JPH118586A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the radio wave delivery areas of a centralized control station from being overlapped by performing confirming processing, while using an auxiliary frequency channel before starting initial setting operation, and receiving an alarm from a terminal station under control, when that terminal station exists in the other centralized control stations around it. SOLUTION: When it is judged by carrier sence that a centralized control station does not exist around at the time of operation in a terminal station mode, radio terminals 104-109 set themselves into a centralized control station mode and function as centralized control stations. When the centralized control station mode is set, while using the auxiliary channel for transmission, a radio terminal A reports the declaration of changing itself into centralized control station mode with respect to the other radio terminals. When a terminal station B is under the control of the other centralized control station existing in the other radio terminals receiving the declaration, this radio terminal B sends an alarm command to the radio terminal A while using the auxiliary channel for transmission and prevents the radio terminal A from being set into a centralized control station mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for providing radio communication services to radio telephones, radio data terminals, and the like accommodated in a system. The present invention relates to a wireless communication system for automatically setting a central control station and facilitating system management.

[0002]

2. Description of the Related Art With the rapid development of digital wireless communication technology in recent years, systems for wirelessly communicating with telephones, data terminals, and peripheral devices have been actively developed.

[0003] Of the digital wireless communication systems, spread spectrum communication is currently receiving attention.

[0004] Spread-spectrum communication is a radio technology characterized by spreading information to be transmitted over a wide frequency band, and is known to have high interference removal capability and excellent secrecy. A frequency in the 2.4 GHz band has been allocated for spread spectrum communication, and is spreading worldwide.

[0005] Broadly speaking, spread spectrum wireless communication systems include direct spread (DS) and frequency hopping (FH).

[0006] In the direct spreading method, secondary modulation is performed by multiplying a carrier wave, which has been subjected to primary modulation by PSK, FM, AM, or the like, by a spreading code wider than transmission data. Since the spectrum of the signal after the spread modulation has a wider band than the spectrum of the signal after the primary modulation, the power density per unit frequency is significantly reduced, and interference with other communications can be avoided.

Further, by using a plurality of the above-mentioned spreading codes, a plurality of communication channels can be provided.

On the other hand, the frequency hopping method uses a 26 MHz (Japan) frequency band that is approved for use at 1 MHz.
In this scheme, transmission data is spread over a wide band by dividing into a plurality of frequency channels having a width of about z and switching frequency channels to be used for each unit time in a predetermined order (pattern).

By using a plurality of frequency switching patterns (hopping patterns), a plurality of communication channels can be provided in the same manner as in the direct spreading system.

In particular, the low-speed frequency hopping (SFH) system has been widely used because of its great advantage that the circuit scale of a frequency synthesizer or the like can be reduced.

Further, if a pattern is used in which adjacent frequency channels are not used in the same unit time, it is possible to minimize the occurrence of data errors and the like due to interference and the like. is there.

Hereinafter, the present radio communication system using the low-speed frequency hopping method will be described. (System Configuration) FIG. 1 shows a system configuration of the wireless communication system.

In this wireless communication system, under the control of a wireless terminal that performs overall control of the system, each wireless terminal to which a communication resource (hopping pattern, etc.) required for wireless communication has been allocated performs pseudo data communication in which data communication is performed directly. It is a control type (hybrid type) system.

In this wireless communication system, a wireless terminal such as a wireless telephone and a wireless data terminal constituting the system autonomously selects two terminal modes at the time of initialization. One is a central control station mode, and the other is a terminal station mode.

A radio terminal operating in the central control station mode (hereinafter, this radio terminal is referred to as a central control station) communicates with a radio terminal operating in the terminal station mode (hereinafter, this radio terminal is referred to as a terminal station). Management, control, frequency allocation, etc.

When the power is turned on, each wireless terminal searches for the presence of a central control station, and if there is no central control station, initializes itself in the central control station mode and thereafter operates as a central control station. I do.

Hereinafter, the individual terminals constituting the system will be described in detail.

This wireless communication system accommodates a public line 102 and provides control data or voice data to / from a network controller 101, a central control station or another terminal station which provides a public network communication service to terminal stations in the system. Control data communication with a radio telephone 103, a central control station or another terminal station for exchanging data, performing a voice call via the public line 102, and performing a so-called extension call between a plurality of terminal stations. And wireless data terminals 104 to 109 for data communication
It consists of.

In the following description, a wireless telephone,
The wireless data terminals and the like are collectively referred to as wireless terminals 110 (103 to 103).
109 generic name).

The wireless terminal 110 is connected to a terminal device (data terminal) having a function of transmitting and receiving data in a burst or a wireless adapter for wireless communication with a data input / output device, or is integrated with them. For example, in addition to a computer 104, a multimedia terminal 105, a printer 106, a facsimile 107, a copying machine 108, and a LAN gateway 109 shown in the figure, an electronic camera, a video camera,
Devices such as scanners correspond to this.

The wireless telephone 103 and the wireless terminal 11
0 is a major feature of the present wireless communication system in that the terminals can freely communicate with each other and can also access the public network 102.

The detailed configuration and operation will be described below. (1) Wireless Telephone FIG. 2 is a block diagram showing the internal configuration of the wireless telephone 103.

The main control unit 201 controls the entire radio telephone 103, and the memory 202 stores a ROM storing a control program of the main control unit 201, a call code (system ID) of the radio communication system, EEPROM for storing sub-ID of wireless telephone, main control unit 201
And a RAM serving as a work area for the control.

The communication path unit 203 includes an input / output block of a handset 208, a microphone 209, a speaker 210, and an ADPC.
The interface of the M codec 204 is provided. The ADPCM codec 204 converts analog voice information from the communication path unit 203 into ADPCM codes, and converts ADPCM-coded information into analog voice information. The channel codec 205
ADPCM-encoded information is subjected to processing such as scrambling and is also time-division multiplexed into a predetermined frame.

Data assembled into a radio frame, which will be described later, using the channel codec unit 205 is transmitted via the radio unit 207 to the main apparatus or the target terminal station. The wireless control unit 206 has a function of performing transmission / reception of the wireless unit 207, frequency switching, carrier detection, level detection, and bit synchronization.

Radio section 207 is a channel codec section 2
The digital information from the antenna 05 is modulated, converted into a format that can be wirelessly transmitted, and sent to an antenna, and the information wirelessly received from the antenna is demodulated and converted into digital information.

