JP3740252B2 - Wireless communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionWireless communication deviceIn particular, the present invention relates to automatic changeover between a control station mode and a terminal station mode.
[0002]
[Prior art]
With the rapid development of digital wireless communication technology in recent years, development of systems that wirelessly communicate with telephones, data terminals, and peripheral devices has been actively conducted.
[0003]
Among the digital wireless communication systems, spread spectrum communication is currently attracting attention.
[0004]
Spread spectrum communication is a wireless technology characterized in that information to be transmitted is spread over a wide frequency band, and is known to have a high ability to remove interference and have excellent secrecy. A 2.4 GHz band frequency is allocated for spread spectrum communication, and is spreading worldwide.
[0005]
Broadly speaking, spread spectrum wireless communication methods include direct spread (DS) and frequency hopping (FH).
[0006]
In the direct spreading method, secondary modulation is performed by multiplying a traveling wave, which has been subjected to primary modulation by PSK, FM, AM, etc., with a spreading code having a wider band than transmission data. Since the spectrum of the signal after the spread modulation is wider than the spectrum of the signal after the primary modulation, the power density per unit frequency is remarkably reduced, and interference with other communications can be avoided.
[0007]
In addition, a plurality of communication channels can be provided by using a plurality of the above-described spreading codes.
[0008]
On the other hand, in the frequency hopping method, the frequency band of 26 MHz (Japan) that is approved for use is divided into a plurality of frequency channels with a width of about 1 MHz, and the frequency channels used for each unit time are arranged in a predetermined order (pattern). ), The transmission data is spread over a wide band.
[0009]
By using a plurality of frequency switching patterns (hopping patterns), it is possible to provide a plurality of communication channels as in the direct spreading method.
[0010]
In particular, the low-speed frequency hopping (SFH) method has been actively used because it has a great advantage in that the circuit scale of a frequency synthesizer or the like can be reduced.
[0011]
If a pattern that does not use adjacent frequency channels in the same unit time is used, it is possible to minimize the occurrence of data errors due to interference or the like.
[0012]
Hereinafter, the wireless communication system using the low-speed frequency hopping method will be described.
(System configuration)
A system configuration of the wireless communication system is shown in FIG.
[0013]
This wireless communication system is a pseudo centralized control type in which each wireless terminal that has been assigned a communication resource (such as a hopping pattern) required for wireless communication performs direct data communication under the control of the wireless terminal that performs overall control of the system ( Hybrid type) system.
[0014]
In this wireless communication system, wireless terminals such as a wireless telephone and a wireless data terminal constituting the system autonomously select two terminal modes at the time of initialization. One is a centralized control station mode, and the other is a terminal station mode.
[0015]
A wireless terminal that operates in the centralized control station mode (hereinafter, this wireless terminal is referred to as a centralized control station) manages communication between wireless terminals that operate in the terminal station mode (hereinafter, this wireless terminal is referred to as a terminal station), Control, frequency allocation, etc.
[0016]
Each wireless terminal searches for the presence of a centralized control station in the vicinity when the power is turned on, and if there is no centralized control station, it initializes itself in the centralized control station mode, and thereafter operates as a centralized control station.
[0017]
Hereinafter, individual terminals constituting the system will be described in detail.
[0018]
This wireless communication system accommodates the public line 102 and exchanges control data or voice data with the network control device 101, the centralized control station or other terminal stations that provide public network communication services to the terminal stations in the system. Control data communication and data communication with the radio telephone 103, centralized control station, or other terminal stations that perform voice calls over the public line 102 and perform so-called extension calls between a plurality of terminal stations It comprises wireless data terminals 104 to 109 that perform the above.
[0019]
In the following description, wireless telephones, wireless data terminals, and the like are collectively referred to as wireless terminals 110 (general numbers 103 to 109).
[0020]
The wireless terminal 110 is a terminal device (data terminal) having a function of transmitting and receiving data in bursts, a data input / output device connected to a wireless adapter that controls wireless communication, or a terminal device integrated with them. For example, in addition to the computer 104, the multimedia terminal 105, the printer 106, the facsimile 107, the copying machine 108, and the LAN gateway 109 shown in the figure, devices such as an electronic camera, a video camera, and a scanner are applicable.
[0021]
A significant feature of this wireless communication system is that these wireless telephone 103 and wireless terminal 110 can freely communicate with each other and can also access the public network 102.
[0022]
The detailed configuration and operation will be described below.
(1) Wireless telephone
FIG. 2 is a block diagram showing an internal configuration of the radio telephone 103. As shown in FIG.
[0023]
The main control unit 201 is responsible for overall control of the radio telephone 103, and the memory 202 is a ROM storing a control program of the main control unit 201, a calling code (system ID) of the radio communication system, An EEPROM for storing the sub ID, a RAM serving as a work area for control of the main control unit 201, and the like.
[0024]
The communication path unit 203 interfaces the input / output blocks of the handset 208, the microphone 209, and the speaker 210 with the ADPCM codec 204. The ADPCM codec 204 converts analog voice information from the speech path unit 203 into ADPCM code and converts ADPCM-coded information into analog voice information. The channel codec 205 performs processing such as scrambling on the ADPCM-encoded information and time-division multiplexes it into a predetermined frame.
[0025]
Data assembled into a radio frame (to be described later) using the channel codec unit 205 is transmitted to the main apparatus and the target terminal station via the radio unit 207. The wireless control unit 206 has functions of performing transmission / reception of the wireless unit 207, frequency switching, carrier detection, level detection, and bit synchronization.
[0026]
The wireless unit 207 modulates the digital information from the channel codec unit 205, converts it into a format that can be wirelessly transmitted, sends it to the antenna, demodulates the information received wirelessly from the antenna, and converts it into digital information.
[0027]
The handset 208 inputs and outputs a call voice signal, and the microphone 209 collects and inputs the voice signal. The speaker 210 outputs a sound signal as a loud voice. The display unit 211 displays a dial number input from the key matrix 212, a public line usage status, 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 the wireless adapter 302 that is connected to or built in the wireless terminal 110.
[0028]
Reference numeral 303 included in the wireless adapter 302 denotes a wireless unit, and an internal configuration thereof will be described later. The main control unit 304 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.
[0029]
The memory 305 includes a ROM for storing a program 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 is equipped with the data adapter 110, for example, a communication interface such as RS232C, Centronics, or LAN, a personal computer, an internal bus of a workstation, such as an ISA bus, a PCMCIA interface, or the like. Is responsible for controlling the communication.
[0030]
The timer 307 provides timing information used by each block inside the wireless adapter 302. The channel codec unit 308 not only assembles and disassembles radio frames as shown in FIG. 6, but also performs simple error detection processing represented by CRC, scramble processing, control of the radio unit 303, and the like.
[0031]
The radio control unit 309 controls transmission / reception switching, frequency switching, and the like of the radio unit 303, and also has a function of performing carrier detection, level detection, and bit synchronization.
