JP4060741B2 - COMMUNICATION SYSTEM, COMMUNICATION BASE STATION DEVICE, AND COMMUNICATION BASE STATION DEVICE CONTROL METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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.
[0002]
[Prior art]
The number of users of PHS (Personal Handy-phone System) mobile terminals tends to increase as a tool for simply transmitting and receiving digital data. The PHS is a so-called cellular communication system, and each mobile terminal selects a base station with the highest signal strength among a plurality of base stations arranged in various places, and between the selected base stations. Wireless communication is performed. In addition, when the signal strength from the currently selected base station falls below a certain level, this mobile terminal searches for another base station with higher signal strength, and if such a base station is searched, Wireless communication is started with a base station having a higher signal strength (handover).
[0003]
Communication between the mobile terminal and the base station is performed at a communication speed of 32 kbps, and time division multiplexing of 4 uplink channels and 4 downlink channels is performed. As shown in FIG. 4, both uplink and downlink are provided with one control channel (CCH) and three transmission channels (TCH) per slot. The mobile terminal and the base station perform call control (call / incoming call, etc.) using the control channel and the transmission channel, and allocate one transmission channel for each uplink and downlink for each portable terminal. Communicating via a transmission channel.
[0004]
The base station is connected to an ISDN line network. A fixed telephone connected to another base station, a public telephone line network (PSTN), or the like via the U interface of the ISDN line network, or a cellular phone line network. Communicate with a mobile phone connected to the. As is widely known, in the ISDN line network, one control D channel (16 kbps) line and two B channel (64 kbps) lines are set. In a conventional base station, two sets are used, and communication is performed using two D channels and four B channels.
[0005]
In this way, the communication speed of the B channel that can be used for communication is twice that of the PHS side, but for voice data, the compression efficiency of voice encoding used on the PHS side is greater than that of the ISDN line network. The audio data that can be transmitted and received on the ISDN B channel 1 line is only the audio signal of one transmission channel of PHS.
[0006]
Therefore, in the conventional PHS, even when the base station communicates with three portable terminals via three transmission channels, only three lines are used for the B channel on the ISDN side. Even though one line is left over, even if a call request is received from another mobile terminal, there is no channel to be allocated on the PHS side, so connection cannot be made.
[0007]
[Non-Patent Document 1]
TTC standard (first edition) Published by: Telegraph and Telephone Technical Committee 1993 Volume II Volume 4 User / Network Interface p.243-p. 245
[0008]
[Problems to be solved by the invention]
Therefore, a system (SDMA system, Space Division Multiple Access) that processes two calls through one transmission channel has been developed to effectively use the remaining B channel on the ISDN side. When performing communication by this SDMA system, two signals to be transmitted / received via the transmission channel that is the target of the SDMA system are compressed by ½, combined, and transmitted by a signal on the PHS side. In theory, it is possible to transmit / receive data for the number of transmission channels 3 × 2 = 6 channels.
[0009]
However, it is desirable to further increase the number of calls that can be handled. Further, it is more preferable if a technique for increasing the number of calls that can be processed matches the current status of the ISDN interface standard.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication system that can accept further calls while adopting the SDMA scheme.
[0011]
[Means for Solving the Problems]
The present invention for solving the problems of the conventional example is a communication system including a communication base station device and a mobile terminal device, wherein the communication base station device is connected to an ISDN network and the mobile phone. A communication base station device that communicates with a terminal device, and communicates with the ISDN network via a plurality of communication network side control channels and a plurality of communication network side data transmission channels. in between the mobile terminal device, comprising at least and one control channel, and N a transmission channel for transmitting a call of the mobile terminal device to less N number than the number of the communication network side data transfer channel, respectively The wireless communication is performed using the slot, and the data related to the call is transmitted to any one of the transmission channels with respect to the calls of the mobile terminal device up to the number of the data transmission channels on the communication network side after the ( N + 1) th unit. If it is possible to synthesize data related to a call transmitted using one transmission channel, first means for synthesizing and transmitting, and if the synthesis is impossible, the N + 1 and subsequent portable terminal devices The second means for transmitting data related to the call using an unused portion of the control channel, and the communication network side control for the call of the mobile terminal device exceeding the number of the data transmission channels on the communication network side. Means for transmitting to and from the ISDN network using a channel .