The handset 208 inputs and outputs a speech signal, and the microphone 209 collects and inputs the speech signal. The speaker 210 loudspeaker outputs the audio signal. The display unit 211 displays the dial number input from the key matrix 212, the use status of the public line, and the like. The key matrix 212 includes dial keys for inputting dial numbers and the like, and function keys such as an outside line key, a hold key, and a speaker key. (2) Wireless Adapter FIG. 3 is a block diagram showing an internal configuration of a wireless adapter 302 connected to or incorporated in the wireless terminal 110.

303 included in the wireless adapter 302
Denotes a radio unit, the internal configuration of which will be described later. Main control unit 3
Reference numeral 04 includes a CPU, peripheral devices that perform interrupt control, DMA control, and the like, an oscillator for a system clock, and the like, and controls each block in the wireless adapter 302.

The memory 305 includes a ROM for storing programs used by the main control unit 304, a RAM used as a buffer area for various processes, and the like. The communication interface unit 306 includes, for example, RS232C, Centronics, L
Communication interfaces such as AN, internal buses of personal computers and workstations, for example, IS
The wireless adapter 302 controls communication using the A bus, the PCMCIA interface, and the like.

The timer 307 provides timing information used by each block inside the wireless adapter 302. The channel codec unit 308 performs not only assembly and disassembly of a radio frame as shown in FIG. 6 but also simple error detection processing represented by CRC, scrambling processing, control of the radio unit 303, and the like.

The radio control unit 309 controls transmission / reception switching and frequency switching of the radio unit 303, and also has a function of performing carrier detection, level detection, and bit synchronization.

The error correction processing section 310 is used to detect or correct a bit or byte error occurring in communication data due to various wireless environments. At the time of transmission, error correction codes are inserted into the communication data to add redundancy to the data, and at the time of reception, bit positions that occur in the received data are calculated by calculating the position and error pattern at which the error occurred by arithmetic processing. correct. (3) Network Control Device FIG. 4 is a block diagram showing the internal configuration of the network control device 101.

The main control unit 401 controls the overall control of the network control device 101. The memory 402 stores programs and call codes (system I) of the present wireless communication system.
D) for storing various data for controlling the main control unit 401, and a RAM for providing a work area for various calculations.

A line interface unit 403 supplies power for receiving the public network line 102, transmits a selection command,
It performs public network line control such as DC loop connection, PCM conversion, selection command reception, and call command transmission.

The ADPCM codec unit 404 converts the analog audio signal received by the line interface unit 403 via the public network 102 into an ADPCM code, transfers the signal to the channel codec unit 405, and encodes the ADPCM code from the channel codec unit 405. The converted audio signal is converted into an analog audio signal.

[0036] The channel codec 405 is an ADPC.
A channel codec unit that performs processing such as scrambling on the M-encoded information and time-division multiplexes the information into a predetermined frame. Data assembled by the channel codec unit 405 into a wireless frame described later is transmitted via the wireless unit. And transmitted to the central control station and the target wireless terminal 110.

The radio control unit 406 controls switching of transmission / reception of the radio unit 407, frequency switching, and the like, and also has a function of performing carrier detection, level detection, and bit synchronization.

The radio section 407 includes the channel codec section 4
In addition to modulating the framed information from 05 and converting it to a format that can be wirelessly transmitted and sending it to the antenna, the information wirelessly received from the antenna is demodulated and processed into digital information.

The tone detector 408 is a detector that detects various tones such as incoming call detection, loop detection, PB signal, dial tone, ring tone, and the like. (4) Wireless Unit FIG. 5 is a block diagram showing a wireless unit having a common configuration in the wireless terminal 110 of the present system.

The transmitting / receiving antennas 501a and 501b are
This is for transmitting and receiving wireless signals efficiently, and the changeover switch 502 switches between the antennas 501a and 501b. A band pass filter (hereinafter, referred to as BPF) 503 is for removing signals in unnecessary bands, and a changeover switch 504 is for switching between transmission and reception.

The amplifier 505 is a receiving system amplifier.
The amplifier 506 is a power control amplifier with a transmission system. The converter 507 includes the 1st. It is a down converter for IF, and converter 508 is an up converter.

The changeover switch 509 switches between transmission and reception, and the BPF 510 removes an unnecessary band signal from the signal converted by the downconverter 507. Converter 511 is
2nd. This is a downconverter for IF, and the two downconverters 507 and 511 constitute a double-version receiving mode.

The BPF 512 has a 2nd. For IF,
The 90-degree phase shifter 513 sets the output phase of the BPF 512 to 90
Phase shift. Quadrature detector 514 is
The BPF 512 detects and demodulates a signal received by the 90-degree phase shifter 513. Further, the comparator 515 is for shaping the output of the quadrature detector 514 into a waveform.

A voltage-controlled oscillator (hereinafter, referred to as VCO) 516 and a low-pass filter (hereinafter, LPF)
517) and a PLL 518 including a programmable counter, a prescaler, a phase comparator, and the like.
Thus, a frequency synthesizer of the receiving system is configured.

VCO 519 for generating a carrier signal
, An LPF 520, a PLL 52 including a programmable counter, a prescaler, a phase comparator, and the like.
1 constitutes a frequency synthesizer for hopping.

The VCO 5 of the transmission system having a modulation function
22, a LPF 523, a PLL including a programmable counter, a prescaler, a phase comparator, and the like.
A transmission frequency synthesizer having a frequency modulation function is configured by 524.

The reference clock oscillator 525 includes various PLLs.
A reference clock for 518, 521, and 524 is supplied, and a baseband filter 526 is a filter for band limitation of transmission data (baseband signal). (5) Wireless Frame In the present wireless communication system, communication services of each wireless terminal are provided using a circuit switching channel for voice communication and a packet switching channel for image, video, and data communication provided in a wireless frame.

FIG. 6 is a block diagram showing the internal structure of a radio frame used in the present invention.

The radio frame used in the present invention is largely divided into a control unit and a data unit. For example, when two terminal stations communicate, each terminal station exchanges the control unit with the central control station. In this case, a communication mode for exchanging the data part with the terminal station of the partner is adopted.

The inside of this radio frame is CNT, LCC
H, two voices, data, and END.

The CNT field is transmitted at the start of each radio frame by the central control station, and the terminal station receives this CNT field to establish bit synchronization and frame synchronization.

The LCCH field is used for control when connecting and disconnecting a line, and when a central control station assigns a hopping pattern to a terminal station prior to line connection.

The two audio fields are used to exchange audio data in both directions, and END indicates a guard time for changing the frequency in the next frame.

Each wireless terminal communicates with the first half (C
Various control commands are exchanged with the central control station in the (NT + LCCH field), the hopping pattern used in the latter half of the communication frame (voice field, data field) is switched, and communication between wireless terminals is performed.

