JPH09116562A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate such a deficiency where an integrated control station is set at a deflected position in a system and also to eliminate such an end station that is unable to exchange the control data with the integrated control station and becomes incapable of communication. SOLUTION: When a power supply is inputted, a radio terminal waits for the radio frame that is sent from an integrated control station included in a radio communication system. If the radio terminal cannot receive the radio frame, the terminal decides that the integrated control station is not included in the system and serves as an integrated control station by itself to perform the initialization. Then the radio terminal serving as an integrated control station compares the highest and lowest receiving levels with each other (SB11). If the receiving sensitivity difference is larger than the fixed value, the control change processing (SB12) is carried out to move the integrated control station. If the receiving sensitivity difference is smaller than the fixed value, a proper position is decided for the integrated. control station, i.e., the radio terminal in the system. Then a usual operation is carried on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system for providing a wireless communication service to a wireless telephone or a wireless data terminal accommodated in a system, and more particularly, to a wireless data terminal being activated in the system. Relates to a wireless communication system suitable for automatically setting a central control station to facilitate system management.

[0002]

2. Description of the Related Art In recent years, with the rapid development of digital wireless communication, a system for wirelessly communicating with a telephone, a data terminal, and peripheral devices has been actively developed. Among the digital wireless communication systems of this type, the spread spectrum communication system is currently attracting attention. The spread spectrum communication method spreads information to be transmitted over a wide band, and is known as a communication having a high interference removal capability and excellent confidentiality. Frequencies in the 2.4 GHz band are assigned to spread spectrum communications in countries around the world, and their use is spreading worldwide. The spread spectrum communication system is roughly classified into a direct spread system (DS system) and a frequency hopping system (FH system).

In the direct spread system, a carrier which is first-order modulated by PSK (Phase Shift Keying), FM (Frequency Modulation), AM (Amplitude Modulation), etc. is multiplied by a spreading code having a wider band than the transmission data. This is the method of secondary modulation.

Since the spectrum of the signal after the above-mentioned spread modulation is wider than the spectrum of the signal after the primary modulation, the power density per unit frequency is remarkably lowered, and interference with other communication is avoided. can do.

On the other hand, the frequency hopping method is licensed for use in spread spectrum radio in Japan.
By dividing the 6 MHz band into a plurality of frequency channels with a width of about 1 MHz, and switching the frequency channel to be used for each unit time in a predetermined order (pattern),
This is a method of spreading transmission data over a wide band.

By using a plurality of frequency switching patterns (hopping patterns) described above, it is possible to provide a plurality of communication channels as in the case of the direct spread system. In particular, the low-frequency hopping modulation method has been widely used because of its great advantages such as the ability to reduce the circuit scale of a frequency synthesizer or the like. Further, by using a pattern in which adjacent frequency channels are not used in the same unit time, it is possible to minimize the occurrence of data error due to interference or the like.

Next, a radio communication system using the above-mentioned low frequency hopping modulation method will be described.

A wireless communication system using the low frequency hopping modulation system is composed of a central control station and a terminal station which manage and control communication between terminals accommodated in the system, and the wireless communication system of the present wireless communication system described later. Using frames, the terminal stations wirelessly communicate with each other based on the control data transmitted from the centralized control station. The system automatically selects any one (or more) of the terminal stations in the system as the central control station.

The radio communication system and the individual terminals constituting the radio communication system will be described in detail below.

As shown in FIG. 7, for example, the wireless communication system comprises a network control device 101, a public line 102, a wireless telephone 103, and wireless data terminals 104 to 109.

To explain the configuration of each section in detail, the network control device 101 accommodates a public line 102 and provides a public network communication service to a terminal station in the system. Wireless phone 103
Exchanges control data or voice data with the centralized control station or another terminal station, performs voice communication via the public line 102, and performs so-called extension communication between a plurality of terminal stations. The wireless data terminals 104 to 109 perform control data communication and data communication with the centralized control station or other terminal stations. The terminal stations of the wireless telephone 103 and the wireless data terminals 104 to 109 are collectively referred to as the wireless terminal 11.
0 (generic number of 103 to 109).

In this case, the wireless data terminals 104-109
The term refers to a terminal device (data terminal) having a function of transmitting and receiving data in a burst or a data input / output device and a wireless adapter that controls wireless communication, or a terminal device that integrates them. For example, in the example of FIG. 7, the computer 104, the multimedia terminal 105,
Printer 106, facsimile 107, copier 108,
In addition to the LAN (Local Area Network) gateway 109, devices such as an electronic camera, a video camera, and a scanner are applicable.

The wireless telephone 103 and the wireless data terminals 104 to 109 described above are large in the present wireless communication system in that they can freely communicate with each other and can access the public line 102 at the same time. It is a feature. The detailed configuration and operation will be described below.

"Wireless Phone" FIG. 8 is a diagram showing an internal configuration of the wireless phone 103 shown in FIG.
, Memory 202, speech path unit 203, ADPCM
(Adaptive Differential Pulse Code Modulatio
n) a codec section 204, a frame processing section 205,
Radio control unit 206, radio unit 207, and handset 208
, A microphone 209, a speaker 210, a key matrix 211, and a display unit 212.

The structure of each of the above-mentioned parts will be described in detail. The main controller 2
01 controls the entire wireless telephone 103. Memory 2
02 is an R storing the control program of the main control unit 201.
OM, call code (system ID) of this wireless communication system
.EEPROM for storing the sub-ID of the wireless telephone 103
(Electrically erasable programmable ROM), RAM serving as a work area for controlling the main control unit 201, and the like. The communication path unit 203 is the handset 20
8, the input / output blocks of the microphone 209 and the speaker 210, and the ADPCM codec unit 204 are interfaced.

The ADPCM codec section 204 converts the analog voice information from the speech path section 203 into an ADPCM code and the ADPCM coded information into analog voice information. The frame processing unit 205 uses the ADP
It has a function as a channel codec section for performing a process such as scrambling on the CM coded information and time-division-multiplexing into a predetermined frame. Frame processing unit 205
The data assembled into a wireless frame, which will be described later, will be transmitted to the main device and the target terminal station via the wireless unit 207.

The radio control unit 206 has the functions of performing transmission / reception of the radio unit 207, frequency switching, carrier detection, level detection, and bit synchronization. The wireless unit 207 modulates the digital information from the frame processing unit 205, converts it into a format that can be wirelessly transmitted, and sends the format to an antenna (not shown).
The information wirelessly received via the antenna is demodulated and converted into digital information. The handset 208 is for inputting and outputting a call voice signal. The microphone 209 collects and inputs a voice signal. The speaker 210 outputs the audio signal in a loud voice. The key matrix 211 includes function keys such as dial keys for inputting dial numbers and the like, external line keys, hold keys, speaker keys and the like. The display unit 212 is
The dial number input from the key matrix 211 and the usage status of the public line are displayed.

