JP2005167403A - Communications system, communication base transceiver station, and control method of communication base transceiver station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communications system realizing communication between a large number of portable terminals and a base station having a suitable throughput. <P>SOLUTION: A communication base station 4 is provided with a downlink buffer 20 for each portable terminal 6 sharing a transmission channel. A control section 12 calculates the ratio Rd (≡Dα/Dsum) of the amount of data Dα stored in the buffer of the portable terminal 6 for assigning a channel, and the total amount of data Dsum of the entire buffer 20. The use of the transmission channel for a period corresponding to a reference value is approved for a terminal α if the Rd is less than a predetermined threshold, otherwise use of the transmission channel for a period longer than the reference value and corresponding to the Rd is granted. If the ratio Rs (≡Sα/Ssum) of the amount of data transmitted Sα of each terminal α and the sum of amount of transmitted data Ssum of all terminals 6 is not smaller than a predetermined threshold, use period is limited to a reference value, regardless of Rd. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system that performs wireless communication with a mobile terminal using a communication base station facility connected to a wired digital communication line.

PHS (Personal) is a simple tool for sending and receiving digital data.
There is a tendency for the number of mobile terminal users to increase. The PHS is a so-called cellular communication system, and each mobile terminal selects a base station having the highest signal strength among a plurality of base stations arranged in various places, and wirelessly communicates with the selected base station. Communicate. The wireless communication channel between the mobile terminal and the base station is time-division multiplexed into 4 slots for uplink and downlink. As shown in FIG. 5, in any of the uplink and downlink, one of the four slots is used as a control channel (CCH), and the remaining three are each used as a transmission channel (TCH). The mobile terminal and the base station perform call control (call / incoming call, etc.) using the control channel and the transmission channel, and basically assign one uplink / downlink transmission channel for each portable terminal, Communication of 32 kbps is performed via the assigned transmission channel.

  Here, when the number of mobile terminals seeking connection to one base station increases and there are not enough slots, control is performed so that a plurality of mobile terminals share the slots. In the control, the base station registers mobile terminals for which connection is requested in a communication waiting queue, and assigns target slots sequentially from the head mobile terminal. Communication between the assigned mobile terminal and the base station is performed using the target slot continuously until a packet data to be transmitted is delimited or a preset time limit is reached. On the other hand, when those events occur, communication with the mobile terminal device is interrupted, the target slot is assigned to the next mobile terminal in the communication waiting queue, and the mobile terminal that interrupted communication is queued at the tail of the queue. The

By the way, in the following Patent Document 1, in communication using ISDN, a communication mode for exchange connection to a communication network according to increase / decrease in the amount of traffic of transmission data even after exchange connection in a certain communication mode is disclosed. It is shown that the communication mode can be switched dynamically.
JP-A-6-164581

  When switching a mobile terminal that uses a slot, the base station performs processing to release the mobile terminal that has been used up to that point, and then becomes usable with the next mobile terminal registered in the queue. The process of establishing a connection, such as carrier sense in each slot, is performed. When many mobile terminals sharing the slot have a small amount of communication data, the mobile terminals are frequently switched, and the dead time required for the processing increases. For this reason, there is a problem that the utilization efficiency of the wireless transmission path is lowered. On the other hand, if the time limit assigned to the mobile terminal is set longer per order, the number of times of switching can be suppressed as a whole. However, in that case, there is a problem in that the order does not come around for a mobile terminal with a small amount of communication data, and instead the throughput decreases and the number of mobile terminals waiting for communication may not decrease.

  An object of the present invention is to solve the above-described problems, and to provide a communication system that realizes communication with a suitable throughput between a large number of mobile terminals and a base station.

  The communication system according to the present invention time-division-multiplexes a radio transmission path into a frame structure composed of a plurality of time slots, assigns the time slot to each of a plurality of portable terminal devices, and connects the portable terminal device and the communication base station device. The communication base station device is provided corresponding to each of the plurality of mobile terminal devices, and includes a plurality of buffers for storing data waiting to be transmitted to the mobile terminal device, and communication waiting Control means for sequentially assigning the time slots to the portable terminal devices, and the control means between the buffers of the amount of data stored in the buffers. The use restriction period of each of the mobile terminal devices is determined based on the magnitude relationship of

  A communication base station apparatus according to the present invention time-division-multiplexes a radio transmission path into a frame structure composed of a plurality of time slots, and assigns the time slot to each of a plurality of portable terminal apparatuses to communicate with the portable terminal apparatus. A plurality of buffers provided corresponding to each of the plurality of mobile terminal devices, and a plurality of buffers for storing data waiting to be transmitted to the mobile terminal device, and the mobile terminal devices waiting for communication in order. And a control means for allocating the time slot by providing a use restriction period, the control means based on the magnitude relationship between the buffers of the amount of data stored in the buffers. The use restriction period of each terminal device is determined.