[0032]
The error correction processing unit 310 is used to detect or correct a bit or byte error generated in communication data due to various wireless environments. At the time of transmission, an error correction code is inserted into the communication data to make the data redundant, and at the time of reception, the bit error generated in the received data is calculated by calculating the position and error pattern where the error has occurred by the arithmetic processing. correct.
(3) Network control device
FIG. 4 is a block diagram showing an internal configuration of the network control apparatus 101.
[0033]
The main control unit 401 is responsible for overall control of the network control apparatus 101. The memory 402 is a ROM that stores a program, a call code (system ID) of the wireless communication system, and the like, for controlling the main control unit 401. And a RAM that provides a work area for various operations.
[0034]
The line interface unit 403 performs power supply for accommodating the public network line 102, selection command transmission, DC loop closure, public network line control such as PCM conversion, selection command reception, and calling command transmission.
[0035]
The ADPCM codec unit 404 converts an analog voice signal received by the line interface unit 403 via the public network 102 into an ADPCM code, transfers the ADPCM code to the channel codec unit 405, and ADPCM-encoded voice from the channel codec unit 405. The signal is converted into an analog audio signal.
[0036]
The channel codec unit 405 is a channel codec unit that performs processing such as scrambling on the ADPCM encoded information and time-division multiplexes into a predetermined frame. The channel codec unit 405 is assembled into a radio frame described later. Data is transmitted to the centralized control station and the target wireless terminal 110 via the wireless unit.
[0037]
The wireless control unit 406 controls transmission / reception switching, frequency switching, and the like of the wireless unit 407, and also has a function of performing carrier detection, level detection, and bit synchronization.
[0038]
The radio unit 407 modulates the framed information from the channel codec unit 405, converts it into a format that can be transmitted by radio, sends it to the antenna, demodulates the information received from the antenna, and processes it into digital information It is.
[0039]
The tone detection unit 408 is a detection unit that detects various tones such as incoming call detection, loop detection, PB signal, dial tone, and ringtone.
(4) Radio unit
FIG. 5 is a block diagram showing a radio unit having a configuration common to the radio terminals 110 of this system.
[0040]
The transmitting / receiving antennas 501a and 501b are for efficiently transmitting and receiving wireless signals, and the changeover switch 502 is for switching 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.
[0041]
The amplifier 505 is a reception system amplifier, and the amplifier 506 is a transmission system power control amplifier. Converter 507 is a 1st. The IF down converter, and the converter 508 is an up converter.
[0042]
The changeover switch 509 is used to switch between transmission and reception, and the BPF 510 is used to remove a signal in an unnecessary band from the signal converted by the downconverter 507. Converter 511 has 2nd. This is an IF down-converter, and the two down-converters 507 and 511 constitute a double-conversion reception form.
[0043]
BPF512 is 2nd. The 90-degree phase shifter 513 is for IF and shifts the output phase of the BPF 512 by 90 degrees. The quadrature detector 514 detects and demodulates the signal received by the BPF 512 and the 90-degree phase shifter 513. Further, the comparator 515 is for shaping the output of the quadrature detector 514.
[0044]
A voltage controlled oscillator (hereinafter referred to as VCO) 516, a low-pass filter (hereinafter referred to as LPF) 517, and a PLL 518 including a programmable counter, a prescaler, a phase comparator, etc. A frequency synthesizer is configured.
[0045]
A carrier signal generating VCO 519, LPF 520, and PLL 521 including a programmable counter, a prescaler, a phase comparator, and the like constitute a frequency synthesizer for hopping.
[0046]
A transmission-system frequency synthesizer having a frequency modulation function is configured by the transmission-system VCO 522 having a modulation function, the LPF 523, and a PLL 524 including a programmable counter, a prescaler, a phase comparator, and the like.
[0047]
The reference clock oscillator 525 supplies a reference clock for various PLLs 518, 521, and 524, and the baseband filter 526 is a band limiting filter for transmission data (baseband signal).
(5) Radio frame
In this wireless communication system, a communication service for each wireless terminal is provided using a circuit switching channel for voice communication and a packet switching channel for image / video / data communication provided in a wireless frame.
[0048]
FIG. 6 is a block diagram showing an internal configuration of a radio frame used in the present invention.
[0049]
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 with each other, each terminal station exchanges the central control station with the control unit while communicating with the other party. The communication mode is to exchange the data part with the terminal station.
[0050]
This radio frame is composed of a total of six fields: CNT, LCCH, two voices, data, and END.
[0051]
The central control station transmits the CNT field at the start of every radio frame, and the terminal station receives the CNT field to establish bit synchronization and frame synchronization.
[0052]
The LCCH field is used for control when a line is connected or disconnected, or when a central control station assigns a hopping pattern to a terminal station prior to line connection.
[0053]
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.
[0054]
Each wireless terminal exchanges various control commands with the central control station in the first half of the communication frame (CNT + LCCH field), switches the hopping pattern used in the second half of the communication frame (voice field, data field), and communicates between wireless terminals. I do.
[0055]
FIG. 7 shows the internal structure of each field of the radio frame.
[0056]
In the figure, CS represents carrier sense, PR represents a preamble for capturing bit synchronization, and SYN represents 31-bit frame synchronization defined by 1 bit (dummy) + RCR.
[0057]
ID is 63-bit calling signal defined by RCR + 1 bit (dummy), UW is 24-bit unique word (for capturing byte synchronization), and BF is 8-bit basic frame number information (1 to 20 as one cycle) ).
[0058]
WA is the system address of the terminal station to be activated among the terminal stations in the sleep state, Rev is reserved, GT is the guard time, CS0, CS1, and CS2 are carrier sense, DA is the system address, and CRC is from BF to LCCH CRC calculation results for data, CF is a guard time for frequency switching, and T / R is a B channel for storing data.
(6) Frequency switching
FIG. 8 shows a conceptual diagram of frequency switching used in this wireless communication system.
[0059]
In this wireless communication system, a 26 MHz frequency band approved for use in Japan is divided into a plurality of 1 MHz wide frequency channels.
[0060]
The centralized control station and the wireless terminal perform communication while switching the frequency channel in a predetermined order every predetermined period. This order is called a hopping pattern.
[0061]
The number of frequency channels used for this hopping pattern is variable, and it is possible to take a pattern in which the frequencies used within the same unit time do not overlap.
[0062]
That is, it can be considered that one hopping pattern forms one communication channel, and up to 16 communications can be supported at the same time.
[0063]
By this method, it is possible to realize a radio communication system having a multi-cell configuration, and a wide communication area can be secured.
[0064]
FIG. 9 shows an example of frequency channel switching operation.
[0065]
In FIG. 9, it is assumed that the wireless terminals A to F operate under the control of the central control station, and the wireless terminals A and B and the wireless terminals D and E are communicating.