The wireless telephone 103 can be composed of a channel codec board described later.

"Wireless Adapter" FIG. 9 is a diagram showing the internal structure of a wireless adapter connected (or built-in) to the wireless data terminal equipment 104 to 109 shown in FIG. Wireless adapter 302 connected to data terminal (peripheral device) 301
Is a wireless unit 303, a main control unit 304, and a memory 305.
A communication interface unit 306, a timer 307,
A channel codec section 308, a radio control section 309,
The configuration includes an error correction processing unit 310.

The configuration of each of the above parts will be described in detail. A data terminal (peripheral device) 301 to which a wireless adapter 302 is connected.
Is a data terminal represented by a computer, or
Peripheral devices represented by printers and facsimiles.
The wireless adapter 302 is a data terminal (peripheral device) 301
Can be connected via a communication cable or internal bus.

The radio section 303 has an internal structure as shown in FIG. 11 described later, which will be described with reference to FIG. The main control unit 304 includes a CPU, peripheral devices that perform interrupt control / DMA (Direct Memory Access) control, an oscillator for a system clock, and the like, and controls each block in the wireless adapter 302. The memory 305 includes a ROM that stores programs used by the main control unit 304, a RAM that is used as a buffer area for various processes, and the like.

The communication interface unit 306 is equipped in the data terminal (peripheral device) 301, for example, RSC232.
C, Centronics (8-bit parallel interface for printers), communication interfaces such as LAN, internal buses of personal computers and workstations such as ISA (Industry Standard Architectrue) bus, PCMCIA (Personal Computer Memory Car)
d International Association) Controls when the wireless adapter 302 communicates using an interface or the like.

The timer 307 supplies timing information used by each block inside the wireless adapter 302. The channel codec unit 308 not only assembles and disassembles radio frames, but also CRC (Cyclic Redundancy).
A simple error detection process represented by Check), a scramble process, a control of the wireless unit 303, and the like are performed. Wireless control unit 3
09 has a function of controlling transmission / reception switching of the wireless unit 303, frequency switching, and the like, and also has a function of performing carrier detection, level detection, and bit synchronization.

The error correction processing unit 310 has a function of detecting or correcting a bit or byte error that occurs in communication data due to various wireless environments. The error correction processing unit 310 inserts an error correction code into the communication data at the time of transmission to give redundancy to the data, and at the time of reception, calculates the position where the error has occurred and the error pattern by arithmetic processing, thereby receiving the received data. Correct the bit error that occurred in.

"Network Control Device" FIG. 10 is a diagram showing the internal configuration of the network control device shown in FIG. 1. The main control unit 401, the memory 402, the line interface unit 403, and the ADP.
CM codec section 404 and channel codec section 40
5, wireless control unit 406, wireless unit 407, and detection unit 4
And 08.

The configuration of each of the above parts will be described in detail. The main controller 4
01 controls the entire network control device. Memory 402
Is composed of a ROM for storing a program and a calling code (system ID) of the present wireless communication system, a RAM for storing various data for controlling the main control unit 401, and a RAM serving as a work area for various calculations. There is. The line interface unit 403 is the public network line 102 (see FIG. 7).
Power supply for accommodating the data, transmission of a selection command, closing of a DC loop, control of a public network such as PCM conversion, reception of a selection command, and transmission of a calling command.

The ADPCM codec unit 404 converts the analog voice signal received by the line interface unit 403 via the public network line 102 into an ADPCM code, transfers the ADPCM code to the channel codec unit 405, and simultaneously the ADPCM code from the channel codec unit 405. The converted audio signal is converted into an analog audio signal. The channel codec unit 405 performs processing such as scrambling on the ADPCM-coded information and time-division-multiplexes it into a predetermined frame. The data assembled into a wireless frame described later by the channel codec unit 405 is transmitted to the centralized control station and the target wireless terminal 110 via the wireless unit.

The radio control section 406 controls the transmission / reception switching, frequency switching, etc. of the radio section 407, and also has the functions of carrier detection, level detection, and bit synchronization. The radio unit 407 modulates the framed information from the channel codec unit 405, converts it into a format that can be wirelessly transmitted and sends it to the antenna, demodulates the information wirelessly received through the antenna, and processes it into digital information. To do. The detection unit 408 detects various tones such as incoming call detection, loop detection, PB signal, dial tone, and ring tone.

"Radio Unit" FIG. 11 is a diagram showing an internal configuration of a radio unit commonly used by the wireless terminals 110 of the present wireless communication system described with reference to FIGS.

The configuration of each part of the radio section will be described in detail below.
a and 501b are transmitting / receiving antennas, 502 is a switch for transmitting / receiving antennas 501a and 501b, and 503.
Is a band pass filter (hereinafter abbreviated as BPF), 50
4 is a transmission / reception changeover switch, 505 is a reception amplifier,
Reference numeral 506 is a transmission amplifier.

Reference numeral 507 is a 1st.IF down converter, 508 is an up converter, 509 is a transmission / reception changeover switch, and 510 is a signal for removing an unnecessary band signal from the signal converted by the 1st.IF down converter 507. BPFs 511 are down converters for the 2nd.IF, and the down converter 507 for the 1st.IF and the down converter 51 for the 2nd.IF.
1 constitutes a reception form of the double conversion system.

Reference numeral 512 is a 2nd.IF BPF, and 513 is a 90-degree phaser. A quadrature detector 514 detects and demodulates the command received by the 2nd.IF BPF 512 and the 90-degree phase shifter 513. 5
Reference numeral 15 is a waveform shaping comparator, 516 is a voltage control type oscillator (hereinafter abbreviated as VCO) of the receiving system, and 517 is a low pass filter (hereinafter abbreviated as LPF). 51
Reference numeral 8 denotes a PLL (Phase Locked Loop) including a programmable counter, a prescaler, a phase comparator, and the like, and the VCO 516, LPF 517, and PLL 518.
The frequency synthesizer of the receiving system is constituted by.

519 is a VC for carrier command generation
O and 520 are LPFs. 521 is a P including a programmable counter, a prescaler, a phase comparator, and the like.
LL, the VCO 519, LPF 520, PLL
A frequency synthesizer for hopping is constituted by 521.

Reference numeral 522 is a transmission system VC having a modulation function.
O and 523 are LPFs. Reference numeral 524 is a P including a programmable counter, a prescaler, a phase comparator, and the like.
LL, and the VCO, LPF, and PLL constitute a frequency synthesizer of a transmission system having a frequency modulation function. Reference numeral 525 is a reference clock for various PLLs 518, 521, 524, and 526 is a band limiting filter for transmission data (baseband command).

[Wireless Frame] In this wireless communication system, the communication service of each wireless terminal is provided by using the circuit switching channel for voice communication and the packet switching channel for image / video / data communication provided in the wireless frame. provide. A centralized control station and a terminal station exist in the system, and the centralized control station manages wireless communication and wireless resources of the entire system.