FIG. 7 shows the configuration inside each field of the radio frame.

In the figure, CS is carrier sense, P is
R indicates a preamble for capturing bit synchronization, and SYN indicates 31-bit frame synchronization defined by 1 bit (dummy) + RCR.

ID is a 63-bit calling signal defined by RCR + 1 bit (dummy), UW is a 24-bit unique word (for capturing byte synchronization), and BF is 8-bit basic frame number information (1 to 20 are 1 to 1). Cycle).

WA is one of the terminal stations in the sleep state.
Rev indicates the reserved system address of the terminal station to be activated, Rev indicates the guard time, GT indicates the guard time, CS0, CS1, and CS2 indicate the carrier sense, DA indicates the system address, and CRC indicates the B.
CRC calculation result for data from F to LCCH,
CF indicates a guard time for frequency switching, and T / R indicates a B channel for storing data. (6) Frequency Switching FIG. 8 shows a conceptual diagram of frequency switching used in the present wireless communication system.

In this wireless communication system, the 26 MHz frequency band approved for use in Japan is 1 MHz.
Divided into multiple frequency channels of width.

The central control station and the wireless terminal perform communication while switching the frequency channel in a predetermined order at regular intervals. This order is called a hopping pattern.

The number of frequency channels used for this hopping pattern is variable, and it is possible to adopt a pattern in which the frequencies used within the same unit time do not overlap.

That is, one hopping pattern can be considered to form one communication channel, and it is possible to support up to 16 communications at the same time.

According to this method, a radio communication system having a multi-cell configuration can be realized, and a wide communication area can be secured.

FIG. 9 shows an example of the frequency channel switching operation.

In FIG. 9, it is assumed that the radio terminals A to F operate under the control of the central control station, and the radio terminals A and B communicate with the radio terminals D and E.

The central control station performs the frequency switching according to a specific hopping pattern (here, for example, the order of f1, f2, f3...), And writes the information for controlling the system to the CNT. Transmitting a radio frame including a field.

Each radio terminal (= terminal station) can be controlled by the central control station by switching to an arbitrary frequency and receiving the CNT field of the central control station.

A central control station and a radio terminal (= terminal station)
Also transmits and receives the LCCH field for exchanging control commands with the same hopping pattern as the CNT field.

A central control station using a control unit and a radio terminal (=
After the negotiation with the terminal station is performed, each wireless terminal (= end station) switches the frequency according to the hopping pattern (different from the hopping pattern used by the central control station) assigned by the central control station, Start data communication.

In the figure, the radio telephones A and B are f1
1, f12, f13..., Wireless telephones D and E are f26 and f
25, f24... Are used.

By this switching process of the frequency channels, it is possible to provide a plurality of (the number of hopping patterns) communication services at the same time.

Hereinafter, the specific operation of the radio communication system will be described in several cases. (1) Basic operation The terminal station in the idle state follows the CNT transmitted from the central control station while following the hopping pattern of the central control station.
The field is constantly monitored.

In order for each terminal station to communicate, it is necessary to negotiate with the central control station using the LCCH field on an arbitrary frequency channel, such as notification of the type of data to be communicated and designation of a hopping pattern. is there.

The LCCH field contains a control command, parameters, and the like, and notifies the user of the presence or absence of an incoming call to an outside line, a request for communication between wireless data terminals, and the like.

After the end of the negotiation, the terminal station switches the hopping pattern to be used, and can communicate with the terminal station of the other party.

Now, detailed operations in some cases will be described below. (1-1) Initialization FIG. 10 is a sequence diagram showing an initialization operation of the wireless terminal after power-on in the wireless communication system.

After the power is turned on, the radio terminal serving as the central control station determines a frequency channel to be used for the hopping pattern, and transmits a radio frame in which a synchronization signal, hopping pattern information and the like are stored in the CNT field at predetermined timings. (1001).

Conversely, if there is a central control station that transmits a radio frame having a valid CNT field in the system and the radio terminal can be a terminal station, the radio terminal receives registration of a terminal address from the user. ,Remember.

Next, the terminal station waits for a radio frame from the central control station at an arbitrary frequency, and upon receiving the CNT field in the radio frame, recognizes the frequency used in the next unit time from the NF in the CNT field. , Change the frequency based on the frequency, and wait for the next radio frame.

After the terminal station repeats the above processing and recognizes the hopping pattern used by the central control station, it requests the central control station to register the terminal station using the LCCH field in the radio frame (1002). ).

To request registration of a terminal station, the global address received by all terminals is written in the DA of the LCCH field in the radio frame to be transmitted, and the information indicating new registration is written in the data part.

The central control station having received the new registration request of the terminal station checks the DA global address, the terminal address in the data field and the registration request information, and registers the terminal address based on the information.

When the registration process is completed, the central control station notifies the newly registered terminal station of the terminal address of the central control station (1003).

The terminal station stores the terminal address of the central control station, and transmits a radio frame in which the start-up completion notification is written in the LCCH field to the central control station (100).
4).

When the central control station receives the start-up completion notification from the terminal station, it shifts to the normal processing. After outputting the start-up completion notification, the terminal station can make a call from the terminal station (1005). (1-2) Initial Setting of Wireless Terminal FIG. 11 is a flowchart showing an initial setting operation of the wireless terminal.

After the power is turned on and the wireless terminal performs internal initialization processing (S1101), it waits for reception of the CNT field of the wireless frame at an arbitrary frequency.

Here, the radio frame (= CNT)
Field) cannot be received (S110).
2) Activate the internal counter, shift the frequency to the next arbitrary frequency channel (S1104), and try receiving a radio frame (= CNT field) again (S110).
2).

If the above operation is repeated and the value of the internal counter becomes 10 without receiving a valid radio frame (S1105), it is determined that there is no central control station in the system, and the central control station mode is determined. Starts the initialization process.

The radio terminal selecting the central control station mode
First, a frequency that can be used for the hopping pattern is selected (S1106). Subsequently, the frequency of the wireless frame in which the hopping pattern information and the global address of the wireless communication system are written in the CNT field is switched according to the hopping pattern (S1109).
It transmits to each terminal station in the system (S1108).

If a terminal station registration request is received from the terminal station during the above operation (S1108), the processing shifts to terminal station registration (S1110).

On the other hand, in step 1102, if a valid radio frame is received from the central control station,
Thereafter, the initialization process is started in the terminal station mode.

[0092] In order to acquire the hopping pattern to be used, the radio terminal that has selected the terminal station mode waits to receive a radio frame from the central control station at an arbitrary frequency.

