WO2011057449A1

WO2011057449A1 - Method and system for reducing interference of control channels between mobile stations

Info

Publication number: WO2011057449A1
Application number: PCT/CN2009/074940
Authority: WO
Inventors: 王欣晖; 李靖
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-11-13
Filing date: 2009-11-13
Publication date: 2011-05-19

Abstract

A method for reducing interference of control channels between mobile stations (MSs) is disclosed by the present invention. The method includes the following steps: MS reports to the network side whether MS supports Shifted Slow Associated Control Channel (SACCH) frame mapping capability; the network side performs a control of Shifted SACCH frame mapping on MS according to the capability reported by MS. A system for reducing interference of control channels between mobile stations is also disclosed by the present invention. The system comprises: a reporting unit, which is located in MS and is used for reporting to the network side whether Shifted SACCH frame mapping capability is supported; a receiving unit, which is located in the network side and is used for receiving the information, reported by MS, indicating whether Shifted SACCH frame mapping capability is supported; a control unit, which is located in the network side and is used for performing a control of Shifted SACCH frame mapping on MS according to the capability reported by MS. The present invention greatly reduces interference between SACCHs of users of Adaptive Multi-user carrier frequencies on One Slot, and improves the whole communication performance of Global System for Mobile Communications (GSM) network.

Description

Method and system for reducing control channel interference between mobile stations

The present invention relates to techniques for reducing control channel interference between mobile stations, and more particularly to a method and system for reducing control channel interference between mobile stations. Background technique

FIG. 1 is a schematic diagram of a network architecture of an existing GSM. As shown in FIG. 1, a network architecture of a Global System for Mobile Communication (GSM) includes a core network, a Base Station Controller (BSC), and a base station. (BTS, Base Station), wherein the base station controller and the base station can be collectively referred to as a base station subsystem (BSS Base Station Subsystem). The interface between the core network and the BSC is called the A interface. The interface between the BSC and the BTS is called the Abis interface. The interface between the BTS and the mobile station (MS, Mobile Station) is called the Um interface. The core network, the BSC and the BTS work together. , to provide complete mobile voice service capabilities to the MS.

As the technology evolves, a flat GSM network architecture emerges. Figure 2 is a schematic diagram of a flat GSM network. As shown in Figure 2, the flat GSM network mainly includes a core network and an enhanced base station (eBTS, Enhanced Base Station). The two layers, wherein the interface between the core network and the enhanced base station is an A interface, and the interface between the enhanced base station and the mobile station is an Um interface, and a new interface is defined between the enhanced base stations, which is called an enhanced base station. The interface can be used for interaction between the enhanced base station and the enhanced base station. Although the traditional GSM system network architecture and the flat GSM network architecture behave the same in the air interface, one of the advantages of the flat GSM network architecture is that it can be combined with the same flattened enhanced version of the high-speed packet. Incoming (HSPA+, High Speed Packet Access + ) or Long Term Evolution (LTE) networks use the same architecture for common language operations. This GSM and HSPA+ or LTE co-linguistic operations will lead The operator wants to dynamically share the limited spectrum resources in different wireless technologies (GSM, HSPA+, LTE, etc.). One application scenario that may occur is: HSPA+ or LTE occupies most of the spectrum resources, while GSM occupancy is more With a small amount of spectrum resources, the number of GSM users will not decrease drastically due to communication habits. This requires the GSM network to provide voice services to these users with relatively less spectrum resources, thus posing a huge challenge to the traditional GSM technology. Because the traditional GSM is a Time Division Multi Access (TDMA) system, the system capacity is limited by time slots (TS, Time Slot) resources, and one TS can only carry one full rate (FR, Full Rate) voice at the same time. User or two half-rate (HR, Half Rate) voice users.

With the continuous evolution of communication technologies, many techniques for improving the efficiency of spectrum utilization have emerged. One of them is the Voice Services over Adaptive Multi-user channels on One Slot (VSAM) technology. The single-slot multi-user channel voice technology allows two FR voice users or four HR voice users to be simultaneously carried in one time slot, thereby improving the support of voice user capacity of the entire GSM network without increasing spectrum resources.

