of decrease in the amount of storage, the decrease rate of the data amount waiting for transmission increases. The priority can be lowered. On the other hand, by multiplied by D _i, a priority for the reduced transmission wait even factor is larger amount of data is large mobile station apparatus 10 (the flow of data stagnation in the temporary storage unit 22 tend to mobile station apparatus 10) To be raised.

  Expression (2) is an expression that is applied to the mobile station apparatus 10 in which the transmission waiting data amount is constant or increasing, and the priority can be increased as the increase rate of the transmission waiting data amount increases.

  Based on the priority calculated in this way, the scheduler unit 24 determines an allocation order when the data transmission unit 23 allocates communication resources to packet data. This process will be described again with reference to FIG.

  FIG. 3 shows time slots 1 to 8. These time slots are transmitted in this order. First, at the transmission timing of time slot 1, the priority calculation unit 242 calculates the priority for each mobile station apparatus 10. Here, it is assumed that the mobile station device 10-1 has the highest priority among the mobile station devices 10-1 to 10-3. Then, the scheduler unit 24 instructs the data transmission unit 23 to allocate communication resources to the mobile station device 10-1.

  The data transmission unit 23 selects the oldest packet data stored in the temporary storage unit 22 for the mobile station apparatus 10-1 according to the instruction of the scheduler unit 24, and transmits it at the transmission timing of the time slot 1.

  Thereafter, similarly, the scheduler unit 24 and the data transmission unit 23 transmit packet data in each time slot.

  As described above, since the base station device 20 calculates the priority based on the storage amount decrease rate, even if the priority of the mobile station device 10 with a large amount of communication data is lowered, the storage amount decrease rate is predetermined. It is possible to keep the value not lower than the value, and to suppress an increase in the amount of data waiting for transmission.

  In addition, the base station device 20 can calculate the priority of the mobile station device 10 with a large amount of communication data so that the storage amount decrease rate does not fall below a predetermined value.

It is a figure which shows the system configuration | structure of the mobile communication system which concerns on embodiment of this invention. It is a figure which shows the functional block of the base station apparatus which concerns on embodiment of this invention. It is explanatory drawing of the communication resource allocation which concerns on embodiment of this invention. It is explanatory drawing of the reception speed and storage amount reduction | decrease speed which concern on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile communication system, 10 Mobile station apparatus, 20 Base station apparatus, 21 Transmission data input reception part, 22 Temporary storage part, 23 Data transmission part, 24 Scheduler part, 240 Reception speed calculation part, 241 Memory | storage amount reduction | decrease speed calculation part 242 Priority calculation unit.

Claims (4)

A base station device that communicates with a plurality of mobile station devices,
Transmission data input receiving means for receiving input of data to be transmitted to each mobile station device;
Temporary storage means for temporarily storing data received by the transmission data input reception means;
A storage amount decrease rate calculating unit that calculates a decrease rate of data stored in the temporary storage unit for each mobile station device;
When calculating the priority when allocating communication resources to each data in order to transmit the data received by the transmission data input receiving means to each mobile station device, at least some of the mobile station devices A priority calculation means for calculating based on the storage amount decrease rate for the mobile station device;
Transmission means for sequentially allocating communication resources to the data stored by the temporary storage means based on the priority and transmitting the data to each mobile station device;
A base station apparatus comprising: The base station apparatus according to claim 1,
Reception speed calculation means for calculating the reception speed of data by the transmission data input reception means for each mobile station device;
Further including
The priority calculation means determines the at least some mobile station devices that calculate the priority based on the storage amount decrease speed based on the reception speed.
A base station apparatus. A priority calculation method for calculating a priority when transmitting data to each mobile station device from a base station device communicating with a plurality of mobile station devices,
A transmission data input receiving step for receiving input of data to be transmitted to each mobile station device;
A temporary storage step of temporarily storing the data received in the transmission data input reception step;
A storage amount decrease rate calculating step for calculating a decrease rate of data stored in the temporary storage step for each mobile station device;
When calculating the priority when allocating communication resources to each data in order to transmit the data accepted in the transmission data input acceptance step to each mobile station device, at least some of the mobile station devices A priority calculation step for calculating based on the storage amount decrease rate for the mobile station device;
A transmission step of sequentially allocating communication resources to the data stored in the temporary storage step based on the priority and transmitting the data to each mobile station device;
The priority calculation method characterized by including. A program for causing a computer to function as a base station device that communicates with a plurality of mobile station devices,
Transmission data input receiving means for receiving input of data to be transmitted to each mobile station device;
Temporary storage means for temporarily storing data received by the transmission data input receiving means;
A storage amount decrease rate calculating unit that calculates a decrease rate of data stored in the temporary storage unit for each mobile station device;
When calculating the priority when allocating communication resources to each data in order to transmit the data received by the transmission data input receiving means to each mobile station device, at least some of the mobile station devices A priority calculation means for calculating based on the storage amount decrease rate for the mobile station device, and sequentially assigning communication resources to the data stored by the temporary storage means based on the priority, Transmitting means for transmitting to the station device;
A program for causing the computer to further function as:

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