FIG. 12 is a diagram showing the internal structure of a radio frame used in the embodiment of the invention described later. The radio frame is roughly divided into a control section and a data section. For example, when two terminal stations communicate with each other, each terminal station exchanges the control section with the central control station while It takes a form of communication for exchanging the data section with the station.

The inside of the illustrated radio frame is CNT, L
It is composed of a total of 6 fields of CCH, two voices, data and END. The CNT field is transmitted by the central control station at the start of the radio frame, and the terminal station
It is used to establish bit synchronization and frame synchronization by receiving the NT field. The LCCH field is used for control when connecting / disconnecting a line, and when the central control station allocates a hopping pattern to a terminal station prior to disconnecting the line. The two audio fields are used to exchange audio data in both directions.
The END field indicates the guard time for changing the frequency in the next frame.

FIG. 13 shows the internal structure of the CNT field of the radio frame, FIG. 14 shows the internal structure of the LCCH field, FIG. 15 shows the internal structure of the data field, and FIG. 16 shows the internal structure of the voice field. FIG. 17 is a diagram showing the internal structure of the END field.

In the figure, CS is carrier sense of 12.8 usec, R is a ramp bit of 6.4 usec, PR is a 56-bit preamble for complementing bit synchronization, SYN is a 31-bit frame defined by 1 bit (dummy) + RCR. Indicates synchronization respectively. ID is a 63-bit calling signal defined by RCR + 1 bit (dummy), UW is a 24-bit unique word (for supplementing byte synchronization), and BF is 8
Bit basic frame number information (1 to 20 is one cycle) is shown.

WA is a terminal station in the sleeve state,
System address of the terminal station to be activated, Rev is reserved, GT is guard time, CS0 / CS1 / CS2 is carrier sense, DA is system address, CRC is BF
To CRCCH data, CRC calculation result, C
F is the guard time for frequency switching, T / R is 32 kb
The B channels for storing ps data are shown respectively. Also,
Numerical values shown in the figure represent the number of bits, and show an example of the length of each part.

"Frequency Switching" FIG. 18 is a conceptual diagram of frequency switching used in this wireless communication system. In a wireless communication system, a 16 MHz frequency band licensed for use in Japan is divided into 16 frequency channels of 1 MHz width for use. The centralized control station and the wireless terminal perform communication while switching 16 frequency channels in a predetermined order at regular intervals. This predetermined order is called a hopping pattern.

The number of frequency channels used for the hopping pattern does not change, and it is possible to adopt a pattern in which the frequencies used do not overlap within the same unit time. That is, one hopping pattern can be considered to form one communication channel, and at the same time, it is possible to support up to 16 communication. Also, when there are multiple connecting devices connected to the centralized control station, different hopping patterns can be used for each connecting device to prevent radio wave interference between the connecting devices. Has become. By the method described above, it is possible to realize a wireless communication system having a multi-cell configuration, and it is possible to secure a wide communication area.

FIG. 19 is a diagram showing an example of the frequency switching operation. In the illustrated example, the wireless terminals A to F are operating under the control of the central control station, and the wireless terminals A and E and the wireless terminals D and
It is assumed that E is communicating. The central control station writes the information for controlling the system while performing frequency switching according to a specific hopping pattern (in the example shown, f1, f2, f3 ... In this order). A wireless frame containing fields is being transmitted. Each wireless 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.

Further, the centralized control station and the wireless terminal (= terminal station)
The LCCH field for exchanging control commands is also transmitted and received with the same hopping pattern as the CNT field. After the centralized control station using the control unit and the wireless terminal (= terminal station) are negotiated, each wireless terminal (= terminal station) is assigned a hopping pattern (used by the centralized control station). The frequency is switched according to the different hopping pattern), and data communication is started. In the illustrated example, a wireless terminal (wireless telephone)
A and B use f16, f25, f24 ... And wireless terminals (radio telephones) D and E use f16, f25, f24. By the above-described frequency channel switching processing, it becomes possible to provide a plurality of communication services (as many as the number of hopping patterns) at the same time.

Next, a specific operation of the present wireless communication system will be described in some cases.

[Detailed Operation] In this wireless communication system, under the control of a central control station that controls the entire system, each wireless terminal assigned with the communication resources necessary for wireless communication directly performs data communication between the terminals. It is a pseudo centralized control type (hybrid type) system. In this central control station, it is not necessary to install a specialized terminal that specializes in system control, and the system automatically sets one of the wireless terminals in the system to the central control station. Does not require user terminal settings. Each wireless terminal exchanges various control commands with the central control station in the first half of the communication frame (CNT, LCCH), switches the hopping pattern used in the second half of the communication frame (voice field, data field), and To communicate.

(1) Basic operation procedure The wireless terminal in the idle state follows the hopping pattern of the central control station and constantly monitors the CNT field transmitted from the central control station. In order for each wireless terminal to communicate, an LCC is used on an arbitrary frequency channel with the central control station.
Using the H field, it is necessary to perform negotiations such as notification of the type of data to be communicated and designation of a hopping pattern. The LCCH field includes control commands, parameters and the like, and notifies the presence / absence of an incoming call to the outside line and a communication request between wireless data terminals. After the negotiation is completed, the wireless terminal can switch the hopping pattern and communicate with the partner wireless terminal.

(1-1) Operation of Wireless Terminal after Power is Turned On FIG. 20 is a sequence showing the operation of the wireless terminal after power is turned on. After the power is turned on, when the wireless terminal becomes the central control station, the frequency channel used for the hopping pattern is determined, and the wireless frame including the CNT field in which the synchronization signal and the hopping pattern information are stored in the wireless frame is set at a predetermined timing. (Step S1). On the contrary, if there is a centralized control station that transmits a wireless frame including a valid CNT field in the system after the wireless terminal is activated and the wireless terminal can become the terminal station, the wireless terminal registers the terminal address. Is received from the user and stored.

Next, the radio frame from the centralized control station is waited at an arbitrary frequency, and when the CNT field in the radio frame is received, the NFR in the CNT field is read and the frequency used in the next unit time is recognized. . The terminal station changes the frequency based on the received frequency and waits for the next radio frame. The terminal station repeats the above processing to recognize the hopping pattern used for CNT field transmission in the centralized control station.

When the above processing is completed in the terminal station, the terminal station requests the central control station to register the terminal station using the LCCH field in the radio frame (step S).
2). In the LCCH field in the radio frame transmitted for requesting the registration of the terminal station, the global address received by all the terminals is written in DA, and the data indicating that new registration is performed is written in the data part. Upon receiving the LCCH field transmitted by the terminal station, the centralized control station confirms that the global address is stored in DA, and if the data field contains the address of the terminal station and the registration request signal, The terminal station address is newly registered based on the information.