If a radio frame is received from the central control station, a frequency to be used in the next unit time is obtained from the NF of the CNT field (S1112), and the terminal station shifts the reception frequency to the frequency channel (S1113). ), And waits for reception of the next radio frame from the central control station.

The terminal station repeats the above operation, and registers the hopping pattern if the frequency has completed one cycle (S1114) (S1115).

Next, the terminal station performs a process for notifying the central control station of the terminal address.

Specifically, the global address received by all terminals is written in the DA of the LCCH field in the radio frame, the registration request and the terminal address are written in the DATA field, and transmitted to the central control station (S111).
6).

After the transmission, the terminal station receives the radio frame while changing the frequency according to the obtained hopping pattern (S1117).

When the terminal address of the terminal is detected by the DA in the LCCH field from the central control station and the registration completion command is confirmed (S1118), the central control station is sent to the L.
The address of the central control station, DA in the CCH field DA
The wireless frame in which the TA start-up completion command is written is transmitted to the central control station (S1119). (1-3) Terminal Station Registration Process of Central Control Station FIG. 12 is a flowchart showing an operation at the time of terminal station registration in the central control station corresponding to the terminal station registration process (S1110) in FIG.

L in the radio frame received by the central control station
When there is a registration request from the terminal station in the CCH field (S1201), the terminal station address is confirmed (S12).
02).

As a result of the terminal station address confirmation, when it is detected that the terminal station address is normal (S1203), the central control station registers the terminal station address and stores the address information (S1204).

Conversely, if the terminal station address is not normal (S
1203), the registration request sent from the terminal station is discarded (S1).
208), and the process ends.

When the registration of the terminal station is completed, the terminal address of the central control station is transmitted to DATA in the radio frame, and the radio frame including the LCCH field in which the address of the terminal station is written to DA is transmitted to the terminal station whose registration has been completed. (S1
205).

After transmission, the central control station cannot confirm the start-up completion notification signal from the registered terminal station (S
In step 1206, it is detected whether a predetermined time has elapsed (S1).
209) If the predetermined time has not elapsed, the system waits again for a start-up completion notification from the terminal station.

When the predetermined time has elapsed, a radio frame for notifying the terminal address of the central control station to the terminal station is transmitted again (S1205).

If the start-up completion notification signal from the terminal station is detected in S1206, a new registration completion processing for the terminal station is performed (S1207), and the processing is terminated. (2) Data Communication Between Terminal Stations Here, a process for performing burst data communication between two terminal stations (wireless terminal 104 and wireless terminal 105) in FIG. 1 will be described in detail below.

FIG. 13 shows a sequence diagram of control commands exchanged between the central control station, the radio terminal 104, and the radio terminal 105.

FIG. 14 is a flowchart showing the processing of the central control station, FIG. 15 is a flowchart showing the processing of the wireless terminal 104, and FIG. 16 is a flowchart showing the processing of the wireless terminal 105.

For convenience of explanation of the operation, the frequency channel at which the terminal station exchanges radio frames with the central control station is f5 in the radio terminal 104 and f7 in the radio terminal 105.

The exchange of commands between the central control station and the radio terminals 104 and 105 is entirely performed by the LC in the radio frame.
It is assumed that this is performed using the CH field. (2-1) Connection processing The terminal station that transmits data exchanges commands such as transmission requests with the central control station, performs frequency switching according to the allocated communication resources such as hopping patterns, and performs communication with the other party. .

When data to be transmitted occurs (S150)
1), the wireless terminal 104 issues a communication request command (1301)
Is transmitted to the central control station (S1502).

Upon receiving the communication request command (1301), the central control station (S1401) secures communication resources such as a hopping pattern for the wireless terminal 104 (S14).
02), a communication setting command (1302) including the communication resource information is transmitted to the wireless terminal 104 (S140).
3).

Upon receiving the communication setting command (1302) (S1503), wireless terminal 104 sets a hopping pattern obtained from the communication resource information in the channel codec.

When the setting is completed in the wireless terminal 104, a communication setting completion command (1303) is transmitted (S
1505).

Next, wireless terminal 104 transmits an address command (1304) for informing the central control station of the terminal address of the transmission destination (S1506).

In the central control station, the address command (13
04) (S1404), the wireless terminal having the terminal address specified in the address command (in this case, the wireless terminal 105) receives the data arrival command (1305).
Is transmitted (S1405).

The wireless terminal 105 that has received the data arrival command (1305) (S1601) receives the data arrival response command (1306) if data can be received.
Is sent to the central control station (S1602).

The central control station having received the data arrival response command (1306) from the wireless terminal 105 (S140)
6) A communication setting command (13) including hopping pattern information used for data communication to the wireless terminal 105.
07) is transmitted (S1407).

Upon receiving the wireless frame and recognizing the communication setting command (1307) in the LCCH field (S1603), the wireless terminal 105 sets a hopping pattern in the channel codec (S1604).

Next, the central control station transmits a communication response command (1308) to wireless terminal 104 (S140).
8) Notify that the wireless terminal 105 has responded.

After confirming the other party's response using the communication response command (1308) (S1507), the wireless terminal 104 transmits a communication start command (1309) to the central control station (S1508), and then performs data communication with the wireless terminal 105 (S1508). 1
310) is started.

When the central control station receives the communication start command (1309) from the wireless terminal 104 (S140)
9) It is determined that the wireless terminal 104 and the wireless data terminal 105 have started data communication, and the communication end command (131)
Wait for 3) (S1410).

After the wireless link is established between the wireless terminal 104 and the wireless terminal 105 as described above, wireless frames are exchanged while switching frequencies according to a common hopping pattern.

At the end of communication, the wireless terminal 104 sends a communication end command (1313) to the central control station.

Upon receiving the communication end command (1313) (S1410), the central control station sets the radio data terminal 10
Communication setting release command (1314,
1315) is transmitted (S1411).

Next, the central control station communicates with the radio terminals 104, 10
The hopping pattern allocated for communication between the five is released (S1412).

The communication setting release command (1314, 1
315), the wireless terminals 104 and 105 receive (S
1511, S1607), clear the communication settings (S1)
512, 1608).

[0127]

In the conventional wireless communication system, the procedures described above are used to provide a wireless terminal in the system with a public line call accommodated by a public network gateway, an extension call, data transmission between data terminals, and the like. We provide communication services.

However, the above-mentioned conventional radio communication system has the following problems with respect to the central control station.

