JP2007013543A - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronization maintenance method so as to make it difficult for a subordinate master machine to release synchronization with a main master machine. <P>SOLUTION: The subordinate slave machine 20 is provided with a reception control channel management part 205 and, when a control channel of the main master machine 10 fails to be received for a specified period of time, control channel scanning of the main master machine 10 is executed in a combination of all the slots and all the carriers while maintaining frame synchronization. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a function in which a dependent parent device maintains wireless synchronization with a main parent device in a wireless system in which a dependent parent device wirelessly synchronizes with a main parent device.

  In recent years, telephones and doorphones have been used in most ordinary homes, and many products using wireless communication have been put into practical use for ease of installation and improvement of convenience.

  Wireless communication devices such as cordless telephones and wireless doorphones used in general homes are mainly digital wireless communication systems from the viewpoint of improving call quality and confidentiality, and most of them improve frequency utilization efficiency. In order to reduce the cost of the apparatus, a time division multiplexing method is adopted.

  From the convenience of the user, a system in which both a telephone and a door phone can be used with a single slave unit is desired. Further, from the viewpoint of radio interference, one master unit in the system operates as a main master unit. Other base units are synchronized with the main base unit (hereinafter, such a base unit is referred to as a subordinate base unit), and a slave unit is required to have a radio system that synchronizes with the main base unit or subordinate base unit. Yes.

As a method for maintaining synchronization, a method is known in which a timer is set for a while to enter a battery saving state, and reception is resumed when the timer expires (Patent Document 1).
JP-A-8-288900

  In the case of the wireless system as described above, the subordinate master unit acquires and maintains synchronization with the main master unit as normally performed by the slave unit. When the subordinate master loses synchronization with the main master, the subordinate master performs resynchronization with the main master. During this synchronization acquisition process, the subordinate master as well as the subordinate master The machine will not be able to operate wirelessly.

  As a method for maintaining synchronization without performing resynchronization, as disclosed in Patent Document 1, a method is proposed in which a timer is set for a while to enter a battery saving state and reception is resumed when the timer expires. In this method, the slave unit synchronized with the subordinate master unit cannot operate wirelessly.

  The problem to be solved is to make it difficult for the subordinate master unit to lose synchronization with the main master unit, and to provide a synchronization maintaining method therefor.

  The present invention provides a reception control channel management unit in a subordinate master unit, and when reception of the control channel of the main master unit fails for a certain period of time, the master unit is used in a combination of all slots and all carriers while maintaining frame synchronization. The main feature is to perform a control channel scan of the machine.

  In the present invention, when the subordinate master unit fails to receive the control channel of the master unit for a certain period of time, the control channel scan of the master unit is performed in all slots and combinations of carriers while maintaining frame synchronization. When the control channel of the master unit is found, there is an advantage that it is difficult to remove the synchronization with the master unit by maintaining the synchronization in the slot and carrier.

  The purpose of the present invention is to make it difficult for the subordinate master unit to lose synchronization with the main master unit. When the subordinate master unit fails to receive the control channel of the master unit for a certain period of time, all slots are maintained while maintaining frame synchronization. This is achieved by performing a control channel scan of the main master unit with all carrier combinations.

  The first invention made to solve the above problem is that in a wireless system in which there is a subordinate master that performs radio synchronization with the master, the slave has failed to receive the control channel of the master for a certain period of time. In this case, a means for scanning the control channel of the main master unit in a combination of all slots and all carriers, and a means for maintaining synchronization in the slot and carrier when the control channel of the main base unit is found When the subordinate master unit fails to receive the control channel of the master unit for a certain period of time, the control channel scan of the master unit is performed in all slots and combinations of all carriers. And has an advantage that it becomes difficult to remove the synchronization with the main master unit.

  The second invention made to solve the above-mentioned problems is characterized by comprising means for maintaining synchronized frame synchronization when the subordinate master unit fails to receive the control channel of the master unit for a certain period of time. In the wireless communication system, during the control channel scan of the main master unit performed in the first invention, the subordinate master unit maintains the frame synchronization with the main master unit, so the probability of receiving the control channel of the main master unit is It has the advantage of being expensive.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2.

