JP4599305B2 - Base station apparatus and control method for base station apparatus - Google Patents

Description

  The present invention relates to a base station apparatus and a control method for the base station apparatus, and more particularly to wireless communication using a time division multiplexing system with a plurality of terminal apparatuses, and each time slot is assigned to two or more terminal apparatuses by call priority control. The present invention relates to a base station apparatus and a base station apparatus control method that can be shared with each other.

  In a radio communication system based on time division multiple access (TDMA), a transmission channel between communication devices is divided into a plurality of time slots, and a carrier frequency (carrier frequency) that can be used for each time slot is assigned and wireless. Communication takes place. When receiving a channel assignment request from a terminal device, the base station device that performs time-division multiplexing wireless communication with each of a plurality of terminal devices selects an available carrier frequency in any empty slot as a communication channel, and The channel is assigned to the call of the terminal device. Here, a call means a series of communications from a connection request between communication devices to connection disconnection (including dormant and inactive). On the other hand, when all the time slots are in use in the base station apparatus and there are no empty slots, there is also a base station apparatus that rejects channel allocation because of a shortage of radio resources, but each time slot is assigned to two or more calls. There are also base station apparatuses that permit channel allocation by performing sharing control, that is, call priority control. In such a base station apparatus, it is possible to share one time slot with a plurality of terminal apparatuses by sequentially switching a call during communication and a call during communication stop at a predetermined timing.

  FIG. 5 is a flowchart for explaining call priority control processing in a conventional base station apparatus. The call priority control process is executed when a channel allocation request is received from a new call, or when the communication data amount of a call in communication reaches a predetermined amount. When the call priority control process is started, the assignment of the communication channel to the call in communication in the time slot selected as the priority control target is canceled and the call is made inactive (S200). Next, in order to check whether or not the communication channel used for the communication is still usable, carrier sense (interference wave measurement) is performed for the communication channel (S202). Carrier sense refers to measuring whether or not an interference signal of a predetermined level or higher is received in a designated communication channel. When the interference signal is not detected in the carrier sense (hereinafter referred to as 1 wave monitor) in S202, that is, when the 1 wave monitor is successful, it is determined that the communication channel is usable (S204). Is subsequently used (S208). On the other hand, when the interference wave signal is detected in the one-wave monitor in S202, that is, when the one-wave monitor fails, it is determined that the communication channel is unusable at that time (S204). In this case, in order to specify a communication channel that can be used in the time slot, carrier sense (for example, 10-wave monitoring) is performed for a plurality of carrier frequencies in the time slot (S206). When a good carrier frequency with few interference waves is specified in the 10-wave monitor, it is determined that the carrier frequency is newly used as a communication channel in the time slot (S208). When the communication channel determined in S208 is assigned to another call that has been inactive (S210), the call priority control process ends.

  In Patent Document 1 below, in a radio base station capable of transmission output and capable of determining a plurality of frequency bands as vacant channels, a plurality of frequency bands can be used without reducing frequency utilization efficiency. A technique for enabling a target free channel determination is disclosed.

  Further, in Patent Document 2 below, in a frame relay network, by determining a transmission throughput time value for each irregular transmission frame information size for each data link connection, congestion is promptly eliminated. In addition, a technique for preventing congestion is disclosed.

  Patent Document 3 below discloses a technique related to a wireless digital subscriber telephone system that increases frequency use efficiency by using FDMA (Frequency Division Multiple Access) / TDMA (Time Division Multiple Access).

  Patent Document 4 listed below gives priority to communication of a specific terminal adapter in D channel and B channel packet communication using an ISDN (Integrated Service Digital Network) line even when the traffic situation of the packet communication is congested. A technique for securing the communication speed is disclosed.

Patent Document 5 below discloses a technique for increasing communication throughput in data transmission via a communication network.
JP-A-11-205847 JP 2000-286890 A JP 2002-204483 A JP-A-8-204748 Special table 2003-515273 gazette

  As described above, in the conventional call priority control process, one-wave monitoring is performed in the time slot subject to priority control, and the ten-wave monitoring is performed only when the one-wave monitoring fails, thereby performing subsequent communication. I was trying to determine the channel. The 10-wave monitor is effective in that it can select a carrier frequency with the least interference wave, but it also causes a reduction in communication throughput due to a large processing load. Therefore, carrier sense is first performed on a communication channel that has been used until immediately before, so that carrier sense is succeeded with a high probability, and the number of executions of 10-wave monitoring is suppressed as much as possible.

