JPH0767169A - Radio communication device - Google Patents

Abstract

PURPOSE:To carry on a communication by a time-division multiplex system moving body system without disconnecting a radio line even in the case of asynchronous interference by performing switching to a predetermined stand-by channel if the asynchronous interference is detected. CONSTITUTION:In the time-division multiplex system moving body system which constitutes a multi-zone by plural radio connecting devices and have a communication with plural mobile equipments, each radio connecting device is provided with an asynchronous interference detection part 107 which can detect the asynchronous interference, and a stand-by channel for asynchronous interference evasion is prepared and reported to the mobile equipments together with a communication signal. A communication channel control part 106 detects the asynchronous interference, and switches the channel to a communication channel previously set for free carrier information when the asynchronous interference is detected. Each mobile equipment detects the unreceivable state of the communication signal which can be received so far and switches the channel to the previously reported communication channel. Consequently, the radio line can be prevented from being disconnected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time division multiplex mobile system in which a plurality of wireless connection devices constitute a multi-zone and communicates with a plurality of mobile units by switching channels when asynchronous interference occurs. The present invention relates to a wireless communication device that prevents disconnection of a line.

[0002]

2. Description of the Related Art In recent years, the spread of mobile communication has been remarkable. In order to meet the increasing demand, development of a digital mobile communication system, which replaces the conventional analog system, is being actively pursued, and a time division multiplex mobile communication system is becoming a reality. Less than,
A conventional channel switching method when asynchronous interference occurs in a conventional time division multiplexing mobile communication system will be described with reference to the drawings.

First, the configuration of the mobile communication system will be described with reference to FIG. Reference numeral 1 is a radio line control device for performing exchange control between a general public network or another mobile communication system and an intra-system radio line, mobile management of a mobile device, and radio management of the system. Device 1
A wireless connection device for setting / releasing a wireless line with a mobile device under the control of a wireless connection and monitoring a wireless channel,
Mobile stations 7, 8 and 9 perform communication through the wireless connection devices 2, 3, 4, and 5 and the wireless line control device 1 while moving in the system, 10A, 10B, 10C and 10D are wireless connection devices 2 and The wireless zones are set for 3, 4, and 5, respectively.

Next, the configuration of the conventional wireless connection device in the mobile communication system will be described with reference to FIG. Reference numeral 11 is an antenna section for transmitting and receiving radio signals to and from a mobile device (not shown), and 12 is radio for converting radio signals transmitted and received by the antenna section 11 and signals input and output from a modem section described later. Reference numeral 13 denotes a modem unit that performs modulation / demodulation on a signal input / output from the radio unit 12, and reference numeral 14 generates / decomposes a TDMA signal for a baseband signal input / output from the modem unit 13 and also generates a frame. A frame generation / decomposition unit for decomposing, a control channel control unit 15 for controlling a control channel,
Reference numeral 6 is a communication channel control unit that controls the communication channel, 17 is a reception level detection unit that monitors the radio channel and detects the reception level, and 18 is an interface unit that interfaces the radio line control device 1 and the radio connection device. , 19 extracts the slot synchronization signal from the signal received by the interface unit 18 to generate a frame.
It is a slot synchronization unit that controls the slot timing of the decomposition unit 14. The configuration of the mobile device is the interface unit 18
Is the same as the wireless connection device except that it replaces the interface unit for the handset.

