WO2012000268A1

WO2012000268A1 - System and method for flexibly controlling scan and handover of mobile station

Info

Publication number: WO2012000268A1
Application number: PCT/CN2010/078563
Authority: WO
Inventors: 宋玉献
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-06-30
Filing date: 2010-11-09
Publication date: 2012-01-05
Also published as: CN102316545A; CN102316545B

Abstract

In the present invention, provided are a system and method for flexibly controlling the scan and handover of a mobile station, which belong to the technical field of the mobile communications. The system includes a mobile station, a serving base station for the mobile station, and one or more neighbor cell base stations. The serving base station broadcasts a neighbor cell broadcast message to the mobile station, and sends to the mobile station a scan response message carrying scan result purpose information, wherein the scan result purpose information is used for indicating whether each neighbor cell base station is the candidate neighbor cell base station for the handover; the mobile station receives the scan response message, scans the neighbor cell base stations according to the start frame number and scan duration, and judges whether each neighbor cell base station is the candidate neighbor cell base station for the handover according to the scan result purpose information carried in the received scan response message; if it is indicated that the neighbor cell base station is not the candidate neighbor cell base station for the handover, the mobile station does not trigger the handover to the neighbor cell base station after the scan. Applying the present invention, the scan mechanism which does not trigger the handover is implemented, and the unnecessary handover is reduced.

Description

System and method for flexibly controlling mobile station scanning switching

Technical field

The present invention relates to a Worldwide Interoperability for Microwave Access (WiMAX) system, and more particularly to a system and method for flexibly controlling mobile station scan switching in a WiMAX system.

Background technique

At present, the application scenarios of WiMAX communication systems mainly include fixed and mobile applications. That is to say, some users use WiMAX services at fixed locations such as homes or companies, while some users use WiMAX services in mobile locations such as mobile vehicles. For mobile users, the signal strength of the serving base station Serving BS (Serving Base Station) may become weaker and weaker during the mobile process, for example, the user is gradually moving away from the base station. In order to meet the user's service quality requirements, the mobile station MS (Mobile Station, also called WiMAX mobile terminal) is required to switch to a base station with better signal quality. In the inter-frequency networking, in order to implement the handover, the corresponding scanning threshold and the switching threshold are configured on the base station, and are carried by the Trigger field in the Downlink Channel Descriptor (DCD) message sent by the base station. Notify the mobile station MS.

The mobile station scans according to the corresponding scan threshold and switching threshold. The scanning mechanism is briefly described below.

When the current signal quality is lower than the scanning threshold, the mobile station MS first completes the current serving base station by using two messages MOB_SCN-REQ and MOB_SCN-RSP (or the base station BS actively transmits the MOB_SCN-RSP message). The interaction of the Serving BS to notify the current serving base station Serving BS that the mobile station MS will leave the current serving base station Serving BS to scan the neighboring base station BS (Base Station), thereby obtaining the signal quality of the neighboring base station BS.

Through scanning, the mobile station MS can obtain the signal quality information of the neighboring base station, and then according to the signal quality and the switching threshold of the source side base station (ie, the current serving base station Serving BS) and the target side base station (ie, the scanned neighboring base station). Decide if you need to switch and cut when you decide to switch Which target side base station to switch to.

In practical applications, sometimes you want to trigger the switchover by scanning. However, in some scenarios, the current serving base station signal may already meet the current communication requirements, or the neighboring base station load is high, etc., and only want to use the scanning mechanism. Obtaining the signal quality of the neighboring base station without generating a handover by using a scanning mechanism; even if the signal quality of the target base station and the current serving base station reaches the switching threshold, the handover is not allowed.

Therefore, in order to meet the various application requirements of the scanning mechanism in such a complicated and varied scenario, a scanning mechanism that flexibly controls whether to trigger the switching is needed.

Summary of the invention

The technical problem to be solved by the present invention is to provide a system and method for flexibly controlling mobile station scanning switching, which is used to solve the problem of application requirements of scanning only without switching when the mobile station scans and switches in the WiMAX system, and realizes scanning switching. Flexible control to adapt to a variety of application scenarios.

In order to solve the above problem, the present invention provides a system for flexibly controlling mobile station scanning handover, including a mobile station MS, a serving base station of a mobile station, and one or more neighboring base stations, where: the serving base station is set to: The mobile station broadcasts the neighboring area broadcast message, and sends a scan response message carrying the scan use information to the mobile station, where the scan use information is used to indicate whether each neighboring base station is a neighboring base station as a handover candidate;

The mobile station is configured to: receive a scan response message, scan the neighboring base station according to the start frame number and the scan duration, and determine, according to the scan use information in the received scan response message, whether the neighbor base station is a neighbor candidate of the handover candidate The base station, if the scanning use information indicates that the neighboring base station is not a neighboring base station of the handover candidate, does not trigger handover to the neighboring base station after scanning.

The mobile station is further configured to: determine, according to the scanning use information, whether the neighboring base station is a neighboring base station as a handover candidate, if the scanning use information indicates the neighboring base station as a neighboring base station of the handover candidate, after the scanning, The mobile station determines whether it is possible to switch to the neighboring base station according to the scan result and the handover threshold. If the handover condition is met, the handover is performed. If the handover condition is not met, the neighbor base station is not used as the handover candidate target. The scan usage information is modified by an existing field in the scan response message, or is a new dedicated field.