[0066]
The central control station includes a CNT field in which information for controlling the system is written while performing frequency switching according to a specific hopping pattern (in this example, the order is f1, f2, f3...) A radio frame is being transmitted.
[0067]
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.
[0068]
In addition, transmission / reception of the LCCH field for exchanging control commands between the central control station and the wireless terminal (= terminal station) is also performed with the same hopping pattern as the CNT field.
[0069]
After the central control station and the wireless terminal (= terminal station) are negotiated using the control unit, each wireless terminal (= terminal not station) is assigned a hopping pattern (the central control station is assigned by the central control station). The frequency is switched in accordance with (different from the hopping pattern to be used) and data communication is started.
[0070]
In the figure, the wireless telephones A and B use f11, f12, f13... And the wireless telephones D and E use f26, f25, f24.
[0071]
By this frequency channel switching process, a plurality of communication services (as many as the number of hopping patterns) can be performed at the same time.
[0072]
Hereinafter, specific operations of the wireless communication system will be described in several cases.
(1) Basic operation
The terminal station in an idle state constantly monitors the CNT field transmitted from the central control station while following the hopping pattern of the central control station.
[0073]
In order for each terminal station to perform communication, it is necessary to negotiate with the centralized control station using the LCCH field in an arbitrary frequency channel, for example, notification of the type of data to be communicated and designation of a hopping pattern.
[0074]
This LCCH field includes a control command, parameters, etc., and notifies the presence / absence of an incoming line, a request for communication between wireless data terminals, etc.
[0075]
After the negotiation is completed, the terminal station can switch the hopping pattern to be used and can communicate with the counterpart terminal station.
[0076]
Now, detailed operations in some cases will be described below.
(1-1) Initialization
FIG. 10 is a sequence diagram showing the initialization operation of the wireless terminal after power-on in the wireless communication system.
[0077]
After turning on the power, the wireless terminal serving as the centralized control station determines a frequency channel to be used for the hopping pattern, and transmits a wireless frame storing a synchronization signal, hopping pattern information, etc. in the CNT field at every predetermined timing (1001). .
[0078]
Conversely, if there is a centralized 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 and stores a terminal address registration from the user. .
[0079]
Next, the terminal station waits for a radio frame from the central control station at an arbitrary frequency, and when receiving the CNT field in the radio frame, recognizes the frequency to be used in the next unit time from the NF in the CNT field, and sets the frequency. Change the frequency based on this and wait for the next radio frame.
[0080]
The terminal station repeats the above processing, recognizes the hopping pattern used in the central control station, and then requests the central control station to register the terminal station using the LCCH field in the radio frame (1002).
[0081]
In order to request registration of a terminal station, a global address received by all terminals is written in the DA of the LCCH field in the radio frame to be transmitted, and information indicating new registration is written in the data portion.
[0082]
The central control station that has received the new registration request for the terminal station confirms the global address of the DA, the terminal address in the data field, and the registration request information, and registers the terminal address based on the information.
[0083]
When the registration process ends, the central control station notifies the newly registered terminal station of the terminal address of the central control station (1003).
[0084]
The terminal station stores the terminal address of the central control station, and transmits a radio frame in which a start-up completion notice is written in the LCCH field to the central control station (1004).
[0085]
When the central control station receives the start-up completion notification from the terminal station, it shifts to normal processing. The terminal station can make a call from the terminal station after outputting the start-up completion notification (1005).
(1-2) Initial setting of wireless terminal
FIG. 11 is a flowchart showing the initial setting operation of the wireless terminal.
[0086]
After the power is turned on and the wireless terminal performs an internal initialization process (S1101), the wireless terminal waits to receive the CNT field of the wireless frame at an arbitrary frequency.
[0087]
If a radio frame (= CNT field) cannot be received for a certain time (S1102), the internal counter is activated, the frequency is shifted to the next arbitrary frequency channel (S1104), and the radio frame (= CNT field) is tried to be received (S1102).
[0088]
The above operation is repeated, and if the value of the internal counter reaches 10 without receiving a valid radio frame (S1105), it is determined that there is no central control station in the system, and the initial setting is performed in the central control station mode. Start processing.
[0089]
The wireless terminal that has selected the central control station mode first selects a frequency that can be used for the hopping pattern (S1106), and then uses the hopping pattern information and the wireless frame in which the global address of the wireless communication system is written in the CNT field as the hopping pattern. While switching the frequency accordingly (S1109), it transmits to each terminal station in the system (S1108).
[0090]
If a terminal station registration request is received from the terminal station during the above operation (S1108), the process proceeds to terminal station registration (S1110).
[0091]
On the other hand, if a valid radio frame is received from the central control station in step 1102, the initial setting process is subsequently started in the terminal station mode.
[0092]
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 in order to acquire a hopping pattern to be used.
[0093]
If a radio frame is received from the central control station, the frequency used in the next unit time is acquired from the NF in the CNT field (S1112), and the terminal station moves the received frequency to the frequency channel (S1113), and then Waiting for reception of radio frames from the central control station.
[0094]
The terminal station repeats the above operation, and if the frequency has made a round (S1114), the hopping pattern is registered (S1115).
[0095]
Next, the terminal station performs processing for notifying the central control station of the terminal address.
[0096]
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 (S1116).
[0097]
After the transmission, the terminal station receives the radio frame while changing the frequency according to the acquired hopping pattern (S1117).
[0098]
When the own terminal address is detected in the DA in the LCCH field from the central control station and the registration completion command is confirmed (S1118), the central control station address and DATA are set up in the DA in the LCCH field to the central control station. The wireless frame in which the completion command is written is transmitted to the central control station (S1119).
(1-3) Centralized control station terminal station registration processing
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.
[0099]
When there is a registration request from the terminal station in the LCCH field in the radio frame received by the central control station (S1201), the terminal station address is confirmed (S1202).
[0100]
As a result of the terminal station address confirmation, if 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).
[0101]
Conversely, if the terminal station address is not normal (S1203), the registration request sent from the terminal station is discarded (S1208), and the process is terminated.
[0102]
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 in DA is transmitted to the terminal station that has completed registration (S1205). .
[0103]
If the central control station cannot confirm the start-up completion notification signal from the terminal station that has completed registration after transmission (S1206), the central control station detects whether a predetermined time has passed (S1209), and if the predetermined time has not passed. Then, wait for the start-up completion notification from the terminal station again.
[0104]
If the predetermined time has elapsed, a radio frame for notifying the terminal address of the centralized control station is transmitted again to the terminal station (S1205).
[0105]
If a startup completion notification signal from the terminal station is detected in S1206, a new registration completion process for the terminal station is performed (S1207), and the process ends.
(2) Data communication between terminal stations
Here, processing in the case of performing burst data communication between two terminal stations (wireless terminal 104 and wireless terminal 105) in FIG. 1 will be described in detail below.
[0106]
FIG. 13 shows a sequence diagram of control commands exchanged among the central control station, the wireless terminal 104, and the wireless terminal 105.
