CN101345987A - Method and base station for realizing fast switching in communication network - Google Patents

Abstract

A method for implementing fast handover and a base station, which mainly includes: firstly, a serving base station selects a target base station for a mobile terminal to be handed over, or, at the same time, a corresponding candidate target base station can also be selected, and the target base station, or , the target base station and the alternative target base station allocate handover dedicated resources for the mobile terminal; then, the mobile terminal can use the allocated handover dedicated resources to perform a handover operation to access the corresponding target base station or alternative target base station. Therefore, the implementation of the embodiment of the present invention can eliminate the need to select the target base station again when the target base station refuses to access, effectively reducing the time spent in the handover process, and can also improve the reliability of the handover process. In a word, the realization of the embodiment of the present invention can reduce the handover delay as much as possible on the basis of ensuring the handover reliability, so as to meet the requirement of the wireless communication system on the handover delay.

Description

Method and base station for realizing fast switching in communication network

technical field

The present invention relates to the technical field of wireless communication, in particular to an implementation scheme of fast switching.

Background technique

During wireless communication, due to the mobile characteristics of the mobile station, it needs to switch between different base stations to obtain better communication performance.

At present, the processing procedure of the handover preparation of the mobile station between BSs (base stations) is shown in Figure 1, and may mainly include the following steps:

Step 1, the serving BS initiates a handover request to multiple candidate target BSs, and the handover request message includes MS (mobile station) context, QoS (quality of service) and other information;

Step 2, multiple candidate target BSs can request the security context parameters of the MS from the Auth ASN GW (Authorization Access Network Gateway);

Step 3, multiple candidate target BSs can also communicate with the Anchor ASN GW to request early registration of the data path;

In the actual handover process, the above steps 2 and 3 can also be omitted;

Step 4, each candidate target BS returns a handover response message to the serving BS according to the handover request received from the serving BS;

Step 5: After receiving the handover response message sent by each candidate target BS, the serving BS determines one or more candidate target BSs, and sends the information (such as base station identification) of one or more candidate target base stations It is given to the MS so that the MS can select a corresponding target BS and perform a handover operation.

In the course of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

The serving BS needs to send handover requests to multiple candidate target BSs during the handover preparation phase, resulting in a long processing time during the handover preparation phase;

Moreover, since the serving BS needs to interact with multiple candidate target BSs during the handover preparation stage, the multiple candidate target BSs cannot prepare resources for the MS handover in the future, which may further increase the processing time required for the MS handover process.

In short, the handover processing solution provided by the above prior art may not meet the handover delay requirements of the system due to the long handover time required during the handover process, especially the handover requirements of mobile stations moving at high speed in the communication system.

Contents of the invention

Embodiments of the present invention provide a method and a base station for realizing fast handover in a communication network, so as to save the time occupied in the handover process and reduce the handover delay of the wireless communication system.

An embodiment of the present invention provides a method for realizing fast switching in a communication network, including:

The serving base station selects a target base station for the mobile terminal to be handed over according to the service quality information and/or radio resource information,

The serving base station notifies the mobile terminal to perform handover according to the selection result.

An embodiment of the present invention provides a base station, including:

A target base station selection unit, configured to select a target base station for the mobile terminal to be handed over according to the quality of service information and/or radio resource information;

A handover notification unit, configured to notify the mobile terminal to perform handover according to the selection result of the target base station selection unit.

It can be seen from the technical solutions provided by the above embodiments of the present invention that only one target base station is selected for the mobile terminal according to the quality of service information and/or radio resource information, and the selection result is relatively accurate, so that there is no need to repeat the target base station during the handover process. The selection of the target base station effectively reduces the time spent in the handover process, and can also improve the reliability of the handover process. In a word, the realization of the embodiment of the present invention can reduce the handover delay as much as possible on the basis of ensuring the handover reliability, so as to meet the requirement of the wireless communication system on the handover delay.

Description of drawings

FIG. 1 is a schematic diagram of the processing process of handover preparation provided in the prior art;

FIG. 2 is a schematic diagram 1 of a specific implementation process provided by an embodiment of the present invention;

FIG. 3 is a second schematic diagram of a specific implementation process provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of an implementation structure of a device provided by an embodiment of the present invention.