However, if adaptive single-slot multi-user channel voice technology is applied, it will inevitably increase mutual interference between users of the same time slot, resulting in degradation of signal reception quality. Since the control channel, such as the Slow Associated Control Channel (SACCH), carries very important control information (power adjustment, frame adjustment, and measurement data, etc.), once the interference increases, the SACCH transmission will cause problems, and the MS will be Communication with the BTS has a big impact, and serious calls may be dropped.

Figure 3 is a schematic diagram of four mobile stations multiplexing HR channel resources in GSM mode. As shown in Figure 3, in the traditional GSM mode, two HR users, one user 1, user 2, multiplex the HR carrier frequency 1, and the other two HRs. User one user 3, user 4 multiplexes HR carrier frequency 2. When the HR carrier frequency 1 and the HR carrier frequency 2 are different frequencies, the SACCH channels between users do not interfere with each other. Multi-purpose in adaptive single-slot In the channel voice mode, four HR users are shared into one time slot, then HR carrier frequency 1 and HR carrier frequency 2 are the same frequency, they use the same SACCH frame mapping method (traditional frame mapping method), user 1 and The SACCH channels of User 3, User 2 and User 4 will become co-channel interference with each other, and since the SACCH always uses the maximum power transmission, the interference problem between the control channels of different mobile stations will be further aggravated.

In order to improve the performance of the SACCH channel, an offset SACCH (Shifted-SACCH) technique has appeared. 4 is a schematic diagram of four mobile stations multiplexing HR channel resources by using offset SACCH frame mapping in GSM mode. As shown in FIG. 4, HR user-user 3 and user 4 use a technique called offset SACCH frame mapping. The technique maps the user in the adaptive single-slot multi-user channel voice subcarrier frequency 1 to the SACCH frame of the user in the adaptive single-slot multi-user channel voice subcarrier frequency 2 to different time slots, that is, not in the same It always appears, so it is impossible to form interference with each other. In addition, when one or more users are in a silent period of DTX (Discontinuous Transmission), the corresponding traffic channel (TCH, Traffic Channel) of the user will turn off the transmit power, and it is in the same adaptive single-slot. The SACCH of other users of the multi-user channel voice channel will not be interfered, thereby improving the performance of the SACCH channel and ensuring the communication quality.

However, in the prior art, the traditional frame mapping method is the only frame mapping method. The traditional mobile station supports the mapping method, and the GSM network can only command new mobile stations that support the offset SACCH frame mapping method to use the partial mapping method. The SACCH frame mapping method is moved, so a method is needed to enable the network side to know whether the mobile station has the offset SACCH frame mapping capability. Summary of the invention

In view of this, the main object of the present invention is to provide a method and system for reducing control channel interference between mobile stations, which can reduce the difference between different mobile stations after using the adaptive single-slot multi-user channel voice technology in the GSM network. Control channel interference.

In order to achieve the above object, the technical solution of the present invention is achieved as follows: A method for reducing control channel interference between mobile stations, comprising:

The mobile station reports to the network side whether the capability of the offset slow auxiliary control channel SACCH frame mapping is supported, and the network side performs the control of the offset SACCH frame mapping on the mobile station according to the capability reported by the mobile station.

Preferably, the mobile station transmits its information supporting the offset SACCH frame mapping capability to one of the mobile station Classmark 3 information to the network side.

Preferably, the mobile station encapsulates Classmark 3 information carrying information supporting the offset SACCH frame mapping capability in a classmark change message, and sends the information to the network side.

Preferably, the classmark change message is sent to the network side, including:

The mobile station sends the classmark change message directly to the network side; or, after receiving the classmark enquiry message sent by the network side, the mobile station sends the classmark change message to the network side.

Preferably, when the mobile station does not support the capability of offsetting the SACCH frame mapping, the Classmark 3 information of the classmark change message to the network side does not include the cell supporting the offset SACCH frame mapping capability.

Alternatively, the mobile station transmits information of its ability to support offset SACCH frame mapping to one of the mobile station Classmark 2 information to the network side.

Preferably, when the mobile station is the calling party, the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability is encapsulated in the CM Service Request message and sent to the network side; When called, the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability is encapsulated in a paging response message and sent to the network side.