[0107]
14 is a flowchart showing processing of the central control station, FIG. 15 is a flowchart showing processing of the wireless terminal 104, and FIG. 16 is a flowchart showing processing of the wireless terminal 105.
[0108]
For convenience of explanation of the operation, the frequency channel for the terminal station to exchange radio frames with the central control station is assumed to be f5 in the wireless terminal 104 and f7 in the wireless terminal 105.
[0109]
Also, it is assumed that the exchange of commands between the central control station and the radio terminals 104 and 105 is all performed using the LCCH field in the radio frame.
(2-1) Connection processing
The terminal station that transmits data exchanges a command such as a transmission request with the central control station, and performs frequency switching according to communication resources such as the assigned hopping pattern to communicate with the other party.
[0110]
When data to be transmitted is generated (S1501), the wireless terminal 104 transmits a communication request command (1301) to the central control station (S1502).
[0111]
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 (S1402), and wirelessly transmits a communication setting command (1302) including this communication resource information. It transmits to the terminal 104 (S1403).
[0112]
Upon receiving the communication setting command (1302) (S1503), the wireless terminal 104 sets the hopping pattern obtained from the communication resource information in the channel codec section.
[0113]
When the above setting is completed in the wireless terminal 104, a communication setting completion command (1303) is transmitted (S1505).
[0114]
Next, the wireless terminal 104 transmits an address command (1304) for informing the central control station of the destination terminal address (S1506).
[0115]
When the central control station receives the address command (1304) (S1404), it transmits a data incoming command (1305) to the wireless terminal (in this case, the wireless terminal 105) having the terminal address specified in the address command (S1405). .
[0116]
The wireless terminal 105 that has received the data incoming command (1305) (S1601) sends a data incoming response command (1306) to the central control station (S1602) if data incoming is possible.
[0117]
Upon receiving the data incoming response command (1306) from the wireless terminal 105 (S1406), the central control station transmits a communication setting command (1307) including hopping pattern information used for data communication to the wireless terminal 105. (S1407).
[0118]
The wireless terminal 105 that has received the wireless frame and recognized the communication setting command (1307) in the LCCH field (S1603) sets the hopping pattern in the channel codec section (S1604).
[0119]
Next, the central control station transmits a communication response command (1308) to the wireless terminal 104 (S1408), and notifies that the wireless terminal 105 has responded.
[0120]
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 (1310) with the wireless terminal 105. Start.
[0121]
When receiving the communication start command (1309) from the wireless terminal 104 (S1409), the centralized control station determines that the wireless terminal 104 and the wireless data terminal 105 have started data communication, and issues a communication end command (1313). Wait (S1410).
[0122]
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 the frequency according to a common hopping pattern.
[0123]
At the end of communication, the wireless terminal 104 transmits a communication end command (1313) to the central control station.
[0124]
The central control station that has received the communication end command (1313) (S1410) transmits a communication setting cancellation command (1314, 1315) to the wireless data terminals 104, 105 (S1411).
[0125]
Next, the centralized control station releases the hopping pattern assigned for communication between the wireless terminals 104 and 105 (S1412).
[0126]
The wireless terminals 104 and 105 that have received the communication setting cancel command (1314, 1315) (S1511, S1607) clear the communication setting (S1512, 1608).
[0127]
[Problems to be solved by the invention]
The conventional wireless communication system provides communication services such as public line calls accommodated by the public network gateway to the wireless terminals in the system, as well as extension calls and data transmission between data terminals, by the above-described procedure. .
[0128]
However, the conventional wireless communication system has the following problems with respect to the central control station.
[0129]
In a wireless communication system, in order to control and manage the entire system, it is necessary to install one or more central control stations in the system. In the conventional wireless communication system, as shown in FIG. 11, a wireless terminal that is first turned on by a user in the system is automatically activated as a centralized control station.
[0130]
In this case, for example, when a wireless terminal (= centralized control station) that is first turned on is installed at a biased 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.
[0131]
Therefore, the present inventionSuitableA positive wireless terminalControl stationCan be set as and can perform smooth wireless communicationTo doFor the purpose.
[0132]
The present invention also enables stable operation.Control stationCan be set efficientlyTo doFor the purpose.
[0133]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides a wireless communication apparatus that selectively sets a control station mode for controlling other wireless communication devices and a terminal station mode to be controlled in the control station mode. And when the wireless communication device is set to the control station mode, the first wireless communication device set to the terminal station mode is previously connected to the control station mode after the wireless communication device. Determination means for determining whether or not the operation has been performed, and transfer means for performing processing for transferring the role of the control station mode to the first wireless communication device according to the determination by the determination means It is characterized by that.
[0136]
BEST MODE FOR CARRYING OUT THE INVENTION
In the wireless communication system according to the first embodiment of the present invention described below, a wireless terminal operating in the centralized control station mode generates a reception frame when receiving a test frame (test data) from the terminal station. The data error rate is measured, and the data error rates of test frames from a plurality of terminal stations are compared. If these values vary more than a certain value, the processing as the central control station is transferred to the terminal station with the lowest data error rate, and it is reset as the terminal station.
[0137]
In the transfer destination wireless terminal, the above error rate comparison is performed as appropriate, and if the data error rate variation is low, the operation of the centralized control station mode is continued. If the data error rate variation is high, the data error rate The processing as the central control station is transferred to another terminal station that is low. By repeating such operations and setting a wireless terminal with a low data error rate as a centralized control station, efficient wireless communication is ensured.
[0138]
Note that, in the description of the conventional example described above, the configuration and operation 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. The description is omitted here. Hereinafter, each part which comprises a present Example is demonstrated.
(1) Channel codec section
FIG. 17 is a block diagram showing an internal configuration of channel codec section 1701 provided in each wireless terminal described above.
[0139]
The channel codec unit 1701 includes a voice input / output unit 1702, an ADPCM codec unit 1703, a main control unit data bus 1704, a main control unit interface 1705, and an ADPCM interface unit 1706.
[0140]
A register 1707 is a control register that determines the internal operation of the channel codec unit, and includes a mode register, a hopping pattern register, a frame number / next frequency number (BF / NF) register, a system ID register, and an intermittent activation terminal address register. Consists of multiple registers. The register 1708 is a command register for storing a communication command in the LCCH field of the radio frame.
[0141]
Further, the channel codec unit 1701 includes a data buffer 1709, a timing generation unit 1710, a CNT channel assembly / disassembly unit 1711, an LCCH assembly / disassembly unit 1712, a data assembly / disassembly unit 1713, and an audio assembly / disassembly unit 1714. A synchronization control unit 1715 that secures synchronization for each frame or bit of a radio frame, 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 radio unit 1723 are included.
[0142]
Hereinafter, the operation of the channel codec unit 1701 will be described.
[0143]
The reference of the operation timing of each channel codec unit 1701 in the system is generated by the timing generation unit 1710 of the channel codec unit 1701 built in the central control station.