[0012]
Further, the present invention for solving the problems of the conventional example is a communication base station apparatus that performs communication with an ISDN network and with a mobile terminal device, and between the ISDN network and the ISDN network. Communicating via a plurality of communication network side control channels and a plurality of communication network side data transmission channels, and carrying up to N portable devices having at least one control channel and fewer than the number of the communication network side data transmission channels Wireless communication is performed using a slot including N transmission channels for transmitting terminal device calls, and N + 1 and subsequent mobile terminal device calls up to the number of data transmission channels on the communication network side A first means for combining and transmitting the data related to the call if it can be combined with the data related to the call transmitted using any one of the transmission channels; If growth is impossible, for the call of the N + 1 units subsequent mobile terminal device, a second means for transmitting data relating to the call using the unused portion of the control channel, the communication network side data transfer For each mobile terminal device call up to the number of channels, each communication network side data transmission channel is used, and for each mobile terminal device call exceeding the number of communication network side data transmission channels, the communication network side control channel And means for transmitting data to and from the ISDN network .
[0013]
Here, when there is a call transmitted using the control channel, if the end of the call transmitted using the transmission channel is detected, the call is transmitted using the control channel instead of the terminated call. The transmitted call may be switched to transmission using the transmission channel.
[0014]
Furthermore, the second means includes a time measuring means for measuring an elapsed time since the transmission of the call using the control channel is started, and when the elapsed time measured by the time measuring means exceeds a predetermined time. The mobile terminal device side related to the call transmitted using the control channel may perform processing for prompting reconnection to another communication base station device.
[0015]
The second means identifies the call type of the N + 1th or later mobile terminal devices when the synthesis is impossible, and rejects the call reception if the call is a voice data call. It is good.
[0016]
A communication base station apparatus control method according to an aspect of the present invention is a communication base station apparatus that performs communication with an ISDN network and with a mobile terminal apparatus, and between the ISDN network and the ISDN network. In this case, communication is performed via a plurality of communication network side control channels and a plurality of communication network side data transmission channels, and at least one control channel and up to N units less than the number of the communication network side data transmission channels. Communication base station apparatuses that perform wireless communication using slots including N transmission channels that respectively transmit calls of mobile terminal apparatuses, up to the number of the data transmission channels on the communication network side from the (N + 1) th station. For a mobile terminal device call, if the data related to the call can be combined with the data related to the call transmitted using any one of the transmission channels, the data is combined and transmitted. When the combining is impossible, for the calls of the N + 1th and subsequent mobile terminal devices, data related to the call is transmitted using an unused portion of the control channel, and the number of data transmission channels on the communication network side For each of the mobile terminal device calls up to, each communication network side data transmission channel is used, and for a mobile terminal device call exceeding the number of the communication network side data transmission channels, the communication network side control channel is used. Control is performed so as to perform transmission with the ISDN network.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the communication system according to the embodiment of the present invention includes a plurality of mobile terminals 1 and communication base stations 2, and the communication base station 2 is connected to an ISDN line network 3. ing. The communication base station 2 basically includes a wireless side communication unit 21, a control unit 22, and a wired side communication unit 23.
[0019]
The mobile terminal 1 communicates with any one of the communication base stations 2 by the PHS method. The portable terminal 1 may be a PHS telephone or a data communication device. The communication base station 2 performs communication by the PHS method with the mobile terminal 1 located in the vicinity thereof as in the conventional case. The communication base station 2 accepts a call request from the mobile terminal 1 side, assigns a call related to the call request to one of the three transmission channels, and transmits voice through the assigned transmission channel. And packet data communication. One of the characteristic features of the present embodiment is that when this communication base station 2 receives a call request, even if there is no vacancy in the transmission channel, the call transmitted on one of the transmission channels By combining or using a control channel, a call related to the call request is processed.
[0020]
That is, the radio side communication unit 21 of the communication base station 2 follows the instruction input from the control unit 22 and, like the conventional one, up (data transmitted from the mobile terminal 1 side to the communication base station 2) down ( (Data transmitted from the communication base station 2 to the terminal device 1) wireless communication using a slot including one control channel and three transmission channels for transmitting three mobile terminal calls, respectively. Do.
[0021]
The wired communication unit 23 performs communication using the U interface with the ISDN network 3 in accordance with an instruction input from the control unit 22. Specifically, the wired side communication unit 23 includes four B channels (communication network side transmission channels) as high-speed channels having a relatively high data rate and D as a low-speed channel having a low data rate. Data is transmitted / received to / from the ISDN line network 3 using two channels (communication network side control channels). The control signal between the communication base station 2 and the ISDN line network 3 is only transmitted / received using one D channel line, and the other D channel line remains unused. Hereinafter, this unused D channel is referred to as an unused D channel.