The operation of the conventional wireless connection device configured as described above will be described below. Before communicating, it is necessary to first set up a control channel. When the power is turned on, the control channel control unit 15 designates a predetermined control channel slot to the frame generation / decomposition unit 14 to send out control data necessary for communication. After the control data is converted into a predetermined frame format by the frame generation / decomposition unit 14,
It is placed in the specified slot. This signal is input to the modem unit 13 and becomes a modulated signal, and is input to the wireless unit 12, where it is frequency converted and amplified to become a wireless signal. The radio signal frequency is designated by the control channel control unit 15 and transmitted from the antenna unit 11. Once started, the control channel will continue to transmit in the same slot. The interface section 18 transmits and receives communication data and control data to and from the radio network controller 1.
The slot synchronization signal is inserted in the signal from the radio network controller 1, the slot synchronization unit 19 extracts the slot synchronization signal, and the frame generation / decomposition unit 14 performs the TDMA.
It controls the timing of signal generation. As a result, slot synchronization of each wireless connection device can be achieved. On the other hand, the mobile device that has received the control signal from the wireless connection device sends back the control signal in synchronization with the transmission timing of the control channel from the wireless connection device. The control signal from the mobile device is received by the antenna unit 11 and input to the control channel control unit 15 via the radio unit 12, the modem unit 13, and the frame generation / decomposition unit 14. Control channel control unit 1
5 operates according to the content of the control signal.

Next, the operation when communicating with a mobile device will be described. In performing communication, the communication channel control unit 16 specifies a slot for a communication channel in the frame generation / decomposition unit 14 and also specifies a radio signal frequency for the radio unit 12. The communication data transmitted from the radio network controller 1 is extracted by the interface unit 18, converted into a predetermined frame format by the frame generation / decomposition unit 14, and then arranged in the slot designated by the communication channel control unit 16. , And is input to the modem unit 13 to be a modulated signal. This modulated signal is converted by the radio unit 12 into a radio signal of a frequency designated by the communication channel control unit 16 and sent from the antenna unit 11. The same applies in the opposite direction, and the communication signal from the mobile device is
The signal is received by the antenna unit 11 and input to the wireless line control device 1 via the wireless unit 12, the modem unit 13, the frame generation / decomposition unit 14, and the interface unit 18.

When performing radio channel monitoring, the reception level detector 17 measures the reception level at one point in the currently communicating slot, and reports the result to the communication channel controller 16. When switching the slot of the communication channel, the communication channel control unit 16 executes the slot switching after instructing the mobile device in communication using the communication channel to switch the slot.

Next, a conventional asynchronous interference avoiding method using the above wireless connection device will be described with reference to FIG.
Here, the asynchronous interference means that an interference wave is generated due to a difference in system clock frequency with the lapse of time between systems communicating using the same frequency. FIG. 8 shows a sequence of communication channel switching between the wireless connection device 2 and the mobile device 6. Here, a 4-multiplex time division multiplex system is used. The double method may be used. In the figure, the communication channel is TCH and the control channel is C.
Abbreviated as CH. It is assumed that the wireless connection device 2 knows which channel to switch to when the channel switching with the mobile device 6 is necessary. In the wireless connection device 2, the reception level detection unit 17 detects the reception level of the currently communicating channel. If the reception level is below the reference value, the mobile device 6
And sends a TCH switching instruction to the currently used communication channel. Synchronization bursts are exchanged between the wireless connection device 2 and the mobile device 6 to switch slots.

[0009]

However, in the above-mentioned conventional asynchronous interference avoidance method, since the communication channel information of the switching destination is put on the communication channel in which the interference has occurred and transmitted, it is guaranteed that this information will reach accurately. There is no. Another characteristic of asynchronous interference is the sudden appearance of a strong interference wave. Since this asynchronous interference wave approaches from the front or back of the slot during communication, it can be accurately detected by measuring the level of only one point in the reception slot. In some cases, the communication channel cannot be switched properly and the wireless line is disconnected.

An object of the present invention is to solve the above problems and to provide a radio communication apparatus capable of switching channels without disconnecting the radio line even when asynchronous interference occurs.

[0011]

In order to achieve the above object, the present invention provides a wireless connection device or a mobile device with an asynchronous interference detection unit for detecting asynchronous interference by another system, and detects the asynchronous interference. By switching to a predetermined backup channel, disconnection of the wireless line is prevented.

