JPH07184252A - Radio communication system - Google Patents

Abstract

PURPOSE:To simplify the configuration of a radio base station in the mobile communication system including a mobile terminal equipment having plural transmission speeds. CONSTITUTION:Radio base stations 210, 210', 210'' provided to radio zones 600, 600', 600'' respectively are connected to a central base station 800 by optical fiber transmission lines 700, 700', 700''. MODEMs 2031, 2032, 2033 for each radio base station, time division multiplexer circuits 2041, 2042, 2043 and code conversion circuits 2051, 2052, 2053 are arranged concentratingly to the central base station 800 and each radio base station is not provided with the circuits as above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio access system for connecting a digital mobile terminal to a public line network using a radio line, and particularly to the same transmission rate and N minutes as the voice coding law of the public line. The present invention relates to a wireless communication device that enables wireless access at a different data transmission rate from a plurality of types of mobile terminals having a single transmission rate.

[0002]

2. Description of the Related Art FIG. 4 shows the configuration of a conventional wireless communication device used in a wireless access system for connecting a mobile terminal in a wireless zone and a public network. The wireless access method uses a wireless zone called a cell (cell) obtained by further dividing a service area, and this wireless zone is called a micro cell, a pico cell, or simply a cell.

In general, in a wireless communication device for mobile communication, in order to narrow the transmission band, the transmission rate is reduced by adaptive differential pulse coding to transmit a voice signal, and N minutes of the voice coding rate of a public line. It is voice-encoded at a transmission rate of 1 and connected to a mobile terminal. In this configuration, time division multiplexing of 4 time slots per radio frequency is performed, and the mobile terminal 100 ₁ having a transmission rate of 1/2 of the voice coding law of the public line and 1/4 of the voice coding law of the public line. An example of a wireless communication device that accesses three types of mobile terminals, a mobile terminal 100 ₂ having a transmission rate of 1 to ₃ and a mobile terminal 100 ₃ having a transmission rate of 1/8 of the voice coding law of a public line, to a public network. Show.
The suffix of the number indicates the type of transmission rate according to the voice coding law of the mobile terminal.

Microcell 600, 600 ', 600 "
The mobile terminals located inside are connected to the respective radio base stations 200, 200 ′ and 200 ″ arranged by radio lines and are connected to the public line network 500 through the public line 400. The radio base station 200 is connected to the antenna 201. , An antenna duplexer 202, and a plurality of modulators / demodulators 203 ₁ , 203 ₂ , 2
03 ₃ and a plurality of time division multiplexing circuits 204 ₁ , 204 ₂ ,
204 ₃ and a plurality of code converters 205 ₁ , 205 ₂ , 2
05 _3, a public line interface circuit 206, which comprises a control circuit 300.

Radio base stations 200, 200 'and 20
0 ″ denotes modulators / demodulators 203 ₁ , 203 ₂ , 203 ₃ , time division multiplexing circuits 204 ₁ , 204 ₂ , 204 ₃ and code converter 20 in order to cope with traffic fluctuations of microcells.
It is necessary to design the numbers of 5 ₁ , 205 ₂ and 205 ₃ in anticipation of peak times.

The antenna 201 is connected to the antenna duplexer 202, and the branch output of the antenna duplexer 202 is the radio base station 20.
0 deployed in modem 203 _1, 203 _2, 203 ₃
Is connected to the modulator / demodulator 20 to receive signals received by the antenna.
3 ₁ , 203 ₂ , 203 ₃ and input to the modulator / demodulator 203
The transmission signals ₁ , 203 ₂ , and 203 ₃ are combined and transmitted from the antenna. The modulators / demodulators 203 ₁ , 203 ₂ , 203 ₃ are time division multiplexing circuits 204 ₁ , 204 ₂ , 204 _{3, respectively.}
And the code conversion output signals of the code converters 205 ₁ , 205 ₂ , and 205 ₃ are time-division demultiplexed. Modem 20
3 ₁ selects a radio signal of the mobile terminal 100 _{1 from} among the radio signals from the mobile terminals 100 ₁ , 100 ₂ , 100 ₃ by a reception filter, demodulates it, and transmits it to the time division multiplexing circuit 204 ₁ and a code converter. 205 ₁ converts the code into a code based on the voice coding law of the public line, converts it into an interface of the public line, and connects to the public line network.

The time division multiplexing circuit 204 ₁ is connected to the outputs of the four code converters 205 ₁ , and the demodulated signal transmitted from the modulator / demodulator is time-divided into four code converters 205 _1.
Then, the speech channel signals from the four code converters 205 ₁ are time-division multiplexed and input to the modulator / demodulator as modulated signals. Time division multiplexing circuit 204 ₂ and time division multiplexing circuit 2
Reference numeral 04 ₃ is connected to eight code converters 205 ₂ and 16 of code converters 205 _{3, respectively,} and performs time division multiplexing with multiplicities of 8 and 16 as in the TDMA multiplexing circuit 204 ₁ .

