JPH10108257A - Tdma radio communication system and its multiplexing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a base station with a small size at a low cost even in a case of extension of channels. SOLUTION: Two time division multiplexer circuits 222 form time slots by n-channel each respectively and output to a modulation circuit 224 every 1/2 period. Thus, the time slots are modulated each in an allocating frequency channel. A transmission amplifier circuit 232 amplifies power of consecutive transmission slots from the modulation circuit 224 and the amplified slot is sent to a communication area from an antenna system 236 through a transmission antenna connection circuit 234. A mobile station receives a prescribed time slot and sends an incoming time slot with the same frequency as that of the prescribed time slot after a 1/2 period. Since a frequency of an outgoing time slot from a base station differs from a frequency of a time slot from the mobile station, the time slots are smoothly received respectively without interference. As a result, channel as two times of (n) channels is multiplexed onto one frame and the method is realized by the single base station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a TDMA radio communication system and a multiplexing method thereof, and more particularly, to a PHS radio communication system.
The present invention relates to a TDMA wireless communication system suitable for use in mobile communication such as a (personal handy phone system) and a multiplexing method thereof.

[0002]

2. Description of the Related Art In recent years, with the development of digital communication equipment, mobile terminals such as mobile phones and car phones have been reduced in size and cost, and their use has been rapidly spreading.
Furthermore, in recent years, a simple wireless system such as a so-called personal handy phone system (PHS), which has been developed from a cordless telephone to enable communication from indoors to outdoors, has become widespread. In such mobile communications, TDMA
(Time division multiple access) type wireless communication systems are effectively applied.

Conventionally, in the above-described TDMA radio communication system, downlink communication from a base station to a mobile station and uplink communication from a mobile station to a base station are alternately performed in time, and uplink / downlink communication is performed.
Communication at the same frequency is realized for each communication slot forming a downlink pair. For example, assuming that the frame period is T and the number of communication slots in one frame is N, the up / down communication time in one frame is T / 2, and the number of lines is N / 2. More specifically, in the current personal handyphone system, a frame having a period of 5 ms is divided into eight, and the first four slots are assigned to downlink slots from the base station to the mobile station, and the latter four slots are allocated to the mobile station. Assigned as uplink slot to base station. As a result, four channels are time-division multiplexed for 2.5 ms for each of uplink and downlink, and bidirectional communication is performed. One channel is allocated to the control slot and the remaining 3
Communication is performed on the channel.

In this case, the base station includes a network interface connected to a fixed network such as a public network, a time division multiplexing circuit for time division multiplexing a signal transmitted via the network interface for every four channels, and a time division multiplexing circuit. Circuit that modulates the modulated signal at the assigned frequency for each slot, a transmission circuit that collectively power-amplifies and transmits the modulated time slots of four channels, and four channels from the mobile station for the downlink slot A receiving circuit for receiving an up time slot for each minute, a demodulating circuit for demodulating each of the received time slots at the same frequency as the modulation frequency, and separating the demodulated slots to reproduce the signals of the respective channels,
And a demultiplexing circuit for sending the data to the network via the network interface.

[0005] Recently, as seen in the spread of mobile phones and the like, the amount of traffic in the base station communication area has been increasing, and it has become necessary to increase the number of lines in the base station. As a countermeasure, a measure is taken to increase the number of lines per base station by incorporating a plurality of wireless devices as described above into one base station, sharing control information slots, and operating these wireless devices in parallel. Have been.

[0006]

However, in the above-mentioned conventional technique, there is a problem that a device configuration per base station becomes large because a plurality of wireless devices are physically incorporated in one base station. Was. Furthermore, there is a problem that the capacity of the base station power supply increases in proportion to the simultaneous operation of a plurality of wireless transmission units.

The present invention solves such disadvantages of the prior art and realizes a TDMA radio communication system capable of configuring a base station with a small and power-saving device when realizing a multi-line base station, and its multiplexing. The aim is to provide a method.

[0008]

In order to solve the above-mentioned problems, a TDMA wireless communication system according to the present invention uses a time-division multiple access from a base station having a predetermined communication area to a plurality of mobile stations in the communication area. TDMA to access and communicate
In a wireless communication system, a base station divides and multiplexes signals for a predetermined number of time slots to a plurality of mobile stations, respectively, and multiplexes signals for a predetermined number of time slots so that frequencies do not overlap at the same time. A plurality of time division multiplexing means for sequentially outputting time slots; and a time slot received from the time division multiplexing means for each predetermined number of time slots is continuously modulated at a frequency of each time slot, and is modulated for each frame. A plurality of modulating means for forming a continuous time slot sequence including a time-division multiplexed signal having a predetermined number of time slots; a plurality of transmitting means for transmitting a transmission frame from the modulating means; A plurality of receiving means for receiving a reception frame including a continuous time slot transmitted from each of the mobile stations, and A plurality of demodulating means for demodulating a transmission frame for each frequency of each time slot; receiving a time slot for each of a predetermined number of time slots multiplexed into a received frame from the demodulating means; A plurality of multiplexing / demultiplexing means for demultiplexing each time slot and reproducing a signal of each time slot.
After setting and transmitting a different frequency in a time slot separated every 2 and assigning that frequency channel to each mobile station, the mobile station receives its own time slot from a transmission frame from the base station, After a lapse of 1/2 of a predetermined number of time slots from the time slot, the time slot of the own station is transmitted on the channel of the allocated frequency. Time-division multiplexed signals are characterized in that they are alternately communicated on the same frequency channel at predetermined intervals in uplink and downlink frames, and are not transmitted on the same frequency channel at the same time.

In this case, the base station includes a plurality of network interfaces connected to the fixed network via a wired line and interfacing with the fixed network for each predetermined number of time slots, and time division multiplexing means for each network interface. It is advantageous if multiplexing and demultiplexing means are provided, each of which can be added for each predetermined number of time slots.

[0010] The base station controls the system by allocating a control slot to at least one of the time slots forming a pair of the transmission frame and the reception frame.