Detailed ways

In the embodiment of the present invention, the serving base station in the wireless communication system selects and determines the corresponding target base station for the MS according to the service quality information and/or radio resource information, or can also select and determine the corresponding target base station according to the service quality information and/or radio resource information The target base station and the candidate target base station, so that the selection result of the target base station or the candidate target base station is relatively accurate, so as to improve the handover success rate and reliability.

In the embodiment of the present invention, the selected target base station, or the target base station and the alternative target base station can also allocate handover dedicated resources for the MS, such as preparing dedicated ranging resources for the MS, so that the MS can use the handover dedicated resources Implement switching operations.

The embodiments of the present invention may be specifically applied to, but not limited to, IEEE802.16 wireless communication systems.

In the above processing process, the serving base station can specifically base on the radio resource information such as the scanning result of the neighboring base station (that is, the measurement report of the neighboring base station), the capability of the MS, the current QoS requirement of the MS, the load information of the neighboring base station, and the neighboring base station. One or more combinations of QoS level information currently supported by the base station make a handover decision, so as to determine the target base station to be handed over by the MS, or determine the corresponding target base station and alternative target base stations. Wherein, the wireless resource information such as load information of neighboring base stations may be acquired by the serving base station from the upper layer network device in a periodic or event-triggered manner.

During the handover process, the target base station may transmit the handover dedicated resource information corresponding to the handover dedicated resource to the serving base station, and the serving base station transmits the handover dedicated resource information to the mobile terminal; or, the target base station may directly transmit the handover dedicated resource information to the mobile terminal. The handover dedicated resource information is transmitted to the mobile terminal. For example, after the target base station or the alternative target base station prepares dedicated handover resources for the MS, the target base station or the alternative target base station can use their respective broadcast messages (such as UL-MAP (uplink mapping) messages, etc.) The dedicated ranging resource information corresponding to the distance resource is notified to the MS as handover dedicated resource information, or the serving base station may forward the dedicated ranging resource information to the MS as handover dedicated resource information through a handover indication message.

During the handover operation process of the MS, the MS may decide the handover time by itself after receiving the handover instruction message sent by the serving base station, or may perform handover immediately after receiving the handover instruction message sent by the serving base station, or After receiving the handover indication message sent by the serving base station, the time to perform the handover operation may be determined according to the time when the MS performs handover notified in the message.

In the embodiment of the present invention, after the serving base station selects an alternative target base station for the mobile terminal, the serving base station may also notify the target base station of the identity of the alternative target base station, so that after the target base station rejects the handover request, the target base station The base station can notify the alternative target base station to process the handover request, thereby further improving the reliability of the handover and reducing the handover delay; After the target base station is selected, it directly communicates with the candidate target base station to handover the mobile terminal to the candidate target base station, so as to further improve handover reliability and reduce handover delay.

In order to facilitate the understanding of the embodiments of the present invention, the specific implementation of the embodiments of the present invention will be further described below by taking several specific application embodiments as examples.

Embodiment one

In the first embodiment, when making a handover decision, the serving base station only selects a target base station to be handed over for the MS, and does not select an alternative target base station for the MS.

As shown in Figure 2, in this embodiment, the handover process may specifically include the following steps:

Step 1, the serving base station selects a target base station to be handed over for the MS;

Specifically, the serving base station may be, but not limited to, based on one of wireless resource information such as the scanning result for neighboring base stations, MS capabilities, current MS QoS requirements, load information of neighboring base stations, and QoS level information currently supported by neighboring base stations. A handover decision is made based on a combination of items or multiple items, so as to determine the target base station to be handed over by the MS;

In order to optimize the use of the entire network resources, when the serving BS makes a handover decision, it can specifically determine the most suitable handover target (i.e., the target BS) based on the above factors. The handover target is not necessarily the optimal handover target; for example, if the current The QoS requirements of the MS are relatively low, and the required transmission rate is relatively low, so the MS does not need to be handed over to the BS that can provide high-level QoS, but only to the BS that can meet its QoS requirements.