Preferably, when the mobile station does not support the capability of offsetting the SACCH frame mapping, the Classmark 2 information of the CM Service Request message sent to the network side does not include the cell supporting the offset SACCH frame mapping capability. >3⁄4 of the paging response message on the network side The Classmark 2 information does not include cells that support the offset SACCH frame mapping capability. Preferably, the controlling, by the mobile station, the offset SACCH frame mapping comprises: the network side sharing a one time slot of the mobile station supporting the offset SACCH frame mapping capability, the SACCH located in the same carrier frequency The frames are assigned to different time slots and the corresponding mobile station is notified.

A system for reducing control channel interference between mobile stations, comprising a reporting unit, a receiving unit, and a control unit, wherein:

The upper unit, located in the mobile station, is configured to support the ability to offset the SACCH frame mapping to the network side;

a receiving unit, located at the network side, configured to receive capability information reported by the mobile station to support offset SACCH frame mapping;

And a control unit, located at the network side, configured to perform control on offsetting the SACCH frame mapping of the mobile station according to the capability reported by the mobile station.

Preferably, the reporting unit sends the information that the mobile station supports the offset SACCH frame mapping capability to the network side as one of the mobile station Classmark 3 information.

Preferably, the reporting unit encapsulates Classmark 3 information carrying information supporting the offset SACCH frame mapping capability in a classmark change message, and sends the information to the network side.

Preferably, the reporting unit directly reports the classmark change message to each side of the network;

Or, after the receiving unit further receives the classmark enquiry message sent by the network side, the reporting unit reports the classmark change message to the network providing side.

Preferably, when the mobile station does not support the capability of offsetting the SACCH frame mapping, the upper 4 unit does not include the capability of supporting the offset SACCH frame mapping in the Classmark 3 information of the classmark change message on the network side. The cell.

Alternatively, the upper unit will support the mobile station with the ability to offset the SACCH frame mapping capability The information is sent to the network side as a cell in the Classmark 2 information of the mobile station.

Preferably, when the mobile station is the calling party, the reporting unit encapsulates the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability in the CM Service Request message, and sends the information to the network side; When the mobile station is used as the called party, the reporting unit encapsulates the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability in the paging response message, and sends the information to the network providing side.

Preferably, when the mobile station does not support the capability of offsetting the SACCH frame mapping, the upper 4 unit does not include the support offset SACCH frame mapping in the Classmark 2 information of the CM Service Request message on the network side. The capability of the cell, the Classmark 2 information of the paging response message reported to the network side does not include the cell supporting the offset SACCH frame mapping capability.

Preferably, the control unit allocates SACCH frames in the same carrier frequency to the different time slots of the mobile station supporting the offset SACCH frame mapping capability of one slot, and notifies the corresponding mobile station.

In the present invention, the mobile station reports its support for the offset SACCH frame mapping to the network side, so that the network side can control the offset SACCH frame mapping of the mobile station according to whether the mobile station supports the offset SACCH frame mapping capability. The invention greatly reduces the interference between the user SACCH in the adaptive single-slot multi-user carrier frequency and improves the overall communication performance of the GSM network. DRAWINGS

Figure 1 is a schematic diagram of the architecture of an existing GSM network;

Figure 2 is a schematic diagram of the architecture of a flat GSM network;

3 is a schematic diagram of multiplexing HR channel resources by four mobile stations in GSM mode;

4 is a schematic diagram of four mobile stations multiplexing HR channel resources by using offset SACCH frame mapping in GSM mode;

FIG. 5 is a flowchart of Embodiment 1 of a method for reducing control channel interference between mobile stations according to the present invention Figure

6 is a flow chart of Embodiment 2 of a method for reducing control channel interference between mobile stations according to the present invention;

7 is a flow chart of Embodiment 3 of a method for reducing control channel interference between mobile stations according to the present invention;

FIG. 8 is a schematic structural diagram of a system for reducing control channel interference between mobile stations according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

If the network uses early classmark sending, the mobile station can use its capability information to support offset SACCH frame mapping as a cell of Class 3 (Classmark 3) when the call is established. During the early class label transmission process, Classmark 3 is encapsulated in the classmark change message and reported to the base station subsystem (network side). The following details how this example reduces control channel interference between mobile stations.