On the other hand, the base station is a slave base station connected by a wireless line to a main base station connected to the fixed network by a wired line, and the slave base station is an arbitrary base station for transmitting and receiving frames for communication with the mobile station. May be used to set a communication channel with the main base station in the time slot.

In this case, the slave base station allocates a control slot to the mobile station to any one of a pair of time slots of the transmission frame and the reception frame, and A time slot may be assigned to a control slot with the main base station.

Further, the base station is provided with m (m is a natural number) time division multiplexing means and demultiplexing means each capable of being mounted, and the modulation means has at least 1 / m channels having different frequencies for every 1 / m frequency band. After receiving the time slot of the mobile station from the transmission frame from the base station, the mobile station may transmit the uplink time slot after 1/2 period.

The base station further comprises time division multiplexing means for multiplexing 2n channel (n is a natural number) lines,
The base station and the mobile station are separated from each other by a demultiplexing unit that separates 2n channel lines.
Each transmission channel may be set to a different frequency.

On the other hand, a multiplexing method according to the present invention provides a TDMA radio communication system in which a plurality of communication channels are time-divided and multiplexed into a predetermined frequency band, and two-way communication is performed in each time-division multiplexed time slot. When multiplexing nXm channels (where n and m are natural numbers) into m frames having a period T, the downlink time slots of the first to n-th channels are sequentially formed in the first frame. Then, in the second frame, the (n + 1) th to (2n) th
Are formed, and thereafter the m-th
A first step of forming downlink time slots up to a frame at intervals of T / n for each frame, and predetermined downlink time slots of the first to n-th time slots formed in the first step. A second step of allocating a frequency, sequentially modulating and transmitting at a frequency allocated to each time slot, and a station receiving the first to n-th downlink time slots transmitted in the second step A third step of transmitting the uplink time slot on the same frequency channel as the downlink time slot after T / 2 cycles from the time when the own time slot is received, and
A fourth step of transmitting the (n + 1) th to (2n) th downlink time slots formed in the first step at the same time as the step following the second step; 1) Allocate different frequencies to the first to nth uplink time slots transmitted in the third step to the 2nd to 2n downlink time slots, respectively, and sequentially modulate at the frequency assigned to each channel. And a fourth step of transmitting
Similarly to the third step and the fourth step, while receiving the uplink time slot after T / 2 cycle transmitted corresponding to the downlink time slot, the uplink time received in the downlink time slot transmitted at the same time A fifth step of allocating a frequency different from the slot and transmitting / receiving up to the m-th frame every n time slots, and thereafter, repeating the first to fifth steps to obtain nXm time slots in the frame of period T Are sequentially time-division multiplexed, and bidirectional communication is performed at the frequency of each assigned channel.

In this case, at least one of the time-division multiplexed nXm time slots is a control slot modulated at a fixed frequency.

The multiplexing method according to the present invention is a method for multiplexing a time division multiplexed signal of n time slots and a time division multiplexed signal of n time slots, wherein 2n time slots are sequentially arranged in each frame. Continuously multiplexed, the interval between the up and down time slot pairs is
This is a method of assigning different frequencies to uplink and downlink time slots transmitted at the same time in the T / 2 cycle.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a TDMA radio communication system and a multiplexing method thereof according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a base station applied to a TDMA wireless communication system according to the present invention. The TDMA wireless communication system according to the present embodiment includes, for example, a base station 20 connected to a public network 10 as shown in FIG.
And a plurality of mobile stations 30 existing in the communication area. The base station 20 and the mobile station 30 are interconnected by a radio frame shown in FIG. Can communicate with the communication terminal 40 connected to the mobile station 30 or the mobile station 30 within the communication area of the same base station 20 or another base station 20. In particular, the TDMA wireless communication system of the present embodiment includes:
The frame configuration between the base station 20 and the mobile station 30 and the device configuration of the base station 20 that realizes the frame configuration have main features.For example, in the present embodiment, a conventional PHS (Personal
al Handy-phone System) will be described with reference to an example in which a single base station 20 realizes a line for accommodating two wireless devices in a base station. In the present invention, it is possible to multiplex 2m lines (m is a natural number) systematically,
The device configuration of the base station 20 of the present embodiment shown in FIG. 1 is a basic component thereof. Further, in the present embodiment, assuming that one conventional apparatus processes n lines, a case of processing 2n lines will be described as an example.

More specifically, as shown in FIG. 1, the base station 20 of this embodiment includes a network connection unit 210, a TDMA processing unit 220, a radio connection unit 230, and a central control unit 240. Network connection part 210
Is a network interface that is connected to the public network 10 by a wired line to provide an interface between the fixed network and the wireless network. In this embodiment, the wired interface 212 and the wired / wireless switch (SW) circuit 214 including. The wired circuit 212 is
A line control circuit that accommodates a wired line for each predetermined line, for example, every n lines, and controls each line;
This is an interface circuit that performs data rate conversion and format conversion between a wired slot and a wireless slot to achieve interface matching with a public network.

The wired / wireless switch circuit 214 is a switch circuit for switching the signal from the wired circuit 212 and the signal from the TDMA processing unit 20 for each predetermined line, and is a switch element such as a semiconductor switch or a memory circuit. And so on. In this embodiment,
Two wired circuits 212 and two wired / wireless switch circuits 214 are provided for each n lines, and the output of the wired / wireless switch circuit 214 for each n lines is a time division multiplexing circuit 222 of the TDMA processing unit 220. Connected to each other.

The TDMA processing unit 220 outputs the switched n
A main processing unit that forms a transmission frame subjected to time division processing from a signal for each line, and reproduces a signal for each n lines from a reception frame received by the wireless connection unit 30. Division multiplexing circuit 222 and modulation circuit 22
4, a demodulation circuit 226 and a demultiplexing circuit 228. In particular, the time division multiplexing circuit 222 and the multiplexing / demultiplexing circuit 228 are provided so as to be able to be added in accordance with the increase in the number of lines, and in this embodiment, two each are mounted. Explaining the details of each part, the time division multiplexing circuit 222 is a wired / wireless switch circuit.
Time division multiplexing of the signals for every n lines from 214 to n
This is a slot forming circuit for forming TDMA slots for each unit. In this embodiment, the two circuits output to the modulation circuit 224 n time slots multiplexed in a time-division manner every half cycle.