The control circuit 300 controls the connection for connecting the wireless line to the public line network 500, and connects to the public line interface circuit 206 to control the line connection of the public line, and the LAPD processing circuit 301, and time division. LA for connecting to the multiplexing circuit 204 ₁ to control the line connection of the wireless line
It is composed of a PDC processing circuit 302, a time division multiplexing circuit used according to the type of transmission speed of the mobile terminal, and a line connection control circuit 303 for controlling the assigned time slot.

The line connection request from the mobile terminal 100 ₂ is
The signal is transmitted to the LAPDC processing circuit 303 of the control circuit 300 through the modulator / demodulator 203 ₁ of the wireless base station 200 and the TDMA demultiplexer 204 ₁ through the control channel of the wireless circuit. The line connection control circuit 303 determines the mobile terminal 100 based on the information on the transmission rate of the mobile terminal 100 ₂ included in the line control information.
_An unused call channel is selected from the code converters 205 ₂ corresponding to the transmission speed of ₂ , and the call line of the public line interface circuit 206 and the wireless line connected to the mobile terminal 100 ₂ are connected to the code converter 205 ₂ , Division multiplex circuit 204
₂ and the modulator / demodulator 203 ₂ . LAPD
The processing circuit 301 sends line connection request information to the public line 400 through the control channel of the public line interface circuit 206 connected to the mobile terminal 100 ₂ via the public line network interface circuit.

[0010]

In the microcell system, the frequency of mobile terminals moving between cells increases as the cell radius decreases, and the number of mobile terminals in a cell fluctuates greatly with time. The bias increases. In order to satisfy the connection quality, in the conventional technique, the number of code converters, the time division multiplexing circuit, and the modulator / demodulator that allow for the peak fluctuation of the traffic of microcells for each type of transmission speed of the mobile terminal are provided in the radio base station. Therefore, the number of code converters, time division multiplexing circuits, and modulators / demodulators is excessive in the steady state. This is a major obstacle to downsizing and economicization of base stations. The selection of the type of transmission rate of the mobile terminal changes at any time with the development of the voice coding system and the diversification of the service type. For this reason,
For each radio base station, it is necessary to frequently perform maintenance work such as addition and removal of a code converter, a time division multiplexing circuit and a modulator / demodulator included in the radio base station.

An object of the present invention is to satisfy the connection quality at the time of maximum traffic, reduce the number of equipments of excessive code converters, time division multiplexing circuits, and modulators / demodulators in a steady state, and perform maintenance work of a radio base station. An object of the present invention is to provide a wireless communication system that can be reduced.

[0012]

A wireless communication device is composed of a centralized base station connected to a public line and a plurality of wireless base stations connected to the centralized base station by an optical fiber transmission line.
A public line interface circuit, a means for converting voice code, a means for performing time division multiplexing, and a modulator / demodulator, which were conventionally arranged in a radio base station, are arranged in a centralized base station, and an electric signal of radio frequency is transmitted through an optical fiber transmission line. Transmit to the wireless base station. Each radio base station is arranged in a micro cell, and the mobile terminal of the micro cell is connected to a public line.

A plurality of types of means for converting a voice code,
A plurality of means for performing time division multiplexing with different multiplexing numbers, a means for switching the transmission path of an electric signal of a radio frequency between the radio base station and the modulator / demodulator, and a radio base station according to the voice code of the mobile terminal. The centralized base station is characterized in that the centralized base station is provided with means for selecting a signal connection path to the modulator / demodulator, means for performing time division multiplexing, and means for converting voice code, and switching the transmission path.

[0014]

In the wireless communication apparatus of the present invention, by arranging a means for converting a plurality of types of voice codes and a means for performing time division multiplexing in a centralized base station, a plurality of different transmission speeds existing in a microcell can be moved. A terminal can access a public line, and means for performing voice code conversion, means for performing time division multiplexing, and a modulator / demodulator are shared by switching distribution among a plurality of microcells. Further, since the electric signal of the radio frequency is transmitted between the radio base station and the toll base station, the position of the toll base station does not depend on the position of the micro cell.

[0015]

FIG. 1 shows a first embodiment of the present invention. In this embodiment, the mobile terminal 100 ₁ whose time division multiplexing number is 4
When a mobile terminal 100 ₂ with half the transmission rate of the mobile terminal 100 _1, the wireless communication device corresponding to the three types of mobile terminals of the mobile terminal 100 ₃ with 1/4 of the transmission rate of the mobile terminal 100 ₁ Is an example.