  In another communication base station apparatus according to the present invention, the control means compares the accumulated data ratio of each buffer with a predetermined accumulated data reference ratio in the total amount of accumulated data of the plurality of buffers. When the accumulated data ratio is less than the accumulated data reference ratio, a predetermined reference period is set as the use restriction period of the corresponding mobile terminal device, and the accumulated data ratio is equal to or greater than the accumulated data reference ratio And a restriction period setting means for setting a period longer than the reference period as the use restriction period of the corresponding mobile terminal device.

  In a communication base station apparatus according to still another aspect of the present invention, the communication base station apparatus includes a monitoring unit that monitors the amount of data transmitted to each of the plurality of portable terminal devices, and the control unit transmits the transmission of the plurality of portable terminal devices. Means for comparing the transmitted data ratio of each mobile terminal device to the total value of the transmitted data amount and a predetermined transmitted data reference ratio, and the limit period setting means is configured such that the transmitted data ratio is equal to the transmitted data ratio. If it is equal to or greater than the data reference ratio, the use restriction period of the corresponding mobile terminal device is suppressed to the reference period.

  Another communication base station apparatus according to the present invention time-division-multiplexes a radio transmission path into a frame structure composed of a plurality of time slots, assigns the time slot to each of a plurality of portable terminal apparatuses, and communicates with the portable terminal apparatus. And a monitoring means for monitoring the amount of data transmitted to each of the plurality of mobile terminal devices, and a use restriction period in order for the mobile terminal device waiting for communication, and the time Control means for allocating slots, and the control means determines the use restriction period of each mobile terminal device based on the magnitude relationship of the transmitted data amount between the mobile terminal devices.

  A method for controlling a communication base station apparatus according to the present invention time-division-multiplexes a radio transmission path into a frame structure composed of a plurality of time slots, assigns the time slot to each of a plurality of portable terminal apparatuses, and Used for a communication base station apparatus having a communication means for performing communication between and a plurality of buffers provided corresponding to each of the plurality of mobile terminal apparatuses, and storing a plurality of buffers for storing data to be transmitted to the mobile terminal apparatus, Comparing the stored data ratio of each buffer with respect to the total amount of stored data of a plurality of buffers and a predetermined stored data reference ratio; and if the stored data ratio is less than the stored data reference ratio, the corresponding A predetermined reference time is set as a use restriction period in which the time slot to which the mobile terminal device is allocated can be used, and the stored data is set. When the ratio is equal to or greater than the accumulated data reference ratio, a step of setting a time longer than the reference time as the use restriction period of the corresponding mobile terminal device; and a total value of transmitted data amounts of the plurality of mobile terminal devices Comparing the transmitted data ratio of each of the mobile terminal devices to a predetermined transmitted data reference ratio, and if the transmitted data ratio is greater than or equal to the transmitted data reference ratio, the corresponding mobile terminal apparatus Suppressing the use restriction period to the reference time.

  According to the present invention, the use restriction period for the mobile terminal device is determined according to the magnitude relationship between the mobile terminals of the buffered transmission waiting data amount for each mobile terminal device. As a result, the use restriction period for a mobile terminal device with a large amount of data waiting to be transmitted is lengthened, switching of the mobile terminal device is reduced, dead time associated with the switching is reduced, and the utilization efficiency of the wireless transmission path is improved. It becomes possible. On the other hand, not the absolute value of the buffered transmission waiting data amount for each mobile terminal device, but the usage restriction period for the mobile terminal device is determined according to the relative size relationship between the mobile terminals of the data amount, The fairness of throughput between portable terminal devices is improved.