Step 2, the serving base station sends a handover request message to the selected target base station, and the handover request message may carry the MS context and the QoS information required by the MS;

Step 3, after receiving the handover request from the serving base station, the target base station prepares dedicated handover resources (such as dedicated ranging resources) for the MS;

For example, after the target base station prepares a dedicated ranging resource for the MS, it may use a broadcast message (such as a UL-MAP message, etc.) to notify the MS of the dedicated ranging resource information corresponding to the dedicated ranging resource, or through The serving base station forwards the dedicated ranging resource information to the MS;

Step 4, the target base station sends a handover response message to the serving base station;

Optionally, the dedicated ranging resource information prepared for the MS may be carried in the handover response message as corresponding handover dedicated resource information, so that the dedicated ranging resource information may be forwarded to the MS through the serving base station.

Step 5: After receiving the handover response message from the target base station, the serving base station sends a handover instruction message to the MS to notify the MS to perform handover;

Wherein, if the handover response message sent by the target base station contains the dedicated ranging resource information prepared for the MS, the serving base station may also carry the dedicated ranging resource information allocated by the target base station for the MS in the handover instruction message sent to the MS. Distance resource information, so that the MS can learn the corresponding access information, that is, obtain the corresponding handover dedicated resource information;

Optionally, the serving base station may also notify the MS of the handover time in the handover instruction message, so as to indicate the time for the MS to specifically perform the handover;

In this step, the handover instruction message may specifically adopt MOB-BSHO-REQ (a handover request message in IEEE802.16e (the request is initiated by the BS)) or MOB-BSHO-RSP (a handover response message in IEEE802.16e) (the message is the handover request initiated by the BS for the MS) message format; A corresponding IE (Information Element) is added to the message as the format of the handover indication message.

Step 6: After receiving the handover instruction message sent by the serving base station, the MS uses the obtained handover dedicated resource (such as a dedicated ranging resource) information to perform ranging with the target base station (that is, perform a handover operation), and access the target base station ;

In this step, the MS can directly obtain the handover dedicated resource (such as a dedicated ranging resource) information from the target base station, and can also indirectly obtain the handover dedicated resource corresponding to the handover dedicated resource allocated by the target base station from the serving base station (such as a dedicated ranging resource). Dedicated ranging resources) information;

In this step, the time for the MS to perform the handover operation may be determined by itself after receiving the handover instruction message sent by the serving base station, or may perform the handover operation after receiving the handover instruction message sent by the serving base station, or After receiving the handover instruction message sent by the serving base station, the handover operation can be performed according to the time carried in the message to instruct the MS to perform the handover;

Step 7: After the MS is handed over to the target base station successfully, the target base station sends a handover completion message to the serving base station, so as to notify the serving base station that the MS has successfully handed over.

Embodiment two

In the second embodiment, when the serving base station makes a handover decision, a target base station to be handed over is selected for the MS, and a candidate target base station is also selected for the MS.

As shown in Figure 3, in this embodiment, the corresponding handover process may specifically include:

Step 1, the serving base station selects a target base station and an alternative target base station for the MS to be handed over

Specifically, the serving base station may base on one of the wireless resource information such as the scanning result for the neighboring base station, the MS capability, the current QoS requirement of the MS, the load information of the neighboring base station, and the QoS level information that the neighboring base station can currently support. or multiple combinations to make a handover decision to determine the target base station and candidate base station to be handed over by the MS;

Step 2, the serving base station sends a handover request message to the target base station;

Specifically, the handover request message may carry the MS context, the QoS information required by the MS, and the ID (identification) of the candidate base station;

After receiving the handover request from the serving base station, the target base station executes steps 3 to 7, or executes steps 3' to 8', which will be described respectively below:

(1) The process from step 3 to step 7 includes:

Step 3, the target base station prepares handover dedicated resources (such as dedicated ranging resources) for the MS;

The target base station can use a broadcast message (such as a UL-MAP message) to notify the MS of the handover-dedicated resource (such as a dedicated ranging resource) corresponding to the handover-dedicated resource (such as a dedicated ranging resource), or it can also use the service The base station forwards the handover dedicated resource (such as dedicated ranging resource) information to the MS;

Step 4, the target base station sends a handover response message to the serving base station;