  However, in a base station apparatus having a relatively high processing speed, when one-wave monitoring is started before signal transmission from a terminal apparatus that has stopped communication is completed, and a transmission wave from the terminal apparatus is detected as an interference wave there were. In addition, since some terminal apparatuses do not stop signal transmission for a while after the communication is disconnected, the base station apparatus may detect a transmission wave from the terminal apparatus as an interference wave. Thus, if the frequency of failure of the 1-wave monitor increases, the frequency of execution of the 10-wave monitor increases and the communication throughput is significantly reduced. If the timing for starting the 1-wave monitor is uniformly delayed in order to increase the success rate of the 1-wave monitor, the start of the 1-wave monitor will be delayed even if it is not necessary, and in any case the throughput will be reduced. There was a problem of doing.

  The present invention has been made in view of the above-described conventional problems, and can improve the success rate of carrier sense executed in call priority control processing and can prevent a reduction in communication throughput. An object is to provide a method for controlling an apparatus.

  In order to achieve the above object, the base station apparatus according to the present invention is capable of wireless communication with a plurality of terminal apparatuses using a time division multiplexing method, and each time slot can be shared by two or more terminal apparatuses. A base station apparatus that stops communication with the first terminal apparatus that is communicating in the communication channel in any one of the time slots, and determines whether or not there is an interfering signal in the communication channel. In the base station apparatus that determines whether to allocate the communication channel, a measurement start timing information storage unit that stores timing information related to the timing of starting the interference wave measurement in association with the attribute information of the first terminal apparatus; The timing information stored in the measurement start timing information storage unit is read based on the attribute information of the first terminal device. Together comprise a disturbance measurement control means for changing the timing of starting the EMI measurement of the communication channel based on the timing information, is characterized in that.

  The base station apparatus control method according to the present invention is a base station capable of wireless communication with a plurality of terminal apparatuses using a time-division multiplexing method and sharing each time slot with two or more terminal apparatuses. A communication device that stops communication with a first terminal device that is communicating in a communication channel in any one of the time slots, and sends the communication channel to the second terminal device according to the presence or absence of an interfering signal in the communication channel. In the control method of the base station apparatus for determining whether to allocate or not, the step of storing in the measurement start timing information storage means the timing information related to the timing of starting the interference wave measurement in association with the attribute information of the first terminal apparatus And the timing information stored in the measurement start timing information storage means based on the attribute information of the first terminal device Read together, and a disturbance measurement control step of changing the timing of starting the EMI measurement of the communication channel based on the timing information, it is characterized in that.

  According to the present invention, in the call priority control process, the start timing of carrier sense (jamming wave measurement) performed after the communication of the first terminal device is stopped is changed based on the attribute information of the first terminal device. It is possible to increase the success rate of carrier sense and prevent a decrease in communication throughput.

  Further, in one aspect of the present invention, the measurement start timing information is associated with the attribute information of the terminal device in accordance with the result of interference wave measurement in the communication channel used by the first terminal device before communication stop. It further includes measurement start timing information updating means for updating the timing information stored in the storage means. In this way, in the call priority control process, it is possible to change the start timing of carrier sense performed after the communication of the first terminal apparatus is stopped according to the past measurement results, and the carrier sense success rate. And a reduction in communication throughput can be prevented.

  In one aspect of the present invention, the timing information is a value based on the number of times that an interference signal of a predetermined level or higher is detected in the interference wave measurement. In this way, in the call priority control process, the start timing of the carrier sense performed after the communication of the first terminal device is stopped is set to the number of times that the interference signal of a predetermined level or more is detected in the measurement so far, that is, the carrier sense. It is possible to change the number based on the number of times of failure, and it is possible to increase the success rate of carrier sense and prevent a reduction in communication throughput.

