JPH08280063A - Wide area radio communication system - Google Patents

Abstract

PURPOSE: To surely deliver a call wave to a mobile terminal by designating radio transmission time for a call signal by a base station and transmitting by radio the call signal simultaneously at a point of time when it arrives at the radio transmission time by a radio base station receiving the call signal and the radio transmission time. CONSTITUTION: In a central base station 10, a packet assembling multiplexer 13 generates a packet at every channel according to the call signal received from a public network 1, and multiplexes it, and transmits it to all radio base stations 20 simultaneously. A time stamp which designates a time for the simultaneous delivery of the call wave is written on each packet header. The radio base station 20, when receiving the packet, separates the time stamp from the call signal of data, and stores the call signal in a buffer at every channel, which forms a queue. When the present time obtained by a satellite signal receiver 21 coincides with the designation time of one time stamp, the call signal transferred with the time stamp is sent out to a transmitter 23 on a corresponding channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide area wireless communication system, and more particularly to a wide area wireless communication system for making simultaneous paging from a plurality of wireless stations.

[0002]

2. Description of the Related Art Generally, a wide area radio paging system is composed of a plurality of central base stations and a plurality of radio base stations connected to each central base station, and the radio base stations connected to the same central base station are: When calling, the same calling signal is sent to all service areas at once. Therefore, near the middle of the two radio base stations, interference of the same radio wave transmitted from both radio base stations occurs, making delivery of the calling radio wave uncertain. In order to reduce such an interference wave, inter-station phase compensation is required, and various methods have been proposed conventionally.

In the inter-station phase compensation method disclosed in Japanese Patent Laid-Open No. 2-276322, the central base station and each radio base station are connected by a wired line, and the time required when a signal is reciprocated through the wired line is reduced. Based on this, the delay time is set and the phase of the ringing signal transmitted from each radio base station is compensated.

Further, in the inter-station phase compensation system disclosed in Japanese Patent Laid-Open No. 61-62244, the central base station and each radio base station are provided with a clock function. The central base station notifies each wireless base station of the time at which the synchronization signal was transmitted, and each wireless base station calculates the signal delay amount based on the transmission time and the arrival time at which the synchronization signal was received, and according to the signal delay amount. Controls transmission of a calling signal from the central base station.

[0005]

However, in each of the above-mentioned conventional methods, the phase adjustment is performed because the phase compensation is performed by measuring the time required between the central base station and each radio base station. Accuracy depends on time measurement accuracy,
There was a limit to the accuracy improvement. In particular, this problem becomes more prominent because high phase adjustment accuracy is required as the speed of the calling signal increases.

Further, in the system in which the central base station measures the signal round-trip time between the radio base stations and corrects the phase, the ringing signal is transmitted while the central base station performs the round-trip time measurement and the phase correction operation. It is not possible, and the calling service is stopped. Further, in the method in which each wireless base station is provided with a clock function to measure the difference between the synchronization signal transmission time and the arrival time, if there is a variation in the clock function of each wireless base station, an error occurs in the phase correction. In order to prevent such an error, each clock function is required to have accuracy as high as an atomic clock, which is not practical in terms of price and maintenance.

An object of the present invention is to provide a wide area wireless communication system and a paging signal transmitting method for surely delivering a paging radio wave to a terminal.

Another object of the present invention is to provide a paging signal transmitting method which achieves highly accurate inter-station phase compensation in a wide area wireless communication system.

[0009]

A wide area wireless communication system according to the present invention includes a base station having a clock function, a plurality of wireless base stations connected to the base station and each having a clock function, and a radio formed by the wireless base station. And a plurality of terminals that receive at least a radio call signal from the nearest radio base station in the area. In the base station, the designated transmission time to be transmitted from the wireless base station is designated for the paging signal transmitted to the wireless base station, and the paging signal and the designated transmission time are transmitted to the plurality of wireless base stations. Each radio base station stores the received paging signal and the designated transmission time in a memory, reads the paging signal from the memory when the current time reaches the designated transmission time, and releases the paging signal as a paging signal to the wireless area.