  In the first embodiment, when the subordinate master unit fails to receive the control channel of the main master unit for a certain period of time, the combination of all slots and all carriers is sequentially scanned and the control channel of the main master unit is found. This is an operation for maintaining synchronization.

  FIG. 1 is a block diagram of a subordinate master in the embodiment of the present invention.

  10 is a master unit connected to a public line, and is a master master unit that is a radio synchronization master of this radio system, 20 is a slave unit that captures synchronization to the master unit 10 and notifies itself of a control channel to a slave unit, 30 This is a slave unit that is wirelessly synchronized with the main master unit 10 and the subordinate master unit 20.

  201 is a wireless reception unit that receives radio signals from the main master unit 10 and the slave unit 30, 202 is a radio transmission unit that transmits radio signals to the main master unit 10 and the slave unit 30, and 203 is synchronized with the main master unit 10. A reception control channel control unit 204 that controls acquisition and synchronization maintenance, 204 is a timing control unit that performs its own clock correction and bit interpolation based on phase difference information between itself and the main base unit 10 sent from the reception control channel control unit 203, 205 Is a reception control channel management unit that instructs the reception control channel control unit 203 to sequentially change the combination of slots and carriers received when the control channel reception of the master base unit 10 becomes a continuous error, and 206 is a subordinate master unit 20 Is a transmission control channel control unit that establishes and releases a control channel to be transmitted to the child device 30, and 207 is a communication channel establishment with the main parent device 10 and the child device 30. Communication channel control unit for performing release, 208 channel selector that performs channel selection using the transmission control channel or traffic channel, 209 is a call control unit for controlling the entire subordinate base unit 20.

  FIG. 2 is a configuration diagram of a radio frame in the embodiment of the present invention. The subordinate master unit and the slave unit are synchronized with the frame timing of the main master unit, the transmission control channel of the main master unit is slot 0, and the transmission control channel of the subordinate master unit is slot 5.

  First, an operation in which the subordinate master unit 20 synchronizes with the main master unit 10 will be described. When synchronization acquisition is requested together with the ID information of the main base unit 10 synchronized with the reception control channel control unit 203 from the call control unit 209, the reception control channel control unit 203 requests the radio reception unit 201 to perform an open search. The wireless reception unit 201 notifies the reception control channel control unit 203 of the ID information received by the open search operation, and if this is different from that of the master base unit 10, the reception control channel control unit 203 performs an open search to the wireless reception unit 201. Notify the continuation of If the received ID information matches that of the main master unit 10, the reception control channel control unit 203 notifies the wireless reception unit 201 that synchronization is maintained, and the wireless reception unit 201 continues reception at that position. Thereafter, the wireless reception unit 201 notifies the reception control channel control unit 203 of the received data, and when all data necessary for synchronization acquisition is received, the reception control channel control unit 203 completes synchronization acquisition to the call control unit 209. To be notified.

  Next, an operation in which the subordinate master 20 starts transmission of the control channel will be described. When the subordinate base unit 20 synchronizes with the main base unit 10, the call control unit 209 requests the transmission control channel control unit 206 to transmit the control channel. When the transmission control channel control unit 206 requests the channel selection unit 208 for slots and carriers to be used for transmission in the control channel, the channel selection unit 208 selects one of the unused slots. For example, as shown in FIG. 2, when the control channel of the main base unit 10 uses slot 0 and the subordinate base unit 20 is synchronized with the control channel, one of the remaining slots 1 to 5 is selected. become. The channel selection unit 208 notifies the transmission control channel control unit 206 of information on the selected slot and carrier, and the transmission control channel control unit 206 requests the radio transmission unit 202 to establish a transmission control channel in the slot and carrier. When the slot 5 is selected, the configuration is as shown in FIG.

