JP2008054168A - Mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system to be connected certainly and rapidly. <P>SOLUTION: In one piece of TDMA slot 500, plural pieces of control channels are constituted along a frequency axis regarding one control channel along a time axis, by comprising plural pieces of subcarriers (plural pieces of sub-channels to which plural pieces of logic numbers are given each) to a frequency axis direction. That is, one piece of TDMA slot 500 includes plural pieces of control channels (that is, plural pieces of control informations), by being applied not only to a multiplexing along the time axis (time-division multiplex) but also to the multiplexing along the frequency axis (frequency multiplex). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile communication system, and more particularly to a technique for quickly and reliably connecting a CS (base station) and a PS (terminal station).

  In a conventional TDMA / TDD type mobile communication system such as PHS, one data slot (TDMA slot) subjected to time division multiplexing including one control channel used for broadcast, simultaneous call, or call connection is used. ) To communicate between CS and PS. That is, the CS transmits one TDMA slot for each link channel assignment request from one PS (for example, three link channel assignment requests from three PSs, TDMA slot was being transmitted).

  Therefore, when link channel assignment requests are sent almost simultaneously from a plurality of PSs, the time required to complete the assignment of link channels to all PSs increases and the time required for channel connection increases. There was a problem. That is, when a link channel assignment request is sent almost simultaneously from a plurality of PSs, some PSs may require an integral multiple of the transmission interval Ti of the call connection control channel (SCCH). Therefore, in a situation where traffic is high, there is a problem in that connection may not be established due to timeout.

  In order to solve such a problem, for example, in Patent Document 1, a broadcast control channel (BCCH) or a general call control channel (PCH) in a superframe configuration is connected to a call under a high traffic situation. Disclosed is a technique for shortening the time required for link channel assignment to all PSs from completion of a link channel assignment request by replacing (control) channel (SCCH) with increasing (steel) SCCH. ing. Note that BCCH is a control channel that broadcasts control information from CS to PS, PCH is a control channel having the same information that is simultaneously transmitted from CS to PS in the general call area, and SCCH is This is a control channel used when a call connection is made between CS and PS.

JP 2004-96145 A

  In Patent Document 1, when the SCCH is increased by PCH steel, the PCH is decreased by that amount, so that incoming calls from the network side to the PS are reduced. Accordingly, it takes a long time for the PCH to reach the called party. As a result, the time until link channel assignment is completed becomes long, and there is a problem that connection is not established under a high traffic situation.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a mobile communication system that can be quickly and reliably connected.

  A mobile communication system according to the present invention provides a radio network from a base station to a terminal station by using a data slot obtained by performing time division multiplexing on a plurality of data blocks constituting a control channel used for broadcast, simultaneous call, or call connection. In this case, one data slot includes a plurality of control channels and frequency-multiplexes the plurality of control channels.

  A mobile communication system according to the present invention provides a radio network from a base station to a terminal station by using a data slot obtained by performing time division multiplexing on a plurality of data blocks constituting a control channel used for broadcast, simultaneous call, or call connection. In this case, one data slot includes a plurality of control channels and frequency-multiplexes the plurality of control channels. Accordingly, the base station can control a plurality of terminal stations and assign a link channel by transmitting only one data slot. Therefore, the time until link channel assignment is completed can be shortened. In addition, a connection can be established even under high traffic conditions. That is, the connection can be made quickly and reliably.

  The mobile communication system according to the present invention is a method of performing time division multiplexing on a plurality of data blocks constituting one control channel in a downlink direction from a base station (CS) to a terminal station (PS). A plurality of control channels are configured by performing frequency multiplexing in a TDMA slot. Specifically, a broadcast control channel (BCCH), a simultaneous call control channel (PCH), or a call connection control channel (SCCH) is used as the control channel. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a block diagram schematically showing a configuration of mobile communication system 1 according to Embodiment 1 of the present invention.

  As shown in FIG. 1, in the mobile communication system 1, a base station (CS) 100 and a terminal station (PS) 200 are connected via a wireless network 300. The base station 100 is connected to the higher level network 400 via a wired line (metal cable, optical fiber, etc.) or a wireless line.