[0010]

The base station specifies the wireless transmission time for the calling signal, and the wireless base station which has received the calling signal and the wireless transmission time wirelessly transmits the calling signal all at once when the wireless transmission time is reached. Therefore, it is possible to simultaneously send out the same ringing radio wave whose phase synchronization has been established from a plurality of radio base stations.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

System Configuration FIG. 1 is a schematic configuration diagram showing an embodiment of a wide area radio calling system according to the present invention. This system comprises a central base station 10 having a satellite signal receiver and a plurality of radio base stations 20 connected to the central base station 10 and also having a satellite signal receiver. The plurality of radio base stations 20 are connected to the central base station 10 via the signal distribution device 30, the high speed modem and the transmission path, and form a wide service area.
It is possible to call a specific mobile terminal 40 within the service area by sending a calling signal all at once from these radio base stations 20.

The central base station 10 is a satellite signal receiving device 1
1, a sending time designating device 12, and a packet assembling / multiplexing device 13, and the packet assembling / multiplexing device 13 is connected to the public network 1 via an admission transfer device 2. The radio base station 20 includes a satellite signal receiving device 21, a demultiplexing device 22,
And a transmitter 23, and the transmitter 23 is provided for each transmission frequency (channel). Here, in order to simplify the explanation, it is assumed that four channels, that is, four frequencies are used. Further, the satellite signal receiving devices 11 and 21 of the central base station 10 and the radio base station 20 respectively have a function of receiving GPS (Global Positioning System) satellite waves from the satellite 50 and extracting time information.

In the central base station 10, the packet assembling / multiplexing device 13 generates packets for each channel in accordance with a calling signal received from the public network 1, multiplexes them and sends them to all the radio base stations 20 at once. As will be described later, each packet header includes a transmitter 23 of the radio base station 20.
A time stamp TIMS designating the time at which the ringing radio waves are simultaneously transmitted is written. Time stamp TI
The MS is generated by the transmission time designation device 12 based on the time information of GPS satellite waves. Time stamp TIMS
The specified time is determined by adding a time equal to or longer than the maximum possible delay time of packet transmission between the central base station 10 and the wireless base station 20 to the current time.

When the packet is received at the radio base station 20, the demultiplexer 22 receives the time stamp T of the header.
The IMS and the data call signal are separated, and the call signal is stored in a buffer for each channel to form a waiting queue. When the current time obtained by the satellite signal receiving device 21 coincides with the designated time of one time stamp TIMS, the paging signal transferred together with the time stamp TIMS is sent to the transmitter 23 of the corresponding channel. In this way, the same calling radio waves are simultaneously transmitted to the service area from all the radio base stations 20 at the same time.

Central Base Station FIG. 2 is a block diagram showing a more detailed configuration of the central base station in this embodiment. The call signal reception device 101 that receives the call signal from the public network 1 refers to the subscriber database 102 and outputs the data D _h necessary for forming the header of the packet to the packet assembling unit 10. The subscriber database 102 stores in advance data regarding each subscriber, such as used frequencies (channels) and baud rates.

The received call signal is edited into a POCSAG signal by the call signal editor 103, and is output to the packet assembling unit 104 as data Dd. On the other hand, the GPS satellite wave is received by the satellite signal receiver 105, and the time extractor 106 extracts the time signal TIMp indicating the current time from the satellite signal. The designated sending time stamper 107 adds the above-mentioned predetermined delay time to the current time signal TIMp to generate a time stamp TIMS indicating the designated sending time, and outputs it to the packet assembling unit 104.

The packet assembling unit 104 forms a header from the data D _h , the time stamp TIMS and other necessary data and adds the header to the data D _d to assemble the packet P _ct and outputs it to the multiplexing unit 109. . Packet transmission control unit 108, according to the allocation frequency FQ of the destination mobile terminal included in the data D _h, multiplexes packets P _ct. That is, four channels respectively corresponding to the four allocated frequencies FQ are multiplexed on one transmission path and transmitted to the signal distribution device 30.

FIG. 3A is a format diagram of the packet P _ct output from the packet assembling unit 109, and FIG. 3B is a time chart of a packet in which four channels are multiplexed.

The data required for the header 301 of the packet is the time stamp TIMS and the data length LENGTH.
Except for the call signal reception device 101. For example, the frequency FQ of the header 301 represents the frequency used by the destination mobile terminal. Call signal reception device 10
1 searches the subscriber database 102 using the destination number of the paging signal received from the public network 1 as a keyword, reads the data Dh such as the allocated frequency FQ and the baud rate number BR of the corresponding destination mobile terminal, and the packet assembling unit 10
Output to 4. The time stamp TIMS is given by the designated transmission time stamper 107 as described above. In addition, the data length LENGTH is equal to the calling signal editor 1
It represents the number of data bits of the POCSAG signal input from 03, and is added when the packet assembling unit 104 assembles a packet.

