JP2815807B2 - Control channel standby method - Google Patents

Abstract

PURPOSE:To prevent an intermodulated wave from being mis-received as a control signal from a base station in the case of multi-channel access in which a control channel and a communication channel is not separated in frequencies. CONSTITUTION:A control channel code CH is added to a frame format of a control signal from a base station. The control channel code CH is information to specify a communication channel used for the transmission of the control signal from the base station. In the mobile station, only when a correct control channel code CH is included in a received signal, the received signal is regarded as the control signal and the operation corresponding to a command code COM of the control signal is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for performing radio communication using a plurality of communication channels as control channels, and more particularly to a control channel waiting method in this system.

[0002]

2. Description of the Related Art Multi-channel access is one of systems for performing wireless communication while effectively using frequency resources.
For example, as shown in FIG. 3, in a mobile communication system including a base station BS and a plurality of mobile stations S1, S2, S3,..., The base station BS and the mobile stations S1, S2, S
Are connected by a plurality of communication channels and control channels. The communication channel here is, for example, B
S is a channel for transmitting information from the base station BS to the mobile stations S1, S2, S3,..., And the control channel is for transmitting a control signal from the base station BS to the mobile stations S1, S2, S3,. Channel. Base station BS and mobile station S
When wireless communication is performed among S1, S2, S3,...
The mobile stations S1, S
2. Even if the number of stations in S3 is large, the system can be configured only by preparing a small number of communication channels and control channels.

When the system configuration is relatively large, a communication channel and a control channel are allocated to different frequencies, and a certain frequency is separated for a communication channel and another certain frequency is separated for a control channel. Used. However, when the system configuration is small, the communication channel and the control channel are shared in frequency in order to use frequency resources more effectively. That is, the frequency used as the control channel may also be used as the communication channel.

FIG. 4 shows the operation of a mobile station in a system in which a communication channel and a control channel are shared.

As shown in FIG. 1, an initial setting operation is first performed in a mobile station (100). That is, it is set from which of the plurality of communication channels (downlink channels) related to signal reception from the base station a signal is to be received (102).

When step 102 is completed, the mobile station performs a control channel acquisition operation (10).
4). That is, it is determined whether or not a control signal has been received via the communication channel set in step 102 (106). If it is determined that no control signal has been received, the process returns to step 102. If it is determined that it was received,
The process proceeds to the standby operation (108).

In the standby operation, first, it is determined whether or not the received control signal is a signal requesting a call (110). If it is determined that a call is requested, the mobile station performs a call operation (112). If it is determined that a call is not requested, the mobile station determines whether an incoming call is requested (114). If it is determined that an incoming call has been requested, the mobile station performs an incoming call operation (116). When it is determined that the incoming call is not requested, the mobile station determines whether or not it is in a state where it cannot receive the control signal (118).
If it is determined that the control signal cannot be received, the operation of the mobile station returns to step 102. If it is determined that the control signal can be received, the process returns to step 110 and the standby operation is repeated.

FIG. 5 shows a frame format of a control signal in this conventional example. As shown in this figure, the frame format of the control signal includes a bit synchronization signal SYN1, a frame synchronization signal SYN2, and an information code DATA.
ATA is system information code SYS, command code C
OM and test code CRC (Cyclic Redundancy check)
Code). Among these information, the bit synchronization signal SYN1 is a signal for ensuring synchronization with each bit constituting the control signal, and is a frame synchronization signal SYN2.
Is a signal for ensuring frame synchronization. The system information code SYS among the signals constituting the information code DATA is information relating to the state of the system and the like, and the command code COM is a command (for example, a call request or an incoming call reception) from the base station to the mobile station. Is shown. Further, the test code CRC is a signal for detecting and correcting a bit error or the like in the control signal frame. In addition,
The information code DATA corresponds to these system information codes SY
In addition to S, the command code COM, and the verification code CRC, the information includes information necessary for the mobile station.

[0009]

As described above, in a system sharing a communication channel and a control channel, frequency resources can be effectively used. But,
In this type of system, the mobile station may not be able to accurately capture the control channel.