Optionally, the message may carry handover dedicated resource (such as dedicated ranging resource) information corresponding to the handover dedicated resource (such as dedicated ranging resource) prepared for the MS, so as to send the target base station to the serving base station. Send information about switching dedicated resources (such as dedicated ranging resources) to the MS;

Step 5: After receiving the handover response message from the target base station, the serving base station sends a handover indication message to the MS to notify the MS to perform handover;

Wherein, if the handover response message sent by the target base station contains the handover dedicated resources (such as dedicated ranging resources) information corresponding to the handover dedicated resources (such as dedicated ranging resources) prepared for the MS, then the serving base station can The indication message carries handover-dedicated resources (such as dedicated ranging resources) information corresponding to the handover-dedicated resources (such as dedicated ranging resources) allocated by the target base station for the MS, so as to notify the MS;

Optionally, the handover instruction message in this step can use the message format of MOB-BSHO-REQ or MOB-BSHO-RSP message, and add corresponding IE (information element) in this message to carry above-mentioned handover dedicated resource ( such as dedicated ranging resources) information;

Step 6, the MS uses the dedicated ranging resources to perform ranging with the target base station and access the target base station;

In this step, the MS can directly obtain the handover dedicated resources (such as dedicated ranging resources) information from the target base station, or can also indirectly obtain the handover dedicated resources (such as dedicated ranging resources) allocated by the target base station from the serving base station. The corresponding handover dedicated resources (such as dedicated ranging resources) information;

In this step, the time for the MS to perform the handover operation may be determined by itself after receiving the handover instruction message sent by the serving base station, or may perform the handover operation after receiving the handover instruction message sent by the serving base station, or After receiving the handover instruction message sent by the serving base station, the handover operation can be performed according to the time carried in the message to instruct the MS to perform the handover;

Step 7: After the MS is handed over to the target base station successfully, the target base station sends a handover completion message to the serving base station, so as to notify the serving base station that the MS has successfully handed over.

(2) The processing from step 3' to step 8' includes:

Step 3', the target base station rejects the handover request;

Step 4', the target base station sends a handover request to an alternative target base station;

Specifically, while denying access, the target base station can forward the information such as the context information of the MS received from the serving base station or the QoS required by the MS to the alternative target base station through the handover request, and can Carry the ID of the serving base station;

Step 5', the target base station sends a handover rejection message to the serving base station;

Specifically, after the serving base station receives the handover rejection message sent by the target base station, the serving base station can notify the MS in the handover indication message to perform the process of accessing from the alternative target base station, so as to realize the handover based on the alternative target base station operate;

Step 6', after the alternative target base station receives the handover request from the target base station, it is then responsible for preparing corresponding handover dedicated resources (such as dedicated ranging resources) for the MS;

In this step, the handover dedicated resource (such as dedicated ranging resource) information corresponding to the dedicated handover dedicated resource (such as dedicated ranging resource) may be sent by the alternative target base station through a broadcast message (such as UL-MAP message, etc.) sent to the MS, or forwarded to the MS through the serving base station;

Optionally, this step may also be omitted, that is, the alternative target base station may not allocate handover dedicated resources (such as dedicated ranging resources) to the MS, and may notify the MS in a broadcast message (such as a UL-MAP message) to perform A common ranging procedure to access an alternative target base station (ie, access to a target base station without utilizing handover dedicated resources (such as dedicated ranging resources)).

Step 7', the MS performs an access process to the alternative target base station;

Specifically, if the MS receives the dedicated handover resource (such as a dedicated ranging resource) prepared for the MS by the alternative target base station sent by the serving base station, the MS uses the dedicated handover resource (such as a dedicated ranging resource) to perform ranging, to execute the access process; or, the MS reads the broadcast message (for example: UL-MAP message) of the alternative target base station, and if the alternative target base station allocates a handover dedicated resource (dedicated ranging resource) for the MS, the handover Dedicated resources (such as dedicated ranging resources) perform ranging to perform access procedures. If the alternative target base station does not allocate handover dedicated resources (such as dedicated ranging resources) for the MS, the MS performs a normal ranging process to perform an access process, that is, it uses contention to access and handover to the alternative target base station;

The manner in which the MS determines the time to execute the handover may adopt the manner described in the previous embodiment;

Step 8', after the MS is successfully handed over to the candidate base station, the target base station sends a handover completion message to the serving base station. The serving base station is notified that the MS has handed over successfully.