The packet P assembled in this way
_ct is arranged in a time slot (channel) determined according to the frequency FQ and transmitted by the packet transmission control unit 108 and the multiplexing unit 109. As shown in FIG. 3 (B), the four channels CH ₁ to CH ₄ packet P1~
P4 is arranged in each predetermined time slot. The packet header of each channel includes time stamps TIMS1 to TIMS4 that represent the designated transmission times determined by the time stamper 107.

Radio Base Station FIG. 4 is a block diagram showing a more detailed structure of the radio base station in this embodiment. The radio base station 20 is provided with a packet receiver 201 and a packet disassembling unit 202, and the received packets of each channel are called signals, frequencies FQ,
It is decomposed into a time stamp TIMS and other control signals. The selector 203 and the buffer 204 store the call signal for each channel under the control of the buffer input / output control unit 205, and the time stamp table 206 stores the time stamp TIMS of the received packet. The GPS satellite wave is received by the satellite signal receiver 207, and the current time signal TIMp is extracted from the satellite signal by the time extractor 208. The transmission timing control unit 209 determines the current time signal T
When IMp reaches the time stamp TIMS, a transmission command is output to the buffer input / output control unit 205 so as to transmit the calling signal of the packet with the time stamp TIMS.

The buffer 204 has four channels CH ₁
A memory that is logically divided into four buffer area respectively corresponding to to CH _4. The buffer area of each channel includes transmitters T _{x1 to} T _{x4 of} corresponding frequencies.
It is connected to the. The buffer input / output control unit 205 controls the selector 203 and the input / output control of the buffer 204. More specifically, the buffer input / output control unit 205 inputs the frequency FQ from the packet disassembling unit 202 and controls the operation of the selector 203 so as to store the paging signal in the buffer area of the corresponding channel according to the frequency FQ.

In the time stamp table 206, the time stamp TIMS of the received packet is input from the packet disassembling unit 202, and the address of the buffer 204 in which the calling signal of the packet is stored is input from the buffer input / output control unit 205. Therefore, the time stamps TIMS of sequentially received packets and the storage addresses of their calling signals are stored in the time stamp table 206.

The transmission timing control unit 209 uses the time stamp TI stored in the time stamp table 206.
The MS and the current time signal TIMp are constantly compared at a predetermined timing. Then, when the two match, the transmission timing control unit 209 outputs a transmission command to the buffer input / output control unit 205 so as to transmit the calling signal corresponding to the time stamp TIMS. Upon receiving the transmission command, the buffer input / output control unit 205 transfers the corresponding calling signal from the buffer 204 to the corresponding transmitting unit T _x, and the calling radio wave of a predetermined channel frequency is emitted from the transmitting unit to the service area. The time stamp TIMS corresponding to the transmitted calling signal is deleted from the time stamp table 206.

FIG. 5 is a timing chart showing the time relationship between the multiplexed packet transmitted by the central base station and the 4-channel calling radio wave transmitted by the radio base station. Central base station 1
0, packet P1 corresponding to four calling frequencies
~ P4 are generated, and the time stamp TIMS indicating the designated sending time is added to each header. These packets are multiplexed and transmitted to the radio base station 20.

In the radio base station 20, each of the received multiplexed packets is decomposed into a control signal such as a calling signal in the data part, a time stamp TIMS in the header part, and a frequency FQ. Then, at the designated sending time indicated by the time stamp TIMS of the packet, the calling signal carried by the packet is sent to the air through the transmitting unit.

Taking the channel CH ₁ as an example, as shown in FIG. 5, the header portion of the packet P1 includes the frequency FQ ₁ and the time stamp TIMS1 corresponding to the channel CH ₁ , and the data portion has a specific destination. A POCSAG signal CS1 for calling the mobile terminal is included. This packet P1 is received by the packet receiver 201, and the packet decomposing unit 202 calls the call signal CS1 and frequency F.
Q1, time stamp TIMS1, and other control signals. The call signal CS1 is stored in the buffer area of the channel CH ₁ in the buffer 204 by the selector 203. Also, the time stamp TIMS
Is stored in the time stamp table 206 together with the address of the buffer 204 in which the corresponding call signal is stored.