[0144]
The central control station transmits a radio frame in synchronization with the timing signal from the timing generator 1710, and the terminal station holds the synchronization according to the frame synchronization word in the radio frame and receives the radio frame.
[0145]
When transmitting CNT field data from the centralized control station, values such as the written hopping pattern, ID, WA, frequency channel number for transmitting CNT field data, frame number / next frame frequency number (BF / NF), etc. Assembled by the CNT assembly / disassembly unit 1711 and sent to the radio unit.
[0146]
On the other hand, when the terminal station recognizes a valid CNT field in the received radio frame, the terminal station extracts the CNT assembly / disassembly unit CNT field and performs various processes according to the data.
[0147]
Further, the ID register in the control register 1707 has a function of a filter for receiving subsequent radio frames only when the system ID in the received radio frame matches the own station.
[0148]
The WA register is used to designate a terminal for restarting a terminal station that is being intermittently received by the central control station.
[0149]
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 uses the hopping pattern register created based on the frequency number written in the NF field. The configuration is generated by shifting.
[0150]
When transmitting a command, data is set in the command register 1708 and incorporated in a radio frame by the LCCH assembling / disassembling unit 1712. When valid LCCH data is received, it is decomposed by the LCCH assembling / disassembling unit 1712.
[0151]
When transmitting audio data using the audio field, the audio data input from the handset 1702 is digitally encoded by the ADPCM codec 1703, and this digital audio is incorporated into the radio frame by the audio assembling / disassembling unit 1714 and wirelessly transmitted at a predetermined timing. To the unit 1724.
[0152]
Conversely, audio data received from the radio unit 1724 is decomposed by the audio assembling / decomposing unit 1714 and output to the ADPCM codec 1703 and the handset 1702 via the ADPCM interface 1706.
[0153]
At the time of data transmission using the data field, the data assembling / disassembling unit 1713 converts the data into serial data and sends the data to the wireless unit 1724 at a predetermined timing. Conversely, when data is received, the data assembling / decomposing unit 1713 converts the data into parallel data.
[0154]
Also, when transmitting data, a CRC code generation unit 1717 can generate a CRC code, store it in the CRC field, and transmit it, and the occurrence of an error can be detected by a CRC check on the receiving side.
[0155]
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 the data imbalance and facilitate the extraction of the synchronization clock.
[0156]
On the other hand, when data is received, when a unique word is detected, descrambling is performed by the descrambler 1720, CRC check is performed, and at the same time, data is input to the decomposing units 1711 to 1714 of each field.
(2) Communication error processing section
In the communication error processing unit, parity data obtained by performing arithmetic processing on the input raw data is added and output as code data, and the number of bytes and position of errors multiplied by the received code data Also, it has a function of calculating an error data value and detecting or correcting an error. This communication error processing unit is provided, for example, as the communication error processing unit 310 of the wireless adapter shown in FIG.
[0157]
The transmitting-side wireless terminal inputs the transmission data to the communication error processing unit and transmits the obtained code data. The reception-side wireless terminal can detect or correct a communication error and reduce adverse effects on data in the wireless environment.
[0158]
FIG. 23 is a block diagram illustrating an internal configuration of the communication error processing unit 2301.
[0159]
In the figure, a control register 2302 inputs a set value necessary for control inside the communication error processing unit from the main control unit. The data buffer 2303 performs input / output control of external byte data. The memory 2304 is used as a buffer for temporarily securing data for arithmetic processing.
[0160]
The syndrome generation unit 2305 is a block that performs arithmetic processing performed by the communication error processing unit at the time of data encoding / decoding. The internal address generation unit 2306 generates and outputs an address of the memory 2304.
[0161]
The error pattern generation unit 2307 calculates an error value multiplied by the received code data. The error position generation unit 2308 calculates the byte position of the error multiplied by the received code data. The error detection unit 2309 detects the number of errors multiplied by the received code data.
[0162]
The parity data generation unit 2310 generates parity data from the value calculated by the syndrome generation unit 2305. The data processing unit 2312 adds the parity data generated by the parity data generation unit 2310 to the raw data at the time of encoding and sends it to the memory, and the code data processed by the error correction unit 2311 at the time of decoding. The parity part is deleted from and sent to the memory.
[0163]
The detailed operation of the wireless communication system to which the present invention is applied will be described below with reference to FIGS.
(3) Terminal mode
The wireless communication system of the present embodiment is a pseudo-concentration in which each wireless terminal that has been assigned a communication resource (hopping pattern, etc.) required for wireless communication directly performs data communication under the management of the wireless terminal that performs overall control of the system. This is a control type (hybrid type) system.
[0164]
The wireless terminal autonomously selects two terminal modes, a centralized control station mode and a terminal station mode, at an initialization stage after power-on.
[0165]
When the power is turned on, each wireless terminal searches for the presence of a centralized control station around it, and if there is no centralized control station, it initializes itself in the centralized control station mode, and then operates as a centralized control station I do.
[0166]
In this embodiment, when the position of the wireless terminal operating in the centralized control station mode in the system is not the optimum position for the system, the centralized control station is moved to the wireless terminal that exists in a more stable position. Perform the process.
[0167]
Here, processing relating to the present invention will be described with reference to FIGS. 1 and 18 to 22.
[0168]
For the sake of convenience, in FIG. 1, the wireless terminal that is powered on first is 104 (terminal address = 01), the wireless terminal that is powered on next is 105 (terminal address = 02), and the initialization of the centralized control station is completed. The terminal station having the lowest communication error rate is 106 (terminal address = 03) and the terminal station having the highest communication error rate is 107 (terminal address = number) by the communication error rate inspection performed by the central control station after the system performs normal operation. 04).
[0169]
In the following description, a wireless terminal that operates in the centralized control station mode is referred to as a centralized control station, and a wireless terminal that operates in the terminal station mode is referred to as a terminal station.
(3-1) Central control station mode
After the power is turned on, the wireless terminal waits for a radio frame transmitted from the central control station existing in the system, and if it cannot receive it, there is no central control station in the system, that is, its own device is the first in the system. It is determined that the terminal is activated at the beginning, and initialization is performed in the centralized control station mode.
[0170]
FIG. 18 shows a flowchart of the operation at the start of the wireless terminal, and FIG. 19 shows an operation flowchart of the initial setting process in the centralized control station mode.
[0171]
After the power is turned on, the wireless terminal 104 performs an internal initialization process (S1801), and then waits for a CNT field in a wireless frame that should be transmitted from the centralized control station on an arbitrary frequency channel (S1802).
[0172]
If a radio frame (only the CNT field is valid) is not received from the centralized control station for a certain period of time, an internal counter is activated (S1803), the frequency is shifted to the next frequency channel (S1804), and the radio frame (CNT field is again transmitted). Only valid) is attempted (S1802).
[0173]
The wireless terminal 104 repeats the operations from S1802 to S1804 described above, and if the value of the internal counter reaches 10 (S1805), the wireless terminal 104 determines that there is no centralized control station in the system. Initial setting is started in the mode (S1806).