The modulation circuit 224 is a modulation circuit that modulates the time slot from the time division multiplexing circuit 222 at a frequency assigned to each channel. In the present embodiment, for example, QPSK (Quadrature Phase Shift Keying) modulation is used. Is applied effectively. In particular, in the present embodiment, the time slots that are always operable and are alternately supplied for every n channels are sequentially modulated to transmit 2n continuous time slots per period T as shown in FIG. Form a frame. In this case, for example, by modulating a first preassigned control slot C _s of the frame at a fixed frequency, the remaining communication slot T _s1 through T
_One of a plurality of frequency channels is sequentially assigned to _s2n-1 and modulated. In particular, in this embodiment,
Control slot C _s the respective time slots comprising assigned at least n slots different frequencies for each time slot location remote modulated.

The demodulation circuit 226 is a circuit that receives a reception frame including continuous time slots transmitted from each mobile station with a delay of one half cycle from the transmission frame from the radio connection unit 30 and demodulates the reception frame for each channel. Yes, in a time slot paired with each time slot of a transmission frame, demodulation is performed at the same frequency to detect each baseband signal. Each detected time slot is supplied to the demultiplexing circuit 228 every n channels.

The demultiplexing circuit 228 is a conversion circuit that separates the time slots for every n channels from the demodulation circuit 226 into the respective time slots and converts the time slots into the original signal for each channel. Wired switch circuit 21
4 sequentially.

Radio connection section 230 transmits a time-division multiplexed transmission frame including time slots of a plurality of channels via an antenna, and also includes continuous time slots sequentially transmitted from a plurality of mobile stations. A wireless interface that receives a received frame.
, An antenna connection circuit 234, an antenna system 236, and a reception amplification circuit 238.

The transmission amplification circuit 232 is a power amplifier for sequentially amplifying the transmission frame from the modulation circuit 224, and is a broadband amplifier for collectively amplifying and outputting the time slots of a plurality of channels included in the transmission frame. The antenna connection circuit 234 is a connection circuit that connects the transmission amplification circuit 232 and the reception amplification circuit 238 to the antenna system 238.
This is an antenna duplexer that matches and combines the transmission signal from the antenna 232 and the reception signal from the antenna system 236.

The antenna system 236 includes a transmission / reception antenna for transmitting the amplified transmission frame toward the communication area and receiving a reception frame coming from a plurality of mobile stations. Various applications are applied depending on the installation location. For example, when the communication area is covered linearly in an urban area, for example, a horizontal directional antenna having directivity along a road is advantageously applied, and when the communication area is covered in a residential area, an omnidirectional antenna is effectively used. Applied. When the antenna is installed on the roof of a building or the like, a beam tilting type antenna having directivity slightly below a horizontal plane is effectively applied. As the reception amplification circuit 238, a low noise amplifier or the like that effectively amplifies a reception frame received from the antenna system 236 via the antenna connection circuit 234 is advantageously applied.

The centralized control section 240 is a control section for controlling the above sections to perform call control and timing control between the mobile station and the network or between the mobile station and the mobile station. CPU) 242 and a clock circuit 244. The central processing unit 242 includes a network connection unit 210 and a TDMA processing unit 220.
Is a main control circuit which is connected to each of the buses and controls each unit by sending a control signal to each of the units. For example, a wire / wireless switch circuit 214 which detects an incoming call from the wire corresponding circuit 212 or the demultiplexing circuit 228 And a call control circuit for making these call settings.

[0029] The central processing unit 242 includes a feeding time division multiplexing circuit 222 generates the control information for synchronization or call connection and channel settings, message generation function of inserting the control slot C _s . Further, at the time of call connection, an idle communication slot is detected from the time division multiplexing circuit 222 and the demultiplexing circuit 228, and the frequencies used in the modulation circuit 224 and the demodulation circuit 226 are managed. The assignment is performed, and the modulation circuit 224
And a channel management unit for sequentially setting the frequencies assigned to the demodulation circuit 226.

In particular, in the present embodiment, different frequencies are set for the channels n slots apart from the transmission frame and the reception frame so that the transmission and reception slots at the same time do not interfere with each other. For example, in the frame shown in FIG. 2, a fixed same frequency is allocated to control slots C _{S and} C _R. In this case, the reception control slot C _R
Communication slot transmitted at the same timing as the reception of
That allocating frequency different from the transmission slot C _S and the receiving slot C _R is the communication slot T _Sn after n slots from the transmission control slot C _S. Similarly, communication slots T _s1 to
Any one of a plurality of frequencies is assigned to T _sn-1 so as not to interfere with a neighboring base station due to, for example, carrier sense. The communication slots T _{Sn + 1 to} T _S2n−1, which are n slots away from each other, further have transmission slots T _{S1 to} T _sn−1 so as not to interfere with the reception slots T _{R1 to} T _Rn−1 paired with them. And assign a different frequency. In the case of this embodiment, different frequencies may be assigned to time slots at least n slots apart.

The clock circuit 244 is a timing generation circuit that sends a clock signal to each of the above-described units to generate processing timing for each of the units. In particular, in this embodiment, each of the time-division multiplexing circuits 222 has a n-number of clocks. A timing signal for generating a time slot is transmitted, and a timing signal for causing the modulation circuit 224 to transmit n time slots alternately every half cycle is transmitted. Is output. Similarly, demodulation circuit 226 and demultiplexing circuit 228 have n
A wired / wireless switch circuit for transmitting a timing signal for separating each time slot and synchronizing with the timing signal
A clock generation circuit that sends clock signals for generating respective timings to the 214 and the wired circuit 212.