  Moreover, according to this invention, the use restriction period to the portable terminal device to a portable terminal device is defined according to the magnitude relationship of the transmitted data amount for every portable terminal device. Thereby, the use restriction period for the mobile terminal device with a large amount of transmitted data can be suppressed. On the other hand, since the mobile terminal device usage limit period is determined according to the relative size relationship between the mobile terminal devices of the data amount, not the absolute value of the transmitted data amount of the mobile terminal device, the transmitted data amount While restricting the use restriction period for many mobile terminal devices, it is possible to assign more use restriction periods to portable terminal devices with a small amount of transmitted data. Therefore, according to the present invention, the fairness of throughput between portable terminal devices is improved.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. As shown in FIG. 1, a communication system according to an embodiment of the present invention is connected to a communication base station 4 connected to an ISDN network 2 or the like via a wired transmission path, and is connected to the communication base station 4 via a wireless transmission path. Mobile terminal 6. The communication system includes a plurality of communication base stations 4 and mobile terminals 6. The communication base station 4 basically includes a wireless side communication unit 10, a control unit 12, and a wired side communication unit 14. The wireless-side communication unit 10 includes a buffer (downward buffer 20) for temporarily storing data to be transmitted to the mobile terminal 6 and a buffer (upstream buffer 22) for temporarily storing data received from the mobile terminal 6. Prepare. For example, the buffers 20 and 22 are configured as storage areas secured on the memory of the communication base station 4 and are prepared in a number corresponding to the mobile terminals 6 that communicate with each other.

  The portable terminal 6 communicates with any one of the communication base stations 4 by the PHS method. The portable terminal 6 may be a PHS telephone or a data communication device. The communication base station 4 uses the same radio channel as the conventional one (uplink (data transmitted from the portable terminal 6 to the communication base station 4)) and downlink (data transmitted from the communication base station 4 to the portable terminal 6). Is time-division multiplexed into a frame structure consisting of one control channel and three transmission channels. Then, by storing and transmitting data in the transmission channel, communication with the mobile terminal 6 located near the communication base station 4 is performed by the PHS method. Incidentally, by configuring the communication base station 4 to be able to use radio channels having different frequencies, the maximum number of transmission channels that can be handled by the communication base station 4 can be made larger than three.

  The communication base station 4 allocates a transmission channel to the mobile terminal 6 requested to be connected, and realizes voice and packet data communication via the allocated transmission channel. Here, when the number of mobile terminals 6 to be connected is equal to or less than the maximum number of transmission channels, the control unit 12 of the communication base station 4 assigns one transmission channel to each mobile terminal 6. In this case, basically, a predetermined time slot of each frame until communication between the communication base station 4 and the mobile terminal 6 is completed is continuously assigned to one mobile terminal 6.

  On the other hand, when the number of portable terminals 6 that request connection exceeds the maximum number of transmission channels, the control unit 12 performs control to share one time slot as a transmission channel among the plurality of portable terminals 6. In this case, a period during which one mobile terminal 6 continues to use a predetermined time slot is limited, and when the limited period comes, the time slot is assigned to another mobile terminal 6 waiting for connection.

  FIG. 2 is a processing flowchart showing an outline of the transmission channel sharing control. The control unit 12 manages, using a queue, mobile terminals 6 that request connection, to which no transmission channel is assigned. This communication waiting queue is formed on the memory of the communication base station 4, for example. When the number of portable terminals 6 that request connection is equal to or less than the maximum number of transmission channels, the communication waiting queue is empty, but when the maximum transmission channels are exceeded, the excess is sequentially registered in this queue.

  When the transmission channel (time slot) to be shared is released from the previous use of the mobile terminal 6 (S50), the control unit 12 assigns a transmission channel to the mobile terminal 6 at the head of the communication queue. (S55). The control unit 12 determines a use restriction period for the assigned mobile terminal 6 by a method described later (S60).

  The mobile terminal 6 to which the transmission channel is assigned transmits / receives data to / from the communication base station 4 in subsequent frames using the mobile terminal 6. When transmission / reception with the mobile terminal 6 is completed or when the use restriction period set in the process S55 has arrived, the control unit 12 determines that a terminal switching factor has occurred (S65), and the mobile terminal 6 The process of releasing the transmission channel assigned to is started (S70). If the terminal switching factor is due to the arrival of the usage restriction period and communication has not yet ended (S75), the portable terminal 6 is registered in the communication waiting queue (S80). The above transmission channel sharing processes S50 to S80 are basically repeated while the mobile terminal 6 waiting for connection exists in the communication waiting queue (S85).

