JPH09168182A - Mobile telephone system and its interference evading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly evade the interference and to carry on the communication without changing the radio frequency of plural transceivers against occurrence of the interference. SOLUTION: A radio base station 500 periodically retrieves the fresh interference evading destination radio frequency after sensing a carrier via a receiving circuit 503c and stores these retrieved radio frequency in a storage means 502c. The station 500 also reports and stores the fresh evading destination radio frequency which are periodically retrieved by the report signals to its follower radio mobile station. When the station 500 or the follower mobile station detects an interference disturbance, both stations quickly switch the operating radio frequency to the interference evading destination radio frequency to evade the interference without switching a transceiver unit TRX.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interference avoidance method for avoiding interference occurring between a radio base station and a radio mobile station, which is applied in a mobile telephone device or the like which communicates with a plurality of radio mobile stations by a TDMA radio communication system. .

[0002]

2. Description of the Related Art Conventionally, in a mobile telephone apparatus or the like which employs a TDMA radio communication system to communicate with a plurality of radio mobile stations, a dedicated radio base station is connected to a dedicated mobile telephone exchange network to provide public services. Is going. Such existing mobile telephone devices include those shown in FIGS. 4 to 6. FIG. 4 is a block diagram showing the overall configuration of the mobile telephone device as a conventional example, FIG. 5 is a block diagram showing the configuration based on each function of the wireless base station shown in FIG. 4, and FIG. 6 is a wireless mobile device shown in FIG. It is a block diagram which shows the structure based on each function of a station.

First, the configurations of a conventional mobile telephone device, a radio base station and a radio mobile station that constitute the conventional mobile telephone device will be described with reference to FIGS. First, in FIG.
0 is a public switched telephone network (PSTN), 201 is a mobile telephone device integrated service digital network (ISDN), 2
Reference numeral 02 is a mobile telephone switching network, 203 is a wireless base station (BS) that constitutes a plurality of wireless zones, and 204 is a wireless mobile station (MS) that is wirelessly connected to the wireless base station.

Next, the configuration of a conventional radio base station will be described with reference to FIG. In FIG. 5, reference numeral 203 is a wireless base station, 301 is a high-speed digital interface unit that is connected to the mobile telephone switching network 202 and that transmits and receives control signals and communication signals at high speed by digital signals, 302 is a CPU 302a including a microcomputer, and a wireless base station. A program memory (ROM) 302b that stores a software program that controls the entire 203, and a RAM 302c that is used as a work area when operating software such as calculation.
And an I / O 302d that controls input / output of signals to be transmitted / received
And the like.

Reference numeral 303 denotes a receiving circuit 303a for each radio base station to measure the electric field strength of each channel, perform carrier sense (verification), report the result to the mobile telephone switching network 202, and use it for frequency selection. A transceiver unit including a plurality of transceiver units TRX for transmitting and receiving control signals and communication signals to and from a plurality of wireless mobile stations 204, each having a different radio frequency, 304 denotes a radio signal to be transmitted to a distant wireless mobile station 204. A radio signal amplification unit 305 that amplifies so as to reach the antenna unit 305 is an antenna unit that transmits and receives a radio digital signal that communicates with the radio mobile station 204.
A three-sector method is employed in which the service is provided every 120 degrees (360/3 = 120).

Next, the configuration of a conventional wireless mobile station will be described with reference to FIG. In FIG. 6, reference numeral 204 is a wireless mobile station, and 401 is an antenna unit 305 of the wireless base station 203.
An antenna section for transmitting and receiving radio communication radio waves to and from
Reference numeral 2 is a radio unit that modulates or demodulates and amplifies a digital TDMA signal transmitted or received by the antenna unit 401, and 403 is a CPU 403a including a microcomputer.
And a memory 40 that stores a software program for controlling the entire wireless mobile station 204 and is used for work such as calculation.
3b, an input signal from the key input unit 405 and the display unit 4
I / O 403 for controlling the input / output of the output signal for 06
It is a control unit including c and the like.

Reference numeral 405 is a key input section for keying in necessary data such as a telephone number, 406 is a display section for displaying a telephone number, control information and a message, and 404 is a microphone 408 for converting the input signal into a voice signal. A voice input / output unit that outputs a voice signal received from the receiver 407, a microphone 408 that inputs a voice, and a receiver 407 that outputs a voice.

Next, the operations of the conventional mobile telephone device, the radio base station and the radio mobile station constituting the same will be described with reference to FIGS. In the above configuration, the mobile telephone switching network 202 exchanges and controls communication between the public telephone switching network 200, the integrated service digital network 201, and a plurality of wireless base stations 203 connected thereto, and uses the same. Assign frequencies and so on. Further, each wireless base station 203 communicates with a plurality of wireless mobile stations 204 existing within its own wireless zone through the channel frequency set between them. As a communication method, a mobile telephone switching network 2
The communication between the wireless base station 203 and the wireless base station 203 is performed by a digital (or analog) cable, and the communication between the wireless base station 203 and the wireless mobile station 204 is performed by a wireless digital time division multiple access (TDMA) method. I am trying to do it.