The transmission timing control unit 209 uses the time signal TIMp obtained from the GPS satellite wave as a clock, and when the designated transmission time indicated by the time stamp TIMS is reached, outputs a transmission command to the buffer input / output control unit 205. According to this sending command, the buffer input / output control unit 205
Reads the address corresponding to the time stamp TIMS stored in the time stamp table 206, and calls the call signal C from the area of the channel CH ₁ of the buffer 204.
It outputs S1 to the transmitter T _x1 . The transmitter T _x1 modulates the carrier wave of the frequency FQ1 using the analog-converted call signal CS1 and releases the carrier wave to the service area. The same applies to call signals of other channels, and as shown in FIG. 5, the call signal CS2 is set in accordance with the designated transmission times TIMS2 to TIMS4.
~ CS4 is sequentially transmitted to the service area.

[0030]

As described above in detail, in the wide area wireless communication system according to the present invention, by designating the sending time of the wireless paging signal in the central base station, the wireless paging signals transmitted from all the wireless base stations are designated. The phase synchronization of can be established with high accuracy.

The central base station and the plurality of radio base stations are GP
Since the time is specified using the time information obtained from the S satellite wave, accurate time can be easily obtained at all base stations regardless of the geographical distance between the central base station and the radio base station. . Therefore, the phase synchronization of the radio ringing signal can be established with higher accuracy.

Further, since the paging signal is packetized and transmitted from the central base station to the radio base station, the paging system can be easily multiplexed even when the paging system has a plurality of channels.
There is no need to increase the number of transmission lines.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a wide area wireless paging system according to the present invention.

FIG. 2 is a block diagram showing a more detailed configuration of a central base station in the present embodiment.

FIG. 3A is a format diagram of a packet P _ct output from the packet assembling unit, and FIG. 3B is a time chart of a packet in which four channels are multiplexed.

FIG. 4 is a block diagram showing a more detailed configuration of a wireless base station in the present embodiment.

FIG. 5 is a timing chart showing a time relationship between a multiplexed packet transmitted by the central base station and a 4-channel calling radio wave transmitted by the wireless base station.

[Explanation of symbols]

1 Public Network 2 Admission Transfer Device 10 Central Base Station 11 Satellite Signal Receiving Device 12 Sending Time Designating Device 13 Packet Assembling Multiplexing Device 20 Radio Base Station 21 Satellite Signal Receiving Device 22 Demultiplexing Device 23 Transmitter 30 Signal Distributing Device 40 Mobile Terminal 50 satellites 101 call signal reception device 102 subscriber database 103 call signal editor 104 packet assembly unit 105 satellite signal receiver 106 time extractor 107 transmission designated time stamper 108 packet transmission control unit 109 multiplexing unit 201 packet receiver 202 packet decomposition part 203 selector 204 buffer 205 buffers output control unit 206 a time stamp table 207 satellite signal receiver 208 time extractor 209 transmission timing control unit 301 header 302 data unit CS paging signals P _ct Paquet DOO P1~P4 allocated frequency TIMp current time signal of the multiplexed packet FQ destination mobile terminal TIMS timestamp T _x1 through T _x4 transmission unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04L 7/00

Claims (7)