[0174]
When the wireless terminal 104 selects the centralized control station mode, a value input by the user using a DIP switch, a dial key such as a telephone, a keyboard such as a computer is stored as a terminal address (S1901), and the next hopping is used. Processing for creating a pattern is performed (S1902).
[0175]
At this time, the wireless terminal 104 inspects all usable frequency channels, selects a frequency with a good radio wave state among them, and sets a random or ordered order as a hopping pattern.
[0176]
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 a terminal station in the system at regular intervals (S1903).
[0177]
At the same time, the wireless terminal 104 monitors the internal timer, and transmits a wireless frame in which a location management command is written in the LCCH field to each terminal station at regular intervals (S1904) (S1905).
[0178]
After transmitting the location management command, the central control station (= wireless terminal 104) waits for a response command from each terminal station while switching the frequency channel (S1906).
[0179]
If a radio frame including a response command is received from the terminal station, the terminal address written in the response command in the LCCH field is read (S1907), and a test frame in which dummy data is written in the data field is transmitted from this terminal. (S1908). If the test frame is received, the dummy data written in the data field of the test frame is sent to the communication error processing unit 310, and the communication error rate is calculated (S1909).
[0180]
Next, the two data of the terminal address and the communication error rate obtained as described above are written as system management information (temporarily SMI1) in the memory as one set (S1910).
[0181]
The central control station repeats the processing from S1904 to S1910 for a predetermined time, and collects system management information of each terminal station in the memory.
[0182]
Then, the central control station (= wireless terminal 104) reads the system management information in the memory and compares the maximum value and the minimum value of the communication error rate (S1911). If the difference (variation) between the maximum value and the minimum value of the communication error rate is greater than or equal to a certain value (S1912), processing for transferring the central control station to another terminal station is started (S1913).
[0183]
If the difference (variation) between the maximum value and the minimum value of the communication error rate is less than a certain value (S1912), the central control station (= wireless terminal 104) determines that the position in the system is appropriate, Continue normal operation.
(3-2) Terminal station mode
The wireless terminal 107 is automatically initialized in the terminal station mode from the wireless terminal 105 that is powered on second and later in the system. Here, the wireless terminal 105 in FIG. 1 will be described as an example.
[0184]
FIG. 20 shows an operation flowchart when the wireless terminal 105 is powered on.
[0185]
The wireless terminal 105 immediately after power-on performs internal initialization (S2001), and then waits for a terminal address set by the user using a keyboard attached to the data terminal (S2002). If it is stored in memory. Next, in order to receive a radio frame (= only the CNT field portion is valid) from the centralized control station (= wireless terminal 104), it waits at an arbitrary frequency (S2004).
[0186]
When the wireless terminal 105 receives a wireless frame from the centralized control station (= wireless terminal 104), the CNT field is read, the global address is read from the ID (S2005), and the frequency channel to be used for the next unit time from NF (S2006). )Remember.
[0187]
Next, after the reception frequency of the radio unit is moved to the frequency channel obtained from the NF field (S2007), the reception standby state is entered again. By repeating this operation, the wireless terminal 105 follows the frequency channel of the central control station, and can recognize the hopping pattern used by the central control station when transmitting the radio frame (only the CNT field is valid) (S2009). .
[0188]
If a location management command is received from the central control station (S2010), a radio frame in which a response command is written in the LCCH field is transmitted to the central control station (S2011). Then, predetermined dummy data is sent to the communication error processing unit, and a test frame in which the dummy data subjected to error correction coding processing is written in the data field is transmitted to the central control station (= wireless terminal 104) (S2012).
(3-3) Change of terminal mode
In S1912 of FIG. 19, when the communication error rate of the test frame received from the terminal station in the system varies more than a certain value, the central control station is not in a position where it can provide stable wireless communication in the system. It judges and performs the process which resets another terminal station in centralized control station mode.
[0189]
FIG. 21 shows a flowchart of the control transfer process.
[0190]
If the communication error rate shows a variation of a certain value or more, it is determined that the central control station (= wireless terminal 104) exists in a biased position in the system and there are terminal stations that are difficult to manage, The terminal address (= wireless terminal 106: 03) of the terminal station having the lowest communication error rate, that is, clear communication was read from the system management information in the memory (S2101).
[0191]
Then, the control transfer command and the system management information SMI1 are stored in the LCCH field and transmitted to the terminal station (wireless terminal 106: 03) (S2103).
[0192]
Thereafter, the central control station waits until a control return command or a change completion command is transmitted from the terminal station to which control has been transferred (S2104).
[0193]
If a control return command is transmitted from the terminal station (wireless terminal 106: 03) (S2104), the system management information SMI1 returned at the same time is read (S2105), and next to the terminal station that previously showed the highest value. Read the terminal address of the terminal station that showed a high reception level.
[0194]
Then, after switching the frequency for this terminal station (S2106), the control transfer command and the system management information SMI1 are stored again in the LCCH field and transmitted to the terminal station (S2107).
[0195]
If a change completion command is received from the terminal station (wireless terminal 106: 03) (S2108), it is restarted to release itself from the central control station (S2109).
(3-4) Processing of terminal station that received control transfer command
The terminal station that has received the control transfer command restarts in the central control station mode, and checks the communication error rate in the same manner as the previous central control station. If the communication error rate does not vary as a result of this check, the terminal station mode is fixed on the assumption that the central control station is in an appropriate position.
[0196]
Conversely, if the communication error rate still varies, check whether the communication error rate from the terminal station that had the worst previous communication error rate has improved, and if so, the position of the central control station Is still not appropriate, but the movement direction of the central control station is interpreted as appropriate, and the operation of the central control station is continued.
[0197]
Also, if the communication error rate of the terminal station that had the worst previous communication error rate is further deteriorated, the central control station interprets that the moving direction of the central control station itself is inappropriate, and Return it to the terminal.
[0198]
FIG. 22 is a flowchart showing details of the above operation.
[0199]
If the terminal station (wireless terminal 106: 03) receives a radio frame from the central control station (= wireless terminal 104) and the command in the LCCH field is a control transfer command (S2201), the system management information (SMI1) is set. The terminal station (wireless terminal 106: 03) is restarted as a central control station (S2202).
[0200]
The centralized control station (= wireless terminal 106) that has been restarted as a centralized control station (= wireless terminal 106) and entered a normal operation state (a state in which a wireless frame in which data is written in the CNT field is continuously transmitted according to a hopping pattern) 106) starts an internal timer at the same time (S2204).
[0201]
When this timer expires, the central control station (= wireless terminal 106) sends the hopping pattern, the hopping pattern assignment status, the terminal station registration status, etc., system management information (assumed to be SMI2) and the location management command to the LCCH The wireless frame stored in the field is transmitted to each terminal station (S2205), and a response command is transmitted from each terminal station while waiting for the frequency channel to be switched (S2206, S2216).