That is, in a system in which the control channel and the communication channel are separated, the frequency of the control channel is different from the frequency of the communication channel, so that the mobile station can correctly capture the control channel. However, when the control channel is shared with the communication channel, the intermodulation of the communication channel and the control channel (I
In some cases, correct control channels cannot be received due to the occurrence of M). In other words, in a system in which a base station transmits using a plurality of communication channels at the same time, these communications are performed.
Intermodulation occurs between the communication channel and the control channel, and an intermodulation wave is generated. If the mobile station is in the vicinity of the base station, there is a possibility that this intermodulation wave may be erroneously received as a control channel. The process after the operation is executed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and prevents an erroneous reception of an intermodulation wave as a control channel when the intermodulation wave is generated. It is another object of the present invention to secure a correct operation of the mobile station.

[0012]

In order to achieve such an object, the present invention provides a mobile station and a base station having a plurality of communication channels for wirelessly communicating with the mobile stations. In a wireless communication system in which a control signal from a base station is transmitted to a mobile station via any of the plurality of communication channels, the control signal specifies a communication channel used for transmitting the control signal. Only when the received signal contains the correct control channel information, the mobile station regards the signal as a control signal and executes a process corresponding to the content of the control signal. It is characterized by.

[0013]

According to the present invention, when a control signal is transmitted from a base station to a mobile station, control channel information is also transmitted at the same time. This control channel information is information for specifying the communication channel used for transmitting the control signal. In the mobile station, only if the received signal contains correct control channel information, that is, information indicating a communication channel that can be used for control signal transmission from the base station,
Processing corresponding to the content of the control signal, for example, a call request or the like is executed. Accordingly, in the present invention, the base station has been transmitted using a plurality of communication channels simultaneously, the communication switch
Even when an intermodulation wave of the channel and the control channel is generated, the mobile station does not receive the intermodulation wave as a control channel by mistake, and the operation of the mobile station becomes more accurate.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The same components as those in the conventional example shown in FIGS. 3 to 5 are denoted by the same reference numerals, and description thereof will be omitted. Further, since the present invention can be executed under the system configuration shown in FIG. 3, the following description assumes the system configuration of FIG. 3, but the present invention does not need to limit the details of FIG.

FIG. 1 shows a frame format of a control signal transmitted from a base station in one embodiment of the present invention. In this frame format, the information code DATA includes a control channel code CH.

The control channel code CH is information for specifying a communication channel used to transmit the control signal. Therefore, when the mobile station receives a signal that appears to be a control signal, the control channel code CH that is correct for the signal, that is, the control channel code C that represents a communication channel (downlink channel) that actually exists.
By determining whether or not H is included, it is possible to know that the received signal is truly a control signal and not an intermodulation wave.

FIG. 2 shows a flow of the operation of the mobile station in this embodiment. As shown in this figure, in the present embodiment, if it is determined in step 106 that a control signal has been received, a channel code match determination is made prior to shifting to the standby operation (108) (120). ). That is, it is determined whether or not the received signal includes the correct control channel code CH, and the process shifts to the standby operation only when it is determined that the received signal includes the correct control channel code CH. If not included, the process returns to the channel setting (102).

Therefore, according to this embodiment, even when an intermodulation wave is generated, the intermodulation wave is not erroneously received as a control signal. This makes it possible to more accurately control the operation of the mobile station using the control signal from the base station.

[0019]

As described above, according to the present invention,
When transmitting a control signal from the base station to the mobile station, control channel information that specifies the communication channel being used is also transmitted, and the mobile station makes a determination regarding the control channel information. When the control channel information is not included, for example, when the received signal is an intermodulation wave, it is not erroneously regarded as a control signal and a control operation such as a call operation is not performed. , The control operation of the mobile station becomes more accurate.

[Brief description of the drawings]

FIG. 1 is a diagram showing a control signal frame format from a base station used in an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of an operation of the mobile station in the embodiment.

FIG. 3 is a block diagram illustrating an example configuration of a wireless communication system using a multi-channel access scheme.

FIG. 4 is a flowchart showing a flow of operation of a mobile station in one conventional example.

FIG. 5 is a diagram showing a control signal frame format from a base station in this conventional example.

[Explanation of symbols]

 SYN1 Bit synchronization signal SYN2 Frame synchronization signal DATA Information code SYS System information code COM Command code CRC Test code CH Control channel code

Claims (1)

(57) [Claims] 1. A base station having a plurality of mobile stations and a plurality of communication channels for wirelessly communicating with the mobile stations;
In a wireless communication system in which a control signal from a base station is transmitted to a mobile station via any of the plurality of communication channels, the control signal includes a communication channel used for transmitting the control signal. Only when the received control signal contains the correct control channel information, the mobile station regards the signal as a control signal, and executes processing corresponding to the content of the control signal. A control channel waiting method characterized by the above-mentioned.