[0022]
The control unit 22 performs processing (call acceptance processing) for accepting a call request received from the mobile terminal 1 through the control channel via the wireless communication unit 21. In addition, the control unit 22 synthesizes and transmits the data of the other call to the data related to the call transmitted using any one of the downlink transmission channels, and transmits the combined data of the plurality of calls. A process (SDMA process) of receiving data using the transmission channel and separating the combined data of each call is performed. Further, the control unit 22 performs a process for transmitting a call using the control channel (temporary call process).
[0023]
Specific operations of these control units 22 will be described in detail below. In the present embodiment, the call acceptance process performed by the control unit 22 of the communication base station 2 is as follows. When accepting the call request, the control unit 22 starts the process shown in FIG. 2, and first checks whether or not there is a free transmission channel (S1). If any of the transmission channels is available (Yes), a process for assigning a call to the available transmission channel is performed (S2), and the process is terminated (A). In this case, the call data related to the call request is transmitted / received via the uplink and downlink transmission channels assigned in step S2.
[0024]
In step S1, if there is no available transmission channel (if No), whether or not the call data related to the call request can be combined with the data transmitted through the predetermined transmission channel. Is determined (S3). This determination may be, for example, determination of whether or not SDMA processing has already been performed, or may be based on the signal strength of data.
[0025]
In this process S3, when the call data relating to the call request can be combined (if Yes), the SDMA process is started for the predetermined transmission channel (S4), and the process is terminated. A detailed description of the SDMA processing is omitted because a communication base station using the technology has already been put into practical use.
[0026]
Further, in the process S3, when the call data relating to the call request cannot be synthesized (if No), the control unit 22 checks whether there is a call transmitted / received via the control channel (S5), If there is no such call (in the case of No), a temporary call process for transmitting / receiving a call related to the call request via the control channel is started (S6), and the process is terminated. This temporary call processing will be described later.
[0027]
In addition, in process S5, when there is already a call transmitted / received via the control channel (in the case of Yes), a signal indicating that the call cannot be accepted to the mobile terminal 1 which has made the call request is displayed. Then, the call is rejected (S7), and the process is terminated.
[0028]
In this process S5, it is merely checked whether or not there is a call that has already been transmitted / received via the control channel, but it is further determined whether or not the call data related to the call request is packet data. If it is not packet data, the process may be shifted to step S7.
[0029]
By the processing of the control unit 22, processing using the SDMA or the control channel is performed for calls with the fourth and subsequent portable terminals, and further calls can be accepted while adopting the SDMA method. Here, if each of the three transmission channels is an object of the SDMA system, it is possible to accept up to six calls. However, since there are only four B channels on the ISDN side, in the case of the present embodiment, in practice, only one transmission channel can be used for SDMA communication.
[0030]
Next, the temporary call process will be described. The control unit 22 instructs the radio-side communication unit 21 to allocate a control channel to the call related to the call request, and transmits / receives data related to the call via the control channel in both uplink and downlink. Here, the control unit 22 may perform control so as to release the control channel at every predetermined timing for data that originally uses the control channel, such as a call request, or data to be transmitted through the control channel. If there is, the call data transmission is interrupted. That is, the control unit 22 transmits / receives data related to a call using an unused portion of the control channel.
[0031]
Further, the control unit 22 determines a line for transmitting / receiving data transmitted / received via the control channel to / from the ISDN line network 3, and transmits the data to / from the ISDN line network 3 via the determined line. The wired communication unit 23 is instructed to send and receive data between the two. Specifically, if there is a vacant B channel on the ISDN side, the control unit 22 instructs to transmit and receive data via the vacant B channel line. In addition, if there is no vacancy in the B channel on the ISDN side, an instruction is given to transmit and receive data using an unused D channel line. Here, when data is transmitted and received using an unused D channel line, the communication speed (16 kbps) is limited, but the call is connected. Although the unused D channel is used here, a free time portion of the D channel used for control may be used.
[0032]
As described above, it is also preferable to perform the following processing for the call related to the extraordinary call processing. That is, when data is transmitted / received using a low-speed channel such as an unused D-channel line, the control unit 22 monitors the usage state (whether there is a vacancy) of the B channel, which is a high-speed channel. When the B channel is available, control is performed so that a call transmitted using the D channel is switched to the B channel that has become available and transmitted.
[0033]
Similarly, on the wireless side (portable terminal side), the usage status of the transmission channel (whether or not there is a vacancy) is monitored, and when the vacant channel is available, the call transmitted using the control channel is Then, control is performed so that the transmission channel is switched to the empty transmission channel.