[0202]
If a radio frame is received from the terminal station, the terminal address written in the response command in the LCCH field is read (S2207), and at the same time, a test frame in which dummy data is written in the data field is transmitted from this terminal. (S2208).
[0203]
If the test frame is received, the dummy data written in the data field of the test frame is sent to the communication error processing unit 310, and the communication error rate is calculated (S2209). Next, the two data of the terminal address and the communication error rate obtained as described above are written as system management information (temporarily SMI1) in the memory as one set (S2210).
[0204]
Next, the centralized control station (= wireless terminal 106) reads SMI2 from the memory and compares the highest value and the lowest value of the communication error rate (S2211).
[0205]
Here, if the difference in communication error rate shows a certain value or more (S2212), it is determined that the position of the central control station is still biased, and the terminal station that was the previous central control station (= wireless terminal 104). The communication error rate data of the terminal station (wireless terminal 107: 04) indicating the lowest level is read from the recorded SMI1), and the current communication error rate (= SMI2) of the same terminal station (wireless terminal 107: 04) (S2213).
[0206]
If the current communication error rate is low (S2214), it is determined that the position of the central control station is improved from the previous central control station, and the operation as the central control station (= wireless terminal 106) is continued. To do.
[0207]
If the communication error rate this time is higher, it is determined that the central control station has not moved in the proper direction (to eliminate the bias in the communication error rate), and the terminal station that was the previous central control station ( = The wireless terminal 104) transmits a wireless frame in which SMI1, SMI2, and a control return command are written in the LCCH field (S2215), and then restarts as the original terminal station.
[0208]
If the difference in communication error rate is equal to or smaller than a certain value in S2212, it is determined that the central control station (= wireless terminal 105) is located at an appropriate position in the system, and the operation is continued.
(3-5) Communication error rate processing
FIG. 24 shows a flowchart of the communication error rate inspection process.
[0209]
The central control station that has received the test frame sends the dummy data written in the data field of the test frame to the communication error processing unit 2301 and calculates the communication error rate (S2501).
[0210]
Next, the obtained two data of the terminal address and communication error rate are written as system management information (temporarily SMI1) in the memory as one set (S2502).
[0211]
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 (S2503).
[0212]
If the difference in communication error rate is greater than a certain value (S2504), the control flag is set to “ON” (S2505).
[0213]
If the difference in communication error rate is equal to or smaller than a certain value, the central control station determines that the position in the system is appropriate, and the process ends.
[0214]
In the first embodiment as described above, the communication error rate is inspected and compared using test frames sent from a plurality of terminal stations to the centralized control station. If it has, the function as a centralized control station is transferred to another wireless terminal, and the own device re-sets up as a terminal station by repeating the stabilization process until the variation in the communication error rate stabilizes below a certain value. Since the control station is not set at a biased position in the system, it is possible to eliminate terminal stations that cannot communicate with the centralized control station and cannot communicate, and the system is balanced and effective. Communication can be secured.
(4) Second embodiment
In the embodiment described above, the communication error rate variation is determined by the communication error rate inspection process and the centralized control station function is transferred. However, radio wave reception between each terminal station using the same test frame is performed. The strength may be inspected, and the central control station function may be transferred based on the variation state.
(4-1) Radio wave intensity processing
FIG. 25 shows a flowchart of the radio field intensity inspection process inside the central control station.
[0215]
If the central control station receives a test frame from the terminal station, the terminal address written in the response command in the LCCH field is read, and at the same time, the reception level is read from the reception level detection unit 1722 inside the channel codec unit (S2401). ), The two data of the terminal address and the reception level value are set as one set and written in the system management information (temporarily SMI1) in the memory (S2402).
[0216]
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 for each terminal station (S2403).
[0217]
If the reception level difference indicates a certain value or more (S2404), the control flag is set to “ON” (S2405).
[0218]
If the reception level difference is less than or equal to a certain value, the central control station determines that the position in the system is appropriate and ends the process.
[0219]
Also, by combining the above-mentioned communication error rate inspection processing and radio wave reception strength inspection processing, the wireless terminal with the smallest communication error rate variation and radio wave reception strength variation is selected and the centralized control station function is transferred. May be performed.
(5) Third embodiment
In the first and second embodiments described above, a wireless terminal serving as a centralized control station uses a test frame to check environmental information such as radio wave intensity and communication error rate for each terminal station. If the location of the mobile station is inappropriate for managing each terminal station, a stabilization process is performed in which the processing of the centralized control station is automatically transferred to a wireless terminal that exists in a position where the most stable communication service can be provided as a system. Therefore, stable wireless communication is provided.
[0220]
However, in these embodiments, for example, when all the wireless terminals in the system are restarted, the stabilization process as described above must be repeated again, which may complicate the process.
[0221]
In addition, when the position of the wireless terminal that is first activated in the system exists at an extreme position in the system, it may be considered that a considerable time is required until the system is stabilized.
[0222]
Therefore, in the following third embodiment, a radio communication system capable of efficiently setting a centralized control station capable of stable operation will be described.
[0223]
In the third embodiment, except for the fact that the operation of the centralized control station mode processing of FIG. 19 of the first embodiment described above is replaced with the flowchart shown in FIG. 26, the other FIGS. 25 is common to the first and second embodiments described above.
[0224]
FIG. 26 shows an operation flowchart of the initial setting process in the centralized control station mode of this embodiment.
[0225]
When the wireless terminal 104 selects the central control station mode, a value input by the user using a DIP switch, a dial key such as a telephone, a keyboard such as a computer is stored as a terminal address (S2601), and hopping to be used next is performed. Processing for creating a pattern is performed (S2602).
[0226]
At this time, the wireless terminal 104 inspects all usable frequency channels, selects a frequency with a good radio wave state among them, and sets a random or ordered order as a hopping pattern.
[0227]
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 at regular intervals to a terminal station in the system (S2603).
[0228]
At the same time, the wireless terminal 104 monitors the internal timer, and transmits a wireless frame in which a location management command is written in the LCCH field to each terminal station at regular intervals (S2604) (S2605).
[0229]
After transmitting the location management command, the centralized control station (= wireless terminal 104) waits for a response command from each terminal station while switching the frequency channel (S2606, S2617).
[0230]
When the power of the wireless terminal 105 is activated and a wireless frame including a response command is received, the terminal address written in the response command in the LCCH field is read (S2607), where the wireless terminal 104 is a system in the memory. From the management information, a history of the terminal address of the wireless terminal operating in the centralized control station mode at the time of the previous system startup is searched (S2608). First, whether the wireless terminal 104 has experience in operating in the previous centralized control station mode. Search for no.
[0231]
If there is no experience (S2609), and if the terminal address of the wireless terminal 105 that has requested registration is included in the history (S2610), that is, the previous wireless terminal 105 operated in the centralized control station mode. If there is experience, it is next determined whether the timing of becoming the central control station is before or after the wireless terminal 104.