The scan response message is a scan response message sent by the serving base station or a response message sent by the serving base station to the scan request message sent by the mobile station.

The present invention also provides a method for flexibly controlling a mobile station scan switch, including:

The serving base station broadcasts a neighbor broadcast message to the mobile station, and sends a scan response message carrying the scan use information to the mobile station, where the scan use information is used to indicate whether each neighbor base station is a neighbor base station that is a candidate for handover;

After receiving the scan response message, the mobile station scans the neighboring base station according to the start frame number and the scan duration, and determines, according to the scan use information in the received scan response message, whether the neighbor base station is a neighboring base station of the handover candidate, if scanning The usage information indicates that the neighboring base station is not a neighboring base station of the handover candidate, and the mobile station does not trigger the handover to the neighboring base station after scanning.

The method further includes: when the mobile station determines, according to the scanning use information, whether the neighboring base station is a neighboring base station of a handover candidate, if the scanning use information indicates the neighboring base station as a neighboring base station of the handover candidate, After the scanning, the mobile station determines whether it is possible to switch to the neighboring base station according to the scanning result and the switching threshold. If the handover condition is met, the handover is performed. If the handover condition is not met, the neighboring base station is not used as the handover candidate target.

The scan usage information is modified by an existing field in the scan response message, or is a newly added dedicated field.

The scan response message is a scan response message sent by the serving base station or a response message of the scan request message sent by the serving base station to the mobile station.

Compared with the prior art, the system and method for flexibly controlling mobile station scan switching in the WiMAX system proposed by the present invention, by using the scanning use information in the MOB-SCN-RSP message to flexibly control whether the target neighboring base station BS is used as a handover candidate The neighboring base station can flexibly control the mobile station to scan the base station that only needs to scan without switching, without triggering the handover process. At the same time, the scanning purpose information can also be used to indicate the scanning process after the scanning is triggered. The invention realizes a scanning mechanism that does not trigger switching, and can be full It is currently necessary to scan data without the need for switching scenarios, thereby reducing unnecessary handovers and overcoming the degradation of quality of service due to handover failures. BRIEF abstract

1 is a schematic diagram of a scanning process of a mobile station scanning in an existing WiMAX system;

2 is a schematic diagram showing a scanning flow of a mobile station scanning in a WiMAX system according to an embodiment of the present invention.

Preferred embodiment of the invention

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings.

In the current WiMAX system, after the mobile station scans, the situation that the handover is not triggered cannot be implemented. The present invention adds a dedicated indication field to the response message or response message sent by the base station to the mobile station, for example, adding a Scan result purpose field. And indicating whether a neighboring base station that is scanned is allowed to be a scanned candidate neighboring base station, and if configured as a candidate neighboring base station, the mobile station only needs to scan the neighboring base station, after scanning The handover procedure is not triggered, which achieves the purpose of not having to switch to the neighbor base station after scanning.

As shown in FIG. 2, a system for flexibly controlling a mobile station scan handover includes a mobile station MS, a serving base station of a mobile station, and one or more neighbor base stations, where:

a serving base station, configured to broadcast a neighbor broadcast message (MOB_NBR-ADV) to the mobile station, notify the mobile station of the current neighbor information, and send a scan response message carrying the scan result purpose information to the mobile station, The scanning usage information is used to indicate whether the neighboring base station is a neighboring base station of the handover candidate, and may have a value of 1 or 0. When the value is 1, the neighboring base station that is not used as the handover candidate is identified as the neighboring base station. After the value is 0, the neighboring base station is identified as the neighboring base station of the handover candidate. After the scanning, the handover is further determined according to the scan result, and the determination may be further performed according to the handover threshold. If the threshold is switched, the switch is performed. If the switch threshold is not reached, the switch may not be performed.

The mobile station MS is configured to receive a scan response message, scan a neighboring base station according to a start frame number and a scan duration, and determine, according to the scan use information in the received scan response message, Whether the scanned neighboring base station is a neighboring base station of the handover candidate, and if yes, whether to perform handover according to the scan result and the handover threshold; if not, it is not necessary to perform handover.

The scan usage information may be obtained by tampering with an existing field in the scan response message, or may be a new field. In an embodiment of the present invention, the neighboring base station BS is represented by adding a Scan result purpose to the BS index part and the BS ID part in the MOB_SCN-RSP message instead of the existing reserved field. Whether to allow switching occurs. As shown in Table 1, the modified MOB-SCN-RSP message neighbor-BS index portion is displayed; as shown in Table 2, the modified MOB-SCN-RSP message-BS ID portion is displayed.