On the other hand, the mobile station 30 according to the present embodiment
A terminal similar to a PHS terminal or the like can be applied, for example, an encoding circuit that encodes voice or the like into a digital signal, a time division circuit that time divides the encoded signal to form a time slot, A modulation circuit that modulates the signal on a frequency channel allocated by the base station, a radio unit that receives a transmission frame from the base station, that is, a downlink frame, and transmits an uplink transmission time slot, and A demodulation circuit for detecting and demodulating a time slot addressed to the station, a signal reproducing circuit for reproducing the demodulated time slot into a continuous digital signal, and a speech decoding circuit for converting the reproduced digital signal to an analog signal;
A control unit that controls each unit to execute call control and timing control with the base station.

Hereinafter, the operation of the TDMA radio communication system according to the present embodiment will be described. FIG. 4 shows a mobile station-base station communication sequence at the time of calling the mobile station. First, the base station 10 generates synchronization information or call information in the central processing unit 242 and supplies it to the time division multiplexing circuit 222 at a predetermined timing. Thus, time division multiplexing circuit 222 is supplied to a modulation circuit 224 by inserting the synchronization / call information to the control slot C _s allocated to the own station. At this time, if any of the (2n-1) communication slots has a communicating slot, the time slot is sequentially formed and supplied to the modulation circuit 224.

The control slot C _s modulation circuit 224 which received the time slot sequence comprising, when receiving the control slot C _s,
Set the frequency of the fixed control slot C _s from the central processing unit 242 modulates the control slot C _s at that frequency,
Similarly, another communication slot is sequentially modulated to form a transmission frame including 2n time slots, and the transmission frame is supplied to the amplifier circuit 232. Thus, the control slot C _s of a predetermined frequency channel is amplified by the amplifier circuit 232, antenna connections 2
The signal is transmitted to the communication area from the antenna 34 via the antenna system 236.

As described above, the synchronization / call information is repeated for each frame and transmitted to the communication area. At this time, the other base stations similarly transmit the control slot at a fixed frequency. However, in adjacent base stations, control slots are allocated to different positions of a frame between base stations so that control channels do not interfere. For example, FIG. 4 shows transmission of control slots from k base stations, and shows a state in which k frames are being transmitted. When the mobile station 30 is not in a call state, it can receive the frequency of the control channel. By receiving this, it is possible to know the transmission timing of the control information of the base station 20 having the communication area including its own station.

[0036] In this state, first, when a call from the mobile station 30, control slot C _s from the base station 20 from the output timing of the control slot C _s of the base station 20 after one cycle of 2 minutes
A transmission request is transmitted using the same frequency channel as. For example, the frame structure shown in FIG. 2, receives the first control slot C _s of the frame, to detect the timing in the control unit, generates an outgoing request message. The generated outgoing call request message, when it is generated at the timing of the control slot C _R from the dividing circuit, is supplied to the modulator. The modulation unit is set the same modulation frequency and the control slot C _s received from the control unit modulates the control slot C _R including a call request from the division circuit time, the base station
After one cycle of 2 minutes, which has received the transmission control slot C _s from the 10 is transmitted from the wireless unit.

[0037] The base station 20 includes an antenna control slot C _R including outbound request message from the antenna system 236 connected circuit 23
4, the signal is amplified by a reception amplifier circuit 238 and supplied to a demodulation circuit 226. It demodulates the control slot C _R The demodulation circuit 226 in the transmission control slot C _s the same frequency into a baseband signal. As a result, the slot converted to the baseband signal becomes a transmission request message, and is transmitted through the demultiplexing circuit 228 to the central processing unit 242.
The central processing unit 242 receives the content and sends a transmission request to the public network 10 through the wired circuit 212.

Next, when the public network 10 receives the transmission request,
The validity is determined, and if valid, a transmission permission is transmitted to the base station 20. When the base station 20 receives the transmission permission from the public network 10 at the central processing unit 242 via the wired circuit 212, the central processing unit 242 selects an available communication slot based on the usage status. At this time, from the selected communication slot, an n-th slot and a frequency channel that is not used in the radio state at the timing of the slot are selected.
Once the slot and frequency are determined, the central processing unit 24
2 indicates that the mobile station 30 that transmitted the call request
Communication slot number s indicating a relative position from the slot C _s for the frequency channel and the control information of the communication slots 30 uses
(-n≤s≤n-1, s is an integer)
It instructs at C _S, to allow the use of appropriate communication slots. Thereafter, the central processing unit 242 sets the frequency channel designated to the mobile station in the modulation circuit 224 and the demodulation circuit 228 corresponding to the corresponding communication slot, and prepares for communication with the mobile station 30.

Next, the mobile station 30, the a receives the same control slot C _S, by setting the frequency channels instructed by the timing of the communication slots instructed by the base station 20, the communication slots Sends a link setting request. Next, the base station 20 selects the mobile station from the received frame.
When a communication slot from 30 is received, the slot is demodulated at the set frequency to detect a link setting request. As a result, the central processing unit 242 sets up a communication path for the wireless / wired switch circuit 214 and returns a response message to the mobile station 30 via the path. As a result, a call connection is established between the mobile station 30 and its communication partner,
Thereafter, base station 20 modulates and demodulates the communication slot at the frequency set as described above, and enters a communication state.

Hereinafter, similarly, when a call is made from another mobile station 30 in the communication area of the base station 20, the call is made via the control slots C _S and C _R and a call permission is issued from the public network 10. Then, the base station 20 selects a communication slot and a frequency channel that are not used at that time, allocates the selected communication slot and the frequency channel to the mobile station 30, and performs call connection. In this case, a communication frequency different from at least n slots apart from the selected communication slot is allocated, and the downlink slot from the base station 20 and the uplink slot of another mobile station 30 are set so as not to interfere with each other.

Next, FIG. 5 shows a communication sequence between the mobile station and the base station when the mobile station receives a call. When the mobile station 30 receives a call, first, an incoming call instruction from the public network 10 to the mobile station 30 is sent to the base station 20. The base station 20 detects an incoming call indication, and inserted to generate the synchronization / call information in the same manner as described above the control slot C _s, the mobile station 30 of the communication area by modulating at a predetermined timing and frequency Send.
Mobile station 30 receives this, after 1 cycle of 2 minutes from the reception timing of the control slot C _s from the base station 20, base station 20
Using the control slot C _s the same frequency channel from delivering incoming response.