First, when the wireless mobile station 204 enters the wireless zone of a certain wireless base station 203, it measures the magnitude of the electric field strength and detects the channel (frequency) used by the wireless base station 203. Then, the wireless mobile station 204 transmits a position registration signal for notifying the wireless base station 203 of its own existence. The position registration signal is the wireless base station 203.
After that, the mobile telephone 204 is registered in the public switched telephone network 200 via the telephone, and then, via the frequency, the wireless mobile station 204 is instructed to exchange communication from the public switched telephone network 200 or change the radio frequency. In addition, off-hook, dialing,
Regarding the explanation of normal communication operation such as confirmation of the destination line,
The explanation is omitted because it is complicated.

[0010] Next, the mobile telephone switching network 202 can instruct the radio base station 203 a plurality of control radio frequency numbers and communication radio frequency numbers prior to or during operation. The radio base station 203 determines a different transmission / reception radio frequency for each transceiver unit TRX according to this instruction. However, the control radio frequency and the communication radio frequency are assigned the same frequency for each transceiver unit TRX.

Then, each radio base station 203 is set to a radio frequency (channel) of a transceiver unit TRX that is physically unused when interference with the radio frequency of the transceiver unit TRX currently in communication occurs. A so-called "handover" method in which a channel is switched by a so-called "intra-zone channel switching" method, that is, a frequency is switched to continue a call or a radio frequency of a transceiver unit TRX of another completely different radio base station is switched. The frequency is switched so that the call can be continued.

[0012] That is, according to the "intra-zone channel switching" method, the radio base station detects the interference interference to the frequency being used, and the radio mobile station 2
When the signal reception error information is received from 04, the wireless mobile station 204 is instructed to switch the frequency to the frequency for another transceiver unit TRX in the same wireless base station, and the wireless mobile station 204 Follow the channel switching instruction to switch to that frequency and continue the call.

On the other hand, according to the "handover" method, when there is no transceiver unit TRX to be switched to its own radio base station, such as when it is all in use, the transceiver unit TRX of another adjacent radio base station is needed as necessary. Switch to and use the radio frequency for communication. Alternatively, in some cases, it is possible to return to the original communication radio frequency and control to continue the call.

As a method of selecting a radio frequency to be used in the radio base station 203, a radio frequency that can be used in advance is set in each transceiver unit TRX of the radio base station 203 according to an instruction from the mobile telephone switching network 202. The method of keeping is adopted. Then, when an interference occurs in the radio frequency being used, it is switched to another idle transceiver unit TRX to use that frequency. When the mobile telephone switching network 202 instructs each radio base station 203 of the radio frequency to be used therein, the radio frequency to be assigned is determined based on the following rules.

[Rule 1] No adjacent channel is assigned. Frequencies on both sides of the already assigned frequency are not assigned. [Rule 2] Do not assign frequencies that interfere with intermodulation. Two already assigned frequencies (fa, f
The frequencies that can be expressed by the following equation from b) are not assigned.

For example, if the frequencies fa and fb are already assigned, the frequencies fc1 and fc2 obtained from fc1 = 2fa-fb fc2 = 2fb-fa may be disturbed and are not assigned. With respect to the number of usable frequency channels by the above equation, all are mutually calculated to find a combination in which no interference occurs, and the usable frequency (channel) is determined for each radio base station. [Rule 3]
Even if the frequency has already been allocated, it is allocated if there is a clear distance that radio waves cannot reach between the wireless base stations.

[0017]

However, in the above-mentioned conventional mobile telephone apparatus of the digital TDMA communication system, the control radio frequency and the communication radio frequency assigned to each transceiver unit TRX are the same.
If there is no other transceiver unit TRX to switch to when interference is received during communication, the control radio frequency must be switched and changed at the same time as the communication radio frequency. There has been a problem that all wireless mobile stations that are registered in the wireless base station and are in communication must also change their operating wireless frequencies such as the control wireless frequency and the communication wireless frequency.

Further, as described above, the radio frequency allocation to the radio base station is made by carefully considering each other so that interference does not occur, but this problem is alleviated and the radio base station is made inexpensive. Therefore, it is considered to equip one radio base station with one transceiver unit TRX having the same control radio frequency and communication radio frequency. However, when only one transceiver unit TRX is equipped, there is a problem that it is difficult to switch the radio frequency to be used when interference is generated.

However, when the control radio frequency and the communication radio frequency use the same frequency, and a radio frequency management system is adopted in which the radio base station autonomously selects and uses a vacant radio frequency. Causes the following problems. That is, 1) The radio frequency of another radio mobile station flows into the radio zone from a remote location and interferes with it. 2) There is a possibility that a radio base station having a large transmission power for transmitting the same radio frequency as the radio frequency used by the radio base station is newly installed to cause interference. 3) The neighboring wireless base stations perform carrier sense asynchronously with the wireless base station and interfere with each other. 4) Harmonics such as third order generated by intermodulation (IM) interfere with each other. 5) Unexpected interference from radiated harmonics from radio equipment.

