JP4755933B2 - Base station apparatus and communication control method - Google Patents

Description

The present invention relates to a base station apparatus and a communication control method, and more particularly to efficient use of radio resources.

  In a mobile communication system, a plurality of base station apparatuses each connected to a network are installed, and the mobile station apparatus communicates with at least one of the base station apparatuses, thereby allowing the network via the base station apparatus. Communicate with.

  However, the line between the base station apparatus and the network may be disconnected due to a failure in the transmission path or a failure in the line-compatible component. In this case, the mobile station device cannot communicate with the network via the base station device.

  The base station apparatus is configured to be able to communicate with a mobile station apparatus existing in a geographically specific area, and this area has a portion that does not overlap at all with the area in charge of other base station apparatuses. Is common. For this reason, when communication with a network cannot be performed via a specific base station apparatus, a mobile station apparatus located in a portion that does not overlap with other areas in the area in charge of the specific base station apparatus Will not be able to communicate at all, even though the base station device is not broken.

Therefore, a base station apparatus (line-disconnected base station apparatus) whose line with the network is disconnected is wirelessly connected to another base station apparatus (line-connected base station apparatus) whose line with the network is not disconnected. There is a mobile communication system in which a mobile station apparatus located in an area of a line disconnection base station apparatus can communicate with a network via a line connection base station apparatus by performing communication (for example, a patent Reference 1).
JP 2001-45569 A

  In the mobile communication system, the mobile station apparatus communicates with the line connection base station apparatus by relaying the line disconnection base station apparatus. At this time, the radio resources used by the mobile station device for communication with the network are doubled as usual. For example, when time division multiplexing using a time slot as a radio resource is taken as an example, one time slot is allocated for communication between a mobile station apparatus and a line disconnection base station apparatus, and the line disconnection base station apparatus and the line Another time slot is also assigned to communication with the connected base station apparatus. The line disconnection base station device performs relay by transmitting communication data received in one time slot using the other. In this way, twice the normal radio resources are used.

  By the way, communication between base station apparatuses that are fixed wireless communication apparatuses and are often installed at high places is usually stable, whereas communication between mobile station apparatuses and base station apparatuses lacks stability. Therefore, when the communication rate is determined in accordance with the radio state, the communication rate for communication between base station apparatuses is usually larger than the communication rate for communication between base station apparatuses and mobile station apparatuses.

  For this reason, when the same amount of radio resources are allocated as described above, a portion that is not used for the radio resources allocated to the communication between base station apparatuses occurs. Since the unused portion is wasted, it has been demanded to eliminate this waste and to efficiently use radio resources.

  Accordingly, one of the objects of the present invention is a mobile communication system in which a mobile station apparatus located in the area of a line disconnection base station apparatus can communicate with a network via the line connection base station apparatus. Another object of the present invention is to provide a base station apparatus and a communication relay method that can realize efficient use of radio resources.

A base station apparatus for solving the above problems is a base that can perform wireless communication with a mobile station apparatus with a mobile station apparatus and wireless communication with a base station apparatus with another base station apparatus. A radio resource allocation determining unit that is capable of controlling radio resource allocation in the radio communication with the base station device, wherein the radio resource allocation determination unit is executing the radio communication with the mobile station device When the wireless communication with the base station device is started at this time, the amount of wireless resources allocated to the wireless communication with the base station device is set to the communication rate of the wireless communication with the mobile station device and the other base station. A wireless state between the base station device and the base station device, the wireless communication with the base station device transmits data from the mobile station device to the other base station device, and Other base station equipment Data is a communication for receiving from, characterized in that.

  For example, when the communication rate of mobile communication with a mobile station device (communication between a base station device and a mobile station device) is twice the communication rate realized by BPSK (multiplicity 1) (in a state where two time slots are allocated), When the radio state of the radio communication with the base station apparatus (communication between base station apparatuses) is a state equivalent to QPSK (multiplicity 2), the radio resource (time slot) allocated to the radio communication with the base station apparatus is the radio with respect to the mobile station apparatus. Half (1) of communication is enough. In the above base station apparatus, such radio resource allocation can be realized, so that the mobile station apparatus located in the area of the line disconnection base station apparatus can communicate with the network via the line connection base station apparatus. In the mobile communication system that can be used, efficient use of radio resources can be realized.

