CN102111832A - Hard-switching method, communication system and base stations - Google Patents

Abstract

The present invention provides a hard handover method, communication system and base station. The method includes: the serving base station sends the medium access control layer version of the terminal to the target base station to be hard handover; the target base station receives the terminal's medium access control layer version. After the MAC layer version of the terminal is compared with the MAC layer version of the target base station, if the MAC layer version of the target base station is smaller than the MAC layer version of the terminal, the Return switch failure message. The present invention enables the target base station to feed back a handover failure message when finding that the MAC Version of the target base station is smaller than the MAC Version of the MS during hard handover, and does not perform resource pre-establishment to avoid resource occupation.

Description

A hard handover method, communication system and base station

technical field

The invention relates to the communication field, in particular to a hard handover method, a communication system and a base station.

Background technique

The mobile WIMAX (Worldwide Interoperability for Microwave Access) system supports MS (mobile terminal) mobile communication. When the MS moves under two adjacent BSs (base stations), handover will occur. For hard handover, it is necessary to negotiate the MAC Version (media access control layer version) capability between the Target BS (target base station) and the MS.

According to the 802.16e protocol description, there are three relationships between the MAC Version of the BS and the MAC Version of the MS:

1. When the MAC Version of the BS is equal to the MAC Version of the MS, the MS can access the BS and maintain the corresponding functions.

2. When the MAC Version of the BS is greater than that of the MS, the MS can access the BS, but the capability of the BS will be reduced.

3. When the MAC Version of the BS is smaller than the MAC Version of the MS, the MS cannot access the BS because the minimum capabilities of the BS cannot meet the requirements of the MS.

It can be seen from the above that during the handover, if the MAC Version of the Target BS is smaller than the MAC Version of the MS, even if the handover preparations are completed, the MS cannot switch access on the Target BS, which will occupy a lot of resources in this case.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for hard handover, a communication system, and a base station, so that the target base station will feed back a handover failure message when it is found that the MAC Version of the target base station is smaller than the MAC Version of the MS during hard handover, and does not Then pre-establish any resources for this terminal to avoid resource occupation.

In order to solve the above technical problems, the present invention provides a method for hard handover, including:

The serving base station sends the medium access control layer version of the terminal to the target base station to be hard handed over;

After receiving the MAC layer version of the terminal, the target base station compares the MAC layer version of the terminal with the MAC layer version of the target base station, if the MAC layer version of the target base station is smaller than the MAC layer version of the terminal If the version of the access control layer is not used, a handover failure message is returned to the serving base station.

Further, the above method has the following characteristics: the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically:

The serving base station sends a first message to the target base station to be subjected to hard handover, where the first message carries the medium access control layer version of the terminal.

Further, the above method has the following characteristics: the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically:

The serving base station sends a second message to the target base station to perform hard handover when waiting for the handover instruction message sent by the terminal for more than a predetermined time, the second message carrying the medium access control layer version of the terminal.

Further, the above method has the following characteristics: the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically:

After receiving the terminal information acquisition message sent by the target base station, the serving base station sends the MAC layer context information of the terminal to the target base station, and the MAC layer context information carries the MAC layer version of the terminal.

Further, the above method has the following characteristics: the target base station sends the MAC layer version of the terminal to the target base station of the next hard handover during the next hard handover process.

The present invention also provides a communication system, including multiple base stations and terminals, wherein:

The serving base station is used to send the medium access control layer version of the terminal to the target base station to be hard handed over;

The target base station is configured to compare the MAC layer version of the terminal with the MAC layer version of the target base station after receiving the MAC layer version of the terminal, and if the MAC layer version of the target base station is less than The medium access control layer version of the terminal returns a handover failure message to the serving base station.

Further, the above-mentioned communication system has the following characteristics:

The serving base station is specifically configured to send a first message to a target base station to be subjected to hard handover, where the first message carries a medium access control layer version of the terminal.

Further, the above-mentioned communication system has the following characteristics:

The serving base station is specifically configured to send a second message to the target base station to perform hard handover when waiting for the terminal to send a handover instruction message for more than a predetermined time, the second message carrying the medium access control layer version of the terminal.

Further, the above-mentioned communication system has the following characteristics:

The serving base station is specifically configured to send the medium access control layer context information of the terminal to the target base station after receiving the terminal information acquisition message sent by the target base station, the medium access control layer context information carrying the medium access control layer context information of the terminal Enter the version of the control layer.

Further, the above-mentioned communication system has the following characteristics:

The target base station is further configured to send the MAC layer version of the terminal to the target base station of the next hard handover during the next hard handover.