FIG. 5 is a flow chart of Embodiment 1 of a method for reducing control channel interference between mobile stations according to the present invention. As shown in FIG. 5, the method for reducing control channel interference between mobile stations in this example includes the following steps:

Step 501: The mobile station sends its own capability information for supporting the offset SACCH frame mapping to the base station subsystem by using a classmark change message. Specifically, the capability information of the offset SACCH frame mapping is supported as a cell of the mobile station class 3 (Classmark 3), and the classmark 3 is encapsulated in the classmark change message during the early class label sending process during call setup. Base station subsystem.

Step 502: The base station subsystem learns, according to the support capability of the offset SACCH frame mapping function in the classmark change message reported by the mobile station, the mobile station's support for the offset SACCH frame mapping function. When the Classmark 3 of the classmark change message reported by the mobile station does not include the capability cell supporting the offset SACCH frame mapping, the base station subsystem considers the mobile The station does not support the offset SACCH frame mapping function. Thus, the method of the present invention will support mobile stations with the ability to offset SACCH frame mapping while also being compatible with mobile stations that do not support the ability to offset SACCH frame mapping.

In the above steps, the manner in which the mobile station reports the support capability information for supporting the offset SACCH frame mapping may be any one or combination of the following:

Using independent cell representation, the independent cell is used to directly indicate that the mobile station supports offset SACCH frame mapping capability;

In the capability level of the mobile station, as long as the mobile station has a capability level to support the offset SACCH frame mapping capability, the mobile station has the ability to support offset SACCH frame mapping.

Step 503: The base station subsystem performs control of offset SACCH frame mapping on the mobile station according to the capability reported by the mobile station.

The base station subsystem allocates the SACCH frames in the same carrier frequency of the mobile station supporting the offset SACCH frame mapping capability of one slot to different time slots, and maps the SACCH frames allocated for the respective mobile stations. The gap resource is notified to each mobile station.

If the network does not use the early class label sending function, in the dedicated mode, the Mobile Switching Center (MSC) can send a Classmark request message to the base station subsystem system to the mobile station. After receiving the Classmark request message, the base station subsystem system receives the Classmark request message. Sending a classmark enquiry message to the mobile station, and after the mobile station ^: to the classmark enquiry message, the capability information for supporting the offset SACCH frame mapping is used as a cell of the mobile station Classmark 3, and is given by the classmark change message. Base station subsystem. After receiving the Classmark change message, the base station subsystem system knows the mobile station's support for the offset SACCH frame mapping function, and then the base station subsystem sends a classmark update message to the MSC to support the mobile station to offset the SACCH frame mapping capability. The situation is reported to the MSC. The following detailed description of how this example reduces control channel interference between mobile stations.

6 is a flow chart of Embodiment 2 of a method for reducing control channel interference between mobile stations according to the present invention As shown in FIG. 6, the method for reducing control channel interference between mobile stations in this example includes the following steps:

Step 601: In the dedicated mode, the MSC can control a specific mobile station to send a Classmark request message to the base station subsystem system.

Step 602: After receiving the Classmark request message, the base station subsystem sends a classmark enquiry message to the mobile station.

Step 603: After receiving the classmark enquiry message, the mobile station uses the capability information of the offset SACCH frame mapping as a cell of the mobile station Classmark 3, and encapsulates the Classmark 3 in the classmark change message by sending a classmark change message. The mobile station supports the capability information of the offset SACCH frame mapping on the base station subsystem.

Step 604: After receiving the Classmark change message, the base station subsystem system knows the mobile station's support for the offset SACCH frame mapping capability. When the mobile station does not report the offset SACCH frame mapping capability, the base station subsystem considers that The mobile station does not support the offset SACCH frame mapping function. The base station subsystem then sends a classmark update message to the MSC, which supports the mobile station's ability to offset the SACCH frame mapping capability by 3⁄4 Μ8.

Step 605: The base station subsystem performs control of offset SACCH frame mapping on the mobile station according to the capability reported by the mobile station.

The base station subsystem allocates SACCH frames in the same carrier frequency of the mobile station supporting the offset SACCH frame mapping capability of one slot to different time slots, and will be used for each corresponding mobile station. The time slot resources of the assigned SACCH frame mapping are notified to each mobile station.