The present invention has been made to solve the above-mentioned conventional problems, and when interference is generated, it is possible to change the radio frequency of a plurality of transceiver units regardless of whether communication is in progress. An object of the present invention is to provide a mobile telephone device and a method for avoiding the interference thereof that can promptly avoid the interference and continue communication without being bothered.

[0021]

In a mobile telephone apparatus and an interference avoidance method therefor according to the present invention, a wireless base station periodically searches and stores a fresh interference avoidance destination radio frequency by carrier sense, and a radio movement under its control is performed. The station is notified of the fresh interference avoidance radio frequency searched by the notification signal on a regular basis and stored, and when the radio base station or the radio mobile station detects interference, it does not switch the transceiver unit. Both of them promptly switch the operating radio frequency to the interference avoidance radio frequency and use it.

According to the present invention, a free radio frequency map in which the interference avoidance radio frequency is registered is provided, and when the interference occurs, the used frequency is immediately switched to the interference avoidance radio frequency and the interference avoidance is promptly avoided. A mobile phone device capable of continuing communication and an interference avoiding method thereof can be obtained.

In addition, by always checking the electric field strength of frequencies registered in the vacant radio frequency map to keep the vacant state fresh and securing the switching frequency when the interference occurs, interference detection is performed. There is provided a mobile phone device and an interference avoiding method thereof capable of smoothly executing interference avoidance in time.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a mobile telephone exchange network, a plurality of radio base stations connected to the mobile telephone exchange network, and each of the radio base stations by a radio digital line. In a mobile telephone device comprising a plurality of wireless mobile stations connected to each other, the wireless base station has a CPU for controlling the wireless base station, and a transceiver unit for wireless communication between the wireless base station and the wireless mobile station. And storage means for storing a radio frequency used by the transceiver unit for radio communication with the radio mobile station, and a receiving circuit for performing carrier sense of the radio frequency assigned to the radio base station. Under the control of the CPU, at least two best available radio frequencies selected as a result of the carrier sense are stored in the storage means, and one of the stored radio frequencies is operated. It is used as a radio frequency, and when interference occurs in the radio frequency, it is switched to the other radio frequency stored in the storage means, and only the radio frequency is switched when the interference occurs. Therefore, the communication can be easily continued.

According to a second aspect of the present invention, the storage means stores the other radio frequency as an interference avoidance radio frequency, and the receiving circuit periodically carries out the carrier sense to the interference avoidance radio frequency. And a new interference avoidance radio frequency is held by periodically notifying the radio mobile station by a notification signal under the control of the CPU, and the radio mobile station instructs to switch from the radio base station. Thus, the operating radio frequency is switched to the interference avoidance radio frequency, and it has an effect that it can be switched to the fresh best interference avoidance radio frequency when interference occurs.

The invention according to claim 3 of the present invention is an interference avoiding method for avoiding interference occurring between a wireless base station and a plurality of wireless mobile stations connected by a wireless digital line, and is available in advance. When a radio frequency is selected and stored as an interference avoidance radio frequency, and the interference occurs, the radio base station includes a step of switching its operating radio frequency to the interference avoidance radio frequency, and the radio frequency is switched when the interference occurs. To continue communication,
When the interference occurs, it has an effect that the operating radio frequency can be simply switched to the interference avoidance radio frequency and communication can be easily continued.

According to a fourth aspect of the present invention, the step of preliminarily selecting and storing the free radio frequency as an interference avoidance radio frequency is autonomously best from a plurality of radio frequencies to which the radio base station is assigned. 2 of the free radio frequencies are selected, one of them is set as the operating radio frequency, and the other is stored as the radio frequency of the interference avoidance destination, and the radio frequency of the interference avoidance destination is always set as a fresh best free state. By maintaining it, there is an effect that interference avoidance can be executed smoothly.

According to a fifth aspect of the present invention, the step of selectively storing the free radio frequency as an interference avoidance destination radio frequency in advance is controlled periodically as an operating radio frequency by an instruction from a mobile telephone switching network. The radio frequency for communication and the radio frequency for communication and the radio frequency for avoiding interference are selected and updated, and the radio base station can simplify the device and operation without needing to search for a free radio frequency by itself. Has the effect of.

According to a sixth aspect of the present invention, the radio base station periodically notifies the radio mobile station of the interference avoidance radio frequency by a broadcast signal, updates and stores the interference avoidance radio frequency, and when the interference occurs. The radio base station includes a step of switching its operating radio frequency to the interference avoidance radio frequency notified by the notification signal by a switching instruction from the radio base station. This has an effect that the interference avoiding radio frequency can be always kept fresh.