When the central processing unit 242 detects an incoming call response from the mobile station 30, the base station 20 operates similarly to the public network 10 as described above.
Sends an incoming response to. In response to this, the public network 10 sends an incoming call permission. Next, when the base station 20 receives the incoming call permission from the public network 10, the central processing unit 242 selects an empty communication slot from the time slot usage status, and selects the n-th slot from that slot and the corresponding slot. Select a frequency channel that is not used in the timing radio condition. Thereby, the base station 20 can communicate with the mobile station 30 with the frequency channel of the communication slot used by the mobile station 30,
Instructs the communication slot number s indicating a relative position of the control slot C _s at the downlink control slot C _s, to allow the mobile station 30 using the corresponding communication slots.

Next, the mobile station 30 transmits a link setting request using the frequency channel specified at the timing of the communication slot specified by the base station 20. base station
Upon receiving this, the central processing unit 242 sets a communication path to the wireless / wired switch circuit 214, and
A response is returned to the mobile station 30. As a result, the called mobile station
The call connection is established between 30 and the communication partner, and thereafter, the communication state is established on the communication channel set by base station 20.

As described above, a call is made or called to the mobile station 30 existing in the communication area of the base station 20. At this time, in this embodiment, 2n channels are multiplexed into a frame having a period T. Hereinafter, the multiplexing method according to the present embodiment will be described in more detail together with the operation of the base station 20.
Since the time division multiplexing circuits 222 are provided, the first time division multiplexing circuit 222 has a control channel from the central processing unit 242 and a maximum (n) from the wired / wireless switch circuit 214.
-1) The communication channels for the lines are connected. Similarly, a communication channel for a maximum of n lines from the wired / wireless switch 214 is connected to the second time division multiplexing circuit 222. As a result, in the first time-division multiplexing circuit 222, the control slot C _s
And communication slots T _{S1 to} T _Sn-1 are sequentially generated by time-dividing the signals of the respective lines. Similarly,
The second time-division multiplexing circuit 222 time-divisions the signal of each line to sequentially generate communication slots T _{Sn to} T _S2n-1 .
At this time, each time-division multiplexing circuit 222 forms each time slot at a time interval of T / 2n according to the clock from the clock circuit 244, and makes each of the n time slots a half cycle. Time-division multiplexing into (T / 2) frames.

Next, when a clock signal at the time slot transmission timing is supplied from the clock circuit 244 to the first time division multiplexing circuit 222, the first time division multiplexing circuit 222 generates the time slots C _S , T Modulation circuit for _{S1 to} T _Sn-1 sequentially
To 224. Accordingly, the modulation circuit 224 modulates each of the time slots C _s , T _{S1 to} T _S2n-1 at the frequency of each channel set by the central processing unit 242, and sequentially outputs the modulated signals to the transmission amplification circuit 232. As a result, the modulated time slots C _S, T _S1 ...
The power is amplified at 2 and transmitted from the antenna system 236 to the communication area via the antenna connection circuit 234.

Downlink time slots C _S , T _{S1 in the} communication area
Mobile station 30 which has received the ..., the mobile station 30 to call synchronously by the control slot C _S example is one period of 2 minutes from the time of receiving the time slot C _S from the base station 20 respectively later, transmits an uplink time slot C _R at the same frequency channel as the downlink time slot C _S. Similarly, the mobile station 30 during communication receives the time slot allocated to itself from among the communication slots T _{S1 to} T _Sn−1 , and receives the same time slot as the downlink time slot received one half cycle after the time slot. It generates uplink time slots T _{R1 to} T _{R -1} modulated by frequency and transmits them to base station 20.

On the other hand, the base station 20 transmits the time slot to the second time division multiplexing circuit 222 one half cycle after the transmission timing is supplied from the clock circuit 244 to the first time division multiplexing circuit 222. A timing clock signal is supplied. As a result, the second time division multiplexing circuit 222 receives the time slot T transmitted from the first time division multiplexing circuit 222.
_{Following Sn-1} , the formed time slots T _{Sn to} T _S2n-1
Are sequentially transmitted to the modulation circuit 224. Second time division multiplexing circuit
The modulation circuit 224 receiving the time slots T _{Sn to} T _S2n-1 from 222 modulates the respective time slots T _{Sn to} T _S2n-1 at the assigned frequency set by the central processing unit 242, and sequentially transmits and amplifies them. Output to the circuit 232. At this time, the time slots T _{Sn to} T _S2n-1 from the second time-division multiplexing circuit 222
Is the time slot from the first time division multiplexing circuit 222
The modulation is performed at a different frequency for each slot at least n slots away from C _S , T _{S1 to} T _Sn-1 . The modulated time slots T _{Sn to} T _S2n-1 are power-amplified by the transmission amplification circuit 232 and transmitted through the antenna connection circuit 234 to the antenna system 236.
Are sequentially transmitted.

At this time, uplink time slots C _R , T _{R1 to} T _Rn-1 from the mobile station 30 sequentially arrive at the antenna system 236,
The signal is received via the antenna connection circuit 234 and the reception amplification circuit 238. At this time, the transmitted time slot T _Sn
To T _S2n-1 and the received time slots C _R , T _{R1 to} T _Rn-1 are transmitted and received at the same timing. However, the time slots T _{Sn to} T _S2n-1 transmitted as described above are n
A slot before the time slot _{C S, T S1 ~T Sn-} 1 and different frequency, time slot C _S to be received, T _S1 ~T _Sn-1
Are the time slots C _S, T _S1 to
Since they have the same frequency as T _Sn-1 , they are smoothly transmitted and received by the base station 20 and the mobile station 30 without interference. For example, when the uplink slot T _R1 paired with the downlink slot T _S1 is transmitted from the mobile station 30, the base station
The downlink slot T _{Sn + 1} is transmitted from 20, and the downlink slot T
_{Sn + 1} is at least the downlink slot T _{S1 in the} modulation circuit 224.
The uplink slot T _R1 is transmitted by the mobile station 30 on the same frequency channel as the downlink slot T _S1 .