In the first and second embodiments above, when the serving base station selects the target base station or the candidate base station, if the serving base station and the target base station are synchronized, the mobile terminal or the serving base station or the target base station or the candidate base station can calculate the The timing offset between the base station and the mobile terminal, and then the mobile terminal obtains the timing offset and uses the timing offset to achieve synchronization with the base station. During the handover process, if the timing offset is calculated by the serving base station or the target base station or the candidate base station, the serving base station or the target base station or the candidate base station notifies the mobile terminal of the timing offset determined by its calculation, for example, by The timing offset is carried in the handover instruction message or broadcast message (for example: UL-MAP message) and sent to the mobile terminal, so that the mobile terminal can adjust the timing offset before performing the ranging operation.

The embodiment of the present invention also provides a base station, which can be used as a serving base station, or as a target base station, or as an alternative target base station, and its specific implementation structure is shown in Figure 4, which mainly includes the following processing units :

(1) a target base station selection unit, used to select a target base station for the mobile terminal to be handed over according to the quality of service information and/or radio resource information;

The target base station selection unit specifically includes:

A parameter information acquisition unit, configured to acquire one of the scanning results for neighboring base stations, mobile terminal capabilities, current quality of service (QoS) requirements of mobile terminals, wireless resource information of neighboring base stations, and QoS level information currently supported by neighboring base stations or multiple parameter information;

A selecting operation unit is configured to select a target base station for the mobile terminal according to the parameter information obtained by the parameter information obtaining unit.

(2) A handover notification unit, configured to notify the mobile terminal to perform handover according to the selection result of the target base station selection unit, so as to facilitate the mobile terminal to quickly switch and access the corresponding target base station.

Optionally, the base station may also include a handover dedicated resource allocation unit and a handover dedicated resource notification unit, wherein:

The handover-dedicated resource allocation unit is used to allocate handover-dedicated resources, such as ranging resources for handover, to the mobile terminal when serving as a target base station;

The handover dedicated resource notification unit is configured to transmit handover dedicated resource information corresponding to the handover dedicated resource allocated by the handover dedicated resource allocation unit to the mobile terminal; specifically, the target base station may directly notify the mobile terminal, or , may also be forwarded to the mobile terminal through the serving base station.

Optionally, in order to further improve the reliability of the handover, in the base station as the serving base station, a corresponding alternative target base station can also be selected for the mobile terminal, so the base station can also include an alternative target base station selection unit and a handover notification processing unit, in:

The alternative target base station selection unit is used to select an alternative target base station for the mobile terminal to be handed over, so that after the mobile terminal cannot access the target base station, it can choose to access the alternative target base station to complete the corresponding switch operation process;

The handover notification processing unit is configured to communicate with the alternative target base station to hand over the mobile terminal to the alternative target base station after learning that the mobile terminal cannot be handed over to the target base station.

Optionally, in order to enable the mobile terminal to obtain a timing offset for synchronization, the base station may further include a timing offset calculation unit and a timing offset notification unit, wherein,

The timing deviation calculation unit is used to calculate the timing deviation between the handover base station and the mobile terminal;

The timing offset notification unit is configured to notify the mobile terminal of the timing offset calculated and determined by the timing offset calculation unit.

To sum up, in the whole handover processing process provided by the embodiment of the present invention, the corresponding handover decision of selecting a target base station is determined based on the load of the neighbor base station, the QoS level information of the neighbor base station, etc., so the reliability of the handover can be effectively improved. performance, and reduce the delay in BS and MS processing and the delay in the handover execution process, so as to meet the requirements of low delay and high reliability in the handover process. In a word, the handover implementation process provided by the embodiment of the present invention has the advantages of simple implementation, low delay, high handover reliability, and does not affect the implementation complexity of the MS.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (15)

1. A method for implementing fast handoff in a communication network, comprising:

the serving base station selects a target base station for the mobile terminal to be switched according to the service quality information and/or the radio resource information,

and the service base station informs the mobile terminal to execute the switching according to the selection result.