[0012]

According to the present invention, with the above configuration, the asynchronous interference detection unit detects the asynchronous interference wave by measuring the reception levels at a plurality of points including both ends of the reception slot. , Communication can be continued without disconnecting the wireless line.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Since the entire configuration of the system is the same as that of the conventional example, refer to FIG. FIG. 1 is a block diagram showing the configuration of an embodiment of a wireless connection device according to the present invention. In FIG. 1, 101 is an antenna unit for transmitting and receiving radio signals to and from a mobile device (not shown), and 102 is an antenna unit 101.
A radio unit for converting a radio signal transmitted / received in and a signal input / output from a modem unit 103 described later, 103 a modem unit for modulating / demodulating a signal input / output from the radio unit 102, and 104 a modem unit A frame generation / decomposition unit that generates / decomposes a TDMA signal with respect to a baseband signal input / output from 103, and also generates / decomposes a frame, 105 is a control channel control unit that controls a control channel, and 106 is a communication channel. A communication channel control unit 107 that controls the wireless channel, 107 an asynchronous interference detection unit that monitors a wireless channel to detect an asynchronous interference wave, and 108 an interface between the wireless line control device 1 (see FIG. 6) and the wireless connection device. The interface unit 109, which takes the signal from the interface unit 108, Extracts Tsu bets synchronizing signals is a slot synchronization unit for controlling the slot timing of the frame generation and decomposition unit 104. The configuration of the mobile device is almost the same as that of the wireless connection device except that the interface unit 108 replaces the interface unit for the handset and the asynchronous interference detection unit.

The operation of the wireless connection device configured as described above will be described below. Before communicating, it is necessary to first set up a control channel. When the power is turned on, the control channel control unit 105 generates a frame
A predetermined control channel slot is designated for the disassembly unit 104, and control data necessary for communication is transmitted. The control data is converted by the frame generation / decomposition unit 104 into a predetermined frame format, and then placed in the designated slot. This signal is input to the modem unit 103 and becomes a modulated signal, and is input to the wireless unit 102 where it is frequency-converted and amplified to become a wireless signal. The radio signal frequency is specified by the control channel control unit 105, and the radio signal is sent from the antenna unit 101 to the slave unit. The interface unit 108 transmits / receives communication data and control data to / from the wireless line control device 1, but the slot synchronization signal is inserted in the signal from the wireless line control device 1, and the slot synchronization unit 109
The slot synchronization signal is extracted and the frame generation / decomposition unit 10
4 controls the timing of generating the TDMA signal. As a result, slot synchronization of each wireless connection device can be achieved. On the other hand, the mobile device that has received the control signal from the wireless connection device sends back the control signal in synchronization with the transmission timing of the control channel from the wireless connection device. The control signal is received by the antenna unit 101, and the wireless unit 102,
It is input to the control channel control unit 105 via the modem unit 103 and the frame generation / decomposition unit 104. The control channel control unit 105 operates according to the content of the control signal.

Next, the operation when communicating with the mobile device will be described. In performing communication, the communication channel control unit 106 designates a slot for a communication channel to the frame generation / decomposition unit 104, and also the wireless unit 102.
Specify the radio signal frequency for. The communication data transmitted from the radio network controller 1 is the interface unit 1
After being extracted by 08, converted into a predetermined frame format by the frame generation / decomposition unit 104, the frame is placed in the slot designated by the communication channel control unit 106 and input to the modem unit 103 to be a modulated signal. This modulated signal is transmitted by the radio section 102 to the communication channel control section 106.
Is converted into a radio signal having a frequency specified by and transmitted from the antenna unit 101. The same applies in the reverse direction, in which the communication signal from the mobile device is received by the antenna unit 101 and is sent to the wireless line control device 1 via the wireless unit 102, the modem unit 103, the frame generation / decomposition unit 104, and the interface unit 108. Is entered.

When performing radio channel monitoring, unlike the conventional case, the asynchronous interference detection unit 107 measures the reception levels at a plurality of points including both ends of the currently communicating slot and sends the result to the communication channel control unit 106. To report. Also, when switching the slot of the call channel,
The communication channel control unit 106 prepares a communication channel for avoiding asynchronous interference in advance, notifies the mobile device of this together with the communication signal, and either the wireless connection device or the mobile device detects the asynchronous interference. In this case, it switches to a preliminarily determined spare channel. When the mobile device detects it, it notifies the wireless connection of the detection, and the wireless connection device switches to the backup channel.