Similarly, the uplink slots T _{Sn to} T _S2n-1 are received by the respective mobile stations 30 without interfering with other channels, and the downlink slots C _R , T _{R1 to} T _Rn-1 are received by the base station 20. Is received. Received time slots C _R , T _{R1 to} T _Rn-1
Are amplified by a reception amplifier circuit 236, demodulated for each channel by a demodulation circuit 226, and converted into baseband signals. Slot converted to baseband signal
C _R , T _{R1 to} T _Rn−1 are separated by the first demultiplexing circuit 228, of which the control slot C _R is detected by the central processing unit 242, and the communication slots T _{R1 to} T _Rn−1 are The signal is sent to the public network 10 or the time division multiplexing circuit 222 via the wired / wireless switch 214.

On the other hand, the mobile station 30 receives the downlink slots T _{Sn to} T _{S2n -1} addressed to the mobile station 30 and, after a half cycle, each of the uplink slots T _Sn on the same frequency channel as the downlink slot.
_{Rn to TR2n-1} are transmitted. At this time, the base station 20 is modulated again by the first time up slot containing the control slot C _S at division multiplexing circuit 222 is supplied to a modulation circuit 224, similarly to the above respective frequency channel transmission Amplifier circuit
232, transmitted from the antenna system 236 via the antenna connection circuit 234. Also in this case, the downlink slots C _S , T _{s1 to} T _Sn−1 transmitted at the same time and the uplink slots T _{Rn to} T _Rn are transmitted.
_R2n-1 uses different frequency channels in the same manner as described above, and is received smoothly without interference. The uplink slots T _{Rn to} T _R2n-1 from the mobile station 30 received by the base station 20 are demodulated at respective frequencies by a demodulation circuit 226 and supplied to a second demultiplexing circuit 228, respectively. It is separated and transferred to a predetermined route via a wireless / wired switch circuit 214.

Similarly, in the base station 20, the time slots multiplexed by the two time-division multiplexing circuits 222 are alternately output every one-half cycle, and the modulation circuit 22 receiving these outputs.
4 always operates, modulates at a frequency set for each channel, and is sequentially transmitted from the antenna of the wireless connection unit 230 to the communication area. The mobile station 30 receives a time slot of a desired channel from the downlink frame from the base station 20, and transmits an uplink time slot on the same frequency channel one half cycle after that. As a result, 2n channels are smoothly multiplexed into a frame having a period T, and bidirectional communication is performed between the plurality of mobile stations 30 and the base station 20.

As described above, according to the TDMA radio communication system and the multiplexing method thereof according to the present embodiment, the base station 20
Common wireless connection 230, modulation circuit 224 and demodulation circuit
226 are connected to two time-division multiplexing circuits 222 and multiplexing / demultiplexing circuits 228, respectively, and are operated alternately, and the frequencies are made different at least in channels separated by n slots. And a TDMA frame obtained by multiplexing 2n channels including received frames. Therefore, the circuits after the modulation circuit 224 and the demodulation circuit 226 are shared, and only the circuit at the preceding stage is added from the time division multiplexing circuit 222 and the demultiplexing circuit 228. A small and inexpensive base station can be realized. Further, since the wireless transmission system can be configured by half of the conventional system, the capacity of the base station power supply can be reduced.

Next, FIG. 6 shows another embodiment of the TDMA radio communication system according to the present invention. According to this embodiment
The TDMA wireless communication system includes a master base station 50 connected to the public network 10 via a predetermined wired line, and a slave base station 60 connected to the master base station 50 via a wireless line. The master base station 50 is accessed using the radio frame shown in FIG. In this figure, the number of time slots in one frame is 2n, and the frame period is T. Each frame includes control slots C _S1 and C _R1 between the mobile station 30 and the base station, and control slots C _S2 and C _R2 between the master base station 50 and the slave base station 60, respectively.
(2n-2) communication slots T _{S1 to} T _S2n-2 and T _{R1 to} T _R2n-1 . A fixed frequency channel is assigned to each of the control slots C _S1 and C _R1 and C _S2 and C _R2, and
_One of a plurality of channels different from the control slot is assigned to T _{S1 to} T _S2n-2 and T _{R1 to} T _R2n-1 . The same frequency is used for the communication slots T _{S1 to} T _S2n-2 and T _{R1 to} T _R2n-1 which form an up / down pair. In this case, different frequency channels are allocated to at least n slots apart from each other, as in the above embodiment, and different frequencies are used for uplink and downlink time slots transmitted and received at the same time.

FIG. 8 shows an example of the internal configuration of the slave base station 60 in this embodiment. In this figure, the difference from the above embodiment is that there is no wired circuit and the received signal from the mobile station 30 in the communication area is a switch circuit.
Connected to the transmission system via 500, transmitted to the master base station 50 via the transmission frame, the signal addressed to the mobile station 30 from the master base station 50 is also returned to the transmission system via the switch circuit 500, This is a point transmitted to the mobile station 30. The same parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In addition, the master base station 60
It can be realized with the same configuration as that of FIG.

Next, referring to FIG. 9, the TDMA according to the present embodiment will be described.
The operation of the wireless communication system will be described. First, the master base station 50 uses the control slots C _{S2 and} C _R2 to transmit synchronization information using a fixed frequency channel defined at k frame intervals (k is a natural number). Alternatively, it sends out call information. This includes a number of frames after receiving this information so that transmission of control slots _CS1 , _CR1 and _{CS2, CR2} of the maximum (k-1) slave base stations 60 and master base station 50 does not collide. Interval specification information indicating whether control information can be transmitted later is inserted.