  Next, a method for determining the use restriction period by the control unit 12 will be described. FIG. 3 is a processing flowchart showing an outline of the determination method. The control unit 12 sums the data amount Di (i = 1 to N) stored in the downlink buffer 20 corresponding to the N mobile terminals 6 sharing the transmission channel, and obtains the total value Dsum. Further, a ratio Rd (≡Dα / Dsum) between the data amount Dα and Dsum stored in the downlink buffer 20 corresponding to the mobile terminal α (α is any one of 1 to N) to which the transmission channel is assigned is calculated (S100 ), According to the comparison result between the ratio Rd and a predetermined threshold value (accumulated data reference ratio) Ld, the process proceeds to a setting process for different use restriction periods T (S105).

  For example, when the period T is Rd <Ld, the use limit period T is set to a predetermined reference value τ0 (S110). When Rd ≧ Ld, in principle, it is set to τ1 longer than τ0 (S115). . As a result, a certain amount of data transmission is ensured for the portable terminal 6 with relatively little accumulated data, while data transmission to the portable terminal 6 with much accumulated data is promoted. Here, τ1 can be a constant value or can be determined according to the value of Rd (for example, τ1 becomes larger as Rd increases). By setting the value τ1 according to the relative value Rd with other mobile terminals 6 instead of the absolute amount Dα of the stored data, a relatively fair throughput can be realized for each mobile terminal 6.

  Further, the threshold value Ld functions as a reference value for determining the relative amount of accumulated data amount between the mobile terminals 6 and can therefore be determined according to the number N of shared mobile terminals. For example, the threshold value Ld is set to a value corresponding to 1 / N. On the other hand, the threshold value Ld may be a constant value.

  The control unit 12 adjusts the use restriction period T based on the amount of data stored in the downlink buffer 20 as described above, while monitoring the amount of data transmitted to the mobile terminal 6 and also depending on the value, the period T Adjust.

  The control is performed, for example, when Rd ≧ Ld (S105). The control unit 12 sums the transmitted data amounts Si (i = 1 to N) of the N mobile terminals 6 sharing the same transmission channel, and obtains the total value Ssum. Then, a ratio Rs (≡Sα / Ssum) between the transmitted data amount Sα and Ssum corresponding to the mobile terminal α (α is any one of 1 to N) taken out from the head of the communication waiting queue is calculated (S120). The use restriction period T is changed in accordance with the comparison result between the ratio Rs and the predetermined threshold (transmitted data reference ratio) Ls (S125).

  For example, when Rs <Ls, the period T remains the principle value τ1 set based on the above-mentioned accumulated data amount. However, when Rs ≧ Ls, the period T is determined by the accumulated data amount. Regardless of the result, the reference value τ0 is set (S110). Thereby, data transmission to the portable terminal 6 in which the amount of transmitted data is significantly larger than other portable terminals 6 is suppressed, while data transmission to the other portable terminals 6 is relatively promoted. Thus, the fairness of the throughput of each mobile terminal 6 is achieved. The suppression of use of the transmission channel for the mobile terminal 6 having a large amount of transmitted data can be continued over a period in which transmission channel assignment is performed a plurality of times for the mobile terminal 6.

  When the mobile terminal 6 released from the transmission channel as described above has not yet completed communication (S75), it is registered in the communication waiting queue (S80). Here, in principle, the control unit 12 registers the portable terminal α at the tail end of the communication waiting queue. However, when the data amount Dα remaining in the downlink buffer 20 is extremely small compared to the other portable terminals 6 (for example, If Rd is smaller than the predetermined threshold value Ld ′, the communication may be terminated early by registering in the middle of the queue or the like so that the next order comes early. FIG. 4 is a schematic process flow diagram of the queuing process S80. The control unit 12 compares the threshold Rd ′ with Ld ′ <Ld and the ratio Rd (S150), and if Rd ≧ Ld ′, registers the portable terminal α at the end of the communication waiting queue (S155). On the other hand, if Rd <Ld ′, interrupt processing for registering the portable terminal α in the middle or at the head of the communication waiting queue is performed (S160). Thus, throughput can be improved by terminating communication itself at an early stage.

1 is a schematic configuration diagram of a communication system according to an embodiment of the present invention. It is a processing flowchart which shows the outline | summary of the transmission channel shared control which concerns on embodiment. It is a processing flowchart which shows the outline | summary of the determination method of the use restriction period which concerns on embodiment. FIG. 5 is a schematic process flow diagram of a queuing process according to an embodiment. It is explanatory drawing which shows the channel structure of general PHS.