  Next, processing performed by the subordinate master 20 to maintain synchronization with the main master 10 will be described. When reception of the control channel of the master base unit 10 fails, a reception error is notified from the radio reception unit 201 to the reception control channel control unit 203. When the reception error continues for a predetermined time, the reception control channel control unit 203 notifies the reception control channel management unit 205 of the deterioration of the reception status of the control channel.

The reception control channel management unit 205 that has received the notification of the deterioration in the reception status of the control channel starts a control channel search in all slots and all carriers. For example, first, slot 0 and carrier 0 are selected, and the reception control channel control unit 203 is requested to switch the reception position.
The reception control channel control unit 203 stops the reception of the control channel so far and then requests the radio reception unit 201 to receive the control channel in slot 0 and carrier 0. The radio reception unit 201 performs reception with a designated combination, and notifies the reception control channel control unit 203 of a reception result (reception error or reception information) each time reception is performed.

  When only a reception error is notified for a certain time, for example, 5 frame times, the reception control channel control unit 203 notifies the reception control channel management unit 205 of reception failure. The reception control channel management unit 205 selects the following combination, for example, slot 1 and carrier 0, and similarly performs control channel reception.

  As described above, the control channel is received while sequentially changing the combination of the slot and the carrier. However, when the ID information of the master base unit 10 is notified from the radio reception unit 201 to the reception control channel control unit 203, the reception is performed. The control channel control unit 203 continues reception with the combination, notifies the reception control channel management unit 205 of successful reception, and the synchronization maintaining operation by the reception control channel management unit 205 is successful. On the other hand, if the ID information of the main base unit 10 cannot be received even if control channel reception is performed in all slot and carrier combinations, the synchronization maintaining operation fails, and the reception control channel control unit 203 performs call control. The unit 209 is notified of the loss of synchronization. By these operations, even when the main base unit 10 does not transmit the control channel movement notification or the subordinate base unit 20 fails to receive the control channel movement notification, it becomes possible to find the destination control channel. It becomes difficult for the subordinate master unit 20 to lose synchronization with the main master unit 10.

(Embodiment 2)
Hereinafter, Embodiment 2 of the present invention will be described with reference to FIG.

  The second embodiment is an operation of simultaneously performing reception in a plurality of slots so as to scan all slots and all carriers in the first embodiment in a short time.

  As in the first embodiment, when the reception error in the control channel continues, the reception control channel control unit 203 notifies the reception control channel management unit 205 of the deterioration of the reception status of the control channel. The reception control channel management unit 205 designates a combination of all slots that perform reception operations and carriers used in the respective slots, and requests the reception control channel control unit 203 to start reception. The reception control channel control unit 203 stops receiving the control channel so far and then requests the radio reception unit 201 to receive the control channel in the designated slot and carrier. The radio reception unit 201 performs reception in the same combination. The reception control channel control unit 203 is notified of the reception result (reception error or reception information) at each slot reception. These operations enable scanning in a plurality of slots at the same time, so that control channel reception can be performed in a shorter time than in the first embodiment. In the same process, it is possible to scan all slots simultaneously.

(Embodiment 3)
The third embodiment of the present invention will be described below with reference to FIGS.

  In the third embodiment, during the operation in which the subordinate master unit fails to receive the control channel of the main master unit for a certain period of time and scans the combinations of all slots and all carriers as described in the first and second embodiments. This is an operation for maintaining frame synchronization with the base unit by clock correction.

  FIG. 1 is a block diagram of a subordinate master in the embodiment of the present invention, and FIG. 3 is a diagram of phase difference detection in the embodiment of the present invention.

  First, an operation in which the sub master 20 that maintains synchronization with the main master 10 performs timing control from the phase difference information will be described. In the subordinate master unit 20 synchronized with the master unit 10, every time a signal from the master unit is received, the reception control channel control unit 203 calculates the phase difference between its own frame timing and the received master unit 10 timing. Measure and notify the timing control unit 204. The information of the phase difference is notified with a signed time with reference to its own timing. For example, in FIG. 3, it is −10 us. The timing control unit 204 performs control so that the reception frame timing is as similar as possible to the timing of the main base unit 10 from the phase difference information. Specifically, correction of its own operation clock, bit interpolation for interpolating a difference in bit units, and the like are performed. By these operations, the phase difference between the main master unit 10 and the subordinate master unit 20 gradually decreases, but the phase difference does not disappear at all.