When the registration process is completed, the central control station notifies the newly registered terminal station of the address of the central control station using the LCCH field of the radio frame (step S3). When the terminal station receives the address of the centralized control station written in the LCCH field, it stores the address of the centralized control station, and after the end of the processing, writes a startup completion notification to the centralized control station in the LCCH field. Transmit a wireless frame (step S
4). When the centralized control station receives the startup completion notification from the terminal station, it shifts to normal processing. After the start-up completion notification is output at the terminal station, transmission from the terminal station becomes possible (step S5).

(1-2) Initial Setting of Wireless Terminal FIG. 21 is a flowchart showing the initial setting operation of the wireless terminal. When the power is turned on, the wireless terminal performs internal initialization processing (step S11), and then receives the CNT field of the wireless frame at an arbitrary frequency (step S11).
12). Here, if the wireless frame (= CNT field) is not received for a certain period of time (the answer in step S12 is negative), the internal counter is activated (step S13), and the frequency is shifted to the next arbitrary frequency channel (step S).
14) Attempt to receive the radio frame (= CNT field) again (step S12).

When the value of the internal counter reaches a predetermined value (for example, 10) without receiving a valid radio frame by repeating the above-mentioned operation (the answer in step S15 is affirmative), the central control station exists in the system. Decide not to
After that, the wireless terminal itself starts the initial setting process as the centralized control station. When the wireless terminal itself becomes the centralized control station, first, the frequency that can be used for the hopping pattern is selected (step S16), and then the hopping pattern information and the wireless frame in which the global address of the present wireless communication system is written in the CNT field is the hopping pattern. While switching the frequency according to (Step S1
9), transmitting to each wireless terminal in the system (step S
17). When the terminal station registration request from the terminal station is received during the above operation (the answer in step S18 is affirmative), the process proceeds to the terminal station registration process (step S20).

On the other hand, in step S12, when the terminal station receives a valid radio frame, the terminal station starts the initialization process thereafter. In order to obtain the hopping pattern to be used, the wireless frame from the central control station is waited for reception at an arbitrary frequency (step S21).
When the terminal station receives the wireless frame from the centralized control station (the answer in step S21 is affirmative), the terminal station acquires the frequency to be used for the next unit time from the NF of the CNT field (step S22) and sets the reception frequency to the corresponding frequency. After moving to the channel (step S23), it waits for reception of a radio frame from the next centralized control station. The terminal station repeats the above operation,
If the frequency has completed one cycle (the answer in step S24 is affirmative), the hopping pattern is registered (step S2).
5).

Next, the terminal station performs a process for notifying the central control station of the terminal address (step S26). Specifically, the global address received by all terminals is written in DA of the LCCH field in the radio frame, and DA
A registration request and a terminal address are written in the TA field and transmitted to the centralized control station. After the transmission, the terminal station receives the radio frame while changing the frequency according to the acquired hopping pattern (the answer in step S27 is positive).

Next, the terminal station receives the LCCH from the central control station.
Detecting its own terminal address in DA in the field, D
When the registration completion command is confirmed in the ATA section (the answer in step S28 is affirmative), the wireless frame in which the address of the centralized control station is written in DA of the LCCH field and the startup completion command is written in the DATA field is transmitted to the centralized control station. It transmits to (step S29).

(1-3) Operation of Centralized Control Station When Registering Terminal Station FIG. 22 shows the terminal station registration processing (step S2 in FIG. 21).
It is a flowchart which shows the operation | movement at the time of the terminal station registration of the centralized control station corresponded to 0). When there is a registration request from the terminal station in the LCCH field in the radio frame received by the centralized control station (Yes in step S31), the terminal station address is confirmed (step S32). As a result of checking the terminal station address, when it is detected that the terminal station address is normal (the answer in step S33 is affirmative), the central control station performs the terminal station address registration process and stores the address information (step S34). On the other hand, when the terminal station address is not normal (the answer in step S33 is negative), the registration request transmitted from the terminal station is discarded (step S38), and the process ends.

When the registration of the terminal station is completed, the wireless frame including the LCCH field in which the terminal address of the central control station is written in DATA in the wireless frame and the address of the terminal station is written in DA is transmitted to the registered terminal station. (Step S35). If the centralized control station cannot confirm the start-up completion notification signal from the terminal station that has completed registration after transmitting the wireless frame (the answer in step S36 is negative),
It is detected whether a predetermined time has passed (step S3).
9).

If the predetermined time has not elapsed (step S
The answer of 39 is negative), and again waits for the start-up completion notification from the terminal station. On the other hand, when the predetermined time has elapsed (the answer in step S39 is positive), the wireless frame for notifying the terminal address of the centralized control station is transmitted again to the terminal station (step S35). When the start-up completion notification signal from the terminal station is detected in step S36, a new registration completion process for the terminal station is performed (step S37), and the process ends.

(2) Data communication between wireless data terminals Here, for example, two wireless data terminals 104A, 10
FIG. 23 shows the processing when burst data communication is performed between 4B.
26 to 26. 23 is a sequence diagram of control commands exchanged among the centralized control station, the wireless data terminal 104A, and the wireless data terminal 104B, FIG. 24 is a processing flow of the centralized control station, FIG. 25 is a processing flow of the wireless data terminal 104A, and FIG. Is a processing flow of the wireless data terminal 104B. For convenience of explanation of the operation, the frequency channel for the wireless data terminal to exchange wireless frames with the central control station is f5 for the wireless data terminal 104A and f7 for the wireless data terminal 104B.

(2-1) Connection Processing A wireless terminal that transmits data needs to exchange commands such as a transmission request with the central control station and receive allocation of resources such as hopping patterns. It is assumed that all commands are exchanged between the centralized control station and the wireless data terminals 104A and 104B by using the LCCH field in the wireless frame.

23 to 26, when data to be transmitted is generated (step S81), the wireless data terminal 104A transmits a communication request command (C41) to the centralized control station (step S82). When the centralized control station receives the communication request command (C41) (step S61), the centralized control station transmits communication resources such as hopping patterns to the wireless data terminal 1.
It is reserved for 04A (step S62), and the communication setting command (C42) including the communication resource information is transmitted to the wireless data terminal 104A (step S63). When the wireless data terminal 104A receives the communication setting command (C42) (step S83), the hopping pattern obtained from the communication resource information is set in the channel codec section (step S84). When the above setting is completed in the wireless data terminal 104A, the communication setting completion command (C4
3) is transmitted (step S85).

Next, the wireless data terminal 104A receiving the wireless ID from the data terminal transmits an address command (C44) to the centralized control station (step S86). When the centralized control station receives the address command (C44) (step S64), the wireless terminal having the terminal address specified in the address command (in this case, the wireless data terminal 1
04B), the data incoming command (C45) is transmitted (step S65). The wireless data terminal 104B receives the data incoming command (C45) (step S10).
1) If the data can be received, the data reception response command (C46) is transmitted to the central control station (step S102).