Further, in this base station apparatus, the radio resource allocation determining unit is responsive to a total amount of radio resources allocated to the base station apparatus radio communication for the plurality of mobile station apparatuses communicating with the base station apparatus. Te, determines a radio resource that is assigned to the counter-base-station device wireless communication, it is also possible.

  According to this, the radio resource to be allocated to the base station apparatus radio communication can be determined based on the sum of radio resources of the base station apparatus radio communication allocated to each mobile station apparatus.

Further, in the base station apparatus, wherein to other base station apparatus, to associate a radio resource allocated for each of the plurality of mobile stations by the radio resource allocation determination unit, wherein each mobile station apparatus, the Transmission means for transmitting the information may be further included.

  According to this, the line connection base station device can associate communication data received by wireless communication with the base station device with the mobile station device based on the radio resource including the communication data.

In addition, the communication control method according to the present invention is a base station capable of performing mobile communication with a mobile station device and wireless communication with a base station device with another base station device. A communication control method in a device, wherein the base station device performs wireless communication with the base station device when the wireless communication with the base station device is started when the wireless communication with the mobile station device is being executed. An amount of radio resources to be allocated is determined based on a communication rate of the mobile communication with the mobile station device and a wireless state between the other base station device and the base station device, and the base station device The wireless communication is a communication for transmitting data from the mobile station apparatus to the other base station apparatus and receiving data from the other base station apparatus .

  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. As shown in the figure, the mobile communication system 1 includes an exchange 10, a base station device 20, and a mobile station device 30.

  The exchange 10, the base station device 20, and the mobile station device 30 are all computers including a CPU and a memory. The CPU is a processing unit for executing a program stored in the memory, and performs processing for controlling each part of each device and realizes functions described later. The memory stores programs and data for carrying out the present embodiment. It also operates as a work memory for the CPU.

  The base station apparatus 20 is installed in various places, and is connected to the exchange 10 via a wired line. In addition, wireless communication is performed between the base station apparatus 20 and the mobile station apparatus 30 existing in an area where radio waves can be transmitted and received. The mobile station device 30 communicates with other communication devices (not shown) via the base station device 20 and the exchange 10.

  When the base station device 20 becomes unable to communicate with the exchange 10 due to a failure of a wired line or the like, the base station device 20 performs wireless communication with other base station devices 20. Thereafter, the mobile station device 30 is connected to the exchange 10 via the two base station devices 20. Hereinafter, the details of the function of the base station apparatus 20 for realizing this will be described. In the following description, it is assumed that the wired line between the base station apparatus 20-1 and the exchange 10 is disconnected.

  FIG. 2 is a diagram illustrating functional blocks of the base station device 20-1. As shown in the figure, the base station device 20-1 functionally includes a radio communication unit 21, a communication rate acquisition unit 23, a radio state acquisition unit 24, and a radio resource allocation determination unit 25. 21 includes an internal modulation system control unit 22.

  The radio communication unit 21 performs radio communication between the mobile station device 30 and the base station device 20-2. This radio communication is multiplexed, and the radio communication unit 21 allocates radio resources for each radio communication, and performs radio communication with the mobile station device 30 between the mobile station device 30 and the base station device 20-2. The base station apparatus wireless communication is performed respectively. Then, the communication data received by one wireless communication is transmitted by the other wireless communication.

  In the present embodiment, a time slot that is a unit of radio resource in time division multiplexing is used as the radio resource. The wireless communication unit 21 assigns one or a plurality of time slots for each wireless communication with respect to the wireless communication performed with the mobile station device 30. The assignment to the wireless communication performed with the base station apparatus 20-2 will be described later.

  The modulation scheme control unit 22 acquires the radio state (SINR (Signal to Interference and Noise Ratio), received power, etc.) of each radio communication. Then, a modulation scheme (QPSK (Quadrature Phase Shift Keying: QPSK multiplicity is 2)) or 16QAM (Quadrature Amplitude Modulation) used in each radio communication according to the acquired radio state. : 16 quadrature amplitude modulation, where the multiplicity of 16QAM is 4. Specifically, a modulation scheme with a relatively high multiplicity is used when the radio condition is relatively good, and a modulation scheme with a relatively low multiplicity is used when the radio condition is relatively poor.