  Next, an operation when the phase difference between the main master unit 10 and the subordinate base unit 20 enters a stable period will be described. When entering the stable period, the adjustment by the timing control unit 204 becomes a substantially periodic operation. If the operation clock is corrected, the clock is increased or decreased repeatedly at a substantially constant cycle. On the other hand, if bit interpolation is performed, bit addition or deletion is repeated at a substantially constant cycle. When the timing adjustment enters the stable period as described above, the timing control unit 204 stores these periods and controls as stable period controls.

  Next, an operation when the subordinate master unit 20 continues to receive errors in the control channel of the main master unit 10 will be described. If the radio receiving unit 201 receives a reception error in the control channel from the main base unit 10, the reception control channel control unit 203 is notified of the reception error, and the reception control channel control unit 203 also notifies the timing control unit 204 of the reception error. When the reception error continues, the timing control unit 204 continues the timing control from the stored stable period control. With these operations, even when the subordinate master unit 20 fails to receive the control channel of the main master unit 10 for a certain period of time, it is possible to maintain frame synchronization with the main master unit 10.

  In the above description, the time division multiplexing system in which the communication channel including the control channel is a fixed carrier has been described. However, the present invention is not limited to this, and there are restrictions on the time division multiplexing radio system that performs frequency hopping. It goes without saying that there is nothing at all. In addition, although only one main master unit has been described, the main master units are synchronized with each other by wired connection, and the master unit is also applied to a wireless system in which a subordinate master unit is wirelessly synchronized with one of them. The

  The present invention makes it difficult for the subordinate master unit to be out of synchronization with the main master unit, so that the slave units synchronized with them can operate stably, and there are a plurality of master units in the system, and they are wirelessly connected. It is suitable for a wireless communication system that synchronizes.

Block diagram of subordinate master in the embodiment of the present invention Radio frame configuration diagram according to an embodiment of the present invention Diagram of phase difference detection in the embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main master unit 20 Subordinate master unit 30 Slave unit 201 Radio reception unit 202 Radio transmission unit 203 Reception control channel control unit 204 Timing control unit 205 Reception control channel management unit 206 Transmission control channel control unit 207 Communication channel control unit 208 Channel selection unit 209 Call control unit

Claims (3)

In a wireless system where there is a subordinate master unit that performs radio synchronization with the master unit, if the slave unit fails to receive the control channel of the master unit for a certain period of time, the master unit is set to the combination of all slots and all carriers. A wireless communication system comprising: means for scanning a control channel of a master unit; and means for maintaining synchronization in a slot and a carrier when a control channel of a master unit is found. 2. The wireless communication system according to claim 1, further comprising means for maintaining synchronized frame synchronization when the subordinate master unit fails to receive the control channel of the main master unit for a predetermined time. In a wireless system where there is a subordinate master that performs wireless synchronization with the master,
When reception of the control channel of the main master unit fails, the radio reception unit of the subordinate base unit notifies the reception control channel control unit of a reception error,
When the reception error continues for a certain time, the reception control channel control unit of the subordinate base unit notifies the reception control channel management unit of the deterioration of the reception status of the control channel,
The reception control channel management unit of the subordinate base unit that has been notified of the deterioration of the reception status of the control channel starts a control channel search in all slots and all carriers,
In the control channel search, the radio reception unit of the subordinate base unit performs reception in the combination of the slot and carrier specified by the reception control channel management unit, and when only a reception error is notified from the radio reception unit for a certain period of time, A wireless communication system, wherein a reception control channel management unit designates a next slot and carrier combination in accordance with a notification of reception failure from a reception control channel control unit.

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