When the central control station receives the data incoming response command (C46) from the wireless data terminal 104B (step S66), it sends the communication setting command (C47) including the hopping pattern communication resource information used for data communication. The data is transmitted to the wireless data terminal 104B (step S67). Upon receiving the communication setting command (C47) in the LCCH field (step S103), the wireless data terminal 104B sets a hopping pattern obtained from the communication resource information in the frame processing unit (step S104).

Next, the centralized control station controls the wireless data terminal 104.
A communication response command (C48) is transmitted to A (step S68) to notify that the wireless data terminal 104B has responded. When the wireless data terminal 104A confirms the partner response by the communication response command (C48) (step S8)
7), communication start command (C49) to the central control station
Is transmitted (step S88), the wireless data terminal 10
Data communication with 4B is started (step S89). When the centralized control station receives the communication start command (C49) from the wireless data terminal 104A (step S69), it determines that the wireless data terminals 104A and 104B have started data communication, and the communication end command (C53).
(Step S70).

After the wireless link is established between the wireless data terminal 104A and the wireless data terminal 104B, wireless frames are exchanged while switching the frequency with a common hopping pattern. At the end of communication, the wireless data terminal 104A transmits a communication end command (C53) to the centralized control station (step S9).
0). When the central control station receives the communication end command (C53) (step S70), it transmits the communication setting cancel command (C54) to the wireless data terminal 104A (step S71).

Next, the centralized control station controls the wireless data terminal 104.
The communication resources such as hopping patterns assigned to A and 104B are released (step S72). When the wireless data terminals 104A and 104B receive the communication setting cancellation command (C54, C55) (step S91,
In step S107), the communication settings are cleared (steps S92 and S108).

[0068]

In the conventional wireless communication system, a public line call, an extension line call, which a public network gateway accommodates in a wireless terminal in the system, is carried out by the above-mentioned procedure.
The purpose is to provide communication services such as data transmission between data terminals. However, the conventional wireless communication system has the following problems regarding the central control station.

That is, in the wireless communication system, it is necessary to install one or more centralized control stations in the system in order to control and manage the entire system. Therefore, in the conventional wireless communication system, a method has been adopted in which the wireless terminal first turned on by the user in the system is automatically activated as a central control station. However, in the conventional method,
For example, the wireless terminal that was first turned on (= centralized control station)
Is set in a biased position in the system, in other words, if the distance from each terminal station is significantly different, there may be terminal stations that cannot exchange control data with the central control station. There was a problem that it would occur. Further, if the centralized control station exists at the central position of the system, there is a problem that even a terminal station within the wireless coverage may be incapable of communication.

The present invention has been made in view of the above points, and solves the problem that the centralized control station is set at an unbalanced position in the system, and cannot communicate control data with the centralized control station, thus making communication impossible. An object of the present invention is to provide a wireless communication system capable of eliminating a terminal station that falls.

[0071]

To achieve the above object, the invention of claim 1 is such that at least one of the plurality of wireless terminals having a wireless section capable of wireless communication constitutes a centralized control station. In the wireless communication system in which the other wireless terminal configures a terminal station and the centralized control station and the terminal station perform wireless communication in a communication form using a wireless frame, the wireless terminal detects a radio wave environment at startup. It is characterized by comprising a detecting means and a selecting means for selecting whether the wireless terminal operates as a central control station or a terminal station based on the detected radio wave environment.

In order to achieve the above-mentioned object, the invention of claim 2 is the wireless communication system according to claim 1, wherein the wireless terminal comprises a measuring means for measuring a radio wave reception intensity and a plurality of terminal stations which have measured. First to compare the radio reception strength of
And a second comparing means for comparing the difference value of the radio wave reception intensity from each terminal station with the specified value of the centralized control station, and the difference value of the radio wave reception intensity is larger than the specified value of the centralized control station. And a terminal station resetting means for resetting itself as a terminal station after transmitting the management information of the central control station to the terminal station having the maximum radio wave reception intensity when judged. It is characterized by doing.

In order to achieve the above object, the invention of claim 3 is the wireless communication system according to claim 1 or 2, wherein the wireless terminal centrally controls itself when it receives the management information as a terminal station. Centralized control station resetting means for resetting as a station and third comparing means for comparing the difference value of the previous radio wave reception intensity and the difference value of the current radio wave reception intensity when resetting itself as the central control station And a transmitting unit that transmits the management information to the central control station when it is determined that the difference value of the previous radio wave reception intensity is smaller, and a terminal station that resets itself as the terminal station after the transmission of the management information. And resetting means.

[0074]

Embodiments of the present invention will be described below with reference to the drawings.

First, the internal configuration and operation of the channel codec section of the radio communication system according to this embodiment will be described. The channel codec section according to the present embodiment is a frame processing section for assembling or disassembling data into the above-described radio frame format, a radio section for performing modulation / demodulation, and an ADPCM codec section for performing digital encoding / decoding of voice. It is roughly divided into.

FIG. 1 is a block diagram centering on the internal configuration of the channel codec section according to the present embodiment, which includes a frame processing section 1, a handset (voice input / output section) 2,
The ADPCM codec section 3 and the wireless section 4 are generally configured.

Further, the frame processing unit 1 includes a main control unit interface (CPU bus I / F) 5 and an ADPCM.
Interface (ADPCM I / F) 6, mode register 7 for operating mode setting, hopping pattern register (HP register) 8, frame number / next frequency number register (BF / NF register) 9, and system I
D register 10 and intermittent activation terminal address register (W
A register) 11, LCCH register 12, and FIF
O buffer 13, timing generator 14, CNT channel assembling / disassembling unit 15, LCCH assembling / disassembling unit 16
A data assembling / disassembling unit 17 and a voice assembling / disassembling unit 18
A frame synchronization unit 19, a unique word (UW) detection unit 20, a CRC encoding / decoding unit 21, a bit synchronization unit 22, a radio control unit 23, and an intermittent reception control unit 24.
A scrambler / descrambler 25, an AD converter 26, a reception level detector 27, and a main controller data bus 28. Reference numeral 29 in the drawing is an interrupt signal.

The configuration and operation of the main part of the channel codec section will be described in detail. The timing generation section 19 of the frame processing section 1 of the channel codec section incorporated in the centralized control station.
Generates a reference for the operation timing of the channel codec section. The centralized control station transmits the radio frame in synchronization with the timing signal generated by the timing generation unit 19. In addition, the terminal station holds the synchronization according to the frame synchronization word in the wireless frame and receives the wireless frame.

When the CNT field data is stored in the radio frame and transmitted from the centralized control station, the main control section uses the HP register 8 in the frame processing section 1 and the system ID.
Necessary values are written in the register 10, the WA register 11, etc., and a frequency channel number according to a hopping pattern for CNT field data transmission is written in the BF / NF register 9. The value in the BF / NF register 9 is updated in synchronization with the timing signal.