According to a seventh aspect of the present invention, the step of switching to the notified interference avoidance radio frequency is performed when the radio mobile station does not receive a notification signal from the radio base station for a predetermined period. Or, when the instruction to change the interference avoidance radio frequency cannot be recognized, the method further includes the step of autonomously switching the operating radio frequency to the stored interference avoidance radio frequency. When the communication from the station is interrupted for a predetermined period or longer, the wireless mobile station autonomously switches the operating radio frequency to the interference avoidance radio frequency, so that the communication failure can be avoided.

Prior to the description of the embodiments of the present invention, the outline of the present invention will be described with reference to the accompanying drawings. The present invention autonomously searches for the freshest and best (unused and low noise) free radio frequency in a radio base station, and stores and uses the free radio frequency,
The free radio frequency is regularly notified to the radio mobile station as the interference avoidance radio frequency, and when interference occurs, the radio base station promptly sets the control radio frequency and the communication radio frequency to the interference avoidance radio frequency. Switching, the wireless mobile station is configured to switch to the interference avoiding radio frequency that has been informed by the instruction of the radio base station or after a lapse of a certain time.

At the start of operation, the radio base station measures the electric field value of the annunciation signal transmitted by a plurality of peripheral radio base stations at least three times per slot by carrier sense to determine whether or not it is in use. This is repeated every prescribed time (for example, 3 minutes) to create a map of used radio frequencies, and the received electric field value of each frequency is stored therein. This is repeated for the allowable radio frequencies to create an empty radio frequency map (white list) and store it in the storage means.

The radio base station sets the highest one of the most suitable radio frequencies in the created whitelist as the free radio frequency to be the control radio frequency and the communication radio frequency, and the second and subsequent spare frequencies. Of these, at least one is set as an interference avoidance destination radio frequency, and its radio frequency number (also referred to as a channel number) is stored.

Therefore, the radio base station starts transmitting the broadcast signal using the control slot at the control radio frequency obtained above. At this time, the communication slot may not be transmitted. The radio base station periodically notifies the subordinate radio mobile station of the interference avoidance radio frequency (by channel number) using the option area (extended information area) of the broadcast signal.

The wireless mobile station first registers its position when it receives the notification signal from the wireless base station (as described above, the position registration is possible even before receiving the notification signal). The interference avoidance destination radio frequency notified by the option area of the received notification signal is stored in a specific area of the memory. In addition, the wireless mobile station periodically performs the reception rate (ratio of successful reception or not) of the received digital signal from the wireless base station during a prescribed period during standby and communication.
The result is notified to the wireless base station. At this time, the interference state can be detected.

The radio base station measures the reception rate of the digital signal received from the radio mobile station and determines that there is interference when the reception failure exceeds a specified value. Further, it is determined whether or not there is interference according to the determination result of the reception rate from the wireless mobile station. When the radio base station determines that there is interference,
Basically, a control radio frequency switching instruction is issued to a plurality of radio mobile stations under its control in addition to a notification signal and a communication signal.
There is no guarantee that it will reach the wireless mobile station due to interference.

The radio mobile station cannot receive the notification signal when receiving the control radio frequency switching instruction from the radio base station or continuously for a fixed time, and the reception electric field value of the radio frequency is a constant value (for example, 10 dBμV). ) If there is the above, it is determined that there is interference, and the operating radio frequency is promptly switched to the interference avoidance radio frequency stored in the interference avoidance storage area, and reception standby is performed by the radio frequency of the exchange destination. Or, continue communication.

In order to refresh the whitelist and blacklist, the radio base station periodically, except during communication,
Execute carrier sense for each radio frequency listed in each whitelist and blacklist sequentially,
If it is determined that a radio frequency in the whitelist is in use, it is moved to the blacklist, and if it is determined that the radio frequency in the blacklist is available, it is moved to the whitelist.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings and FIGS. 1 to 3. FIG. 1 is a block diagram showing the configuration based on each function of a low cost radio base station according to an embodiment of the present invention, and FIG. 2 shows interference avoidance radio frequencies in the low cost radio base station and radio mobile station shown in FIG. FIG. 3 is a diagram showing a radio frequency storage area to be stored, and FIG. 3 is a diagram showing a low cost radio base station shown in FIGS. 1 and 2 and an interference avoiding procedure using the radio frequency storage area. The configuration of the wireless mobile station used in the present embodiment is the same as that of the conventional wireless mobile station described above, and thus the description thereof will be omitted.

First, the configuration of a low-cost radio base station according to the present embodiment will be described with reference to FIG.
In FIG. 1, reference numeral 500 is a radio base station, 501a is a high-speed digital interface unit connected to the mobile telephone switching network 202 for high speed transmission and reception of data transmission such as control signals and communication signals, and 501b is connected to a public telephone network such as NTT. It is a public telephone network interface unit that performs communication control between them, and the high-speed digital interface unit 501a and the public telephone network interface unit 501b coexist in one radio base station 500, or in the case where only one of them is equipped. Good.

