JP4981868B2 - Wireless relay device - Google Patents

Description

  The present invention relates to a wireless relay device that relays wireless communication between a mobile station and a base station in a wireless communication system.

  Conventionally, a radio relay apparatus for relaying radio communication between a mobile station PS and a base station BS in a radio communication system of a four channel multiplexing TDMA-TDD (Time Division Multiple Access-Time Division Duplex) as shown in FIG. 1 is provided. The wireless relay device 1 includes two systems of a BS-side wireless communication unit 2, a PS-side wireless communication unit 3, a communication control unit 4 that controls transmission / reception operations of the BS-side wireless communication unit 2 and the PS-side wireless communication unit 3, Power supply 5 that supplies operating power is mounted, and the BS side radio communication unit 2 performs radio communication with the base station BS via the antenna 2a for the base station BS, and at the same time moves with the PS side radio communication unit 3 Wireless communication is performed with the mobile station PS via the station PS antenna 3a. (See "Second Generation Cordless Telephone System Standard (RCR STD-28)").

  At present, a time length of 5 msec is defined as one frame, and further divided into eight equal parts is defined as one slot (time length 0.625 msec), and a plurality of carriers are frequency-multiplexed for each absolute slot. Then, as shown in FIG. 2, the transmission signal from the base station BS to the mobile station PS (hereinafter referred to as “downlink”) is assigned with four slots S1 to S4 in the downlink section A in one frame, from the mobile station PS. A transmission signal to the base station BS (hereinafter referred to as “uplink”) is assigned with four slots S1 to S4 in the uplink section B in one frame. That is, one base station BS can theoretically process communications with a maximum of four mobile stations PS simultaneously. One absolute slot includes 160-bit data, and 160-bit data is transmitted in half duplex every 5 msec between one mobile station PS and the base station BS. If it sees, the communication speed of 32 kbps will be obtained, and the communication speed of a maximum of 128 kbps will be obtained in 4 slots.

  In addition, PHS uses a radio frequency in the 1.9 GHz band. For example, radio waves of a base station BS installed outdoors are difficult to reach a mobile station PS in a building. Conventionally, a wireless relay device that relays each transmission radio wave with the mobile station PS has been used, and there are some that perform high-speed packet communication by using a plurality of slots simultaneously.

  During communication, slot assignment is performed to determine which absolute slot is used to exchange communication data. The absolute slot used for communication between the base station BS and the wireless relay device 1 is assigned by the base station BS. The wireless relay device 1 has the right to determine the allocation slot for the absolute slot used for communication between the mobile station PS and the wireless relay device 1.

  Therefore, when data to be transmitted occurs in the mobile station PS, the data transmission process cannot be performed immediately, the wireless relay device 1 is requested to assign an absolute slot, and the wireless relay device 1 Data exchange is started after the absolute slot assignment is completed by requesting the BS to assign the absolute slot.

  The procedure from the absolute slot allocation request stage until the allocation slot is determined and data is actually exchanged is called link channel establishment processing. This link channel establishment process is performed using a control signal for controlling the setting of the slot and the like without using a communication signal for actual data exchange. The speed of communication performed using the wireless relay device 1 is determined by the number of absolute slots transmitting control signals in each of the four slots. That is, if control signals are transmitted in as many absolute slots as possible before entering the link channel establishment process, the wireless relay device 1 can efficiently process the allocation request from the mobile station PS by that amount. As a result, the communication speed is increased at the stage of actual data communication.

  Therefore, conventionally, in a normal link channel establishment process, a call loss rate at which a link cannot be established is reduced by assigning an unused slot as a link channel. (For example, see Patent Document 1)

JP 2002-26798 A (paragraph number [0043], FIGS. 1 and 2)

  By the way, in a public wireless communication system such as a mobile phone or PHS, it is necessary to know the location of the mobile station PS when the mobile station PS receives a call. Location registration processing is performed when moving from one management area to another.

  FIG. 5 shows a mobile station PS in a public wireless communication system comprising base stations BS1 to BS4 each having management areas C1 to C4 and a location registration information database DB connected to the base stations BS1 to BS4 via a network NW. An example in the case of moving from one management area C2 to another management area C3 is shown.

  When the mobile station PS that has detected that it has moved from the management area C2 configured by the base station BS2 to the management area C3 configured by the base station BS3 makes a location registration request through the base station BS3, the location of the mobile station PS Information is registered or updated in the location registration information database DB via the network NW.