Next, a specific method of switching the backup channel will be described with reference to FIG. Now, it is assumed that the mobile device 6 and the wireless connection device 2 are in communication using the slot 2 of the frequency f1. A spare channel slot that is not normally used (slot 4 in this case) is prepared for the wireless connection device 2, and an empty carrier is searched using this slot. The information on this empty carrier is placed in the communicating slot 2 and notified to the mobile device 6 as an empty carrier information notification (in this case, the frequency f2,
Slot 4). When a free carrier becomes unusable, a new free channel is searched for, updated and notified. During this period, the wireless connection device 2 is provided with the asynchronous interference detection unit 10
In step 7, the reception levels at a plurality of points in the communicating slot are measured, and the result is reported to the communication channel control unit 106.
In accordance with this measurement result, the communication channel control unit 106 detects asynchronous interference, and when asynchronous interference is detected, switches to the communication channel (frequency f2, slot 4) notified as free carrier information. Mobile device 6
Detects that a communication signal that has been received up to now cannot be received, and the communication channel (frequency f2,
Switch to slot 4). As a result, the communication channel is switched without using the communication channel that has received the interference, and the disconnection of the wireless line can be prevented. At the end of communication on an empty carrier, this slot is used as an empty slot and operates in the same manner.

Next, another method of switching the backup channel will be described with reference to FIG. In this method, the wireless connection device 2 is not specially provided with a slot dedicated to the backup channel, and the same operation is performed using an empty slot in the normally used slots. When there is no empty slot, the control channel slot is used to search for an empty carrier. The operation when the control channel slot is used will be described below. It is assumed that the mobile device 6 and the wireless connection device 2 are currently communicating using the slot 2 of the frequency f1. Since the wireless connection device 2 has no empty slot,
A free carrier is searched for using the control channel slot. Since the control channel slot is used intermittently, it is possible to search for a vacant carrier during this interval. Information about this empty carrier is in slot 2 during communication.
And notifies the mobile device 6 as an empty carrier information notification (in this case, frequency f2, slot 4). When an empty slot becomes unusable, a new empty channel is searched, updated and notified. During this time, the wireless connection device 2 measures the reception levels at a plurality of points in the communicating slot by the asynchronous interference detection unit 107 and reports the result to the communication channel control unit 106. In accordance with this measurement result, the communication channel control unit 106 detects asynchronous interference, and when asynchronous interference is detected, switches to the communication channel (frequency f2, slot 4) notified as free carrier information. The mobile device 6 detects that the communication signal that has been received so far cannot be received, and switches to the previously notified communication channel (frequency f2, slot 4). As a result, the communication channel is switched without using the communication channel that has received the interference, and the disconnection of the wireless line can be prevented.

Next, another method of switching the backup channel will be described with reference to FIGS. 4 and 5. Figure 5
Represents the slot usage status of each wireless connection device.
A plurality of slots for spare channel candidates are provided in the wireless connection devices 2, 3, 4, 5 under the control of the wireless line control device 1, and each connection device sequentially searches for an empty carrier. It is assumed that the mobile device 6 and the wireless connection device 2 are currently communicating using the slot 2. The wireless connection device 2 is
It is impossible to search for an empty carrier because there are no empty slots. The wireless line control device 1 knows all the usage states of the slots of the wireless connection devices 2, 3, 4, and 5, and the wireless connection devices 3 each having an empty slot,
Free carrier search requests are sent to 4 and 5 in order. Receiving this request, each wireless connection device 3, 4, 5 searches for an empty carrier and reports the result to the wireless line control device 1. Upon receiving this result, the wireless line control device 1 sends to the wireless connection device 2 the empty carrier information from the wireless connection device 4 that has searched for an empty carrier in the same slot 2 as the wireless connection device 2 currently in communication. Notify as information. Upon receiving this information, the wireless connection device 2 places it in the communicating slot 2 and notifies it to the mobile device 6 as a free carrier information notification. When the vacant carrier becomes unusable, each wireless connection device 3, 4, 5 searches for a new vacant channel, updates it to the wireless line control device 1, and notifies it. This update information is notified to the wireless connection device 2 as free carrier information. During this period, the wireless connection device 2
The asynchronous interference detector 107 measures the reception levels at a plurality of points in the communicating slot and reports the result to the communication channel controller 106. In accordance with this measurement result, the communication channel control unit 106 detects asynchronous interference, and if asynchronous interference is detected, switches to the communication channel notified as free carrier information. Mobile device 6
Detects that the communication signal that has been received up to now cannot be received, and switches to the communication channel notified in advance.
As a result, the communication channel is switched without using the communication channel that has received the interference, and the disconnection of the wireless line can be prevented. In this method, since the same slot as the backup channel is used, there is an advantage that a peripheral connection device can perform a search instead of a wireless connection device that cannot be searched due to a lack of slots.