Further, 502 is a CPU 5 composed of a microcomputer.
02a and a program memory (ROM) 502b storing a software program for controlling the entire wireless base station.
And a RAM (also referred to as a storage unit) 502c used as a work area when working a software program such as calculation
And an I / O 502d that controls input / output of signals to be transmitted / received
A control unit 504 for controlling the entire wireless base station including the above, and an antenna unit 504 for wirelessly transmitting and receiving digital signals communicating with the wireless mobile station 204.

Reference numeral 503 denotes one transceiver unit TRX including a transmitter 503a and a receiver 503b for transmitting / receiving control signals and communication signals to / from the wireless mobile station 204, and usable channels (frequency).
And a reception circuit 503c for measuring the electric field strength of a radio wave transmitted from a radio base station in the vicinity and performing carrier sensing to search for the best channel and a channel to be used instead when there is interference interference. It is a transceiver unit that performs wireless communication with a plurality of wireless mobile stations 204 using the control radio frequency and the communication radio frequency.

Next, referring to FIG. 2, the radio base station 500
The configuration of a so-called white list, which is a free radio frequency map (or list) stored in the free radio frequency map in the radio frequency storage area provided in a part of the RAM 502c of FIG. 2A shows a white list in which the radio frequencies usable by the radio base station 500 are listed in the radio frequency storage area on the radio base station side, and FIG. 2B shows the white list. FIG. 2 shows a whitelist after interference avoidance, which lists available radio frequencies after interference avoidance in a radio frequency storage area on the radio base station side, and FIG. 2C shows a blacklist for storing prohibited radio frequencies. .

Further, (1-1) of FIG. 2 shows the interference avoidance destination radio frequency b stored in the interference avoidance destination storage area of the radio mobile station side, which is notified by the broadcast signal from the radio base station side, and FIG.
(1-2) indicates the interference avoidance radio frequency c stored in the interference avoidance storage area on the radio mobile station side, which is notified by the broadcast signal from the radio base station side after the interference avoidance.

In the white list in (1) of FIG. 2, the radio frequency (channel number) which is not used by the peripheral radio base stations 500 within the radio frequency band permitted by the radio base station 500 from the mobile telephone device. ) Is stored, the first "operating radio frequency a" indicates the channel number currently used for operation between the radio base station 500 and the radio mobile station 204, and the second "interference avoidance radio frequency b" is When interference is detected during operation on the first channel, the radio base station 500 and a plurality of radio mobile stations 204 under the radio base station indicate new radio frequencies to be used as interference avoidance destinations. Multiple spare channel numbers (c
~ F) are shown.

As in (1) of FIG. 2, the white list in (2) of FIG. 2 stores radio frequencies (channel numbers) that are not used by the surrounding radio base station 500, and the first "operating radio" is stored. The frequency “b” is the radio base station 500 and the radio mobile station 2 which have been moved from the second to the beginning by avoiding interference.
Indicates the channel number actually used for operation between 04 and 2
The second "interference avoidance radio frequency c" indicates a channel number increased from the backup c to the interference avoidance radio frequency, and in the third and subsequent lists, a backup g is added at the end of a plurality of backup channel numbers ( d-g) are shown. In this example, the channel numbers are sequentially increased from the bottom, but the list may be replaced each time.

The black list in (3) of FIG. 2 shows the channel numbers forbidden there listed in the radio frequency storage area of the radio base station 500. For example, the operating frequencies of neighboring radio base stations are shown. In other words, the channel numbers of the radio frequencies that have been subjected to the interference, or that clearly cause the generation of the interfering waves due to "intermodulation" with respect to the radio base station of the self and the surroundings are listed.

In the interference avoidance destination storage area on the side of the wireless mobile station in (1-1) of FIG. 2, the interference avoidance destination radio frequency b which is notified by the broadcast signal from the radio base station and stored therein is stored. In the interference avoidance destination storage area on the side of the wireless mobile station in (1-2) of 2, due to interference, the wireless mobile station moves the radio frequency operated by the instruction of the radio base station to the interference avoidance destination radio frequency or by itself. Shows that after moving the radio frequency operated by the radio frequency controller to the interference avoidance destination radio frequency, a new interference avoidance destination radio frequency c indicated by the notification signal from the radio base station is stored.

Next, the outline of the interference avoidance procedure will be described with reference to FIG. First, (1) of FIG. 3 shows a radio frequency switching procedure when interference is detected while waiting for communication. When the wireless base station 500 (BS) finds interference, the wireless base station 500 (BS) uses a broadcast signal to send a plurality of wireless mobile stations 2 under its control.
04 (MS1 to MS3) is issued a control radio frequency switching instruction, that is, a switching instruction to switch the operating radio frequency to the interference avoidance radio frequency. The wireless mobile station 204 (MS1 to MS3) is within a specified time (for example, 1
During the second second), the operating frequency is switched to the interference avoidance radio frequency stored in the memory 403b of its own.