  In the case of PHS, this location registration starts processing upon a request for establishing a location registration link channel for circuit switching from the mobile station PS. First, as shown in FIG. 6, when a location registration link channel establishment request is directly transmitted from the mobile station PS to the base station BS using the control signal, the absolute slot selected by the base station BS is changed to the location registration link channel. Assigned to the mobile station PS. Then, after the location registration link channel is established, location registration processing using a communication signal is performed. When the location registration process is completed, the base station BS transmits a disconnect command (DISC) to the mobile station PS, and the mobile station PS returns an unnumbered confirmation response (UA) to the base station BS. A radio channel disconnection is transmitted to the mobile station PS to release the radio channel, and the mobile station PS returns a radio channel disconnection completion to the base station BS.

  Next, as shown in FIG. 7, when a location registration link channel establishment request is transmitted from the mobile station PS to the base station BS via the radio relay device 1 using the control signal, the base station BS The selection process is performed, and the absolute slot selected by the base station BS is assigned to the radio relay apparatus 1 as a position registration link channel on the base station BS side. Further, the channel selection process of the mobile station PS is performed by the radio relay apparatus 1, and the absolute slot selected by the radio relay apparatus 1 is allocated to the mobile station PS as a position registration link channel on the mobile station PS side. After the location registration link channel is established in this way, location registration processing using a communication signal is performed between the mobile station PS and the base station BS via the wireless relay device 1. When the location registration process is completed, the base station BS transmits a disconnection command (DISC) to the mobile station PS via the radio relay apparatus 1, and the mobile station PS transmits an unnumbered confirmation response (UA) via the radio relay apparatus 1. To the base station BS, the base station BS transmits a radio channel disconnection to the mobile station PS via the radio relay apparatus 1 to release the radio channel, and the mobile station PS communicates wirelessly via the radio relay apparatus 1. A channel disconnection completion is returned to the base station BS.

  Since the location registration link channel establishment request transmitted from the mobile station PS to the wireless relay device 1 is circuit-switched link channel establishment, the wireless relay device 1 has been conventionally used for the purpose of preventing deterioration in call quality. Has selected an absolute slot different from the absolute slot assigned to the radio relay apparatus 1 by the base station BS.

  Here, circuit switching differs from packet switching in that it is a communication system that always occupies an absolute slot while the link is established. Therefore, the absolute slot must be linked before allocation of the absolute slot during location registration processing. Even if it is used for exchanging control signals such as a channel establishment request, once it is assigned, it cannot be used for the purpose of exchanging control signals thereafter. This operation will be described below with reference to FIGS.

  In FIG. 8A, the BS-side radio communication unit 2 of 4 slots in the downlink receives a control signal from the base station BS, and this is relayed and transmitted to the mobile station PS by the PS-side radio communication unit 3 in the 4 slots of downlink. This state is indicated by a broken-line arrow.

  At this time, as indicated by a solid arrow in FIG. 8B, a location registration link channel establishment request is received from the mobile station PS at the timing of the absolute slot S1, and control signals for location registration link channel establishment are exchanged. It is assumed that the processing is performed in the upstream and downstream absolute slot S1.

  In this case, in the allocation channel selection process, the absolute slot that has already exchanged communication signals (no corresponding slot in the example of FIG. 8) is excluded, and the optimum absolute slot is selected from the remaining absolute slots. Here, it is assumed that the absolute slot S2 is assigned to the base station BS side and the absolute slot S3 is assigned to the mobile station PS side as indicated by the white arrows in FIG. 8C.

  The operation of the radio relay apparatus 1 in this location registration link channel establishment process will be described in more detail with reference to FIG. 9. In the radio relay apparatus 1, the PS-side radio communication unit 3 is connected to the mobile station PS by a control signal. When the exchange location registration link channel establishment request is received (step K100), the BS side radio communication unit 2 has the same absolute slot as the absolute slot from which the PS side radio communication unit 3 has received the location registration link channel establishment request (FIG. 8). Then, the absolute slot S1) is used to relay to the base station BS using a control signal (step K101).

  The base station BS that has received the location registration link channel establishment request selects an absolute slot (absolute slot S2 in FIG. 8) that can be determined to be optimal because the noise level is low among the absolute slots that are not used for communication signal exchange. The same absolute slot as the slot that received the location registration link channel establishment request is selected for the radio relay apparatus 1 that is selected as the link channel assignment on the base station BS side and is the transmission source of the location registration link channel establishment request (in FIG. 8, the absolute slot The link channel assignment on the base station BS side is transmitted by the control signal using S1).