  The communication rate acquisition unit 23 acquires a communication rate of wireless communication performed by the mobile station device 30. The communication rate here indicates a future throughput of the mobile station device 30. Specifically, the communication rate acquisition unit 23 is based on the radio resources allocated to the radio communication performed by the mobile station device 30 by the radio communication unit 21 and the modulation scheme determined by the modulation scheme control unit 22. The communication rate of wireless communication performed by the device 30 is acquired.

  In a specific example, if the number of time slots assigned to radio communication performed by the mobile station device 30 is 2, and the communication rate determined by the multiplicity of the determined modulation scheme is 10 kbps, the mobile station device 30 The communication rate of the wireless communication performed by is 10 × 2 = 20 kbps.

  The wireless state acquisition unit 24 acquires the wireless state of wireless communication performed with the base station device 20-2. Here, for the radio communication performed with the base station apparatus 20-2, the modulation scheme determined by the modulation scheme control unit 22 is acquired, and the communication rate corresponding to the modulation scheme is acquired as the radio state.

  In a specific example, if the communication rate determined by the multiplicity of the determined modulation method is 30 kbps, the wireless state of wireless communication performed with the base station apparatus 20-2 is also 30 kbps.

  The radio resource allocation determining unit 25 determines radio resources to be allocated to the base station apparatus radio communication based on the communication rate of the mobile station apparatus radio communication and the radio state of the base station apparatus radio communication. Specifically, based on the communication rate acquired by the communication rate acquisition unit 23 and the wireless state acquired by the wireless state acquisition unit 24 for wireless communication performed by a certain mobile station device 30, the mobile station device 30 The amount of radio resources to be allocated to radio communication performed with the base station apparatus 20-2 is determined.

  For example, in the above example, since the communication rate acquired by the communication rate acquisition unit 23 is 20 kbps and the wireless state acquired by the wireless state acquisition unit 24 is 30 kbps, wireless communication performed with the base station device 20-2. The amount of radio resources to be allocated for is 2/3 time slots.

  The radio communication unit 21 allocates radio communication performed with the base station device 20-2 determined by the radio resource allocation determination unit 25 for each mobile station device 30 performing radio communication with the radio communication unit 21. The amount of radio resources is summed to calculate the required amount of radio resources. And according to this required radio | wireless resource amount, a radio | wireless resource is allocated to the radio | wireless communication performed between base station apparatuses 20-2.

  Further, the radio communication unit 21 generates a radio resource correspondence table for associating radio resources for radio communication performed with the base station device 20-2 and the mobile station device 30 with respect to each mobile station device 30. The radio | wireless resource allocated with respect to the radio | wireless communication performed between base station apparatuses 20-2 is determined concretely. Then, the communication data received from the mobile station device 30 is transmitted to the base station device 20-2 using the radio resource stored in association with the mobile station device 30 in the radio resource correspondence table. Also, the radio communication unit 21 acquires the radio resource including the communication data for the communication data received from the base station device 20-2, and stores the radio resource in association with the radio resource in the radio resource correspondence table. Transmit to the mobile station device 30.

  Further, the radio communication unit 21 transmits the generated radio resource correspondence table to the base station device 20-2. For the communication data received from the base station device 20-1, the base station device 20-2 acquires a radio resource that includes the communication data, and stores the radio resource in association with the radio resource in the radio resource correspondence table. It is handled as communication data received from the mobile station device 30. Further, communication data addressed to a certain mobile station device 30 received from the exchange 10 is transmitted to the base station device 20-1 using a radio resource stored in association with the mobile station device 30 in the radio resource correspondence table. To send.

  The processing described above will be described again in detail with reference to a specific example of time slot allocation.

  FIG. 3 is an explanatory diagram for explaining an example of use of a time slot when a certain mobile station device 30 starts communication. Each square shown in the figure indicates a time slot. “C” means a time slot used as a control channel. In general, the control channel is included in 20 frames (transmission / reception repeating unit composed of a total of 8 time slots of transmission time slot 4 and reception time slot 4) at a rate of 1 frame.