The radio base station 500 (BS) also switches to the designated interference avoidance radio frequency. Then, the wireless base station 500 (BS) is the wireless base station 204 (MS1).
~ MS3) immediately starts transmitting a notification signal by a new radio frequency. Then, the wireless mobile station 204 in the vicinity
Receives a new interference avoidance radio frequency by the notification signal, stores it, and enters a continuous standby state.

Next, (2) of FIG. 3 shows a radio frequency switching procedure when interference is generated during communication. The radio base station 500 (BS) and the radio mobile station 204 (MS1 and MS).
2) is in communication with the wireless mobile station 204 (MS3) and is on standby. Therefore, when the interference is detected, the radio base station 500 (BS) causes the radio mobile station 204 (M
A radio frequency switching instruction is transmitted to S1 and MS2) during communication.

A switching instruction is issued to the radio mobile station 204 (MS3) in the standby mode so as to switch its operating radio frequency to the interference avoidance radio frequency, as described in (1) of FIG. send. Each wireless mobile station 204 (MS1
~ MS3) promptly switches to a new radio frequency according to the switching instruction, and also switches the radio base station 500 (BS) to restart communication. After switching the communication,
Radio base station 500 (BS) and radio mobile station 204 (MS
1 to MS3) can continue communication while maintaining the operation timing before switching.

Referring now to FIGS. 1-3, and in particular FIG.
The interference avoidance operation and interference avoidance procedure of the mobile telephone device according to the present embodiment will be described in detail with reference to FIG. First, in FIG. 1 and FIG. 2, the control unit 502 of the radio base station 500 controls the software installed therein to detect carrier intensity information (reception electric field value information) of the electric field strength of the radio frequency in the receiving circuit 503c. ) Is sampled (for example, 3 times in 6.66 ms). Then, by adopting the highest value among them, the radio frequency number lower than the specified electric field value (for example, 4 dBμV) while also supporting the carrier sense against the extreme fading that is temporarily determined to have no carrier. Executes the function of selectively collecting (channel number) from the range of the specified wireless band.

Next, when the radio base station 500 is started to operate, the radio frequency (the one with the lowest received electric field value at the time of carrier sensing) (the one with the lowest received electric field value at the time of carrier sensing) is selected from among the available radio frequency numbers collected by the receiving circuit 503c. The radio frequency a) of 1) is set as the operating radio frequency a of the radio base station 500, but here, at least one other free radio frequency number (interference avoidance radio frequency b in FIG. 1) at the time of occurrence of interference is used. The interference avoidance destination control radio frequency and the communication radio frequency are stored in the radio frequency storage area of the RAM 502c of the radio base station 500.

The radio base station 500 starts its operation, starts transmitting an annunciation signal to the subordinate radio mobile station 204 by using the control radio frequency, and the radio base station 500 radios its RAM 502c. The interference avoidance radio frequency (in this example, the frequency b, which is the same as before without interference) to be stored is notified in the frequency storage area. This interference avoidance radio frequency is periodically notified to the radio mobile station 204 by using the spare area (for example, extended information setting area) of the broadcast signal. The radio mobile station 204 receives from the radio base station 500 the interference avoidance radio frequency b as the channel number of the interference avoidance control radio frequency which is switched and used when interference is generated by the broadcast signal,
This is stored in the interference avoidance destination storage area ((1-1) in FIG. 2) of the memory 403b in the wireless mobile station 204.

Next, with reference to FIGS. 2 and 3, the frequency or channel switching procedure when interference is received will be described in detail. (1) of FIG. 3 shows the wireless base station 50.
0 (BS) shows a frequency switching procedure during standby in which the radio frequency is switched in the standby state of communication, and (2) in FIG.
Shows a frequency switching procedure during communication in which the wireless base station 500 (BS) switches the wireless frequency during communication.

First, the radio base station 50 shown in (1) of FIG.
In the standby state of communication by 0 (BS), when detecting interference by itself by carrier sense or when receiving a report of the interference condition from the subordinate wireless mobile station 204, the wireless base station 500 (BS). All radio mobile stations 204 under its control (MS1, MS2, MS3 in (1) of FIG. 3) are instructed by a notification signal to update or switch the control radio frequency by interference detection a prescribed number of times (for example, three times).
After the notification, the interference avoidance radio frequency b is switched to the operating radio frequency, that is, the new control radio frequency. After switching the control radio frequency, the notification signal is notified by the new radio frequency.

When the wireless mobile station 204 receives the control radio frequency switching instruction by receiving the notification signal, the interference avoidance information notified by the notification signal before is stored in the interference avoidance storage area of the memory 403b (FIG. 6). Interference is avoided by using the destination radio frequency b ((1-1) in FIG. 2) as its operating radio frequency, and the interference avoidance destination radio frequency c notified by the notification signal after this time interference avoidance is stored in the memory 403b ( It is stored in the interference avoidance destination storage area of FIG. 6) as the interference avoidance destination radio frequency c after interference avoidance (FIG. 2).
(1-2)).