In a wireless communication system, at least one centralized control station must be installed in the system in order to control and manage the entire system. In a conventional wireless communication system, as shown in FIG. 11, a method has been adopted in which a wireless terminal first turned on by a user in a system is automatically started as a central control station.

In this case, for example, when the wireless terminal (= centralized control station) which is first turned on is installed in a skewed position in the system, that is, when the distance from each terminal station is significantly different, There may be a terminal station that cannot exchange control data with the control station.

Therefore, according to the present invention, in the above-described operation of setting a centralized control station, it is possible to prevent a plurality of centralized control stations having overlapping radio wave ranges from being set, and to ensure proper system operation. The purpose is to provide a system.

[0132]

According to the present invention, a centralized control station and a terminal station are constituted by a plurality of radio terminals having a radio section capable of radio communication, and voice and / or characters and / or characters using radio frames are used. Or in a wireless communication system for image and / or video data communication,
The wireless terminal, when initializing and / or resetting its own operation mode to the central control station mode, a declaration means for declaring to that effect to another wireless terminal, and another wireless terminal receiving the declaration When a warning indicating the presence of another central control station is received from the terminal, the terminal itself is initialized or held in the terminal station mode, and the other wireless terminal enters the control of the other central control station as a relay station. And control means for executing the operation in the terminal station mode.

[0133]

BEST MODE FOR CARRYING OUT THE INVENTION In the radio communication system described below, a backup channel that normally performs only reception is provided in a frequency channel set by a central control station.

When each wireless terminal of the system starts up or operates in the terminal station mode, if it determines that there is no centralized control station around it by carrier sense, it sets its own device to the centralized control station mode, It has the ability to function as a central control station. Then, at the time of setting such a centralized control station mode, the wireless terminal (tentatively, wireless terminal A) declares that its own device is to be changed to the centralized control station mode by using the spare channel for transmission. To other wireless terminals.

Here, among the other wireless terminals receiving the declaration, there is a terminal station (tentatively a wireless terminal B) under the control of another central control station (a temporary control station A). In this case, the wireless terminal B sends a warning command to the wireless terminal A using the spare channel for transmission, and prevents the wireless terminal A from setting the central control station mode.

Therefore, the radio terminal A that has received the warning command performs the initial setting of the terminal station mode, or maintains the state of the terminal station mode, and keeps the radio terminal B until a new central control station starts up around it. As a relay station, central control station A
And operates as a terminal station. In this way, it is possible to prevent a plurality of central control stations having overlapping radio wave ranges from being set.

In the above description of the conventional example, FIG.
The configurations and operations shown in FIGS. 1 to 10, 15, and 16 except for the operation at the time of initial setting of the wireless terminal shown in FIG. 1 are common to the present embodiment, and description thereof is omitted. Hereinafter, each unit constituting the present embodiment will be described. (1) Channel Codec Section FIG. 17 is a block diagram showing an internal configuration of channel codec section 1701 provided in each of the above-described wireless terminals.

The channel codec 1701 includes an audio input / output unit 1702 and an ADPCM codec 170
3, a main control unit data bus 1704, a main control unit interface 1705, and an ADPCM interface unit 1706.

A register 1707 is a control register for determining the internal operation of the channel codec, and includes a mode register, a hopping pattern register, a frame number / next frequency number (BF / NF) register, a system ID register, an intermittent activation terminal. The address register includes a plurality of registers. The register 1708 is a command register for storing a communication command in an LCCH field of a radio frame.

Further, the channel codec section 1701
Data buffer 1709 and timing generator 1710
, CNT channel assembling / disassembling unit 1711, LCCH
Assembling / disassembling unit 1712 and data assembling / disassembling unit 1713
, A voice assembling / disassembling unit 1714, and a synchronization control unit 17 for ensuring synchronization of the radio frame for each frame or bit.
15, a unique word detection unit 1716, a CRC encoding / decoding unit 1727, a radio control unit 1718, an intermittent reception control unit 1719, a scrambler / descrambler 1720, an AD converter 1721, a reception level detection unit 1722 and a wireless unit 1723.

Hereinafter, such a channel codec 1
The operation of 701 will be described.

Each channel codec section 17 in the system
01 is based on the timing generator 17 of the channel codec 1701 built in the central control station.
Generated at 10.

In the central control station, the timing generator 171
The wireless frame is transmitted in synchronization with the timing signal of 0, and the terminal station receives the wireless frame while maintaining synchronization according to a frame synchronization word in the wireless frame.

When transmitting CNT field data from the central control station, the written hopping pattern,
ID, WA, frequency channel number for transmitting CNT field data, frame number / next frame frequency number (B
F / NF) and the like are assembled by the CNT assembling / disassembling unit 1711 and sent to the radio unit.

On the other hand, if the terminal station recognizes a valid CNT field in the received radio frame,
The T assembling / disassembling unit CNT field is extracted and various processes are performed according to the data.

The ID register inside the control register 1707 has a filter function of receiving a subsequent radio frame only when the system ID in the received radio frame matches the own station.

The WA register is used by the central control station for specifying a terminal for restarting the terminal station during intermittent reception.

Since the frequency number stored in the NF field follows the hopping pattern of the CNT field, the hopping pattern used in the voice field and the data field is the hopping pattern created based on the frequency number written in the NF field. The register is generated by shifting the time of the register.

When transmitting a command, data is set in the command register 1708 and the LCCH assembling / disassembling unit 1 is set.
Embedded in the radio frame at 712 and the valid LC
When receiving the CH data, the LCCH assembling / disassembling section 1712 decomposes the data.

When transmitting voice data using a voice field, voice data input from handset 1702 is digitally encoded by ADPCM codec 1703, and this digital voice is incorporated in a radio frame by voice assembling / disassembling section 1714, and is transmitted to a predetermined frame. The data is transmitted to the radio unit 1724 at the timing.

Conversely, voice data received from radio section 1724 is decomposed by voice assembling / decomposing section 1714, and A
ADPC via DPCM interface 1706
Output to M codec 1703 and handset 1702.

At the time of data transmission using the data field, the data is converted serially in the data assembling / disassembling section 1713 and transmitted to the radio section 1724 at a predetermined timing. Conversely, when data is received, data assembling /
The decomposing unit 1713 performs parallel conversion on the data.

At the time of data transmission, a CRC code generation unit 1717 can generate a CRC code, store the CRC code in the CRC field, and transmit the data. The CRC check on the receiving side can detect the occurrence of an error.

At the same time, all transmission data other than the frame synchronization word and the unique word are scrambled by a scrambler in order to reduce data imbalance and facilitate synchronization clock extraction.