The wireless communication device of the present invention is provided with an antenna 201.
And a plurality of radio base stations 210, 21 configured by an electro-optical signal converter 207 that transmits an electric signal of a radio frequency.
0 ', 210 ", and a centralized base station 800 for transmitting radio frequency signals by centrally arranging modulators and connecting a plurality of microcells with optical fiber transmission lines 700, 700', 700".

The transmission wave of the mobile terminal 100 ₁ is received by the antenna 201 of the radio base station 210, converted into an optical signal by the electro-optical converter 207, and transmitted to the toll base station through the optical fiber transmission line 700. The optical signal transmitted from the centralized base station is converted into a radio frequency electric signal by the electro-optical converter 207, amplified to a required transmission power, and transmitted to the space by the antenna 201.

The toll base station 800 includes an electro-optical converter 801 for converting a radio frequency electric signal into an optical signal, a distribution / combining switch 802 for switching a transmission path of the radio frequency electric signal, and modulators / demodulators 203 ₁ , 203 _2. , 203 ₃ ,
Time division demultiplexers 204 ₁ , 204 ₂ , 204 ₃ , code converters 205 ₁ , 205 ₂ , 205 ₃ for converting speech coding rules of public lines and mobile terminals, public line interface circuit 206, centralized It is composed of a control circuit 310.

From the radio base station 201 to the optical fiber transmission line 7
00 modem 203 ₁ corresponding to the type of the transmitted optical signal transmission speed of electrooptic converter 801 are input is converted into an electric signal of a radio frequency is connected to the distribution switch 802 to the mobile terminal 101 ₁ by time division Multiplex circuit 204 ₁ ,
It is connected to the code converter 205 ₁ and connected to the public line via the public line interface circuit 206.

Further, the speech channel of the public line is transmitted via the public line interface circuit 206 to the code converter 205.
₁ is input and converted to the transmission rate of the mobile terminal 100 ₁ , is input to the time division multiplexing circuit 204 ₁ , is multiplexed on the TDMA time slot, is modulated by the modulator / demodulator 203 ₁ , is input to the distribution switch circuit 802, and is moved. Terminal 100 ₁
To the optical fiber transmission line 700 and the electro-optical converter 801 connected to the wireless base station connected by the wireless line.

The distribution switch 802 is a distribution combiner 803.
And a 1-input n-output switch 804 to distribute and combine a plurality of input signals, and a received signal of the wireless base station 210 transmitted from the wireless base station 210 through the optical fiber transmission line 700 is converted by the electro-optical converter 801. A distributor / combiner 803 for converting the electric signal of the radio frequency converted into the electric signal
And the modulator / demodulators 203 ₁ and 2 selected by the centralized control circuit 310 by inputting to the 1-input n-output switch 804.
It is output to the demodulation inputs of 03 ₂ and 203 ₃ . Modem 2
The modulated outputs of 03 ₁ , 203 ₂ , and 203 ₃ are input to the 1-input n-output switch 804, input to the branching / combining unit 803 selected by the centralized control circuit 310, and combined with other modulator output signals to perform electro-optical conversion. The optical signal is input to the device 801, converted into an optical signal, and transmitted to the wireless base station 201.

The centralized control circuit 310 includes a switching control circuit 31.
5 ₁ , 315 ₂ , 315 ₃ and the line connection control circuit 313
An information storage circuit 314 that stores and holds the line connection, and L
APD processing circuit 301 and LAPDC processing circuit 302
Composed of. The LAPDC processing circuit 302 performs control of a wireless channel with a mobile terminal through a modulator / demodulator 203 ₁ and transmits a control channel.
1 transmits the line control information to and from the public line through the control line of the public line.

FIG. 2 is an explanatory diagram of time division multiplexing of a wireless line and control of a centralized control circuit 310 for distributing burst signals by a distribution switch in this embodiment.
In the down line, a public line call channel 401
Is converted into the speech coding law of the mobile terminal by the code converter and becomes the code conversion signal 402 ₁ of the mobile terminal, which is sequentially output for each data of the number of bits of the burst length by time division multiplexing to become the modulation signal 403 ₁ . The code-converted signal 402 ₂ is a signal coded at a transmission rate that is one half that of the code-converted signal 402 ₁ , and is a modulated signal 4 obtained by performing time-division multiplexing of eight call signals.
It becomes 02 ₂ . Likewise code conversion signals 402 _3, the modulated signal subjected to time division multiplexing of the 16 speech signal be code converted signal 402 _one quarter encoded signal 1 for the transmission rate of 40
2 ₃ Each modulator / demodulator is modulated according to the modulation signal 403, and the connection path of the radio base station can be switched in burst units by the distribution switch. The distribution switch repeats distribution switching of connection paths at a cycle of 16 bursts, which is the longest burst transmission cycle. The line connection control circuit 313 receives the line control information by the LAPD processing circuit 301 and the LAPDC processing circuit, and controls the connection route and time slot. The line connection control circuit 313 stores the status of the connection path and time slot in the line connection information storage circuit 314 as a distribution switching table 406, and outputs the modulated output signals 403 ₁ , 403 ₂ , and 403 _{3 according} to the distribution switching table. Radio base station transmission signals 404, 404 ', and 404 "are transmitted by repeating time division multiplexing and frequency multiplexing for each slot at the longest burst transmission cycle. The uplink channel is the reverse process of the downlink channel.