Explanation of symbols

2 ISDN line network, 4 communication base station, 6 mobile terminal, 10 wireless side communication unit, 12 control unit, 14 wired side communication unit, 20 downstream buffer, 22 upstream buffer.

Claims (6)

A communication system in which a wireless transmission path is time-division multiplexed into a frame structure composed of a plurality of time slots, and the time slots are allocated to a plurality of mobile terminal devices to perform communication between the mobile terminal device and a communication base station device. There,
The communication base station device
A plurality of buffers provided corresponding to each of the plurality of mobile terminal devices, and a plurality of buffers for storing data waiting to be transmitted to the mobile terminal device;
In order for the mobile terminal device waiting for communication, a control means for allocating the time slot by providing a use restriction period;
Have
The control means includes
Determining the use restriction period of each of the mobile terminal devices based on the magnitude relationship between the buffers of the amount of data stored in each of the buffers;
A communication system characterized by the above. A communication base station apparatus that performs time division multiplexing on a radio transmission path into a frame structure composed of a plurality of time slots, assigns the time slot to each of a plurality of mobile terminal apparatuses, and performs communication with the mobile terminal apparatus,
A plurality of buffers provided for each of the plurality of portable terminal devices, and a plurality of buffers for storing data waiting to be transmitted to the portable terminal device;
In order for the mobile terminal device waiting for communication, a control means for allocating the time slot by providing a use restriction period;
Have
The control means includes
Determining the use restriction period of each of the mobile terminal devices based on the magnitude relationship between the buffers of the amount of data stored in each of the buffers;
A communication base station apparatus. In the communication base station apparatus according to claim 2,
The control means includes
Means for comparing the stored data ratio of each buffer with respect to the total amount of stored data of the plurality of buffers and a predetermined stored data reference ratio;
When the accumulated data ratio is less than the accumulated data reference ratio, a predetermined reference period is set as the use restriction period of the corresponding mobile terminal device, and when the accumulated data ratio is equal to or greater than the accumulated data reference ratio, Limit period setting means for setting a period longer than the reference period as the use limit period of the corresponding mobile terminal device;
A communication base station apparatus comprising: In the communication base station apparatus according to claim 2 or 3,
Monitoring means for monitoring the amount of transmitted data to each of the plurality of portable terminal devices;
The control means includes
Means for comparing the transmitted data ratio of each of the mobile terminal devices and the predetermined transmitted data reference ratio in the total value of the transmitted data amounts of the plurality of mobile terminal devices;
The limit period setting means includes
When the transmitted data ratio is equal to or higher than the transmitted data reference ratio, the usage restriction period of the corresponding mobile terminal device is suppressed to the reference period,
A communication base station apparatus. A communication base station apparatus that performs time division multiplexing on a radio transmission path into a frame structure composed of a plurality of time slots, assigns the time slot to each of a plurality of mobile terminal apparatuses, and performs communication with the mobile terminal apparatus,
Monitoring means for monitoring the amount of data transmitted to each of the plurality of portable terminal devices;
In order for the mobile terminal device waiting for communication, a control means for allocating the time slot by providing a use restriction period;
Have
The control means includes
Determining the use restriction period of each of the mobile terminal devices based on the magnitude relationship of the transmitted data amount between the mobile terminal devices;
A communication base station apparatus. A communication means for time-division-multiplexing a radio transmission path into a frame structure composed of a plurality of time slots, allocating the time slot to each of a plurality of portable terminal apparatuses, and communicating with the portable terminal apparatus; and the plurality of portable terminals It is provided for each terminal device, and is used for a communication base station device having a plurality of buffers for storing data waiting to be transmitted to the mobile terminal device,
Comparing the accumulated data ratio of each buffer with respect to the total amount of accumulated data of the plurality of buffers with a predetermined accumulated data reference ratio;
When the stored data ratio is less than the stored data reference ratio, a predetermined reference time is set as a use restriction period in which the corresponding time slot to which the corresponding mobile terminal device is assigned can be used, and the stored data ratio is If it is equal to or greater than the accumulated data reference ratio, setting a time longer than the reference time as the use restriction period of the corresponding mobile terminal device;
Comparing the transmitted data ratio of each of the mobile terminal devices and the predetermined transmitted data reference ratio in the total value of the transmitted data amounts of the plurality of mobile terminal devices;
When the transmitted data ratio is equal to or greater than the transmitted data reference ratio, the use restriction period of the corresponding mobile terminal device is suppressed to the reference time;
A control method for a communication base station apparatus, comprising:

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