Conversely, upon receiving data, if a unique word is detected, the descrambler 1720 performs descrambling, performs a CRC check, and inputs data to the decomposing units 1711 to 1714 of each field. (2) Communication error processing unit The communication error processing unit adds parity data obtained by performing an arithmetic process to the input raw data, outputs the resulting data as code data, and multiplies the received code data. It has a function of calculating the number of bytes, the position of the error, and the error data value, and detecting or correcting the error. This communication error processing unit is provided, for example, as the communication error processing unit 310 of the wireless adapter shown in FIG.

The transmitting-side radio terminal inputs the transmission data to the communication error processing section and transmits the obtained code data. The wireless terminal on the receiving side can detect or correct a communication error and reduce adverse effects on data in a wireless environment.

FIG. 22 is a block diagram showing the internal configuration of communication error processing section 2201.

In the figure, a control register 2202 inputs a set value necessary for control inside the communication error processing unit from the main control unit. The data buffer 2203 controls input and output of byte data with the outside. The memory 2204 is used as a buffer for temporarily securing data for arithmetic processing.

The syndrome generation unit 2205 is a block for performing arithmetic processing performed by the communication error processing unit at the time of data encoding and decoding. The internal address generation unit 2206 generates and outputs an address of the memory 2204.

The error pattern generator 2207 calculates an error value multiplied by the received code data. The error position generation unit 2208 calculates the byte position of the error multiplied by the received code data. Error detection unit 2209
Detects the number of errors multiplied by the received code data.

The parity data generator 2210 generates parity data from the value calculated by the syndrome generator 2205. The data processing unit 2212 adds the parity data generated by the parity data generation unit 2210 to the raw data at the time of encoding, and sends the raw data to the memory. At the time of decoding, the encoded data processed by the error correction unit 2211 is processed. , Delete the parity part and send it to the memory.

Hereinafter, the detailed operation of the wireless communication system to which the present invention is applied will be described with reference to FIGS. (3) Terminal Mode In the wireless communication system of this embodiment, each wireless terminal that has been allocated a communication resource (hopping pattern or the like) required for wireless communication directly receives data under the control of the wireless terminal that performs overall control of the system. This is a pseudo centralized control type (hybrid type) system that performs communication.

The wireless terminal autonomously selects two terminal modes, a central control station mode and a terminal station mode, in an initialization stage after power-on.

When the power is turned on, each wireless terminal searches for the presence of a centralized control station, and if there is no centralized control station, initializes itself in the centralized control station mode.
Operates as a central control station.

If the location of the central control station in the system is not appropriate for system operation (determined from environmental data such as radio field intensity and communication error rate), the central control station is installed at a position where the system is more stable. The right of the centralized control station is transferred to the specified wireless terminal.

Also, the system management information obtained when the system was operating last time is searched by the wireless terminal that starts up in the central control station mode, and without checking the radio field intensity and the communication error rate, either of the two systems can be used as a system. If it is possible to empirically determine whether to operate as the central control station mode, omit the radio field strength inspection and the measurement of the communication error rate, and transfer the central control station between wireless terminals, that is, to stabilize the system. It is characterized in that the required time is reduced.

For convenience, in FIG. 1, the wireless terminal to be powered on first is 104 (terminal address = 01), and the wireless terminal to be powered up next is 105 (terminal address = 0).
2) After the initial setting of the centralized control station is completed and the system performs normal operation, the terminal station with the lowest communication error rate is determined by the communication error rate check performed by the centralized control station to be 106 (terminal address = 03), and the most A terminal station having a high error rate is assumed to be 107 (terminal address = 04).

In the following description, a radio terminal operating in the central control station mode is called a central control station, and a radio terminal operating in the terminal station mode is called a terminal station. (3-1) Central control station mode After power-on, the wireless terminal waits for a radio frame transmitted from the central control station existing in the system, and if it cannot receive the radio frame, there is no central control station in the system. It is determined that the terminal is the first terminal started in the system, and the terminal is initialized in the central control station mode.

FIG. 18 is a flowchart of the operation at the time of starting the radio terminal, and FIG. 19 is a flowchart of the operation of the initial setting process in the central control station mode.

After the power is turned on, the radio terminal 104 performs an internal initialization process (S1801), and waits for a CNT field in a radio frame to be transmitted from the central control station on an arbitrary frequency channel (S1801). S1802).

If the radio frame (only the CNT field is valid) is not received from the central control station for a fixed time, the internal counter is started (S1803), the frequency is shifted to the next frequency channel (S1804), and the radio frame Attempt to receive (valid only for the CNT field) (S18)
02).

The wireless terminal 104 repeats the above operations from S1802 to S1804, and when the value of the internal counter becomes 10
(S1805), the frequency channel is switched to the spare channel f20 (S1806), and a confirmation command is transmitted (S1807). Note that the spare channel f2
0 is a frequency channel normally provided exclusively for reception in each wireless terminal.

Next, the process waits for a warning command on the spare channel f20 (S1808), and upon receiving the warning command, shifts to terminal station mode processing (S1809).
In this terminal station mode processing, the terminal station that has transmitted the warning command operates as a relay station. However, when a situation occurs where each wireless terminal can directly communicate with the central control station due to movement of the position or the like, direct communication is performed without using a relay station.

If a warning command is not received in S1808, the internal timer is checked (S181).
0), wait for reception until the internal timer expires. Then, if the warning command is not received even after the internal timer expires, it is determined that there is no central control station in the system, and thereafter, the apparatus itself starts initialization in the central control station mode (S1811).

When the radio terminal 104 selects the central control station mode, a value input by the user using a DIP switch, a dial key of a telephone or the like, a keyboard of a computer or the like is stored as a terminal address (S1901). A process for creating a hopping pattern to be used is performed (S1902).

At this time, the wireless terminal 104 examines all available frequency channels, selects a frequency having a good radio wave condition from among the frequencies, and randomly or arbitrarily arranges the frequency under a certain condition as a hopping pattern.

After that, the radio terminal 104 transmits the system management information (global address, hopping pattern, hopping pattern allocation status, etc.) to the CNT every predetermined time.
The wireless frame written in the field is transmitted to a terminal station in the system (S1903).

At the same time, the wireless terminal 104 monitors the internal timer, and transmits a wireless frame in which a position management command has been written in the LCCH field to each terminal station at regular time intervals (S1904) (S1905).

After transmitting the position management command, the central control station (= wireless terminal 104) waits for a response command to be transmitted from each terminal station while switching frequency channels (S1906, S1917).