In the above description, the radio mobile station 204 receives an instruction to change the interference avoidance radio frequency from the radio base station 500 (BS), but the radio base station 500 (BS) uses the announcement signal. ), If the instruction to change the interference avoidance radio frequency cannot be recognized by the radio mobile station 204, or if the broadcast signal cannot be received for a certain period of time, the radio mobile station 204 sets the operating radio frequency to the interference avoidance storage area. It is possible to switch to the interference avoidance destination radio frequency stored in the above and wait for its reception.

Next, as shown in (2) of FIG. 3, the radio base station 500 (BS) causes the radio mobile station 204 (eg MS
1 and MS 2), when it detects interference, or when it recognizes interference from the reception error information from the wireless mobile station 204, the wireless base station 5
00 (BS) is the wireless mobile station 204 (eg,
For the MS1 and MS2), the call signal during communication is stolen, and during this period, a radio frequency switching instruction during communication is notified,
A wireless mobile station 204 not in communication (for example, (2) in FIG. 3)
The MS 3) is notified of the update or switching of its own control radio frequency, that is, the operating radio frequency, by a notification signal.

The radio base station 500 (BS) notifies the update of the control radio frequency, and then the operating radio frequency (control radio frequency and communication radio frequency) is stored in its own radio frequency storage area. Switch to the avoidance destination radio frequency b, and change to the storage location of the interference avoidance destination radio frequency,
The frequency that was the backup c before the change is increased as the interference avoidance radio frequency c, the backups d to f are successively moved up to the backup storage position, and the backup g is added to the last, and (2) in FIG. Set in the whitelist after interference avoidance as shown in.

On the other hand, the radio mobile station 204 (MS1 to MS) that has received the radio frequency switching instruction or the radio frequency update notification.
In 3), the interference avoidance destination radio frequency b stored in the interference avoidance destination storage area is switched to the operating radio frequency and waits for resumption of communication. And the wireless base station 500 (BS)
Is the same as before the frequency switching, at the transmission timing,
The notification signal is transmitted to all the wireless mobile stations 204 by the switched new control radio frequency. The radio frequency notified here is the interference avoidance radio frequency c that has newly become the interference avoidance radio frequency ((2) in FIG. 2), and the radio mobile station 204 (MS1 to MS3) receives this and creates a new radio frequency. The interference avoidance radio frequency c is stored in the interference avoidance storage area ((1-2) in FIG. 2).

When the radio mobile station 204 does not receive the notification signal for a certain period of time or when there is no switching instruction, the radio frequency to be operated is the interference avoidance destination radio frequency stored in the interference avoidance destination storage area (for example, FIG. 2). The frequency is switched to (1-2) frequency c), and the reception is awaited. As a result, communication can be continued.

The interference avoidance method according to the present embodiment configured as described above can easily realize interference avoidance, so that the radio frequency for control and the radio for communication are controlled without providing a spare of the transceiver unit TRX. Since it is sufficient to equip only one small transceiver unit TRX having the same frequency, it is possible to provide a small and inexpensive radio base station.

Further, since the radio base station 500 always keeps the frequency b at the beginning of the interference avoidance radio frequency of the white list fresh, the radio base station 500 is in a standby state instead of communicating, and a prescribed cycle (for example, 3 minutes). Career sense every time. When it determines that it is in use (for example, the interference avoidance radio frequency b), it adds it to the blacklist, and reserves c stored next in the next carrier sense cycle.
About career sense.

The blacklist is updated once every N times (for example, in the form of interrupting the whitelist refresh cycle).
It can be updated by performing carrier sense 5 times (15-minute cycle). Carrier sense in the black list is sequentially performed from the beginning of the black list, and when it is determined that the black list is empty, the carrier sense can be deleted from the black list and added to the white list.

As the transmission method applied to the present invention, full rate transmission (20 ms is divided into 3 divisions (slots)) and half rate transmission (40 ms is divided into 6 divisions (slots)) can be used. , And radio waves of one radio frequency can be separately used in a time division manner.

In the above description, the method in which the radio base station autonomously searches for the best available radio frequency by the carrier sense and adopts the result is mainly explained. May be used to set the operating radio frequency and the interference avoidance radio frequency according to an instruction from the mobile telephone switching network. Also, the above explanation is
The case where the control radio frequency and the communication radio frequency are the same has been described, but of course, the case where they are different can be applied.

[0069]

The interference avoidance method for a mobile telephone device according to the present invention is configured as described above, and in particular, the radio base station periodically searches for the radio frequency of the interference avoidance destination by carrier sense, and the radio movement under the control of the subordinate mobile station. For the station, the fresh interference avoidance radio frequency retrieved by the notification signal is periodically notified and stored, and when the radio base station or the radio mobile station detects the interference, it is troublesome to switch the transceiver unit. Instead, both of them are promptly switched to the best interference avoiding radio frequency, so that the interference can be smoothly avoided and the communication can be continued at the best radio frequency without noise.