Receiving the control information from master base station 50, slave base station 60 transmits a synchronization / call in control slot _CS1 to mobile station 30 in its own area based on the information. Thereby, the mobile station 30 knows the transmission timing of the control slots C _S1 and C _R1 of the slave base station 60. When making a call from a mobile station, first, after a half cycle from the transmission timing of the downlink control slot _CS1 of the slave base station 60, a call request is made using the same frequency channel as the downlink control slot _CS1. Send

Next, when receiving a transmission request from mobile station 30 in uplink control slot C _R1 , slave base station 60 returns the transmission request to master base station 50 using control slot _CS2 . As a result, master base station 50 sends a call request to public network 10 and sends a call permission to the public network.
Upon receipt from 10, a free communication slot is selected from the usage status of the radio frame, and an n-th slot and a frequency channel not used in the radio state at the timing of the slot are selected from that slot. The communication slots and frequency channels are determined, as the communication slots used the slot number s indicating a relative position from the frequency channel and the control slot C _S at between base stations, the control slot C
Return at _R2 . At this time, the master base station 50
The central processing unit sets the frequency instructed to the slave base station 60 in the modulation circuit and the demodulation circuit corresponding to the corresponding communication slot, and prepares for communication with the slave base station 60.

Next, the slave base station 60 becomes the master base station 50.
_Is received in the control slot C _R2 , an available communication slot is selected according to the use state of the radio frame, and an n-th slot and a frequency not used at the timing of the slot are selected from that slot. The communication channel is instructed to the mobile station 30 in the control slot _CS1 as in the above embodiment. Thereby, the slave base station 60 sets the frequency assigned from the master base station 50 to the communication slot with the master base station 50, and
The frequency assigned by the own station is set to the communication slot with 30, and preparation for communication with each is performed.

Next, the mobile station 30 receives the allocation of the communication channel by the control slot C _S1 from the slave base station 60 transmits a link establishment request using the communication channel. When receiving the link setting request, the slave base station 60 transfers the link setting request to a communication slot with the master base station 50 and transmits the request. Accordingly, when receiving the link setting request, master base station 50 sets a communication path in the wireless / wired switch circuit and transmits a response message to slave base station 60.

The slave base station 60 receiving the response message
Is connected to the mobile station 30-slave base station 60-
A return path is set so that communication with master base station 50 is possible, and a response message is transmitted to mobile station 30. Or later,
The mobile station 30 and the communication partner are call-connected, and two-way communication is performed. That is, the uplink time slot from the mobile station 30 is determined by the antenna system 236, the antenna connection circuit 234, and the demodulation circuit.
226-Received by the receiving system of the demultiplexing circuit 228, connected to the upstream time slot of the time division circuit 222 to the master base station 50 via the switch circuit 500, and the upstream time slot is connected to the time division circuit 222-modulation circuit 224-Antenna connection circuit 234-Master base station via transmission system of antenna system 236
Sent to 50. The downlink time slot from the master base station 50 is received by the reception system of the slave base station 60, connected to the downlink time slot with the mobile station 30 of the time division multiplexing circuit 222 through the switch circuit 500, and transmitted by the transmission system. Is transmitted to the mobile station 30 via.

Similarly, when a call is received to the mobile station 30, the call is connected in the control procedure between the master base station 50, the slave base station 60, and the mobile station 30 in the same manner as described above, and the same as in the above embodiment. Communication can be performed.

As described above, according to the present embodiment, the public network 10
A base station similar to the above embodiment connected to the master base station
The base station shown in FIG. 8 connected to the master base station 60 by the radio frame shown in FIG.
As the control slots C _S1 and C _R2 from the slave base station 60 to the mobile station 30 and the control slots C _S2 and C _R2 between the base stations, the master base station 50 uses up to (k−1) units. Slave base station
By deploying 60, the communication area can be expanded. This is because, in a conventional base station, transmission and reception are alternately performed, so that communication between base stations cannot be performed using the same interface. However, in this embodiment, since it is possible to always perform transmission and reception using a radio frame as shown in FIG. 7, communication between base stations including communication with the mobile station 30 uses the same interface. Can be realized. In this case, for example, when the communication area is expanded in an area where the traffic volume is small, the construction of the connection line between the slave base station and the public network is unnecessary, which is effective. When the traffic volume increases in the future, the slave base station 60 can be connected to a public network simply by adding a wired circuit 212 similar to the above embodiment,
As a result, the base station can be used as a master base station, and the number of lines can be easily increased.

In each of the above embodiments, the case where two time-division multiplexing circuits 222 and demultiplexing circuits 228 for processing n lines are mounted and time slots of 2n channels are multiplexed has been described as an example. In the present invention, a predetermined number of lines, for example, m time-division multiplexing circuits and demultiplexing circuits for processing n lines may be mounted. In this case, one frame includes nXm time slots, and the upstream time slots are received after receiving the downstream time slots.
It is good to transmit every T / m cycle.

In the first embodiment, only one control channel is used to handle (2n-1) communication channels. However, in the present invention, a plurality of control channels are provided for every n channels. Thus, lines for a plurality of conventional base stations may be handled.

[0065]

As described above, according to the TDMA radio communication system and the multiplexing method of the present invention, the radio system is shared,
Since a plurality of time-division multiplexing means and multiplexing / demultiplexing means are mounted, the base station can be realized in a small size and at low cost. In addition, since the wireless system is shared, power supply power can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a base station applied to a TDMA wireless communication system according to the present invention.

FIG. 2 is a diagram illustrating an example of a radio frame applied to the embodiment in FIG. 1;

FIG. 3 is a diagram illustrating an example of a wireless communication system to which the base station in FIG. 1 is applied;

FIG. 4 is a sequence diagram for explaining an operation of the TDMA wireless communication system according to the embodiment of FIG. 1;

FIG. 5 is a sequence diagram for explaining an operation of the TDMA wireless communication system according to the embodiment of FIG. 1;

FIG. 6 is a diagram showing another embodiment of the TDMA wireless communication system according to the present invention.