  The base station 100 includes a TDMA / TDD control unit 10, an RF unit 20, and a processor unit 30. Note that the RF unit 20 may be mounted with one system or may be mounted with a plurality of systems.

  The TDMA / TDD control unit 10 is for controlling a physical layer, and includes a modulation unit 11, a format generation unit 12, a code unit 13, a demodulation unit 14, a data extraction unit 15, and a decoding unit 16.

  The RF unit 20 is for performing transmission / reception.

  The processor unit 30 controls the TDMA / TDD control unit 10 from the upper level (for example, call connection control, handover control, resource management, format control, compression control, and code control).

  The transmission signal input from the upper network 400 to the TDMA / TDD control unit 10 is subjected to code processing such as compression in the code unit 13, generated in the format in the format generation unit 12, and OFDMA such as IFFT processing in the modulation unit 11. Modulated and transmitted to the PS 200 via the RF unit 20.

  The received signal input from the PS 200 to the TDMA / TDD control unit 10 via the RF unit 20 is subjected to OFDMA demodulation such as FFT processing in the demodulation unit 14, extracted in the data extraction unit 15, and extracted in the decoding unit 16. Decoding processing such as decompression is performed.

  The mobile communication system 1 enters a link channel establishment phase triggered by a link channel establishment request from the PS 200 or an instruction from the upper network 400. In this link channel establishment phase, each PS 200 identifies and extracts data for itself from control channel data such as SCCH transmitted from the CS 100, thereby performing a predetermined operation (defined in advance or from the CS 100). Move to (operation based on instructions).

  FIG. 2 is a schematic diagram showing a configuration example of a TDMA slot (data slot) 500 of a control channel such as SCCH transmitted from CS 100 to PS 200 (downlink method) in mobile communication system 1 of FIG. FIG. 3 is a schematic diagram showing a configuration example of a TDMA slot 501 related to a control channel such as SCCH used in a conventional mobile communication system for comparison.

  In FIG. 3, one TDMA slot 501 includes synchronization bits, identification information (including PS-ID in the downlink direction and CS-ID in the uplink direction), control information, error detection bits, and the like. The plurality of data blocks are time-division multiplexed. That is, one TDMA slot 501 includes only one control channel along the time axis.

  On the other hand, in FIG. 2, since one TDMA slot 500 includes a plurality of subcarriers (a plurality of subchannels assigned with a plurality of logical numbers) in the frequency axis direction, A plurality of control channels can be formed along the frequency axis. That is, one TDMA slot 500 is subjected not only to multiplexing along the time axis (time division multiplexing) but also multiplexing along the frequency axis (frequency multiplexing), whereby a plurality of control channels (that is, a plurality of control channels). Control information).

  In one control channel to which one subchannel logical number is assigned, the identification information including the PS-ID, the control information, the end code indicating the end of the slot, and the burst from each PS 200 are overlapped. A guard time, which is a protection period for prevention, and a synchronization bit are added. Note that this end code may be omitted. Further, an error correction bit may be arranged after the control information. In addition, the control channels may be arranged in the order of the subchannel logical numbers on the frequency axis, or may be arranged randomly.

  Therefore, as shown in FIGS. 4 to 5, CS 100 transmits only one TDMA slot 500 even when link channel allocation requests are transmitted almost simultaneously from a plurality of (three in the figure) PS 200. As a result, control information can be notified to each PS 200 and a link channel can be allocated. In FIG. 5, a control channel group 600 is composed of BCCH 601, PCH 602, and SCCH 603 (superframe configuration), and link channel allocation is performed by the first SCCH 603 after a link channel establishment request is sent. (The right direction is the positive direction of the time axis.)

  Although FIG. 5 shows the case where PCH steel is not used, this embodiment may be applied to the case where PCH steel is used. That is, as described above, in the conventional mobile communication system, there is a problem that when the SCCH is increased by performing PCH steal, incoming calls to the PS 200 are reduced. In the mobile communication system 1, since the number of PCHs reduced by PCH steel can be reduced, incoming calls that are reduced can be reduced. In FIG. 5, it is assumed that BCCH 601 includes data related to PCH 602.