Table 1

Table 2

For(j=0;j<N Recommended BS Full;

Recommended BS ID 48 BS IDs ofBSs that MS shall scan

Shall be set to 0 ObO for HO

Reserved Scan result purpose 1 Obi only scan

ObOOO: Scanning without association

Scanning type 3 ObOOl : Scanning with association level 0:

Association without coordination ObOlO: Scanning with association level 1 : association with coordination

ObO 1 1: Scanning with association level 2: network assisted association

OblOO-Obl ll : ^TOd/ The scan response message MOB_SCN-RSP may be a scan response message sent by the base station or may be a response message of the scan request message MOB_SCN-REQ sent by the base station to the mobile station.

As shown in FIG. 2, the method for flexibly controlling mobile station scan switching of the WiMAX system of the present invention includes:

First, the serving base station broadcasts a neighbor broadcast message (MOB_NBR-ADV) to the mobile station to notify the mobile station of the current neighbor information;

Then, the serving base station sends a scan response message carrying the scan result purpose information to the mobile station, where the scan use information is used to indicate whether each neighboring base station is a neighboring base station that is a candidate for handover;

The scanning usage information may be a value of 1 or 0. When the value is 1, the neighboring base station that does not serve as a handover candidate is identified by the neighboring base station, and does not switch after scanning. When the value is 0, the neighboring base station is identified. It is a neighboring base station that is a handover candidate, and after scanning, further determines whether to perform handover according to the scan result and the handover threshold.

After receiving the scan response message, the mobile station MS scans the neighboring base station according to the start frame number and the scan duration, and determines whether the neighbor base station is a candidate of the handover candidate according to the scan use information in the received scan response message. The area base station, if yes, judges whether to perform handover according to the scan result and the handover threshold; if not, it is not necessary to perform handover.

The scan usage information may be obtained by tampering with an existing field in the scan response message, or may be a new field Scan result purpose. If a neighboring base station in the scan response message sets the Scan result purpose to 1, it indicates that the neighboring base station is not used as a neighboring base station of the handover candidate, and after the scanning is finished, no matter how good the signal of the neighboring base station is, regardless of the Whether the signal reaches the handover threshold will not be used as a candidate neighboring base station for handover.

The present invention determines whether the neighboring base station can be used as a handover candidate neighboring base station after scanning the neighboring base station by using a Scan result purpose field in the specified neighboring base station in the scan response message, and if so, according to the scan result and switching The threshold then determines whether to perform the handover; if not, it is not necessary to perform the handover. In this way, it is possible to flexibly decide whether to proceed after scanning to obtain the scan result. Switching, which can be applied to scenarios that need to be switched, or to scenarios that only need to obtain scan results without switching, has good flexibility and applicability.

While the preferred embodiments of the present invention have been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

Industrial applicability

Compared with the prior art, the system and method for flexibly controlling mobile station scan switching in the WiMAX system proposed by the present invention, by using the scanning use information in the MOB-SCN-RSP message to flexibly control whether the target neighboring base station BS is used as a handover candidate The neighboring base station can flexibly control the mobile station to scan the base station that only needs to scan without switching, without triggering the handover process. At the same time, the scanning purpose information can also be used to indicate the scanning process after the scanning. The present invention implements a scanning mechanism that does not trigger a handover, and satisfies the scenario requirements that currently need to scan data without switching, thereby reducing unnecessary handover and overcoming the degradation of service quality due to handover failure.

Claims

Claim

A system for flexibly controlling a mobile station scan handover, comprising a mobile station, a serving base station of the mobile station, and one or more neighbor base stations, wherein:

The serving base station is configured to: broadcast a neighboring cell broadcast message to the mobile station, and send a scan response message carrying the scan use information to the mobile station, where the scan use information is used to indicate whether each neighboring cell base station is a neighboring base station as a handover candidate. ;

2. The system of claim 1 wherein

The mobile station is further configured to: determine, according to the scanning use information, whether the neighboring base station is a neighboring base station as a handover candidate, if the scanning use information indicates the neighboring base station as a neighboring base station of the handover candidate, after the scanning, Whether the handover to the neighboring base station can be determined according to the scan result and the handover threshold; if the handover condition is met, the handover is performed, and if the handover condition is not met, the neighboring base station is not used as the handover candidate target.

3. The system according to claim 1 or 2, wherein

4. The system of claim 1 wherein

The scan response message is a scan response message sent by the serving base station, or a response message sent by the serving base station to the scan request message sent by the mobile station.

5. A method for flexibly controlling a mobile station scan switch, comprising:

After receiving the scan response message, the mobile station scans the neighboring base station according to the start frame number and the scan duration. And determining, according to the scanning use information in the received scan response message, whether the neighboring base station is a neighboring base station as a handover candidate, and if the scanning use information indicates that the neighboring base station is not a neighboring base station of the handover candidate, moving after scanning The station does not trigger a handover to the neighboring base station.

6. The method of claim 5, the method further comprising:

When the mobile station determines whether the neighboring base station is a neighboring base station of the handover candidate according to the scanning use information, if the scanning use information indicates the neighboring base station as the neighboring base station of the handover candidate, after the scanning, the mobile station according to the mobile station The scan result and the handover threshold determine whether it is possible to switch to the neighboring base station; if the handover condition is met, the handover is performed, and if the handover condition is not met, the neighbor base station is not used as the handover candidate target.

7. The method according to claim 5 or 6, wherein

8. The method of claim 5, wherein