  In the radio relay apparatus 1 that has been assigned on the base station BS side (step K102), the communication control unit 4 uses the BS side radio communication unit 2 in the absolute slot (absolute slot S2 in FIG. 8) assigned to the base station BS side. If the PS-side radio communication unit 3 recognizes that the control signal is being transmitted / received (step K103), the relay process of the control signal becomes impossible after the assignment, so that the control for the assigned absolute slot is not possible. Signal transmission / reception is stopped (step K104). In FIG. 8, since the control signal is transmitted and received in the absolute slot S2 assigned to the base station BS side before the assignment, the control in the absolute slot S2 is performed on both the base station BS side and the mobile station PS side at this stage. Stop transmission / reception of signals.

  Next, of the absolute slots excluding the absolute slot (absolute slot S2 in FIG. 8) assigned by the base station BS in step K102, the communication control unit 4 can determine that the optimum slot is suitable due to a low noise level or the like. (Absolute slot S3 in FIG. 8) is selected as the link channel assignment on the mobile station PS side (step K105).

  Then, similarly to the processing on the base station BS side, the communication control unit 4 recognizes that the control signal is transmitted and received in the slot assigned to the mobile station PS side (absolute slot S3 in FIG. 8) (step K106). ), Control signal transmission / reception is stopped (step K107). In FIG. 8, since the transmission / reception of the control signal is performed before the selection in the absolute slot S3 assigned to the mobile station PS side, at this stage both the base station BS side and the mobile station PS side are used for control in the absolute slot S3 Stop sending and receiving signals.

  After that, the PS-side radio communication unit 3 starts from the same absolute slot (absolute slot S1 in FIG. 8) as the slot that received the location registration link channel establishment request to the mobile station PS that originally transmitted the location registration link channel establishment request. The absolute slot on the mobile station PS side selected by link channel allocation (absolute slot S3 in FIG. 8) is notified by a control signal (step K108).

  Since the process of establishing the location registration link channel is completed at this stage, the base station BS and the mobile station PS use the assigned absolute slots S2 and S3, and the location registration procedure using the communication signal via the wireless relay device 1. Can be performed.

  In this way, in the process of establishing the location registration link channel, in the absolute slots S2 and S3, since the relay process of the control signal becomes impossible after the assignment, the control performed in FIG. The signal transmission / reception is stopped in the absolute slots S2 and S3.

  This state is shown in FIG. 8 (c). The white arrow represents the exchange of communication signals for position registration processing in the assigned channel.

  After that, when the location registration process is completed, the absolute slots S2 and S3 used for the location registration process are released, and the state shown in FIG. 8D is reached. At this time, the absolute slot S1 that is no longer used for the location registration process. And the control signal is relayed only by S4.

  However, even in that case, if enough time is secured after the location registration process is completed, the link channel establishment request for actual data communication was used for the location registration process by the timing sent from the mobile station. Although there is no problem because preparations are made so that control signals can be exchanged again even in an absolute slot, depending on the mobile station PS, as shown in FIG. 10, immediately after location registration and disconnection of the link channel A link channel establishment request for actual data communication is transmitted to the base station BS via the radio relay station 1, and data communication is performed by receiving allocation of the link channel from the base station BS via the radio relay station 1. In this case, for example, in the case of PHS, the link channel establishment request signal can be processed in at least 2 out of 4 slots. , There is a possibility that the original transmission rate is not obtained.

  As described above, in the location registration link channel establishment process, unlike the normal link channel establishment process, the processing efficiency of the allocation request from the mobile station PS is poor, and as a result, the communication speed may be slow.

  The present invention has been made in view of the above-mentioned reasons, and its purpose is to secure an absolute slot for control signal exchange as much as possible even immediately after the location registration processing of a mobile station. An object of the present invention is to provide a wireless relay device that can obtain a desired communication speed.

  The invention of claim 1 comprises a plurality of time-division multiplexed absolute slots, comprising two systems of wireless communication means for communicating with a base station and a mobile station, and a communication control means for controlling the operation of the wireless communication means. Is used in a wireless communication system that performs wireless communication between a mobile station and a base station by using a wireless relay device that relays each transmission radio wave between the mobile station and the base station. For circuit-switched communications sent and received by the wireless communication means communicating with the mobile station at the time of registration of the absolute slot and mobile station location registered in the circuit-switched communication signal sent and received by the wireless communication means communicating with the base station at the time of registration When the control signal is transmitted / received in the absolute slot assigned to the signal, the communication control means stores the control signal transmission / reception timing in advance and then transmits the control signal in the assigned absolute slot. The transmission and reception of the control signal is stopped, characterized in that to start the transmission and reception of the control signal after the location registration of the mobile station.