FIG. 7 is a flow chart of Embodiment 3 of a method for reducing control channel interference between mobile stations according to the present invention. As shown in FIG. 7, the method for reducing control channel interference between mobile stations in this example includes the following steps:

Step 701: When transmitting the full layer three message to the base station subsystem, the mobile station sends the information supporting the offset SACCH frame mapping capability to the base station subsystem. If the mobile station is the calling party, the CM Service Request message in the full layer three message is reported to the base station subsystem. If the mobile station is the called party, the mobile station is sent to the base station through the paging response message in the full layer three message. system.

Specifically, the mobile station encapsulates the capability information of the offset SACCH frame mapping as a cell of the mobile station Classmark 2, and encapsulates the Classmark 2 in the CM Service Request message or the paging response message, by sending a CM Service Request message or paging The response message reports the capability information of the mobile station supporting the offset SACCH frame mapping to the base station subsystem.

Step 702: The base station subsystem learns the support of the mobile station for the offset SACCH frame mapping function according to the support capability of the offset SACCH frame mapping function carried in the full layer three message reported by the mobile station. When the mobile station does not report the offset SACCH frame mapping capability, the base station subsystem considers that the mobile station does not support the offset SACCH frame mapping capability.

Step 703: The base station subsystem performs control of offset SACCH frame mapping on the mobile station according to the capability reported by the mobile station. The base station subsystem allocates the SACCH frames in the same carrier frequency of the mobile station supporting the offset SACCH frame mapping capability of one slot to different time slots, and maps the SACCH frames allocated for the respective mobile stations. The gap resource is notified to each mobile station.

In summary, with the above technical solution provided by the embodiment of the present invention, the mobile station can inform the base station subsystem of its own support capability for the offset SACCH frame mapping, so as to enable the base station subsystem to know whether the mobile station supports the offset SACCH frame mapping capability. The information can be used to control the offset SACCH frame mapping of the mobile station according to whether the mobile station has the offset SACCH frame mapping capability, which reduces the interference between the mobile station SACCH and improves the communication performance of the GSM.

FIG. 8 is a schematic structural diagram of a system for reducing control channel interference between mobile stations according to the present invention. As shown in FIG. 8, the system for reducing control channel interference between mobile stations includes a reporting unit 80, a receiving unit 81, and a control unit 82. The reporting unit 80 is located in the mobile station, and is configured to report whether the capability of the offset SACCH frame mapping is supported to the network side. The receiving unit 81 is located at the network side, and is configured to receive whether the mobile station reports the offset SACCH frame mapping. The capability information is located on the network side, and is configured to perform control of offset SACCH frame mapping on the mobile station according to the capability reported by the mobile station.

The upper unit 80 sends the information that the mobile station supports the offset SACCH frame mapping capability to one of the mobile station Classmark 3 information to the network side. Specifically, the "3⁄4 unit 80" encapsulates the Classmark 3 information carrying the information supporting the offset SACCH frame mapping capability in the classmark change message, and sends the information to the network side. The mobile station does not support the offset SACCH frame. When the capability of the mapping is performed, the Classmark 3 information of the classmark change message reported by the reporting unit 80 to the network side does not include a cell that supports the offset SACCH frame mapping capability.

Alternatively, the upper unit 80 sends the information of the mobile station's ability to support the offset of the SACCH frame as a cell in the mobile station Classmark 2 information to the network side.

Specifically, when the mobile station is used as the calling party, the reporting unit 80 will carry the support offset. The Classmark 2 information of the information of the SACCH frame mapping capability is encapsulated in the CM Service Request message and sent to the network side. When the mobile station is called, the reporting unit 80 will carry the information supporting the offset SACCH frame mapping capability. The Classmark 2 information is encapsulated in a paging response message and sent to the network side. When the mobile station does not support the capability of offset SACCH frame mapping, the upper unit 80 does not include a letter supporting the offset SACCH frame mapping capability in the Classmark 2 information of the CM Service Request message on the network side. The Classmark 2 information of the paging response message reported to the network side does not include a cell that supports the offset SACCH frame mapping capability.

The control unit 82 allocates SACCH frames located in the same carrier frequency to the mobile stations supporting the offset SACCH frame mapping capability of one slot, and notifies the corresponding mobile station.