When the power of the wireless terminal 105 is turned on and a wireless frame including a response command is received, the LCCH
The terminal address written in the response command in the field is read (S1907), and here the wireless terminal 104 is read.
Searches the history of the terminal address of the wireless terminal that operated in the central control station mode at the time of the previous system startup from the system management information in the memory (S1908), and first, the wireless terminal 104 operates in the previous central control station mode. Find out if you have any experience.

If there is no experience (S1909), next, if the terminal address of the wireless terminal 105 that has requested registration is included in the history (S1910), that is, the previous wireless terminal 105 If the user has experience operating in the mode, it is next determined whether or not the time of becoming the central control station is before or after the wireless terminal 104.

Then, as a result of this determination, the wireless terminal 104
If it is earlier (S1911), that is, according to the previous result, it is determined that the wireless terminal 104 operates in the centralized control station mode more stably than the wireless terminal 105 to perform systemically stable communication. Continue processing in mode. Further, the wireless terminal 104 waits for a test frame to be transmitted from the wireless terminal 105 (S1912).

When the test frame is received, the radio wave intensity processing (S1913) and the communication error rate processing (S1
914), and as a result, when it is determined that the central control station should be transferred (S1915), the process proceeds to a terminal mode change process (S1916).

In S1911, if it is later than the own device, the wireless terminal 104 determines that the wireless terminal 105 operating in the central control station mode is systemically stable, and shifts to the terminal mode change process (S1916). I do. (3-2) Terminal Station Mode Wireless Terminal 10 Powered On Second and Later in System
From 5 the wireless terminal 107 is automatically initialized in the terminal station mode. Here, the wireless terminal 105 in FIG. 1 will be described as an example.

FIG. 20 shows an operation flowchart when the power of the wireless terminal 105 is turned on.

Immediately after the power is turned on, the wireless terminal 105 performs internal initialization (S2001), and waits for the input of a terminal address set by the user using a keyboard attached to the data terminal (S2002). , Is stored in the memory. Next, in order to receive a radio frame (= valid only in the CNT field portion) from the central control station (= radio terminal 104), the mobile station stands by at an arbitrary frequency (S2004).

When the wireless terminal 105 receives a wireless frame from the central control station (= wireless terminal 104), the CNT field is read, the global address is read from the ID (S2005), and the frequency channel used in the next unit time is read from the NF. (S2006) is stored.

Next, after moving the reception frequency of the radio unit to the frequency channel obtained from the NF field (S200)
7) Re-enter the reception standby state. By repeating this operation, the wireless terminal 105 follows the frequency channel of the central control station, and can recognize the hopping pattern used when the central control station transmits a radio frame (only the CNT field is valid) (S2009). .

Further, if a position management command is received from the central control station (S2010), a response command is sent to LC
The wireless frame written in the CH field is transmitted to the central control station (S2011). Then, the predetermined dummy data is sent to the communication error processing unit, and the test frame in which the dummy data subjected to the error correction coding processing is written in the data field is sent to the central control station (= wireless terminal 104) (S2012). (3-3) Terminal Station Warning Processing In S1808 of FIG. 18 described above, the peripheral terminal stations that have received the declaration of the wireless terminal to be set to the central control station mode already have a central control station in the system. If it is recognized, a warning command is transmitted to the declaration by the spare channel f20.

FIG. 21 is a flowchart showing the operation of the terminal station in the idle state including the warning process.

In a certain frequency channel, when a transmission request is generated inside the terminal station (S2101) or when a data arrival command is received from another wireless terminal in the system (S2102), the processing shifts to transmission / reception processing. Otherwise, the terminal station switches the frequency channel according to the given hopping pattern (S
2103) If the switched frequency channel is f20 (S2104), the process waits for reception of the confirmation command (S2105). Here, if the confirmation command is received, it is determined that there is a wireless terminal that is newly starting up in the central control station mode, and a warning command is transmitted at f20 (S2106). (3-4) Radio Wave Strength Processing FIG. 23 shows a flowchart of the radio wave intensity inspection processing inside the central control station.

When the central control station receives the test frame from the terminal station, it reads the terminal address written in the response command in the LCCH field, and at the same time, checks the reception level from the reception level detection section 1722 inside the channel codec section. The data is read (S2301), and the two data of the terminal address and the reception level value are written as one set in the system management information (provisionally SMI1) in the memory (S2302).

Next, the central control station reads the system management information (SMI1) in the memory, and compares the maximum value and the minimum value of the reception level of each terminal station (S2303).

If the reception level difference indicates a certain value or more (S2304), the control flag is turned on (S2304).
305).

If the reception level difference is equal to or smaller than the predetermined value, it is determined that the position of the central control station in the system is appropriate, and the processing is terminated. (3-5) Communication Error Rate Processing FIG. 24 shows a flowchart of the communication error rate inspection processing.

The central control station having received the test frame,
The dummy data written in the data field of the test frame is sent to the communication error processing unit 2301, and the communication error rate is calculated (S2401).

Next, the obtained two data of the terminal address and the communication error rate are written as one set as system management information (tentatively SMI1) in the memory (S240).
2).

The central control station reads the system management information in the memory, and compares the maximum value and the minimum value of the communication error rate for each terminal station (S2403).

If the difference between the communication error rates indicates a certain value or more (S2404), the control flag is turned on (S2404).
2405).

If the difference between the communication error rates is equal to or smaller than a predetermined value, it is determined that the position of the central control station in the system is appropriate, and the processing is terminated.

In the wireless communication system according to the present embodiment as described above, when the power supply of the wireless terminal located outside the radio wave coverage of the central control station is started, the control command from the central control station cannot be received. This wireless terminal is also set in the central control station mode. As a result, in some cases, an area where the radio wave coverage of the two central control stations overlaps is created, and there is a possibility that the wireless terminals arranged in the area cannot communicate.

Therefore, as described above, a radio terminal that is going to start up in the centralized control station mode performs a confirmation process using a spare frequency channel before entering the initial setting operation. If there is a terminal station that is under control, to receive a warning from that terminal station,
For example, even when two centralized control stations are about to start up on the same floor, it is possible to prevent the radio wave reach areas of the two centralized control stations from overlapping, and eliminate a terminal station that cannot communicate.

[0203]

As described above, according to the present invention,
When the wireless terminal sets its own operation mode to the central control station mode, declares the fact to other wireless terminals, and receives a warning from another wireless terminal indicating the presence of another central control station. Since the mobile station itself is in the terminal station mode and the other wireless terminal is used as a relay station and under the control of the other centralized control station to execute the operation in the terminal station mode, a plurality of centralized radio wave coverage areas overlap. Control stations can be prevented from being set, and proper system operation can be ensured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a wireless system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a wireless telephone according to the embodiment.