In the frame processing section 1, the data from each register is assembled by the CNT channel assembling / disassembling section 15 and sent to the radio section 4. On the other hand, when the terminal station recognizes a valid CNT field in the received wireless frame, the CNT channel assembling / disassembling unit 15 disassembles the CNT field and performs various processes according to the CNT field.

The system ID register 10 is used to receive a subsequent wireless frame only when the system ID in the received wireless frame matches the own station.
The WA register 11 is used by the centralized control station to specify a terminal for restarting a terminal station that is receiving intermittently. The HP register 8 is rewritten using BF / NF data. The frequency number stored in the NF field is CNT.
Since the field hopping pattern is followed, the hopping pattern used in the voice field and the data field is generated by time-shifting the hopping pattern register created based on the frequency number written in the NF field.

When transmitting the LCCH field data, the LCCH assembling / disassembling unit 16 assembles the data set in the LCCH register 12 by the main control unit of the wireless terminal on the transmitting side. In addition, the valid LC in the received radio frame
When the CH data is confirmed, it is decomposed by the LCCH assembling / disassembling unit 16 and stored in the LCCH register 12.

At the time of transmitting voice data using the voice field, the voice data input from the handset (voice input / output unit) 2 is digitally encoded by the ADPCM codec unit 3 and then the frame processing unit 1 via the ADPCM interface 6. Is taken into. The voice assembling / disassembling unit 18 of the frame processing unit 1 assembles the digitally encoded voice data into input voice data, and sends the input voice data to the radio unit 4 at a predetermined timing. Also, the voice assembling / disassembling unit 18
On the contrary, decomposes the voice data received from the wireless unit 4,
Output to the ADPCM codec unit 3 and the handset (voice input / output unit) 2 via the DPCM interface 6.

At the time of data transmission using the data field, the data assembling / disassembling unit 17 converts the data into serial data and sends it to the radio unit 4 at a predetermined timing. On the contrary, when the data assembling / disassembling unit 17 receives the data from the wireless unit 4, the data assembling / disassembling unit 17 converts the data into parallel data. Further, at the time of data transmission, the CRC encoding / decoding unit 21 generates a CRC code, stores it in the CRC field and transmits it. As a result, the error check can be detected by the CRC check on the receiving side.

At the same time, all the transmission data other than the frame synchronization word and the unique word are scrambled by the scrambler / descrambler 25 in order to reduce the data imbalance and facilitate the extraction of the synchronization clock. Conversely, when a unique word is detected during data reception, the scrambler / descrambler 25 descrambles the data, performs a CRC check, and inputs the data to the decomposing unit of each field.

Next, detailed operations of the radio communication system in which the above-mentioned channel codec section according to the present embodiment is mounted will be described with reference to FIGS. 2 to 6. Note that the configuration of this wireless communication system is the same as that of FIG. 7 described above, and a description thereof will be omitted.

[Operation immediately after power-on] At least one centralized control station is always required in the wireless communication system. In the present embodiment, the wireless communication system in which power is first turned on in the wireless communication system. It is characterized by being automatically determined by the terminal. Further, in the present embodiment, when the automatically selected position of the central control station in the wireless communication system is not the optimum position for the system, the wireless communication system at the position where the wireless communication system is stabilized is present. The feature is that the centralized control station is moved to the terminal.

In the present embodiment, referring to FIGS. 2 to 6 and FIG. 7, the initial setting of the centralized control station and the terminal station and the processing for moving the centralized control station to the position where the wireless communication system is stabilized will be described. explain. For the sake of convenience, the wireless terminal which is first turned on in FIG. 7 is referred to as 104 (terminal address =
01), the next wireless terminal to be turned on is 105 (terminal address = 02), the initial setting of the centralized control station is completed, and the system receives normal operation. 106 terminal stations with a high reception level (terminal address = 03), 1 terminal station with the lowest reception level
07 (terminal address = 04).

(1) Operation of Radio Terminal as Central Control Station When the radio terminal 104 is turned on, the radio terminal 1
Reference numeral 04 waits for a wireless frame transmitted from the central control station in the wireless communication system, and when the wireless frame cannot be received, determines that there is no central control station in the system, and the wireless terminal 104 itself becomes the central control station. Initialize.

2 and 3 are operation flowcharts when the power of the wireless terminal 104 is turned on. After the power is turned on by the user, the wireless terminal 104 performs an internal initialization process (step SA1) and then determines whether or not a wireless frame is received from the centralized control station (step SA2). When the CNT field in the wireless frame is received from the centralized control station at an arbitrary frequency (Yes in step SA2), the process proceeds to the initialization setting process of the terminal station (step SA7).

On the other hand, when the wireless frame (only the CNT field is valid) is not received from the central control station for a certain period of time (the answer to step SA2 is negative), the internal counter is activated (step SA3) and the frequency is assigned to the next frequency channel. Shift (step SA4), and again the radio frame (CNT
Attempt to receive the field) (step SA5). When the value of the internal counter reaches a predetermined value (for example, 10) by repeating the above operation (the answer in step SA5 is affirmative),
After judging that there is no central control station in the system,
The wireless terminal 104 itself performs initial setting as a centralized control station (step SA6).

When the wireless terminal 104 serves as the central control station, the value input by the user using the DIP switch, the dial key of the telephone or the like, the keyboard of the computer or the like is stored as the terminal address (step SB1), A process for creating a hopping pattern used for is performed (step SB2). At this time, the wireless terminal 104 inspects all the available frequency channels, selects a frequency with a good radio wave condition from each frequency channel, and selects a frequency that is random or a certain order as a hopping pattern.

Thereafter, the wireless terminal 104 transmits a wireless frame in which system management information (global address, hopping pattern, allocation status of hopping pattern, etc.) is written in the CNT field to the terminal station in the system at regular intervals (step SB3). ). At the same time, the wireless terminal 10
4 monitors the internal timer and monitors the constant time (step SB
4) The wireless frame in which the location management command is written in the LCCH field is transmitted to each terminal station (step SB5).

After transmitting the position management command, the centralized control station (= wireless terminal 104) waits for a response command from each terminal station (step SB6). When the radio frame including the response command is received from the terminal station (the answer in step SB6 is affirmative), the terminal address written in the response command in the LCCH field is read (step SB7), and at the same time, the channel codec section is received. The reception level is read from the level detection unit 27 (see FIG. 1 above) (step SB8), and two sets of data are regarded as one set, and the system management information (provisionally SM
I1) (step SB9).

Next, the centralized control station (= wireless terminal 104) reads the SMI1 in the memory, compares the maximum value and the minimum value of the reception level, and searches for the reception sensitivity difference (step SB10). When the reception sensitivity difference shows a certain value or more (the answer in step SB10 is affirmative), the process shifts to a control change process for moving the central control station (step SB1).
2). On the other hand, when the reception sensitivity difference is less than a certain value (No in step SB10), it is determined that the position of the centralized control station (= wireless terminal 104) in the system is proper, and normal operation is continued. To do.