  According to the present invention, at the time of location registration of the mobile station, stop of transmission / reception of the control signal does not occur by any of slot assignment from the base station to the radio relay apparatus and slot assignment from the radio relay apparatus to the mobile station, Absolute slots for exchanging control signals can be secured as much as possible, and an expected communication speed can be obtained during data communication immediately after the position registration process.

  As described above, according to the present invention, an expected communication speed can be obtained by securing an absolute slot for exchanging control signals as much as possible even immediately after location registration processing of a mobile station. There is an effect.

It is a figure which shows the structure of the radio relay apparatus with which this invention is applied, and the outline | summary of the system with which this apparatus is applied. It is a figure which shows the slot structure of the radio relay apparatus with which this invention is applied. It is a figure which shows the flow of the position registration link channel establishment process in the radio relay apparatus of the basic composition of this invention. It is a figure which shows the flow of the position registration link channel establishment process in the radio relay apparatus of embodiment of this invention. It is a figure which shows the concept of a location registration process. It is a figure which shows the sequence between the base station at the time of position registration, and a mobile station. It is a figure which shows the sequence between the base station at the time of position registration, a radio relay apparatus, and a mobile station. (A)-(d) It is a figure which shows the transition of the slot usage condition at the time of the position registration process in the conventional wireless relay apparatus. It is a figure which shows the flow of the position registration link channel establishment process in the conventional radio relay apparatus. It is a figure which shows the sequence between the base station at the time of communication generation, a radio relay apparatus, and a mobile station.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Basic configuration)
The configuration of the wireless relay device 1 of this basic configuration is shown in FIG. 1 in the same manner as the conventional example described in the background art. Is used in a wireless communication system such as a PHS that relays wireless communication, and relays wireless communication that performs packet switching and circuit switching between the mobile station PS and the base station BS, and its slot configuration is the same as the conventional example As shown in FIG. 2, the communication supports a maximum of 128 kbps. In addition, the same code | symbol is attached | subjected to the structure similar to a prior art example, and description is abbreviate | omitted.

  Hereinafter, the location registration link channel establishment processing flow by the wireless relay device 1 of this basic configuration will be described with reference to FIG.

  In the wireless relay device 1, when the PS-side wireless communication unit 3 receives a circuit-switched location registration link channel establishment request from the mobile station PS using a control signal (step K 1), the BS-side wireless communication unit 2 The wireless communication unit 3 relays to the base station BS by a control signal using the same absolute slot as the slot that received the location registration link channel establishment request (step K2).

  The base station BS that has received the location registration link channel establishment request uses, as a link channel assignment on the base station BS side, an absolute slot that can be determined to be optimal due to a low noise level among slots that are not used for communication signal exchange. To the radio relay apparatus 1 that is the transmission source of the link channel establishment request, and allocates the link channel on the base station BS side with the control signal using the same absolute slot as the slot that received the location registration link channel establishment request. Send.

  In the radio relay apparatus 1 that has been assigned on the base station BS side (step K3), the communication control unit 4 is configured to have the BS side radio communication unit 2 and the PS side radio communication unit 3 in absolute slots assigned to the base station BS side. If it is recognized that the control signal is transmitted / received (step K4), the transmission / reception of the control signal in the assigned absolute slot is stopped (step K5).

  The operation so far is the same as that of the conventional wireless relay device.

  Next, as an operation of the radio relay apparatus 1, there is a process of determining an absolute slot to be allocated to the mobile station PS, but here, a process different from that of the conventional apparatus is performed.

  Specifically, the communication control unit 4 has so-called idle slots (unused slots) that are not used for transmission / reception of communication signals and control signals in the BS side radio communication unit 2 and the PS side radio communication unit 3. Whether there is an idle slot is checked (step K6). If an idle slot exists, the idle slot is preferentially selected as a link channel assignment on the mobile station PS side (step K7).

  However, if there is no idle slot, the communication control unit 4 has a low noise level among the absolute slots excluding the absolute slot assigned from the base station BS in step K3, as in the processing in the conventional apparatus. The absolute slot that can be determined to be optimal by the above is selected as link channel allocation on the mobile station PS side (step K8), and transmission / reception of control signals in the allocated absolute slot is stopped (step K9).

  Then, the PS-side radio communication unit 3 uses the same absolute slot as the slot that received the location registration link channel establishment request to the mobile station PS that originally transmitted the location registration link channel establishment request, by link channel allocation. The absolute slot on the selected mobile station PS side is notified by a control signal (step K10).