The present invention also provides a base station, which is used to compare the MAC layer version of the terminal with its own MAC layer version after receiving the MAC layer version of the terminal issued by the currently serving base station, If its own MAC layer version is smaller than that of the terminal, it returns a handover failure message to the current serving base station.

To sum up, a hard handover method, communication system and base station provided by the present invention can make the target base station find that the MAC Version of the target base station is smaller than the MAC Version of the MS during hard handover, and feed back a handover failure message without resource allocation. Pre-establishment to avoid resource occupation; and enable the target base station to maintain the ability to be compatible with the MAC Version of the MS during hard handover, and to pass the MAC Version of the MS to the target base station in the next handover process to ensure the target Base station supports MS.

Description of drawings

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present invention;

Fig. 2 is a flowchart of a hard handover method according to an embodiment of the present invention.

Detailed ways

In order to reduce resource occupation, the serving base station (Serving BS) provided by the present invention carries the MAC Version field of the MS in the handover request message (for example, R6_HO-REQ message) sent to the target base station (Target BS), so that the target The base station negotiates the capabilities of the two in the handover preparation stage. If the capability of the target base station is insufficient, it will no longer pre-establish any resources for this terminal, and directly reply a handover failure message (HO-RSP message) to avoid unnecessary resource occupation. Similarly, in an uncontrolled handover, and when the target base station receives a handover confirmation message whose type is Unconfirm, the target base station also needs to negotiate the capabilities of the two.

The preferred embodiments of the technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of a communication system according to an embodiment of the present invention. As shown in Fig. 1, the communication system according to this embodiment includes: a plurality of base stations and terminals. Other base stations at the current location are called target base stations.

Wherein, the serving base station is used to send the MAC Version of the terminal to the target base station to be subjected to hard handover. Specifically, after receiving the handover request message sent by the terminal, the serving base station may carry the MAC Version of the MS in the handover request message sent to the target base station; it may be that the MAC Version of at least one target base station is greater than or equal to the MS's In the case of MAC Version, if the serving base station has not received the handover request message sent by the terminal within the predetermined time, the serving base station will automatically send a handover confirmation message (non-confirmation type) to all neighboring cell base stations, and the handover confirmation message will carry The MAC Version of the MS; it can also be that in the handover process where resources are not established for the terminal to switch to the target base station, the terminal sends a ranging request message to the determined target base station, and the target base station receives the ranging request message sent by the terminal , sending a request message for acquiring terminal information to the serving base station, and the serving base station sends the MAC Context information of the terminal to the target base station after receiving the request message, and the MAC Context information carries the MAC Version of the MS.

The target base station is used to compare the MAC Version of the terminal with the MAC Version of the target base station after receiving the MAC Version of the terminal. If the MAC Version of the target base station is smaller than the MAC Version of the terminal, no resources will be pre-established for this terminal. And return a handover failure message to the serving base station. This reduces resource usage

Fig. 2 is the flowchart of the method for the hard handover of the embodiment of the present invention, as shown in Fig. 2, the method of the present embodiment comprises the following steps:

S101. The serving base station sends the MAC Version of the MS to the target base station to be subjected to hard handover.

S102. After receiving the medium access control layer version of the terminal, the target base station compares the MAC Version of the MS with the MAC Version of the target base station. If the MAC Version of the target base station is greater than or equal to the MAC Version of the MS, then execute step S103; if the target If the MAC Version of the base station is smaller than the MAC Version of the MS, step S104 is performed.

S103. The target base station returns a handover success message to the serving base station.

S104, the target base station returns a handover failure message to the serving base station, and does not pre-establish any resources for the terminal, which can reduce resource occupation.

The hard handover method of the present invention will be described in detail below with three specific embodiments.

Example 1

In the corresponding message sent by the serving base station to the target base station, a new TLV (TYPELEN VALUE, type, length, value) is added to carry the MAC Version of the MS, and the MACVersion of the MS is transferred from the serving base station to the target base station, and then the target base station Compare the MAC Version with its own MAC Version. If the MAC Version of the target base station is greater than or equal to the MAC Version of the MS, the target base station is allowed to do the handover preparation work, otherwise the serving base station does not do the handover preparation work, and directly replies with the handover failure message (HO -RSP) to the serving base station, and the serving base station notifies the MS that the target base station cannot be the target of the final handover reentry. The detailed process is as follows:

Step 1: The serving base station receives a handover request (MOB_MSHO-REQ) message sent by the MS.

Step 2: The serving base station sends a handover request message (HO-REQ) to multiple target base stations, carrying the MAC Version of the MS, for example carrying a new TLV (see Table 1 and Table 2 for the definition of the new TLV).