[Claims] 1. A base station having a clock function, and a plurality of radio base stations each connected to the base station and having a clock function,
In a wide area wireless communication system consisting of a plurality of terminals that receive at least a wireless paging signal from the nearest wireless base station within a wireless area formed by the plurality of wireless base stations, the base station transmitting to the wireless base station. A designated time signal for designating a designated transmission time to be transmitted from the radio base station in response to the paging signal, and a designated time signal indicating the paging signal and the designated transmission time, to the plurality of radio base stations. Each of the plurality of radio base stations includes a receiving unit that receives the calling signal and the designated time signal, a storage unit that stores the calling signal, and a time point when the designated time is reached. A transmission timing control means for reading out the calling signal from the storage means, and a radio for converting the calling signal read out from the storage means into the wireless calling signal. A signal unit, consisting of a wide area radio communication system, characterized in that. 2. The information transmitting means comprises an information block forming means for forming a predetermined information block composed of the ringing signal and a designated time signal indicating the designated transmission time, and the information blocks, the plurality of radio base stations. Information block transmitting means for transmitting to the information block, the receiving means, the information block receiving means for receiving the information block, an information block disassembling means for extracting the calling signal and the transmission designated time signal from the information block, The wide area wireless communication system according to claim 1, comprising: 3. A base station, a plurality of radio base stations connected to the base station, and a plurality of radio base stations that receive at least a radio paging signal from the nearest radio base station within a radio area formed by the plurality of radio base stations. In the wide area wireless communication system including the terminal, the base station includes a first satellite signal receiving unit that receives a satellite signal including time information, and a first clock unit that keeps a current time using the time information. A plurality of time designation means for designating a designated transmission time to be transmitted from the wireless base station in response to a paging signal transmitted to the wireless base station; and a plurality of designated time signals indicating the paging signal and the designated transmission time. And a second satellite signal receiving means for receiving the satellite signal, and a second means for notifying a current time using the time information. Time Counting means, receiving means for receiving the calling signal and the designated time signal, storage means for storing the calling signal, and reading the calling signal from the storing means when the current time reaches the designated time. A wide area wireless communication system comprising: a transmission timing control means; and a wireless transmission means for converting the calling signal read from the storage means into the wireless calling signal. 4. The information block forming means for forming a predetermined information block composed of the call signal and a designated time signal indicating the designated transmission time; and the information block, wherein the information block is formed by the plurality of radio base stations. Information block transmitting means for transmitting to the information block, the receiving means, the information block receiving means for receiving the information block, an information block disassembling means for extracting the calling signal and the transmission designated time signal from the information block, The wide area wireless communication system according to claim 3, wherein the wide area wireless communication system comprises: 5. A base station having a clock function, and a plurality of radio base stations connected to the base station and each having a clock function,
A plurality of terminals that receive a radio paging signal from the nearest radio base station in a radio area formed by the plurality of radio base stations, each of the terminals through a predetermined channel among a plurality of channels. In the wide area wireless communication system for receiving the wireless paging signal, the base station, with respect to the paging signal transmitted to the wireless base station, a time designating unit that designates a transmission designated time to be transmitted from the wireless base station, An information block forming unit that forms a predetermined information block composed of the calling signal and a designated time signal indicating the designated transmission time; and the plurality of radio bases by multiplexing the information blocks corresponding to the plurality of channels. Multiplex transmission means for transmitting to the station, each of the plurality of radio base stations: Demultiplexing means for decomposing for each channel, information block decomposing means for extracting the calling signal and the designated transmission time signal from the information block, storage means for storing the calling signal for each channel, and reaching the designated time Transmission timing control means for reading the call signal from the storage means for each channel at the time point, and wireless transmission means for converting the call signal read from the storage means to the wireless call signal for each channel, A wide-area wireless communication system comprising: 6. A base station, a plurality of radio base stations connected to the base station, and a plurality of radio call signals received from the nearest radio base station within a radio area formed by the plurality of radio base stations. In a wide area wireless communication system in which each of the terminals receives the radio paging signal through a predetermined channel among a plurality of channels, the base station receives a satellite signal including time information. A first satellite signal receiving means, a first clock means for marking a current time using the time information, and a designated transmission time to be transmitted from the radio base station in response to a calling signal transmitted to the radio base station. Time designation means for designating, information block forming means for forming a predetermined information block composed of the calling signal and the designated time signal indicating the designated transmission time, and the plurality of channels Multiplex transmitting means for multiplexing the information blocks corresponding to a plurality of wireless base stations and transmitting the multiplexed information blocks to the plurality of wireless base stations, wherein each of the plurality of wireless base stations receives the satellite signal. Means, second clock means for ticking the present time using the time information, demultiplexing means for decomposing the multiplexed information block for each channel, the calling signal and the transmission designated time from the information block An information block decomposing means for extracting a signal, a storing means for storing the calling signal for each channel, a transmission timing control means for reading the calling signal for each channel from the storing means when the designated time is reached, Wireless transmission means for converting the ringing signal read from the storage means into the wireless ringing signal for each channel, Wide-area wireless communication system that. 7. A base station having a clock function, and a plurality of radio base stations each connected to the base station and having a clock function,
A call signal transmission method in a wide area wireless communication system, comprising: a plurality of terminals that receive at least a wireless call signal from a nearest wireless base station within a wireless area formed by the plurality of wireless base stations; A designated transmission time to be transmitted from the radio base station for the ringing signal to be transmitted, and transmits the ringing signal and a designated time signal indicating the transmission designated time to the plurality of radio base stations; Storing the call signal and the designated transmission time received by each of the wireless base stations in the memory, reading the call signal when the designated transmission time is reached, and converting the read signal to the wireless call signal. A method for transmitting a paging signal in a wide area wireless communication system.