  In one aspect of the present invention, the attribute information of the terminal device is identification information of the terminal device. In this way, in the call priority control process, it is possible to change the start timing of carrier sense performed after the communication of the first terminal device is stopped based on the identification information of the first terminal device. The success rate of the sense can be increased, and a decrease in communication throughput can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a mobile communication system 10 employing a time division multiplexing system according to an embodiment of the present invention. As shown in the figure, a mobile communication system 10 is connected to a communication network 16 via a wired transmission path and a base station apparatus 12 via a radio transmission path that is time-division multiplexed with the base station apparatus 12. And a plurality of terminal devices 14.

  FIG. 2 is a functional block diagram of the base station apparatus 12. The base station device 12 includes a control unit 20, a storage unit 30, a wireless communication unit 40, and a wired communication unit 50, and assigns any time slot to each call of each terminal device 14, and each of them. Wireless communication is performed with the terminal device 14 by a time division multiplexing method. Also, the base station apparatus 12 can share each time slot with two or more terminal apparatuses 14 by call priority control described later.

  The wireless communication unit 40 includes an antenna 42, a wireless unit 44, and a signal processing unit 46. The antenna 42 is connected to the radio unit 44. The radio unit 44 includes a transmission unit and a reception unit, and sequentially switches between transmission and reception by controlling the antenna 42 in a time division manner. The transmission unit of the radio unit 44 includes an up converter, a power amplifier, and the like, converts the baseband signal input from the signal processing unit 46 into a transmission signal, amplifies it to a transmission output level, and outputs it to the antenna 42. The reception unit of the radio unit 44 includes a low noise amplifier, a down converter, and the like, converts a reception signal received by the antenna 42 into a baseband signal, amplifies it, and outputs it to the signal processing unit 46. The signal processing unit 46 converts the transmission data input from the wired communication unit 50 into a baseband signal and outputs the baseband signal to the wireless unit 44 so that it can be transmitted to a desired terminal device 14. Further, the baseband signal from each terminal device 14 input from the wireless unit 44 is converted into received data and output to the wired communication unit 50.

  The wired communication unit 50 is connected to the communication network 16 via a wired transmission line such as an ISDN line, and is also connected to the signal processing unit 46 to transfer a plurality of data between the plurality of communication lines and the signal processing unit 46. Give and receive.

  The control unit 20 includes a channel allocation control unit 22, an interference wave measurement control unit 24, and a measurement start timing information update unit 26, and controls the entire base station apparatus 12. The control unit 20 includes a CPU and a memory.

  The storage unit 30 includes a measurement start timing information storage unit 32, and stores information used when the interference wave measurement control unit 24 controls the execution of carrier sense. The storage unit 30 is configured by a memory of the control unit 20, for example.

  In response to the channel assignment request from the terminal device 14, the channel assignment control unit 22 selects any empty slot in the base station device 12, and uses any carrier frequency that can be used in the empty slot as a communication channel. Assigned to the call of the terminal device 14. When all the time slots are used for communication, the channel assignment control unit 22 selects one of the time slots in use, and performs control (call priority control) to share the time slot with a plurality of calls. )I do.

  In the call priority control process, the channel assignment control unit 22 cancels the assignment of the communication channel to the call of the terminal device 14 (hereinafter referred to as the first terminal device) in communication in any time slot, and in the time slot. A communication channel determined according to the result of carrier sense (1 wave monitor or 10 wave monitor) to be executed is assigned to a call of another terminal device (hereinafter referred to as a second terminal device). The call of the first terminal device for which the allocation of the communication channel has been released is temporarily stopped, that is, inactive, but any one of the communication channels is again controlled by call priority control executed at a predetermined timing. Is assigned to return to the state where communication is possible. Such call priority control requires that each time slot be shared by two or more calls until the number of terminal devices 14 communicating with the base station device 12 becomes equal to or less than the number of time slots in the base station device 12. It is repeatedly executed at a predetermined timing until it disappears. In this way, the channel assignment control unit 22 can share one time slot with two or more terminal devices 14 by sequentially switching a call during communication and a call under communication at a predetermined timing. With this call priority control, the base station apparatus 12 can start communication with the terminal apparatus 14 that newly requests channel assignment even when there is no empty slot.