  As shown in FIG. 6, when allocating link channels to three PSs 200 using a conventional TDMA slot 501, it is necessary to transmit three TDMA slots 501. Therefore, by using the TDMA slot 500 according to the present embodiment, it is possible to reduce the time required to complete the allocation of link channels to all PSs 200 as compared to the case where the TDMA slot 501 is used ( In FIG. 5, the time t1 is substantially the same as that in FIG. 6, but the times t2 and t3 are shorter than those in FIG.

  In addition, as shown in FIG. 7, even when the reception level deteriorates in a plurality (n: natural number of 3 or more) PS200 and two CS100s are switched by handover, link channel assignments for all PS200 are assigned. This can be done by sending out one TDMA slot 500. Therefore, the time required for handover can be shortened.

  Thus, in the mobile communication system 1 according to the present embodiment, one control channel is configured from a plurality of data blocks by performing time division multiplexing, and a plurality of controls are performed by applying frequency multiplexing. One TDMA slot 500 is formed from the channel. Accordingly, the CS 100 can control a plurality of PSs 200 and allocate a link channel by transmitting only one TDMA slot 500. Therefore, the time until link channel assignment is completed can be shortened. In addition, a connection can be established even under high traffic conditions. That is, the connection can be made quickly and reliably.

<Embodiment 2>
In the first embodiment, the case has been described in which each PS 200 identifies and extracts data for itself from control channel data such as SCCH transmitted from the CS 100. However, the present invention is not limited thereto, or each PS 200 can detect a frequency band including data for itself by including data related to the subchannel logical number in addition to data related to the PCH 602 as in the BCCH 601a shown in FIG. It may be.

  In BCCH 601 that does not include data related to the subchannel logical number, each PS 200 is informed in advance from CS 100 as to which subcarrier (subchannel) in TDMA slot 500 includes control information for itself. Since there is not, each needs to search the entire TDMA slot 500.

  According to control channel group 600a of FIG. 8 according to the present embodiment, CS 100 can notify each PS 200 of data related to the subchannel logical number used for frequency multiplexing using BCCH 601a. Therefore, each PS 200 does not need to search the entire TDMA slot 500, so that in addition to the effect of the first embodiment, the load of each PS 200 can be reduced.

<Embodiment 3>
In the first and second embodiments, as shown in FIG. 2, a plurality of subcarriers (a plurality of logical numbers are assigned respectively) by multiplexing along the frequency axis in one TDMA slot 500. However, in addition to this, multiplexing may be further performed using a CDMA system.

  FIG. 9 is a schematic diagram illustrating a configuration example of the TDMA slot 500a according to the third embodiment. The TDMA slot 500a in FIG. 9 is m-fold code-divided by assigning m (m: a natural number of 3 or more) code numbers based on the CDMA scheme in the TDMA slot 500 in FIG. 2 according to the first embodiment. (This embodiment is not limited to the first embodiment, and may be applied to the second embodiment.)

  Further, control channel group 600b in FIG. 10 is obtained by performing code division multiplexing in control channel group 600 in FIG. 5 according to Embodiment 1 and arranging BCCH 601a in place of BCCH 601. The BCCH 601a includes data related to a code (code) number in addition to data related to the PCH 602 and data related to the subchannel logical number.

  As described above, the TDMA slot 500a according to the present embodiment can include more control channels (control information) by performing code division multiplexing. Therefore, in addition to the effects of the first and second embodiments, there is an effect that the connection can be made more quickly and reliably.

<Embodiment 4>
In the first to third embodiments, as shown in FIG. 2, the case where a plurality of control information is included in one TDMA slot 500 has been described. However, this control information may be compressed.

  FIG. 11 is a schematic diagram illustrating a configuration example of the TDMA slot 500b according to the fourth embodiment. The TDMA slot 500b in FIG. 11 has a reduced total data length (burst length) by compressing control information into compressed data and compressed information (decompressed key) in the TDMA slot 500 in FIG. 2 according to the first embodiment. However, more control information is included (this embodiment is not limited to the first embodiment but may be applied to the second to third embodiments).