Table 1 newly added field defines the MAC Version of the MS

type TBD Length inoctets 1 value MAC Version ofMS：Version number of IEEE 802.16supported on this channel.1：Indicates conformance with IEEE Std 802.16-20012：Indicates conformance with IEEE Std 802.16c-2002and its predecessors3：Indicates conformance with IEEE Std 802.16a-2003andits predecessors4：Indicates conformance with IEEE Std 802.16-20045：Indicates conformance with IEEE Std 802.16-2004andIEEE Std 802.16e-20056：Indicates conformance with IEEE Std 802.16-2004，IEEE Std 802.16e-2005and IEEE Std 802.16f-20057：Indicates conformance with IEEE Std 802.16- 2004, IEEE Std 802.16e-2005, IEEE Std 802.16f-2005 and IEEE Std 802.16g-20078-255: Reserved Description The MAC Version of the terminal. See 802.16e protocol [148] Parent TLV MS Info

The attributes appearing in Table 1 are: Type (type), Length (length), Value (value),

Description (Description), Parent TLV (Paternal TLV).

Table 2 The position of the newly added field in MS INFO TLV

The attributes appearing in Table 2 are: Type (type), Length (length), Value (value), Description (description), Elements (element), Message Primitives That Use ThisTLV (use this TLV message scope).

Step 3: Each target base station compares the MAC Version of the MS with its own MAC Version. If the MAC Version of the target base station is greater than or equal to the MAC Version of the terminal, the target base station is allowed to do the handover preparation work, and perform steps 4 to 7; if If the MACVersion of the target base station is smaller than the MAC Version of the terminal, go to step 8.

Step 4: The target base station obtains the Context (context) from the Auth ASN GW (Authentication Gateway Server), this step is optional.

Step 5: The Data Path (data path) of the target base station is pre-established, and the data channel between the target base station and the core network is pre-established. This step is optional.

Step 6: The target base station replies a successful handover response message (HO-RSP) to the serving base station, indicating that resource pre-establishment of the target base station is completed.

Step 7: The serving base station replies with a handover success message (MOB BSHO-RSP message) to the MS.

Step 8: The target base station does not do the handover preparation work, and directly replies the failed handover response message (for example, HO-RSP) to the serving base station, and the serving base station notifies the MS that the target base station cannot be used as the target of the final handover reentry, so as to avoid unnecessary resource usage.

Example 2

In this example, as long as the MAC Version of a target base station is greater than or equal to the MAC Version of the terminal in Example 1, that is, as long as the terminal receives the handover success message sent by the serving base station, the MS sends a handover indication message (MOB_HO- IND), if the serving base station does not receive the handover instruction message (MOB_HO-IND) sent by the MS, it will send a handover confirmation message (type: non-confirmation type) (HO_Cnf(UN Confirm)) to the neighboring cell base station after the timer expires ), this message also needs to carry the MAC Version of the MS, and the neighboring cell base station saves this parameter, and transmits the MAC Version of the MS to the target base station of the next handover in the next handover. The detailed process is as follows:

Step 10: In Embodiment 1, the MAC Vesion of at least one target base station is greater than or equal to the MAC Vesion of the terminal, and when the terminal receives a successful handover response message (MOB_HO-RSP), the MS sends a handover instruction to the serving base station message (MOB_HO-IND), but the serving base station has not actually received it, or the terminal has not sent a handover indication message (MOB_HO-IND) to the serving base station.

Step 11: The serving base station has never received the handover instruction message MOB_HO-IND sent by the terminal, and sends a handover confirmation message HO_Cnf (Unconfirm) to all its neighboring BSs when waiting for MOB_HO-IND to exceed the predetermined time;

The handover confirmation message carries the MAC Version of the MS, that is, the new field TLV (see Table 1 and Table 2 for the definition of the new field TLV). All neighboring base stations save this TLV. When the terminal switches to the next target base station, it also needs to transfer the MAC Version of the terminal to the target base station for the next handover.

Step 12: All neighboring base stations use the MAC Version of the MS to compare with their own MACVersion,

If the MAC Version of the neighboring cell base station is greater than or equal to the MAC Version of the terminal, then allow the neighboring cell base station to do handover preparation work, and perform steps 13-24;

If the MAC Version of the neighboring cell base station is smaller than the MAC Version of the terminal, the neighboring cell base station does not perform handover preparation work, which can save the resources of the neighboring cell base station.

Step 13: All neighboring cell base stations reply an ACK message (HO_ACK) to the serving base station.

Step 14: The neighboring cell base station obtains the Context (context) from the Auth ASN GW (Authentication Gateway Server), this step is optional.