[0034]
As a result, when the original call processing using the transmission channel, the B channel, or the like becomes possible, the data is transmitted / received back to the original call processing.
[0035]
Also, here, the channel availability is monitored, and the channel for call processing is switched when the channel is available, but at the timing when the temporary call processing is started, a timer (not shown) is started to start timing. When the time counted by the timer exceeds a predetermined time, the communication terminal 1 that is transmitting / receiving data via the control channel is disconnected or explicitly The instruction may prompt a handover (reconnection) to another communication base station 2.
[0036]
Further, the control unit 22 identifies and stores the type of call (voice data call and packet data call) transmitted using the transmission channel, and uses the transmission channel. If there is a packet data call among the calls, a process of switching the channel with a call transmitted using the control channel may be performed at every predetermined timing (for example, a regular timing).
[0037]
Further, in the above description, the type of call transmitted and received using the control channel is not limited, but a low-speed channel such as the D channel is used with the ISDN network 3 as described above. If this is unavoidable, it may be impractical to process a call for voice data because the data transmission rate is limited.
[0038]
Therefore, before the process S5 shown in FIG. 2, the control unit 22 identifies the type of call related to the call request, and if it is a packet data call (not a voice data call), If the process of S5 and subsequent steps is performed and the call is a voice data call, the process may proceed to process S7 to reject the call.
[0039]
Next, the operation of the communication system according to the present embodiment will be described with reference to FIG. FIG. 3 shows an outline of which channel data related to the calls A to E are transmitted and received. The left side of FIG. 3 shows the wireless side channel, and the right side shows the wired side channel (ISDN channel). ).
[0040]
First, when a call request for a call A, a call B, and a call C is made from each of the plurality of portable terminals 1, the communication base station 2 assigns each call to the transmission channels TCH1 to TCH3 and accepts them, Further, using the three B channels, data of each call is transmitted to and received from the ISDN network 3 (FIG. 3A).
[0041]
In this state, when the communication base station 2 further accepts a call request for the call D, the communication base station 2 determines whether the call D can be combined by the SDMA method, and if it determines that the call D can be combined. The call D is combined with a call transmitted through any one of the transmission channels TCH1 to TCH3 and transmitted. FIG. 3 illustrates a case where the call C is combined with TCH3. Further, the communication base station 2 simultaneously transmits the data related to the call C and the call D from the two mobile terminals 1 at the time of the transmission channel (in this example, TCH3) that is the target of the SDMA method. Although they are received, they are separated into the data of call C and the data of call D by a known method in the SDMA system, and on the wired side, each of call A to call D is transmitted on each of the four B channels. (FIG. 3B).
[0042]
Further, when the call request for the call E is further accepted in the state shown in FIG. 3B, the communication base station 2 identifies whether or not the call E is a packet data call, and the packet data If it is a call, it is accepted and transmission / reception of data of the call E is started via the control channel CCH. On the wired side, this call E data is transmitted and received via the unused D channel (FIG. 3C).
[0043]
Eventually, when the call A is disconnected, the communication base station 2 detects that the transmission channel TCH1 and the B channel 1 line are vacant, and sets a channel for transmitting / receiving the data of the call E from the control channel CCH. The transmission channel is switched to TCH1, and the wired side is switched from the unused D channel to the vacant B channel (FIG. 3 (d)).
[0044]
The present invention is not limited to the processing in the PHS base station connected to the ISDN line as described above. That is, a communication base that performs wireless communication with a mobile terminal device using a slot including at least one control channel and N transmission channels for transmitting calls of N mobile terminal devices, respectively. The present invention can be applied to any station device.
[0045]
That is, in such a communication base station apparatus, for a call with the N + 1th and subsequent mobile terminal apparatuses, the data related to the call is changed to the data related to the call transmitted using any one of the transmission channels. If the combination is possible, the combination is transmitted, and if the combination is not possible, the data related to the call is transmitted using the control channel for the call to the N + 1th and subsequent mobile terminal devices.
[0046]
Further, in this case, when there is a call transmitted using the control channel, if the termination of the call transmitted using the transmission channel is detected, the control channel is used instead of the terminated call. The transmission of the call being transmitted is switched to the transmission using the transmission channel used by the call whose termination is detected.
[0047]
Further, the elapsed time from the start of transmission of the call using the control channel is counted, and when the elapsed time exceeds a predetermined time, the portable terminal device related to the call transmitted using the control channel On the side, processing for prompting reconnection to another communication base station apparatus may be performed.