  Further, control channel group 600c in FIG. 12 is obtained by compressing control channel group 600 in FIG. 5 according to Embodiment 1 and arranging BCCH 601c in place of BCCH 601. BCCH 601c includes data related to the decompression key in addition to data related to PCH 602 and data related to the subchannel logical number.

  Thus, in TDMA slot 500b according to the present embodiment, more control information can be included by performing compression. Therefore, in addition to the effects of the first to third embodiments, there is an effect that the connection can be made more quickly and reliably.

  In the above description, the case of including more (2n) control information (control channels) than in FIG. 2 has been described with reference to FIG. 11. However, the present invention is not limited to this, or as shown in FIG. The same number (n) of control information as in FIG. 2 may be included. Thereby, since the burst length can be reduced, the reception operation time of the PS 200 can be shortened. Therefore, it is possible to reduce power consumption during standby by partially turning off the receiving device built in PS200.

  Further, in the above description, the case where frequency multiplexing is performed in TDMA slots 500, 500a to 500c related to a control channel such as SCCH has been described with reference to FIGS. As shown in FIG. 14, frequency multiplexing may be performed in a TDMA slot 500d related to a TCH (call channel). In FIG. 14, by performing frequency multiplexing, one TDMA slot 500d includes synchronization burst information, call setting acceptance information, function request response information, and authentication response information necessary for a call. Thereby, CS 100 can establish a call to a plurality of PSs 200 by transmitting only one TDMA slot 500d.

1 is a block diagram schematically showing a configuration of a mobile communication system according to a first embodiment. 4 is a schematic diagram showing a configuration example of a TDMA slot according to Embodiment 1. FIG. It is a schematic diagram which shows the structural example of the TDMA slot for a comparison. FIG. 6 is a diagram showing link channel assignment using TDMA slots according to the first embodiment. FIG. 6 is a diagram showing link channel assignment using TDMA slots according to the first embodiment. It is a figure which shows the link channel allocation using the TDMA slot for a comparison. 6 is a diagram illustrating handover using a TDMA slot according to Embodiment 1. FIG. 6 is a schematic diagram illustrating a configuration example of a channel group according to Embodiment 2. FIG. FIG. 10 is a schematic diagram illustrating a configuration example of a TDMA slot according to a third embodiment. 6 is a schematic diagram illustrating a configuration example of a channel group according to Embodiment 3. FIG. FIG. 10 is a schematic diagram illustrating a configuration example of a TDMA slot according to a fourth embodiment. 6 is a schematic diagram illustrating a configuration example of a channel group according to Embodiment 4. FIG. FIG. 10 is a schematic diagram illustrating a configuration example of a TDMA slot according to a fourth embodiment. FIG. 10 is a schematic diagram illustrating a configuration example of a TDMA slot according to a fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile communication system, 10 TDMA / TDD control part, 11 Modulation part, 12 Format production | generation part, 13 Code part, 14 Demodulation part, 15 Data extraction part, 16 Decoding part, 20 RF part, 30 Processor part, 100 Base station ( CS), 200 terminal station (PS), 300 wireless network, 400 host network, 500, 501 TDMA slot, 600 control channel group, 601 BCCH channel, 602 PCH, 603 SCCH.

Claims (6)

A mobile communication system that transmits a data slot obtained by performing time division multiplexing to a plurality of data blocks constituting a control channel used for broadcast, simultaneous call, or call connection from a base station to a terminal station via a wireless network. And
One data slot includes a plurality of the control channels, and a frequency multiplex is applied to the plurality of control channels. The mobile communication system according to claim 1,
The control channel used for the broadcast is a mobile communication system including a logical number used for the frequency multiplexing as data. The mobile communication system according to claim 1 or 2,
The one data slot is a mobile communication system in which code multiplexing is applied to the plurality of control channels. A mobile communication system according to any one of claims 1 to 3,
The one data slot is a mobile communication system in which control information included in the control channel is compressed. The mobile communication system according to claim 4, wherein
A mobile communication system that partially turns off a receiving device built in the terminal station during a period when the control information is not included in the data slot due to the compression. A mobile communication system according to any one of claims 1 to 5,
A mobile communication system using a call channel instead of the control channel.

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