FIG. 3 is a block diagram showing a configuration of a wireless adapter in the embodiment.

FIG. 4 is a block diagram showing a configuration of a network control device in the embodiment.

FIG. 5 is a block diagram illustrating a configuration of a wireless unit in the embodiment.

FIG. 6 is an explanatory diagram showing a configuration of a radio frame in the embodiment.

FIG. 7 is an explanatory diagram showing a configuration of each field of a radio frame in the embodiment.

FIG. 8 is an explanatory view conceptually showing a frequency switching operation in the embodiment.

FIG. 9 is an explanatory diagram showing an example of a frequency switching operation in the embodiment.

FIG. 10 is a sequence diagram showing an operation of the wireless terminal after power is turned on in the embodiment.

FIG. 11 is a flowchart illustrating a conventional initial setting operation of a wireless terminal.

FIG. 12 is a flowchart illustrating an operation of the central control station at the time of terminal station registration in the embodiment.

FIG. 13 is a sequence diagram showing an operation at the time of communication between wireless terminals in the embodiment.

FIG. 14 is a flowchart showing processing of a central control station in the embodiment.

FIG. 15 is a flowchart showing an operation of the wireless terminal in the embodiment.

FIG. 16 is a flowchart showing another operation of the wireless terminal in the embodiment.

FIG. 17 is a block diagram illustrating a configuration of a channel codec unit in the embodiment.

FIG. 18 is a flowchart showing an operation at the time of activation of the wireless terminal in the embodiment.

FIG. 19 is a flowchart showing an operation of a central control station mode process in the embodiment.

FIG. 20 is a flowchart showing an operation of a terminal station mode process in the embodiment.

FIG. 21 is a flowchart showing an operation of the terminal station in an idle state in the embodiment.

FIG. 22 is a block diagram illustrating a configuration of a communication error processing unit in the embodiment.

FIG. 23 is a flowchart showing communication error processing in the embodiment.

FIG. 24 is a flowchart showing a radio wave intensity process in the embodiment.

DESCRIPTION OF SYMBOLS 101: Network control device, 102: Public line, 103: Wireless telephone, 104: Computer, 105: Multimedia terminal, 106: Printer, 107: Facsimile, 108: Copy machine, 109: LAN gateway

Claims (7)

[Claims] A centralized control station and a terminal station are configured by a plurality of wireless terminals having a wireless unit capable of wireless communication, and voice and / or character and / or image and / or video data communication using a wireless frame is provided. In the wireless communication system performing, when the wireless terminal initializes and / or resets its own operation mode to the central control station mode, a declaration unit that declares to that effect to another wireless terminal; Receiving a warning indicating the presence of another centralized control station from another wireless terminal that has received the information, initializes or holds the terminal itself in the terminal station mode, and uses the other wireless terminal as a relay station to perform the other centralized control. Control means for executing operation in a terminal station mode under control of a control station. 2. The wireless terminal according to claim 1, wherein the wireless terminal includes: a receiving unit that receives control information from the central control station; a measuring unit that measures a time during which the control information is not received by the receiving unit; Receiving control information from a central control station by the receiving means, a terminal station mode setting means for setting an operation mode of the terminal itself to a terminal station mode, and receiving the control information by the receiving means in the terminal station mode. A terminal station operation executing means for executing the operation of the terminal station based on the control information; and in the initial state, it has been determined that the receiving means has not received control information from the central control station for a first predetermined time or more. A centralized control station mode initial setting means for initially setting the operation mode of the terminal itself to a centralized control station mode; and A central control station mode resetting unit that sets the operation mode of its own device to the central control station mode when it is determined that the time during which control information from the central control station is not received by the means has continued for a second predetermined time or more; And a central control station operation executing means for executing an operation as a central control station in the central control station mode. 3. The wireless terminal according to claim 1, wherein the other wireless terminal receives the declaration, and if there is a central control station under its control, the other wireless terminal performs the centralized control according to the declaration. A warning that prevents the setting of the control station mode is transmitted to the wireless terminal that has made the declaration, and the relay device functions as a relay station between the central control station that is under control of itself and the wireless terminal that has made the declaration. A wireless communication system, comprising: 4. The wireless terminal according to claim 1, wherein each wireless terminal in the system has means for using a part of a frequency channel as a spare channel. A wireless communication system, wherein the communication is performed using the spare channel. 5. The wireless terminal according to claim 1, wherein the wireless terminal in the system is a first communication unit for wirelessly communicating between the central control station and the terminal station, and the terminal stations are wirelessly connected to each other. A wireless communication system comprising: a second communication unit that communicates; and the exchange of the declaration and the warning is performed using the second communication unit. 6. A wireless terminal comprising a wireless unit capable of wireless communication and performing voice and / or character and / or image and / or video data communication using a wireless frame with another wireless terminal, Receiving means for receiving control information from the central control station; measuring means for measuring the time during which control information is not received by the receiving means; in the initial state, when the control information from the central control station is received by the receiving means A terminal station mode setting means for setting the operation mode of the terminal itself to a terminal station mode; and executing a terminal station operation for executing an operation of the terminal station based on the control information received by the receiving means in the terminal station mode. Means; and, in an initial state, a time during which control information from the central control station is not received by the receiving means continues for a first predetermined time or more Central control station mode initial setting means for initially setting the operation mode of the own device to the central control station mode, and a time during which the control information is not received from the central control station by the receiving means in the terminal station mode. A central control station mode resetting means for setting its own operation mode to a central control station mode when it is determined that the operation has continued for a second predetermined time or more; Centralized control station operation executing means for performing the following, when initializing and / or resetting the operation mode of the own device to the centralized control station mode, declaring means for declaring to that effect to another wireless terminal; If a warning indicating the presence of another centralized control station is received from the received other wireless terminal, the terminal is initialized or held in the terminal station mode, and the other wireless terminal is used as a relay station. Wireless terminals, characterized in that it comprises a control means for entering under the control of the serial other centralized control station executes the operation of the terminal station mode, the. 7. A wireless communication method for performing voice and / or character and / or image and / or video data communication using a wireless frame with another wireless terminal by a wireless unit capable of wireless communication. When setting the central control station mode on the terminal,
Declare that to other wireless terminals, and when consent is received from other wireless terminals, execute operation in the central control station mode,
A wireless communication method comprising: executing a terminal station mode operation using another wireless terminal as a relay station when receiving a warning from another wireless terminal.