In the interference avoidance method for the mobile telephone device according to the present invention, since the interference avoidance radio frequency is set, interference avoidance can be easily realized. Therefore, only one transceiver unit TRX is used. Since the wireless base station can be configured as a result, a small-sized and inexpensive wireless base station can be provided.

Since the interference avoiding method for the mobile telephone device according to the present invention can be realized by the software of the CPU and the ROM, it is possible to flexibly deal with the addition and change of the function.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a low-cost radio base station according to an embodiment of the present invention based on each function.

FIG. 2 is a diagram showing a radio frequency storage area used in the low-cost radio base station shown in FIG.

FIG. 3 is a diagram showing an interference avoidance procedure using a radio frequency storage area of the low cost radio base station shown in FIGS. 1 and 2;

FIG. 4 is a configuration diagram showing an overall configuration of the mobile telephone device as a conventional example.

5 is a block diagram showing the configuration of each function of the radio base station shown in FIG.

FIG. 6 is a block diagram showing the configuration of each function of the wireless mobile station shown in FIG.

[Explanation of symbols]

 200 Public Switched Telephone Network 201 Service Integrated Digital Network 202 Mobile Telephone Switched Network 203, 203a to 203d Radio Base Station 204, 204a to 204f Radio Mobile Station 301 High Speed Digital Interface Unit 302 Control Unit 302a, 502a CPU 302b, 502b ROM 302c, 502c RAM 302d, 502d I / O 303 Transceiver unit TRX Transceiver unit 303a Reception circuit 304 Radio signal amplification unit 305, 401, 504 Antenna unit 402 Radio unit 403 Control unit 403a CPU 403b Memory 403c I / O 404 Audio input / output unit 405 Key input unit 406 Display unit 407 Receiver 408 Microphone 500 Wireless base station 501a High-speed digital interface unit 501b Public telephone network interface unit 5 02 Control unit 503 Transceiver unit 503a Transmitter unit of transceiver unit 503b Receiver unit of transceiver unit 503c Receiver circuit

Claims (7)

[Claims] 1. A mobile telephone comprising a mobile telephone exchange network, a plurality of radio base stations connected to the mobile telephone exchange network, and a plurality of radio mobile stations connected to the radio base stations by radio digital lines. In the device, the radio base station includes a CPU that controls the radio base station, a transceiver unit that performs radio communication between the radio base station and the radio mobile station, and the radio mobile station by the transceiver unit. Including a storage unit for storing a radio frequency used for the radio communication of the radio base station and a receiving circuit for performing a carrier sense of the radio frequency assigned to the radio base station, and the result of the carrier sense is selected by the control of the CPU. At least two best available radio frequencies are stored in the storage means, and one of the stored radio frequencies is used as an operating radio frequency. When the interference occurs mobile telephone apparatus, characterized by switching using the other radio frequency stored in the storage means. 2. The storage means stores the other radio frequency as an interference avoidance radio frequency, and the receiving circuit periodically keeps the interference avoidance radio frequency fresh by carrier sense and controls the CPU. Periodically notifies the radio mobile station of a new interference avoidance radio frequency by a notification signal, and the radio mobile station receives the operating radio frequency of the interference avoidance radio by a switching instruction from the radio base station. The mobile telephone device according to claim 1, wherein the mobile telephone device is switched to a frequency. 3. An interference avoidance method for avoiding interference occurring between a radio base station and a plurality of radio mobile stations connected by a radio digital line, wherein an empty radio frequency is selected in advance as an interference avoidance destination radio frequency. When the interference occurs, the radio base station includes a step of switching its operating radio frequency to the interference avoidance radio frequency, and when the interference occurs, the radio frequency is switched to continue communication. Characteristic interference avoidance method. 4. The step of preliminarily selecting and storing an empty radio frequency as an interference avoidance destination radio frequency autonomously selects two best empty radio frequencies from a plurality of radio frequencies to which the radio base station is assigned, 4. The interference avoidance method according to claim 3, wherein one of them is set as an operating radio frequency and the other is stored as an interference avoidance radio frequency. 5. The step of preliminarily selecting and storing an empty radio frequency as an interference avoidance destination radio frequency periodically interferes with a control radio frequency and a communication radio frequency as operating radio frequencies according to an instruction from a mobile telephone switching network. The interference avoidance method according to claim 3, wherein the avoidance destination radio frequency is selected and updated. 6. The radio base station periodically notifies the radio mobile station of an interference avoidance radio frequency by a broadcast signal, updates and stores the radio frequency, and stores the radio frequency according to a switching instruction from the radio base station when interference occurs. The interference avoidance method according to claim 3, 4 or 5, comprising a step of switching an operating radio frequency to an interference avoidance destination radio frequency notified by the notification signal. 7. The step of switching to the notified interference avoidance radio frequency is performed when the radio mobile station has not received a notification signal from the radio base station for a predetermined period, or an instruction to change the interference avoidance radio frequency. 7. The interference avoidance method according to claim 6, further comprising the step of autonomously switching the operating radio frequency to the stored interference avoidance destination radio frequency when it is not recognized.