FIG. 7 is a diagram illustrating an example of a radio frame applied to the embodiment in FIG. 6;

FIG. 8 is a block diagram illustrating an example of a slave base station applied to the embodiment in FIG. 6;

FIG. 9 is a sequence diagram for explaining an operation of the TDMA wireless communication system according to the embodiment of FIG. 6;

[Explanation of symbols]

 10 Public network 20 Base station 30 Mobile station 210 Network connection section 212 Wired circuit 214 Wired / wireless switch circuit 220 TDMA processing section 222 Time division multiplexing circuit 224 Modulation circuit 226 Demodulation circuit 228 Demultiplexing circuit 230 Wireless connection section 232 Transmission amplification circuit 234 Antenna connection circuit 236 Antenna system 238 Receive amplification circuit

Claims (10)

[Claims] 1. A TDMA wireless communication system in which a base station having a predetermined communication area accesses and communicates with a plurality of mobile stations in the communication area by time division multiple access, wherein the base station includes the plurality of mobile stations. The signals for each predetermined number of time slots are time-divided and multiplexed,
A plurality of time-division multiplexing means for sequentially outputting time slots of a predetermined number of time slots so that frequencies do not overlap each other at the same time; and a time slot received for each of the predetermined number of time slots from the time-division multiplexing means. A plurality of modulating means for continuously modulating at a frequency of each time slot to form a continuous time slot sequence including a predetermined number of time slot multiplexed signals for each frame; A plurality of transmitting means for transmitting a transmission frame; a plurality of receiving means for receiving a reception frame including continuous time slots transmitted from a plurality of mobile stations corresponding to the transmission frame; A plurality of demodulating means for demodulating the received frame for each frequency of each time slot; Each was duplicated by receiving time slots per predetermined number of time slots,
A plurality of demultiplexing means for separating the signals for each time slot and reproducing a signal of each time slot, wherein the base station is separated from the modulation means by at least a half of a predetermined number of time slots. A different frequency is set in the specified time slot and transmitted, and the frequency channel is assigned to each of the mobile stations. The mobile station receives the time slot of its own station from the transmission frame from the base station. The time slot of the own station is transmitted on the channel of the allocated frequency after a lapse of a predetermined number of time slots from the slot by 1/2, and the system uses a plurality of time division Multiplexed signals alternately communicate on the same frequency channel at predetermined intervals in uplink and downlink frames, and simultaneously communicate on the same frequency channel. TDMA radio communication system, wherein the never transmitted in Le. 2. The system according to claim 1, wherein the base station includes a plurality of network interfaces connected to a fixed network via a wired line, and interfacing with the fixed network every predetermined number of time slots. A TDMA radio communication system, wherein the time division multiplexing means and the demultiplexing means are provided for each of the network interfaces, and each of the time division multiplexing means and the demultiplexing means is formed so as to be able to be added every predetermined number of time slots. 3. The system according to claim 2, wherein the base station assigns a control slot to at least one of a pair of time slots of a transmission frame and a reception frame. TDMA wireless communication system. 4. The system according to claim 1, wherein the base station is a master base station connected to a fixed network via a wired line and a slave base station connected via a wireless line. A TDMA radio communication system, wherein a communication channel with a main base station is set in an arbitrary time slot of a transmission / reception frame for communicating with the mobile station. 5. The system according to claim 4, wherein the slave base station is a control slot between the mobile station and any one of a pair of time slots of a pair of a transmission frame and a reception frame. A TDMA radio communication system characterized by allocating a control slot to a main base station to any other pair of time slots. 6. The system according to claim 1, wherein the base station is provided with m (m is a natural number) time-division multiplexing units and demultiplexing units, respectively. The mobile station sets a channel of a different frequency at least for each 1 / m frequency band in the modulating means, and the mobile station receives its own time slot from the transmission frame from the base station, and then, after receiving the time slot of its own station, the uplink time after each half cycle. A TDMA radio communication system for transmitting slots. 7. The system according to claim 1, wherein the base station includes a time division multiplexing unit that multiplexes 2n channels (n is a natural number).
Multiplexing / demultiplexing means for demultiplexing 2n channel lines, wherein the base station and the mobile station have a pair of uplink and downlink time slots having a half cycle, TDMA wireless communication systems, wherein transmission channels of the TDMA are set to different frequencies. 8. A multiplexing method in a TDMA wireless communication system in which a plurality of communication channels are time-divided and multiplexed in a predetermined frequency band, and two-way communication is performed in each of the time-division multiplexed time slots. The method comprises: when multiplexing nXm channels (where n and m are natural numbers) into m frames having a period T, sequentially forming downlink time slots of the first to n-th channels in a first frame; Subsequently, in the second frame, the (n + 1) th to (2n) th downlink time slots are formed, and thereafter, the downlink time slots up to the mth frame are sequentially formed every n frames for each frame at intervals of T / n. A predetermined frequency is assigned to each of the first step and the down time slots of the first to n-th time slots formed in the first step, and the frequency is assigned to each of the time slots. A second step of transmitting the next modulated signal; and a station receiving the first to n-th downlink time slots transmitted in the second step. A third step of transmitting the uplink time slot on the same frequency channel as the downlink time slot after each / 2 cycle, and the (n + 1) th step formed in the first step at the same time as the third step. A fourth step of transmitting the (n + 1) th to (2n) th downlink time slots following the second step, and transmitting the (n + 1) th to (2n) th downlink time slots in the third step, respectively. A fourth step of allocating different frequencies to the first to n-th uplink time slots and sequentially modulating and transmitting at the frequency allocated to each channel; Downtime as well as the process of In addition to receiving the uplink time slot after the T / 2 cycle transmitted corresponding to the slot, the downlink time slot transmitted at the same time is assigned a different frequency from the uplink time slot received, and the downlink time slot is transmitted every n time slots. A fifth step of transmitting and receiving up to m frames, and thereafter, the first to fifth steps are repeated to sequentially time-division multiplex nXm time slots in a frame of period T, A multiplexing method in a TDMA wireless communication system, characterized in that two-way communication is performed by: 9. The method according to claim 8, wherein at least one of the time-division multiplexed nXm time slots is a control slot modulated at a fixed frequency. A multiplexing method in a TDMA wireless communication system. 10. The method according to claim 8, wherein the method further comprises adding n time slots to the time division multiplexed signal.
This is a method of multiplexing time-division multiplexed signals of time slots, in which 2n time slots are sequentially multiplexed in each frame, and the time slot interval of each pair of uplink and downlink is T / 2 cycle. A multiplexing method in a TDMA wireless communication system, wherein simultaneously transmitted uplink and downlink time slots have different frequencies.