  The measurement start timing information storage unit 32 stores timing information related to the timing at which carrier sense is started in association with the attribute information of the first terminal device. FIG. 3 is a diagram illustrating an example of timing information stored in the measurement start timing information storage unit 32. As shown in the figure, the measurement start timing information storage unit 32 is associated with the identification information of the first terminal device, for example, and the carrier sense (1) performed after the communication of the first terminal device is stopped. The number of times that an interference signal of a predetermined level or higher is detected in the wave monitor) is stored. The attribute information of the first terminal device may be information (model name, product model number) for specifying the model of the terminal device. In addition, the timing information may be a value updated in accordance with the record of carrier sense, such as the number of times that an interference signal of a predetermined level or higher is detected in the one-wave monitor, that is, the number of times the one-wave monitor has failed. It may be a flag value indicating the degree of necessity of changing the start timing, a constant indicating a waiting time until carrier sense is started, or the like.

  The interference wave measurement control unit 24 controls the execution of carrier sense (1-wave monitor or 10-wave monitor) required when the channel allocation control unit 22 determines a communication channel to be allocated to a call. Further, the interference wave measurement control unit 24 reads the timing information stored in the measurement start timing information storage unit 32 based on the attribute information of the first terminal device, and based on the timing information, the first terminal The timing at which one-wave monitoring is started in the communication channel used before the apparatus stops communication is changed. For example, if the measurement start timing information storage unit 32 stores a wait time until carrier sense is started in association with the model number of the terminal device, one wave is generated for each model of the terminal device that has stopped communication. It is possible to delay the monitor start timing.

  In addition, as shown in FIG. 3, the measurement start timing information storage unit 32 stores the number of times that the one-wave monitoring performed after the communication of the terminal device is stopped in association with the identification information of the terminal device. If it does in this way, it will become possible to change the start timing of 1 wave monitor based on the frequency | count of the failure for every terminal device which stopped communication. In this case, only when the number of failures is a predetermined number or more, the start timing of the one-wave monitor may be delayed by a time calculated based on the number of failures. In this case, when the number of failures of one-wave monitor due to the deterioration of the radio wave condition is significantly smaller than the number of failures of one-wave monitor due to the processing performance of the base station device or the characteristics of the terminal device, both failure causes Can be discriminated, and a decrease in throughput due to uniformly delaying the start timing of one-wave monitoring can be prevented. In other words, it is possible to delay the start timing of the one-wave monitor only when communication of the terminal device that frequently causes the latter failure is stopped, and to start the one-wave monitor at a normal timing in other cases. In the example shown in FIG. 3, for example, the control of delaying the start of the one-wave monitor is possible only when the terminal identification information whose number of failure times of the one-wave monitor is 10 or more has stopped communication with the terminal device of PS # 2. It becomes.

  The measurement start timing information updating unit 26 associates the measurement start timing information with the attribute information of the first terminal device according to the performance of the one-wave monitor in the communication channel used by the first terminal device before the communication stop. The timing information stored in the information storage unit 32 is updated. For example, as illustrated in FIG. 3, when the measurement start timing information storage unit 32 stores the number of times one-wave monitoring has failed in association with the identification information of the terminal device, the measurement start timing information update unit 26 has 1 Each time the wave monitor fails, 1 is added to the number of times stored in the measurement start timing information storage unit 32 in association with the attribute information of the first terminal device.

  Next, call priority control processing according to the embodiment of the present invention will be described with reference to the flowchart of FIG. Here, a case where communication with the first terminal device is stopped and communication with the second terminal device is started or restarted will be described as an example.

  When the call priority control is started, the channel assignment control unit 22 releases the assignment of the communication channel to the call of the first terminal device in communication (S100). Next, the interference wave measurement control unit 24 reads the timing information stored in the measurement start timing information storage unit 32 based on the attribute information of the first terminal device, and performs one-wave monitoring based on the timing information. It is determined whether it is necessary to delay the start timing (S102). When it is determined that it is not necessary to delay the start timing, the interference wave measurement control unit 24 starts one-wave monitoring at a normal timing (S106). Conversely, when it is determined that it is necessary to delay, after waiting for the wait time calculated based on the timing information (S104), one-wave monitoring is started (S106). Note that in the 1-wave monitor, it is measured whether or not an interference wave signal of a predetermined level or higher is received in the communication channel whose assignment to the call of the first terminal device is cancelled.