(2) Initial Setting of Radio Terminals as Terminal Stations The radio terminals 105 to 107 which are powered on after the second power supply in the radio communication system are automatically initialized as terminal stations. Here, the wireless terminal 105 of FIG. 1 will be described as an example.

FIG. 4 is an operation flowchart when the power of the wireless terminal 105 is turned on. The wireless terminal 105 immediately after the power is turned on
After initializing internal settings (step SC1), if the user inputs a terminal address to be set by using a keyboard attached to the data terminal, the terminal address is stored (step SC2), and an arbitrary value is stored. Switch to frequency (step SC3).

Next, the wireless terminal 105 waits for reception at an arbitrary frequency in order to receive a wireless frame (only the CNT field portion is valid) from the centralized control station (= wireless terminal 104) (step SC4). When the wireless terminal 105 receives a wireless frame from the centralized control station (= wireless terminal 104) (the answer in step SC4 is affirmative), the CNT field in the wireless frame is read and the global address is read from the ID (step SC5). , NF stores the frequency used for the next unit time (step SC
6).

Next, after the reception frequency of the radio section is moved to the obtained frequency channel (step SC7), the reception standby state is entered again. By repeating this operation, the wireless terminal 105 follows the frequency channel of the centralized control station (= wireless terminal 104), and when the centralized control station (= wireless terminal 104) transmits a wireless frame (only the CNT field is valid). It is possible to recognize the hopping pattern used for (step SC9). When the wireless terminal 105 receives the location management command from the central control station (= wireless terminal 104) (the answer in step SC10 is affirmative), the wireless frame in which the response command is written in the LCCH field is transmitted to the central control station (= wireless terminal). (Step SC11).

(3) Control transfer processing in the centralized control station If there is a variation in the reception sensitivity of the wireless frame received from the terminal station in the wireless communication system in step SB11 in FIG. 3 above a certain value, the centralized control station Determines that it is not located at an equal distance from each terminal station in the system, and performs processing for transferring the central control station to another terminal station.

FIG. 5 is an operation flowchart of the control transfer processing of the centralized control station. If the reception sensitivity varies more than a certain value, it is determined that there is a terminal station that is difficult to manage because the centralized control station (= wireless terminal 104) exists in a biased position in the system, and the reception level The terminal address of the terminal station having the highest value (= 03, the terminal address of the wireless terminal 106) is read (step SD1). Next, the frequency is switched (step SD2), the control transfer command and the system management information SMI1 are stored in the LCCH field, and the terminal station (= wireless terminal 106, terminal address: 0
3) is transmitted (step SD3).

After that, the central control station (= wireless terminal 104)
Waits until a control return command or a change completion command is sent from the terminal station to which control has been transferred. When the control return command is transmitted from the terminal station (= wireless terminal 106, terminal address: 03) (the answer in step SD4 is affirmative), the system management information SMI returned at the same time is sent.
1 is read (step SD5), and the terminal address of the terminal station having the next highest reception level of the terminal station having the highest reception level is read.

After switching the frequency for the terminal station (step SD6), the control transfer command and system management information SMI1 are stored again in the LCCH field and transmitted to the terminal station (step S7). On the other hand, the terminal station (= wireless terminal 106, terminal address: 03)
When the change completion command is received from (step S8
Is answered in the affirmative), the central control station (= wireless terminal 104) restarts to release itself from the central control station (step SD9).

(4) Processing of Terminal Station Immediately after Receiving Control Transfer Command The terminal station receiving the control transfer command restarts as a centralized control station and performs reception sensitivity inspection. As a result of the reception sensitivity inspection, when there is no variation in the reception sensitivity difference, the central control station determines that the central control station is located at an appropriate position, and the central control station fixes the position. On the other hand, if there is still a variation in the reception sensitivity difference, check whether the reception level from the terminal station, which had the lowest reception level last time, has improved, and if the reception level has improved, still concentrate. Although the position of the control station is not proper, it is judged that the moving direction of the central control station is proper, and the operation of the central control station is continued. On the contrary, if the reception level is deteriorated, it is determined that the moving direction of the centralized control station itself is inappropriate, and the centralized control station is returned to the original terminal.

FIG. 6 is an operation flowchart of the terminal station to which control has been transferred. When the terminal station (= wireless terminal 106, terminal address: 03) receives a wireless frame from the centralized control station (= wireless terminal 104) and the command in the LCCH field is a control transfer command (the answer to step SE1 is affirmative). ), The system management information SMI1 is read, and the terminal station (= wireless terminal 106, terminal address: 03) is restarted as a centralized control station (step SF2). After restarting as the centralized control station (= wireless terminal 106), the system enters a normal operation state (a state in which wireless frames with data written in the CNT field are continuously transmitted according to a hopping pattern) (step SE3). (= Wireless terminal 106) simultaneously activates an internal timer (step SE4).

When the internal timer expires (the answer to step SE4 is affirmative), the central control station (= wireless terminal 10
6) LCC includes system management information (provisionally SMI2) in which a hopping pattern, a hopping pattern allocation status, a terminal station registration status, and the like are written, and a location management command.
The wireless frame stored in the H field is transmitted to each terminal station (step SE5), and it waits for a response command to be transmitted from each terminal station (step SE6). When a wireless frame is received from the terminal station (Yes in step SE6), the terminal address written in the response command in the LCCH field is read, and at the same time, the reception level detecting section 27 (see FIG. Read the reception level from (see step SE7), 2
One set of data is written in the system management information SMI2 (step SE8).

Next, the centralized control station (= wireless terminal 106) reads the system management information SMI2 from the memory and compares the maximum value and the minimum value of the reception level (step SE).
9). When the reception sensitivity difference shows a certain value or more (the answer in step SE10 is affirmative), it is determined that the position of the central control station is still biased, and the terminal station (wireless terminal 107, terminal The reception level data of the address: 04) is read and compared with the current (= SMI2) reception level of the same terminal station (wireless terminal 107, terminal address: 04) (step SE12).

When the reception level this time is higher, it is judged that the position of the central control station is improved than the position of the previous central control station (the answer to step SE13 is affirmative), and the central control station (= The operation as the wireless terminal 106) is continued.
On the other hand, if the current reception level is worse, it is determined that the centralized control station is not moving in the proper direction (eliminating the bias in the reception sensitivity), and the terminal station (=
The system management information SMI1, SMI is sent to the wireless terminal 104).
After transmitting the radio frame in which 2 and the control return command are written in the LCCH field (step SE14),
Restart as the original terminal station.

If the reception sensitivity difference is less than the predetermined value in step SE10, it is determined that the centralized control station (= wireless terminal 105) is located at an appropriate position in the system, and the operation is continued.