2. The method of claim 1, wherein the step of selecting a target base station for the mobile terminal to be handed off comprises:

the service base station selects a target base station for the mobile terminal according to one or more of the combination of the current QoS requirement of the mobile terminal, the wireless resource information of the adjacent base station and the current QoS grade information supported by the adjacent base station.

3. The method according to claim 1 or 2, wherein the radio resource information comprises at least load information.

4. The method of claim 1, further comprising: and the service base station selects an alternative target base station for the mobile terminal to be switched.

5. The method of claim 4, further comprising:

the alternative target base station distributes special switching resources for the mobile terminal;

and informing the mobile terminal of the switching dedicated resource information corresponding to the switching dedicated resource through a self broadcast message or through a service base station.

6. The method of claim 5, further comprising:

the mobile terminal reads the broadcast message of the alternative target base station, if the alternative target base station is judged to distribute the special switching resource for the mobile terminal, the mobile terminal is switched to the alternative target base station by utilizing the special switching resource, otherwise, the mobile terminal is switched to the alternative target base station by adopting a competition access mode.

7. The method according to claim 4, 5 or 6, wherein after the serving base station selects the candidate target base station for the mobile terminal, the method further comprises:

the service base station informs the target base station of the identifier of the alternative target base station, and the target base station informs the alternative target base station of processing the switching request after rejecting the switching request;

or,

the service base station informs the target base station of the identifier of the alternative target base station, the target base station informs the alternative target base station to process the switching request after rejecting the switching request, and the target base station also transmits the context information of the mobile terminal, the service quality required by the mobile terminal and/or the identifier of the service base station to the alternative target base station;

or,

and the service base station communicates with the alternative target base station after knowing that the mobile terminal can not be switched to the target base station, so as to switch the mobile terminal to the alternative target base station.

8. The method of claim 4, 5 or 6, further comprising:

calculating the timing deviation between the switched base station and the mobile terminal by the service base station or the target base station or the alternative target base station, and informing the timing deviation to the mobile terminal; alternatively, the timing offset is determined by direct calculation by the mobile terminal.

9. The method of claim 1, 2, 4, 5, or 6, further comprising:

allocating, by the target base station, handover-specific resources to the mobile terminal;

and the target base station transmits the special resource information for switching to the mobile terminal so as to enable the mobile terminal to utilize the special resource for switching to execute switching operation.

10. The method of claim 9, wherein the step of the target base station transmitting the handover-specific resource information to the mobile terminal comprises:

the target base station transmits the special resource information to the service base station, and the service base station transmits the special resource information to the mobile terminal;

or,

and the target base station directly transmits the special resource information for switching to the mobile terminal.

11. A base station, comprising:

a target base station selection unit, which is used for selecting a target base station for the mobile terminal to be switched according to the service quality information and/or the wireless resource information;

and the switching notification unit is used for notifying the mobile terminal to execute switching according to the selection result of the target base station selection unit.

12. The base station of claim 11, further comprising:

a handover dedicated resource allocation unit for allocating a handover dedicated resource to the mobile terminal when serving as a target base station;

a handover dedicated resource notifying unit, configured to transmit handover dedicated resource information corresponding to the handover dedicated resource allocated by the handover dedicated resource allocating unit to the mobile terminal.

13. The base station of claim 11, wherein the target base station selecting unit specifically comprises:

a parameter information acquiring unit, configured to acquire one or more parameter information of a current QoS requirement of the mobile terminal, radio resource information of an adjacent base station, and QoS class information currently supported by the adjacent base station;

and the selection operation unit is used for selecting a target base station for the mobile terminal according to the parameter information acquired by the parameter information acquisition unit.

14. The base station of claim 11, 12 or 13, further comprising:

the alternative target base station selection unit is used for selecting an alternative target base station for the mobile terminal to be switched;

and the switching notification processing unit is used for communicating with the alternative target base station after knowing that the mobile terminal cannot be switched to the target base station, so as to switch the mobile terminal to the alternative target base station.

15. The base station of claim 11, 12 or 13, further comprising:

a timing deviation calculation unit for calculating a timing deviation between the base station and the mobile terminal after the handover;

and a timing deviation notification unit for notifying the timing deviation calculated and determined by the timing deviation calculation unit to the mobile terminal.

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