  Since the location registration link channel establishment process is completed at this stage, the base station BS and the mobile station PS can perform the location registration procedure via the wireless relay device 1 using the allocation slot.

  In this way, by using this wireless relay device 1, since the absolute slot in the idle state is preferentially selected as the allocation slot for the mobile station PS, transmission / reception is stopped by the location registration link channel establishment process. Therefore, even if an actual data communication request is generated immediately after the location registration process, the probability that an intended communication speed can be obtained increases.

(Embodiment)
The configuration of the wireless relay device 1 of the present embodiment is the same as the basic configuration, and the same components are denoted by the same reference numerals and description thereof is omitted.

  Hereinafter, the location registration link channel establishment processing flow by the wireless relay device 1 of the present embodiment will be described with reference to FIG.

  When the wireless relay device 1 receives a request for establishment of a location registration link channel for circuit switching from the mobile station PS using a control signal (step K40), control is performed using the same absolute slot as the slot that received the request for establishment of the location registration link channel. Relay to the base station BS using a signal for use (step K41).

  The base station BS that has received the location registration link channel establishment request uses, as a link channel assignment on the base station BS side, an absolute slot that can be determined to be optimal due to a low noise level among slots that are not used for communication signal exchange. The link channel assignment is transmitted by the control signal using the same absolute slot as the slot that has received the location registration link channel establishment request to the wireless relay device 1 that is the source of the link channel establishment request.

  In the radio relay apparatus 1 that has been assigned on the base station BS side (step K42), the communication control unit 4 is configured to have the BS side radio communication unit 2 and the PS side radio communication unit 3 in absolute slots assigned to the base station BS side. If it is recognized that the control signal is transmitted / received (step K43), the transmission / reception timing of the control signal is stored in the storage area (step K44), and then the control signal is transmitted / received in the assigned absolute slot. Is stopped (step K45).

  Next, in the same manner as the processing in the conventional apparatus, the communication control unit 4 determines an optimum slot that can be determined to be optimum when the noise level is low among the absolute slots excluding the absolute slot assigned from the base station BS in step K42. Is selected as the link channel allocation on the mobile station PS side (step K46), and the communication control unit 4 uses the absolute slot allocated on the mobile station PS side for the BS side radio communication unit 2 and the PS side radio communication unit 3 for control. If it is recognized that the signal is transmitted / received (step K47), the transmission / reception timing of the control signal is stored in the storage area (step K48), and then the transmission / reception of the control signal in the assigned absolute slot is stopped. (Step K49).

  Then, the PS-side radio communication unit 3 uses the same absolute slot as the slot that received the location registration link channel establishment request to the mobile station PS that originally transmitted the location registration link channel establishment request, by link channel allocation. The absolute slot on the selected mobile station PS side is notified by a control signal (step K50).

  Since the location registration link channel establishment process is completed at this stage, the base station BS and the mobile station PS can perform the location registration procedure via the wireless relay device 1 using the allocation slot.

  Thereafter, when the location registration processing is completed, the transmission / reception timing of the control signal in the absolute slot allocated to the base station BS and mobile station PS stored in the storage area is read, and the transmission / reception of the control signal is immediately performed at the timing. To start.

  In this way, by using this wireless relay device 1, it is possible to start transmission / reception of control signals using transmission / reception timing stored in advance immediately after completion of the location registration processing. Even if an actual request for data communication occurs immediately after that, the intended communication speed can always be obtained.

DESCRIPTION OF SYMBOLS 1 Radio relay apparatus 2 BS side radio communication part 2a BS antenna 3 PS side radio communication part 3a PS antenna 4 Communication control part 5 Power supply BS Base station PS Mobile station

Claims (1)

  Two systems of wireless communication means for communicating with a base station and a mobile station, and a communication control means for controlling the operation of the wireless communication means, and using a plurality of time-division multiplexed absolute slots, Used in a wireless communication system that performs wireless communication with a base station, and in a wireless relay device that relays each transmitted radio wave between the mobile station and the base station, communicates with the base station at the time of mobile station location registration. Absolute slots assigned to circuit-switched communication signals transmitted / received by the wireless communication means to be performed and absolute slots assigned to circuit-switched communication signals transmitted / received by the wireless communication means communicating with the mobile station at the time of mobile station location registration When the control signal is transmitted / received in the communication control means, the communication control means stores the control signal transmission / reception timing in advance and then transmits / receives the control signal in the assigned absolute slot. Wireless relay apparatus characterized by the stop, starts the transmission and reception of the control signal after the location registration of the mobile station.

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