As described above, according to this embodiment,
The wireless terminal activated as the central control station measures the reception level of the wireless frame at the time of reception, and compares the reception levels of the wireless frames transmitted from a plurality of terminal stations,
If there is a certain level of variation in these reception level values, transfer the processing as the central control station to the terminal station with the highest reception level, reset itself as a terminal station,
Also, compare the reception levels again at the transfer destination wireless terminal.If the reception level is improved, fix the central control station thereafter, and if the reception level is not improved, change the reception level difference. Since the centralized control station is repeatedly transferred until is stabilized below a certain value, it is possible to eliminate the problem that the centralized control station is set in a biased position in the system as in the past. There is no terminal station that cannot exchange control data and loses communication.

[0111]

As described above, according to the invention of claim 1, at least one of the plurality of wireless terminals provided with a wireless unit capable of wireless communication constitutes a centralized control station and other In the wireless communication system in which the wireless terminal configures a terminal station, and the centralized control station and the terminal station perform wireless communication in a communication mode using a wireless frame, the wireless terminal includes a detection unit that detects a radio wave environment at the time of start-up, Since the wireless terminal is provided with a selecting means for selecting whether to operate as a centralized control station or as a terminal station based on the detected radio environment, the centralized control station has a biased position in the system as in the past. You can solve the problem that is set to
As a result, there is an effect that there is no terminal station in which control data cannot be exchanged with the centralized control station and communication is lost.

According to the invention of claim 2, in the radio communication system according to claim 1, the radio terminal compares the radio wave reception intensity from a plurality of terminal stations with the measuring means for measuring the radio wave reception intensity. The first comparing means and the second comparing means for comparing the difference value of the radio wave reception intensity from each terminal station with the specified value of the central control station, and the difference value of the radio wave reception intensity is more than the specified value of the central control station. When it is determined to be large, a transmission means for transmitting the management information of the central control station to the terminal station having the maximum radio wave reception strength, and a terminal station resetting means for resetting itself as the terminal station after the transmission of the management information are provided. Since it is provided, like the invention of claim 1, it is possible to solve the problem that the centralized control station is set in a biased position in the system as in the conventional case. As a result, the centralized control station and the control data are saved. Edge that cannot be exchanged and loses communication Station an effect that does not exist.

According to the invention of claim 3, in the wireless communication system according to claim 1 or 2, the wireless terminal resets itself as a centralized control station when receiving management information as a terminal station. The resetting means, a third comparing means for comparing the difference value of the previous radio wave reception intensity with the difference value of the current radio wave reception intensity when resetting itself as the central control station, and the third comparison means of the previous radio wave reception intensity Since it has a transmitting means for transmitting the management information to the central control station when it is determined that the difference value is smaller, and a terminal station resetting means for resetting itself as the terminal station after transmitting the management information. Similarly to the invention of claim 1, it is possible to solve the problem that the centralized control station is set at an unbalanced position in the system as in the conventional case, and as a result, communication is not possible with the centralized control station to exchange control data. The terminal station that becomes impossible An effect that no longer standing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an internal configuration of a channel codec section according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a start-up operation of a wireless terminal which is initially turned on according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a start-up operation of a wireless terminal which is first powered on according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a start-up operation of wireless terminals which are powered on after the second power supply according to the embodiment of the present invention.

FIG. 5 is a flowchart showing control transfer processing of the centralized control station according to the embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the terminal station to which control has been transferred according to the embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a wireless communication system using a low frequency hopping modulation method.

FIG. 8 is a block diagram showing an internal configuration of a wireless telephone.

FIG. 9 is a block diagram showing an internal configuration of a wireless adapter connected to or built in a wireless data terminal device.

FIG. 10 is a block diagram showing an internal configuration of a network control device.

FIG. 11 is a block diagram showing an internal configuration of a wireless unit commonly used by wireless terminals of a wireless communication system.

FIG. 12 is an explanatory diagram showing an internal configuration of a radio frame.

FIG. 13 is an explanatory diagram showing an internal structure of a CNT field.

FIG. 14 is an explanatory diagram showing an internal structure of an LCCH field.

FIG. 15 is an explanatory diagram showing an internal structure of a data field.

FIG. 16 is an explanatory diagram showing an internal structure of an audio field.

FIG. 17 is an explanatory diagram showing an internal structure of an END field.

FIG. 18 is an explanatory diagram showing the concept of frequency switching used in a wireless communication system.

FIG. 19 is an explanatory diagram showing an example of a frequency switching operation.

FIG. 20 is a sequence diagram showing an operation of the wireless terminal after the power is turned on.

FIG. 21 is a flowchart showing an initial setting operation of the wireless terminal.

FIG. 22 is a flowchart showing an operation of the centralized control station at the time of newly registering a terminal station.

FIG. 23 is a sequence diagram showing an operation at the time of communication between wireless data terminals.

FIG. 24 is a flowchart showing processing of a centralized control station.

FIG. 25 is a flowchart showing an operation of the wireless data terminal.

FIG. 26 is a flowchart showing an operation of the wireless data terminal.

[Explanation of symbols]

 1 frame processing unit 3 ADPCM codec unit 4 wireless unit 27 reception level detecting unit 104 to 107 wireless terminal

Claims (3)

[Claims] 1. A central control station and at least one of the plurality of wireless terminals provided with a wireless unit capable of wireless communication constitutes a central control station, and another wireless terminal constitutes a terminal station. In a wireless communication system in which a station performs wireless communication in a communication form using a wireless frame, the wireless terminal is a detection unit that detects a radio wave environment at startup, and the radio terminal serves as a central control station based on the detected radio wave environment. A wireless communication system comprising: a selection unit that selects whether to operate or to operate as a terminal station. 2. The radio communication system according to claim 1, wherein the radio terminal includes a measuring means for measuring radio wave reception strength and a first comparing means for comparing the measured radio wave reception strengths from a plurality of terminal stations. And second comparing means for comparing the difference value of the radio wave reception intensity from each terminal station with the specified value of the centralized control station, and when it is determined that the difference value of the radio wave reception intensity is larger than the specified value of the centralized control station. In addition, a transmission means for transmitting the management information of the centralized control station to the terminal station having the maximum radio wave reception intensity, and a terminal station resetting means for resetting itself as the terminal station after the transmission of the management information. A characteristic wireless communication system. 3. The wireless communication system according to claim 1, wherein the wireless terminal resets itself as a centralized control station when receiving the management information as a terminal station, and a centralized control station resetting means. , A third comparison means for comparing the difference value of the previous radio wave reception intensity with the difference value of the current radio wave reception intensity when resetting itself as the central control station,
Transmitting means for transmitting the management information to the central control station when it is determined that the difference value of the previous radio wave reception strength is smaller,
A wireless communication system comprising terminal station resetting means for resetting itself as a terminal station after transmitting the management information.