  When an interference wave signal of a predetermined level or more is given in the one-wave monitor in S106, that is, when the one-wave monitor is successful, the channel assignment control unit 22 determines that the communication channel is usable (S108) It is determined to continue using the communication channel (S114). On the other hand, when the interference wave signal is detected in the one-wave monitor in S106, that is, when the one-wave monitor fails, the channel assignment control unit 22 determines that the communication channel is unusable at that time. (S108). In this case, the measurement start timing information update unit 26 updates the timing information stored in the measurement start timing information storage unit 32 in association with the identification information of the first terminal device (S110). Then, the interference wave measurement control unit 24 performs carrier sense (10-wave monitor) for a plurality of carrier frequencies in the time slot in order to specify a communication channel that can be used in the same time slot as the communication channel (S112). ). When a good carrier frequency with few interference waves is specified in the 10-wave monitor, the channel assignment control unit 22 determines to newly use the carrier frequency as a communication channel in the time slot (S114). Finally, the channel assignment control unit 22 assigns the communication channel determined in S114 to the other call in the inactive state (S116), and the call priority control process ends.

  According to the base station apparatus and the base station apparatus control method described above, it is possible to increase the success rate of carrier sense executed in call priority control processing and prevent a decrease in communication throughput.

  The present invention is not limited to the above embodiment. For example, the present invention can be applied not only to a mobile communication system but also to any kind of wireless communication system including a base station apparatus and a plurality of terminal apparatuses.

1 is an overall configuration diagram of a mobile communication system according to an embodiment of the present invention. It is a functional block diagram of the base station apparatus which concerns on embodiment of this invention. It is a figure which shows an example of a measurement start timing information storage part. It is a flowchart explaining the priority control process of the call which concerns on embodiment of this invention. It is a flowchart explaining the priority control process of the call in a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Mobile communication system, 12 Base station apparatus, 14 Terminal apparatus, 16 Communication network, 20 Control part, 22 Channel allocation control part, 24 Interference wave measurement control part, 26 Measurement start timing information update part, 30 Storage part, 32 measurement Start timing information storage unit, 40 wireless communication unit, 42 antenna, 44 wireless unit, 46 signal processing unit, 50 wired communication unit.

Claims (5)

A base station device capable of wireless communication with a plurality of terminal devices by a time division multiplexing method and sharing each time slot with two or more terminal devices, and a communication channel in any of the time slots In the base station apparatus that determines whether to stop communication with the first terminal apparatus in communication and to allocate the communication channel to the second terminal apparatus according to the presence or absence of an interference signal in the communication channel,
Measurement start timing information storage means for storing timing information relating to timing for starting interference wave measurement in association with attribute information of the first terminal device;
The timing information stored in the measurement start timing information storage unit is read based on the attribute information of the first terminal device, and the timing for starting the interference wave measurement in the communication channel is changed based on the timing information. Including interference measurement control means,
A base station apparatus. The base station apparatus according to claim 1,
The timing information stored in the measurement start timing information storage means in association with the attribute information of the terminal device in accordance with the result of interference wave measurement in the communication channel used by the first terminal device before the communication stop Further includes measurement start timing information updating means for updating
A base station apparatus. The base station apparatus according to claim 2,
The timing information is a value based on the number of times a jamming signal of a predetermined level or more is detected in the jamming wave measurement.
A base station apparatus. In the base station apparatus in any one of Claims 1 thru | or 3,
The attribute information of the terminal device is identification information of the terminal device.
A base station apparatus. A base station device capable of wireless communication with a plurality of terminal devices by a time division multiplexing method and sharing each time slot with two or more terminal devices, and a communication channel in any of the time slots Of controlling a base station apparatus to stop communication with the first terminal apparatus in communication and determine whether to allocate the communication channel to the second terminal apparatus according to the presence or absence of an interfering signal in the communication channel In
Storing in the measurement start timing information storage means timing information related to the timing of starting the interference wave measurement in association with the attribute information of the first terminal device;
The timing information stored in the measurement start timing information storage unit is read based on the attribute information of the first terminal device, and the timing for starting the interference wave measurement in the communication channel is changed based on the timing information. Including an interference measurement control step,
A control method for a base station apparatus.

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