  First, base station apparatus 20-1 assigns time slots to wireless communication for transmitting and receiving control channels to and from base station apparatus 20-2. Specifically, a time slot (time slot 40 in FIG. 3) in which the base station apparatus 20-2 transmits a control channel, a time slot (time slot 41 in FIG. 3) receiving a control channel, And the time slots (the time slot 42 and the time slot 43 in FIG. 3) corresponding to each device are allocated to the wireless communication for transmitting and receiving the control channel to and from the base station device 20-2.

  The base station apparatus 20-1 transmits the control channel received from the base station apparatus 20-2 in the time slot 42 in the time slot (time slot 45 in FIG. 3) assigned to its own control channel transmission. Also, the control signal from the mobile station apparatus 30 is received in the time slot (time slot 44 in FIG. 3) allocated to the reception of the control channel of the own apparatus, and is transmitted to the base station apparatus 20-2 in the next time slot 43. . Thus, the control channel is relayed, and the mobile station device 30 establishes communication. In addition, when performing control channel transmission / reception with the mobile station device 30 in this way, the base station device 20-1 acquires a communication rate of wireless communication performed by the mobile station device 30.

  FIG. 4 is an explanatory diagram for explaining an example of time slot allocation when three mobile station apparatuses 30 (mobile station apparatuses 30-1 to 30-3) perform communication. In the figure, “t” means a time slot used as a communication channel.

  Here, it is assumed that the communication rate of the wireless communication performed by each mobile station device 30 is 10 kbps, and the wireless state of the wireless communication performed with the base station device 20-2 is 30 kbps. Here, it is assumed that one time slot is assigned to each radio communication performed by each mobile station device 30.

  In this case, the base station apparatus 20-1 assigns three of the four transmission time slots in the frame to the wireless communication performed with the mobile station apparatus 30, and the remaining one is assigned to the base station apparatus 20-2. Assign to the wireless communication between. Similarly, three of the four reception time slots in the frame are assigned to wireless communication performed with the mobile station device 30, and the remaining one is assigned to wireless communication performed with the base station device 20-2. . And these are matched and memorize | stored in a radio | wireless resource correspondence table.

  In a specific example, the transmission time slot 50 assigned to the mobile station device 30-3 is associated with the first 1/3 of the transmission time slot 52 assigned to the wireless communication performed with the base station device 20-2. . Also, the transmission time slot 51 assigned to the mobile station device 30-2 is associated with the middle 1/3 of the transmission time slot 52 assigned to the wireless communication performed between the base station device 20-2. Further, the transmission time slot 53 assigned to the mobile station device 30-1 is associated with the last 1/3 of the transmission time slot 52 assigned to the wireless communication performed between the base station device 20-2.

  Then, the base station apparatus 20-1 transmits the communication data received from each mobile station apparatus 30 to the base station apparatus 20-2 using radio resources determined based on the radio resource correspondence table. Similarly, the communication data received from the base station apparatus 20-2 is transmitted to the mobile station apparatus 30 stored in association with the received radio resource.

  As described above, generally, a control channel is included at a rate of 1 frame per 20 frames. In the present embodiment, a control channel is further included at a rate of 1 frame for wireless communication with the base station apparatus. , 20 frames contain control channels at a rate of 2 frames. In the above example, the allocation of radio resources is determined without considering this control channel, but actually, the radio resource allocation determination unit 25 performs radio communication with the base station apparatus according to the ratio of control channels. It is preferable to determine radio resources to be allocated.

  In a specific example, when a time slot for performing radio communication with a base station apparatus is used as a control channel, assuming that the communication rate determined by the multiplicity of the modulation scheme is 30 kbps, actually, 30 × ( 20-2) / 20 = 27 kbps. The radio resource allocation determination unit 25 determines radio resources to be allocated to the base station apparatus radio communication based on this value.

  The processing described above will be described again in more detail with reference to the processing flow of the base station apparatus 20.

  FIG. 5 is a diagram illustrating a processing flow of the base station device 20-1 that is a line disconnection base station device and the base station device 20-2 that is a line connection base station device. As shown in the figure, when the base station apparatus 20-1 detects a line disconnection (S1), first, a synchronization signal (the base station apparatus 20-2 that is a counterpart of the base station apparatus wireless communication) According to S10), resynchronization processing between base station apparatuses is performed (S2).