Although the above embodiments are examples in which the wireless connection device is provided with the asynchronous interference detection unit, it is also possible to provide the same asynchronous interference detection unit in each mobile device to operate in the same manner.

[0021]

As described above, according to the present invention, a wireless connection device or a mobile device is provided with an asynchronous interference detection unit capable of detecting asynchronous interference, and a standby channel for avoiding asynchronous interference is prepared in advance for communication. By notifying the mobile device together with the signal, the communication can be continued without disconnecting the wireless line when the asynchronous interference occurs.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless connection device according to an embodiment of the present invention.

FIG. 2 is a sequence diagram showing a method for avoiding asynchronous interference according to an embodiment of the present invention.

FIG. 3 is a sequence diagram showing another method of avoiding asynchronous interference according to an embodiment of the present invention.

FIG. 4 is a sequence diagram showing another method of avoiding asynchronous interference according to an embodiment of the present invention.

5 is a schematic diagram showing an example of channel allocation to slots in the embodiment of FIG.

FIG. 6 is a block diagram showing the configuration of a mobile communication system.

FIG. 7 is a block diagram showing a configuration of a conventional wireless connection device.

FIG. 8 is a sequence diagram showing a conventional communication channel switching method.

[Explanation of symbols]

 101 antenna section 102 radio section 103 modem section 104 frame generation / decomposition section 105 control channel control section 106 communication channel control section 107 asynchronous interference detection section 108 interface section 109 slot synchronization section

Claims (5)

[Claims] 1. A wireless line control device that controls wireless lines in a plurality of wireless zones; a plurality of wireless connection devices that are connected to the wireless line control device by wire to form the wireless zones; and the wireless connection device. In a mobile communication system based on a time division multiplexing system, which comprises one or more mobile units that communicate with each other via a wireless line, an asynchronous interference detection unit that detects asynchronous interference by the other system in the wireless connection device, and an asynchronous interference detection unit. In this case, the wireless communication device is provided with a control unit that prevents disconnection of the wireless line by switching to a predetermined backup channel. 2. A slot that is not normally used for a spare channel is prepared in the wireless connection device, and the wireless connection device searches for an empty carrier by using the slot, and communicates information of this empty carrier. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus carries out transmission on a channel, and when asynchronous interference is detected, the channel is switched to this empty carrier for communication. 3. A free carrier is searched in advance by using an empty slot in slots normally used by the wireless connection device for a spare channel, and the wireless connection device, when the empty slot does not exist, 2. The channel switching is performed by searching for a vacant carrier using a control channel slot.
The wireless communication device according to. 4. A plurality of slots for spare channel candidates are prepared in advance in a plurality of wireless connection devices under the control of one wireless line control device, and a free carrier is sequentially searched in each connection device. The wireless communication device according to claim 1, wherein channel switching is performed. 5. The mobile device is provided with an asynchronous interference detector, and when either the wireless connection device or the mobile device detects asynchronous interference, the mobile device is switched to a predetermined backup channel. 5. The wireless communication device according to any one of 1 to 4.