FIG. 3 shows a second embodiment of the present invention. L
The input / output of the APDC processing circuit 302 is the time division multiplexing circuit 20.
It is different from the second embodiment in that the mobile terminal is connected to the radio channel control channel by inputting / outputting to / from 4 ₄ and the modulator / demodulator 204 ₃ . The modulator / demodulator 204 ₃ is a time division multiplexing circuit 204 ₄
The input / output signals of the time-division multiplexed LAPDC processing circuit 302 are modulated and demodulated. The control circuit 315 ₄ performs line connection control of the mobile terminal connected by a branch combiner 803 performs a switching control for each burst of 1 input n output switch 804 and a plurality of radio base stations.

[0025]

As described above, in the wireless communication apparatus for connecting the wireless line of the present invention to the public line network, the centralized base station is provided with a plurality of types of time division multiplexing circuits and modulators / demodulators corresponding to the transmission speed types of mobile terminals. Centrally located at the base station, a time-division multiplexed signal of radio frequency for each burst is switched to a plurality of radio base stations by a distribution switch and connected. Therefore, the number of modulators / demodulators and the number of time-division multiplex circuits can be reduced by the large grouping effect without deteriorating the connection quality. In addition, since the time division multiplexing circuits of a plurality of radio base stations are centrally installed in the centralized base station, it is possible to reduce the work involved in the construction of addition and removal due to the high efficiency of the voice coding system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of the present invention.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional configuration.

[Explanation of symbols]

100 ₁ , 100 ₂ , 100 ₃ Mobile terminal 200, 200 ′, 200 ″ Radio base station 201 Antenna 202 Antenna duplexer 203 ₁ , 203 ₂ , 203 ₃ , 203 ₄ Modulator / demodulator 204 ₁ , 204 ₂ , 204 ₃ , 204 ₄ time division multiplexing circuit 205 _1, 205 _2, 205 _3, 205 ₄ transcoder 210, 210 ', 210 "radio base station 207 electrooptic converter 300 control circuit 301 LAPD processing circuit 302 LAPDC processing circuit 303 line connection control circuit 304 Storage circuit 310 Centralized control circuit 313 Line connection control circuit 314 Storage circuit 315 ₁ , 315 ₂ , 315 ₃ , 315 ₄ Switching control circuit 400 Public line 500 Public line network 600, 600 ', 600 "Micro cell 700, 700', 700 ”Optical fiber transmission line 800 Centralized base station 801 Electro-optical converter 02 distribution switch 803 branch combiner 804 1 input n-output switch 401 public line communication channel 402 _1, 402 _2, 402 ₃ code conversion signals 403 _1, 403 _2, 403 _3-modulated output signal 404, 404 ', 404 "base Station transmission signal 406 switching control table

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H04Q 7/30 7/38

Claims (1)

[Claims] 1. A radio base station and a plurality of mobile terminals are wirelessly connected by a time division multiplexing method, and a burst allocation cycle is set according to the data transmission rate of each mobile terminal between the mobile terminal and the radio base station. In a wireless communication system in which mobile terminals of different types of data transmission speeds simultaneously access wireless base stations by burst-transmitting wireless signals, multiple base stations installed in each wireless zone and each wireless base station And a centralized base station that is connected to each radio base station by an optical fiber transmission line and transmits a radio frequency signal, and the centralized base station includes a network interface circuit that is connected to a public network. Performs time division multiplexing with a plurality of means for converting the data transmission rate of the voice coding law of the public line network corresponding to the data transmission rate of a plurality of types of mobile terminals. A number of time-division multiplexing circuits, a plurality of modulators / demodulators, means for converting an electric signal of a radio frequency into an optical signal, means for switching a connection path between a modulator output signal and a demodulator input signal and a radio base station, A switching control circuit that controls switching of the connection path, an LAPD processing circuit that sends line connection information to a public line through a public channel control channel, and a LAPDC that sends line connection information to a mobile terminal through a wireless line control channel. Processing circuit, LAPD processing circuit and LAPDC
The mobile terminal includes a line connection control circuit for controlling the line connection by the switching control circuit from the public line and wireless line connection information transmitted from the processing circuit, and a connection information storage circuit for storing the state of the switching connection. A wireless communication system characterized by performing time division multiplexing with different numbers of multiplexing for each type of speed and connecting a mobile terminal having a different transmission speed and a public line network.