  Note that the base station apparatus 20-1 performs communication at the synchronization timing obtained by the resynchronization process only for communication with the base station apparatus 20-2, and for communication with the mobile station apparatus 30 up to that point. Communication may be performed at the synchronization timing. In this case, the base station apparatus 20-1 may perform communication in a state where there is an offset (shift) in the synchronization timing between the base station apparatus radio communication and the mobile station apparatus radio communication. .

  When the resynchronization processing is completed, the base station device 20-1 searches for a time slot used by the base station device 20-2 for transmission / reception of the control channel (S11), and the base station device 20-2 uses the time slot. Starts transmission / reception of the control channel. Further, a process of relaying the control channel of the base station device 20-2 to the mobile station device 30 is started (S3).

  In this case, if the control channel of the base station apparatus 20-1 and the control channel of the base station apparatus 20-2 use the same time slot, the base station apparatus 20-1 transmits and receives its own control channel. The time slot to be used is changed. After notifying the mobile station device 30 through the control channel, the time slot is changed.

  When the connection request is received from the mobile station device 30 (S4), the base station device 20-1 acquires the communication rate of the mobile station device wireless communication (S5) and also acquires the wireless state of the base station device wireless communication. (S6). And based on these, a radio | wireless resource is allocated with respect to base station apparatus radio | wireless communication (S7), and the relay of a communication channel is started (S8). The base station apparatus 20-2 performs transmission / reception of the communication channel relayed by the base station apparatus 20-1 (S12).

  As described above, according to the base station apparatus 20, the mobile station apparatus 30 located in the area of the line disconnection base station apparatus can perform communication with the network via the line connection base station apparatus. In the body communication system 1, efficient use of radio resources can be realized.

It is a figure which shows the system configuration | structure of the mobile communication system concerning embodiment of this invention. It is a figure which shows the functional block of the base station apparatus concerning embodiment of this invention. It is explanatory drawing for demonstrating the usage example of the time slot when the mobile station apparatus concerning embodiment of this invention starts communication. It is explanatory drawing for demonstrating the example of time slot allocation in case the three mobile station apparatuses concerning embodiment of this invention communicate. It is a figure which shows the processing flow of the base station apparatus concerning embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile communication system, 10 switch, 20 Base station apparatus, 21 Radio communication part, 22 Modulation system control part, 23 Communication rate acquisition part, 24 Radio state acquisition part, 25 Radio resource allocation determination part, 30 Mobile station apparatus

Claims (4)

A base station apparatus capable of performing mobile communication with a mobile station apparatus and wireless communication with a base station apparatus with another base station apparatus,
Radio resource allocation determining means capable of controlling radio resource allocation in the base station apparatus radio communication,
The radio resource allocation determining means includes
When the radio communication with the base station apparatus is started when the radio communication with the mobile station apparatus is being executed, the amount of radio resources allocated to the radio communication with the base station apparatus is set as the radio communication with the mobile station apparatus Determined based on the communication rate and the wireless state between the other base station device and the base station device ,
The wireless communication with the base station device is communication for transmitting data from the mobile station device to the other base station device and receiving data from the other base station device.
A base station apparatus. The radio resource allocation determining means includes
Radio resources allocated to the base station apparatus radio communication according to the total amount of radio resources allocated to the base station apparatus radio communication for the plurality of mobile station apparatuses communicating with the base station apparatus decide,
The base station apparatus according to claim 1. Transmitting means for transmitting, to the other base station apparatus, information for associating the radio resources allocated to each of the plurality of mobile station apparatuses by the radio resource allocation determining means and each mobile station apparatus;
The base station apparatus according to claim 2, further comprising: A communication control method in a base station device capable of performing mobile communication with a mobile station device and wireless communication with a base station device with another base station device,
The base station device
When the radio communication with the base station apparatus is started when the radio communication with the mobile station apparatus is being executed, the amount of radio resources allocated to the radio communication with the base station apparatus is set as the radio communication with the mobile station apparatus Determined based on the communication rate and the wireless state between the other base station device and the base station device,
The wireless communication with the base station device is communication for transmitting data from the mobile station device to the other base station device and receiving data from the other base station device.
A communication control method characterized by the above.

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