It should be understood by those skilled in the art that the system for reducing control channel interference between mobile stations shown in FIG. 8 is designed to implement the foregoing method for reducing control channel interference between mobile stations, and the processing in the system shown in FIG. The function of the unit can be understood by referring to the related description in the foregoing method for reducing control channel interference between mobile stations. The functions of each processing unit can be implemented by a program running on a processor, or can be realized by a specific logic circuit.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for reducing control channel interference between mobile stations, comprising: the mobile station reporting to the network side whether the capability of offsetting the slow auxiliary control channel SACCH frame mapping is supported, the network side according to the moving The capability of the station reporting controls the mobile station to offset the SACCH frame mapping.

The method according to claim 1, wherein the mobile station reports its information supporting the offset SACCH frame mapping capability to one of the mobile station Classmark 3 information to the network side.

3. The method according to claim 2, wherein the mobile station encapsulates Classmark 3 information carrying information supporting the offset SACCH frame mapping capability in a classmark change message, and sends the information to the network side.

The method according to claim 3, wherein the classmark change message is sent to the network side, including:

The method according to claim 3, wherein when the mobile station does not support the capability of offsetting the SACCH frame mapping, the Classmark 3 information of the classmark change message of >3⁄4 on the network side does not include support. A cell that offsets the SACCH frame mapping capability.

6. The method according to claim 1, wherein the mobile station gives information about its ability to support offset SACCH frame mapping as one of the cells in the mobile station Classmark 2 information. Network side.

The method according to claim 6, wherein when the mobile station acts as a calling party, the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability is encapsulated in a CM Service Request message, and sent To the network side; When the mobile station is called, the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability is encapsulated in a paging response message and sent to the network side.

The method according to claim 7, wherein when the mobile station does not support the capability of offsetting the SACCH frame mapping, the Classmark 2 information of the CM Service Request message of >3⁄4 on the network side is not included. The cell that supports the offset SACCH frame mapping capability does not include the cell that supports the offset SACCH frame mapping capability in the Classmark 2 information of the paging response message on the network side.

The method according to any one of claims 1 to 8, wherein the controlling the offset SACCH frame mapping of the mobile station comprises:

The network side allocates SACCH frames in the same carrier frequency of the mobile station supporting the offset SACCH frame mapping capability of one slot to different time slots, and notifies the corresponding mobile station.

10. A system for reducing control channel interference between mobile stations, characterized by comprising a reporting unit, a receiving unit and a control unit, wherein:

The system according to claim 10, wherein the reporting unit reports the information that the mobile station supports the offset SACCH frame mapping capability to the cell in the mobile station Classmark 3 information. Network side.

The system according to claim 11, wherein the reporting unit encapsulates Classmark 3 information carrying information supporting the offset SACCH frame mapping capability in a classmark change message, and sends the information to the network side.

The system according to claim 12, wherein the reporting unit directly sends the classmark change message to the network side;

The system according to claim 12, wherein, when the mobile station does not support the capability of offsetting the SACCH frame mapping, the upper unit sends a Classmark 3 message of a classmark change message of >3⁄4 to the network side. Cells that support offset SACCH frame mapping capabilities are not included.

The system according to claim 10, wherein the reporting unit uses the information of the mobile station to support the capability of offsetting the SACCH frame mapping as a cell in the Class 2 information of the mobile station. Said network side.

The system according to claim 15, wherein when the mobile station is a calling party, the reporting unit encapsulates Classmark 2 information carrying information supporting the offset SACCH frame mapping capability in a CM Service Request message. And sent to the network side; when the mobile station is called, the reporting unit encapsulates the Classmark 2 information carrying the information supporting the offset SACCH frame mapping capability in the paging response message, and sends the message to the paging response message. Said network side.

The system according to claim 16, wherein when the mobile station does not support the capability of offsetting SACCH frame mapping, the upper unit sends a >3⁄4 CM Service to the network side.

The Classmark 2 information of the Request message does not include the cell that supports the offset SACCH frame mapping capability, and the Classmark 2 information of the paging response message to the network side does not include the cell that supports the offset SACCH frame mapping capability.

The system according to any one of claims 10 to 17, wherein the control unit is located at a mobile station that supports an offset SACCH frame mapping capability sharing a time slot. The SACCH frames in the same carrier frequency are allocated to different time slots and notified to the corresponding mobile station.