[0048]
【The invention's effect】
According to the present invention, further calls can be accepted while adopting the SDMA scheme.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram of a communication system according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation example of the control unit 22 of the communication base station 2;
FIG. 3 is an explanatory diagram showing an outline of call processing by the communication base station 2;
FIG. 4 is an explanatory diagram illustrating an example of a general PHS channel configuration;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mobile terminal, 2 Communication base station, 3 ISDN circuit network, 21 Wireless side communication part, 22 Control part, 23 Wired side communication part

Claims (6)

A communication system including a communication base station device and a mobile terminal device,
The communication base station device
A communication base station device that performs communication with an ISDN network and with the mobile terminal device,
Communication with the ISDN network is performed via a plurality of communication network side control channels and a plurality of communication network side data transmission channels,
In between the mobile terminal device, including at least the one control channel, and N a transmission channel for transmitting a call of the mobile terminal device to less N number than the number of the communication network side data transfer channel, respectively Wireless communication using the slot,
From the (N + 1) th device onwards, for calls of portable terminal devices up to the number of data transmission channels on the communication network side, data related to the calls is related to calls that are transmitted using any one of the transmission channels. If the data can be combined, the first means for combining and transmitting,
A second means for transmitting data related to the call using an unused portion of the control channel for the call of the N + 1th and subsequent mobile terminal devices when the combining is impossible;
Means for transmitting calls to and from the ISDN network using the communication network side control channel for calls of mobile terminal devices exceeding the number of data transmission channels on the communication network side;
A communication system comprising: A communication base station device that performs communication with an ISDN network and with a mobile terminal device,
Communication with the ISDN network is performed via a plurality of communication network side control channels and a plurality of communication network side data transmission channels,
Wireless communication is performed using a slot including at least one control channel and N transmission channels that respectively transmit calls of up to N mobile terminal apparatuses smaller than the number of data transmission channels on the communication network side. ,
From the (N + 1) th device onwards, for calls of portable terminal devices up to the number of data transmission channels on the communication network side, data related to the calls is related to calls that are transmitted using any one of the transmission channels. If the data can be combined, the first means for combining and transmitting,
A second means for transmitting data related to the call using an unused portion of the control channel for the call of the N + 1th and subsequent mobile terminal devices when the combining is impossible;
For each mobile terminal device call up to the number of communication network side data transmission channels, each communication network side data transmission channel is used, and for mobile terminal device calls exceeding the number of communication network side data transmission channels, Means for transmitting to and from the ISDN network using the communication network side control channel;
A communication base station apparatus. In the communication base station apparatus according to claim 2 ,
When there is a call transmitted using the control channel, if the termination of the call transmitted using the transmission channel is detected, the call is transmitted using the control channel instead of the terminated call. A communication base station apparatus, wherein call transmission is switched to transmission using the transmission channel. In the communication base station apparatus according to claim 2 or 3 ,
Furthermore, the second means includes time measuring means for measuring an elapsed time since starting transmission of a call using the control channel,
When the elapsed time measured by the time measuring unit exceeds a predetermined time, the portable terminal device related to the call transmitted using the control channel is urged to reconnect to another communication base station device. A communication base station apparatus that performs processing.   In the communication base station apparatus according to any one of claims 2 to 4,
  The second means identifies a call type of the (N + 1) th and subsequent mobile terminal devices when the synthesis is impossible, and rejects acceptance of the call if the call is a voice data call. A communication base station device.   A communication base station device that performs communication with an ISDN network and with a mobile terminal device,
  Communication with the ISDN network is performed via a plurality of communication network side control channels and a plurality of communication network side data transmission channels,
  Wireless communication is performed using a slot including at least one control channel and N transmission channels that respectively transmit calls of up to N mobile terminal apparatuses smaller than the number of data transmission channels on the communication network side. Communication base station device
  From the (N + 1) th device onwards, for calls of portable terminal devices up to the number of data transmission channels on the communication network side, data related to the calls is related to calls that are transmitted using any one of the transmission channels. If it can be combined with data, combine it and transmit it.
  When the combination is impossible, for the call of the N + 1 and subsequent mobile terminal devices, data related to the call is transmitted using an unused portion of the control channel,
  For each mobile terminal device call up to the number of communication network side data transmission channels, each communication network side data transmission channel is used, and for mobile terminal device calls exceeding the number of communication network side data transmission channels, To transmit to and from the ISDN network using the communication network side control channel,
  A control method for a communication base station apparatus, comprising:

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