[0232]
If the result of this determination is before the wireless terminal 104 (S2611), that is, according to the previous result, the wireless terminal 104 operated in the centralized control station mode than the wireless terminal 105 is a system-stable communication. The processing in the centralized control station mode is continued. Further, the wireless terminal 104 waits for a test frame to be transmitted from the wireless terminal 105 (S2612).
[0233]
If the test frame is received, the radio wave intensity process (S2613) and the communication error rate process (S2614) are performed. As a result, if it is determined that the central control station should be transferred (S2615), the process continues. The process proceeds to the terminal mode change process (S2616).
[0234]
In S2611, if it is after the own device, it is determined that the wireless terminal 105 operating in the centralized control station mode is more systematically stable than the wireless terminal 104, and the process proceeds to terminal change processing (S2616).
[0235]
In the wireless communication system according to the present embodiment as described above, the wireless terminal operating in the centralized control station mode, the movement history of the centralized control station from the previous system management information at the stage of receiving the registration request from the terminal station. The wireless terminal that requested the registration has been operated in the central control station mode last time, and became a central control station after the own terminal (that is, a stable position from the self terminal when the system was started last time) Radio wave intensity described in the first and second embodiments by providing a function for determining whether or not to transfer the central control station to the terminal. Check the environment information such as communication error rate, and repeat the stabilization process every time the system is restarted to automatically transfer the centralized control station to the position where the most stable communication service can be provided as a system. It is no longer necessary, it is possible to shorten the time of the launch of the system.
[0236]
In the above third embodiment, the conditions for becoming a centralized control station are set with reference to past performance, communication error rate, and radio wave reception strength. However, past performance and communication error rate, or past performance and radio wave A configuration based on the reception intensity is also included in the present invention.
(6) Other embodiments
In the first and second embodiments described above, the function of the centralized control station is transferred by determining the communication error rate and the variation in radio wave reception intensity for each terminal in the system by exchanging test frames. If the communication error rate or radio wave reception intensity detected by exchanging test frames exceeds the allowable range according to the criteria set in the centralized control station in advance, the communication error If the function of the centralized control station is transferred to a terminal with good rate and radio wave reception strength, the burden of processing to calculate by comparing the maximum value and minimum value of the communication error rate and radio wave reception intensity for each terminal will be reduced. This can be reduced and a simpler system can be configured.
[0237]
In the third embodiment described above, the system management information is transmitted from the central control station to each terminal station at regular intervals, so that the system management information is shared by each terminal in the system. The history of each terminal station is determined based on the system management information owned by the own wireless terminal, but instead, the history of each terminal station is individually stored in each wireless terminal, and the central control station If the functions of the central control station and the terminal station are transferred by comparing the history of both when accessing the terminal station, the system management information is transferred from the central control station to each terminal station at regular intervals. A simple system can be provided by reducing the burden of transmitting data to the network.
[0238]
In this case, since the history of the central control station is compared with the history of one terminal station instead of referring to the terminal history of the entire system, there are cases where frequent function transfer operations occur. . Therefore, in order to avoid such frequent function transfer operations, when there are appropriate conditions for transferring functions, for example, when the performance of the central control station and the terminal station differ significantly, the function transfer operation It is effective to do this.
[0239]
In the third embodiment described above, the presence / absence and timing of a record of functioning as a centralized control station as history information are determined. In the system management information, information on error rate and reception strength at the time of communication is determined. May be stored, and the eligibility as a centralized control station may be determined in consideration of these.
[0240]
【The invention's effect】
  As explained above, according to the present invention,Based on the past history, it is possible to determine a device that exists at a position more suitable for the control station than the own device, and it is possible to quickly set an appropriate wireless device as the control station.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a wireless system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a radio telephone in the first embodiment.
FIG. 3 is a block diagram showing a configuration of a wireless adapter in the first embodiment.
FIG. 4 is a block diagram showing a configuration of a network control device in the first embodiment.
FIG. 5 is a block diagram showing a configuration of a radio unit in the first embodiment.
FIG. 6 is an explanatory diagram showing a configuration of a radio frame in the first embodiment.
FIG. 7 is an explanatory diagram showing a configuration of each field of a radio frame in the first embodiment.
FIG. 8 is an explanatory diagram conceptually showing a frequency switching operation in the first embodiment.
FIG. 9 is an explanatory diagram showing an example of a frequency switching operation in the first embodiment.
FIG. 10 is a sequence diagram showing an operation of the wireless terminal after power is turned on in the first embodiment.
FIG. 11 is a flowchart showing an initial setting operation of a conventional wireless terminal.
FIG. 12 is a flowchart showing an operation at the time of terminal station registration of the centralized control station in the first embodiment.
FIG. 13 is a sequence diagram showing an operation during communication between wireless terminals in the first embodiment.
FIG. 14 is a flowchart showing processing of a centralized control station in the first embodiment.
FIG. 15 is a flowchart showing the operation of the wireless terminal in the first embodiment.
FIG. 16 is a flowchart showing another operation of the wireless terminal in the first embodiment.
FIG. 17 is a block diagram showing a configuration of a channel codec unit in the first embodiment.
FIG. 18 is a flowchart showing an operation at the time of activation of the wireless terminal in the first embodiment.
FIG. 19 is a flowchart showing the operation of centralized control station mode processing in the first embodiment.
FIG. 20 is a flowchart showing an operation of terminal station mode processing in the first embodiment.
FIG. 21 is a flowchart showing an operation of a terminal mode change process in the first embodiment.
FIG. 22 is a flowchart showing the operation of the terminal station after the terminal mode change process in the first embodiment.
FIG. 23 is a block diagram showing a configuration of a communication error processing unit in the first embodiment.
FIG. 24 is a flowchart showing communication error processing in the first embodiment.
FIG. 25 is a flowchart showing radio wave intensity processing in the second embodiment of the present invention.
FIG. 26 is a flowchart showing an initial setting process in the centralized control station mode in the third embodiment of the present invention.
[Explanation of symbols]
101: Network control device,
102 ... Public line,
103 ... wireless telephone,
104: Computer,
105 ... multimedia terminal,
106: Printer,
107: facsimile,
108 ... copier,
109: LAN gateway.

Claims (2)

In a wireless communication device,
Setting means for selectively setting a control station mode for controlling other wireless communication devices and a terminal station mode to be controlled in the control station mode;
When the wireless communication device is set to the control station mode, the first wireless communication device set to the terminal station mode has previously operated as the control station mode after the wireless communication device. Determining means for determining whether or not;
Transfer means for performing processing for transferring the role of the control station mode to the first wireless communication device in accordance with the determination by the determination means;
A wireless communication apparatus comprising: In claim 1,
Determining means for determining a communication environment with the first wireless communication device;
A wireless communication apparatus that performs a transfer process by the transfer means or a determination process by the determination means in accordance with the determination by the determination means.

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