Step 15: Pre-establish data paths for all neighboring cell base stations that have not pre-established resources.

Step 16: The MS sends a ranging request message (RNG-REQ) (purpose=1, carrying Serving BSID (identification of the serving base station)) to one of the neighboring cell base stations.

Since the adjacent cell base station has pre-established resources for the terminal, the adjacent cell base station can accept the terminal to re-enter the network after receiving the ranging request message, and there is no need to establish resources for it, so as to speed up the handover.

Step 17: The MS re-enters the network on one of the neighboring base stations.

Step 18: The neighboring cell base station and the source gateway server (Anchor ASN GW) that accept the terminal re-entry perform the data path establishment process.

Step 19: The base station in the neighboring cell that accepts the re-entry of the terminal sends a handover completion message (HO_Complete) to the serving base station, notifying the serving base station that the terminal has completed re-entry into the network.

Step 20: The serving base station replies an ACK message (HO_ACK) to the neighboring cell base station that accepts the re-entry of the terminal.

Step 21: The serving base station releases the data path.

Step 22: The serving base station sends a handover confirmation message (type: cancel) (HO_Cnf(cancel)) to other unselected neighboring base stations, notifying the unselected neighboring base stations to release established resources.

Step 23: The unselected neighboring cell base station replies HO_ACK to the serving base station, and the serving base station releases itself.

Example 3:

In the uncontrolled handover process in which resources are not established for the terminal to switch to the target base station, it is necessary to pass the MSContext Rpt (terminal context) message to the terminal when obtaining the MAC Context (media access control layer context) of the terminal. The MAC Version is passed to the target base station. The detailed process is as follows:

Step 30: The MS sends a ranging request message (RNG-REQ) (purpose=1, carrying Serving BSID (identification of the serving base station)) to a selected target base station.

Step 31: The target base station obtains the MAC Context of the terminal from the serving base station;

After receiving the RNG-REQ message sent by the terminal, the target base station sends a request message to the serving base station to obtain the MAC Context of the terminal,

After the serving base station receives the request message of the target base station, it sends the MAC Context information of the terminal to the target base station through the MSContextRpt message, and carries a new TLV in the MSContextRpt message (see Table 1 and Table 2 for the definition of the new TLV), and uses the new TLV to Define the MAC Version of the terminal. The Target BS saves this TLV, and transfers the TLV to the next TargetBS during the next switchover.

Step 32: The target base station compares the MAC Version of the MS with its own MAC Version,

If the MAC Version of the target base station is greater than or equal to the MAC Version of the terminal, the Target BS is allowed to do the handover preparation work, and perform steps 33 to 40;

If the MAC Version of the target base station is smaller than the MAC Version of the terminal, the target base station does not continue the handover process to reduce the resource occupation of the target base station. At the same time, an interrupt message (RNG-RSP(abord)) is returned to the MS to inform the MS that the handover and reentry failure on this target base station has failed, and the MS is asked to select another target base station to continue the handover and reentry.

Step 33: The target base station obtains the Context from the Auth ASN GW (Authentication Gateway Server).

Step 34: MS re-enters the network on the target base station:

Step 35: The target base station and the source gateway server (Anchor ASN GW) perform a data path establishment process.

Step 36: The target base station sends a handover completion message (HO_Complete) to the serving base station, notifying the serving base station that the MS has completed re-entry into the network.

Step 37: The serving base station replies a handover response message (HO_ACK) to the target base station.

Step 38: The serving base station releases the data path.

Step 39: The serving base station sends a handover confirmation message (type: cancel) (HO_Cnf(cancel)) to other unselected BSs, notifying the unselected BSs to release the established resources.

Step 40: The unselected BS replies HO_ACK to the serving base station, and the serving base station releases itself.

From the above implementation method, by carrying the TLV of the MAC Version of the MS from the serving base station to the target base station, the target base station performs capability negotiation based on this TLV and its own MAC Version. If the current handover is supported, this handover is allowed, otherwise, it is rejected. switching times.

The method provided by the present invention is widely applicable to communication systems requiring hard handover, and is especially suitable for R4 scenarios, R6 scenarios and R8 scenarios.

Of course, the present invention can also have other various embodiments, and those skilled in the art can make various corresponding changes and deformations according to the present invention without departing from the spirit and essence of the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (11)

1. A method of hard switching, comprising: The serving base station sends the medium access control layer version of the terminal to the target base station to be hard handed over; After receiving the MAC layer version of the terminal, the target base station compares the MAC layer version of the terminal with the MAC layer version of the target base station, if the MAC layer version of the target base station is smaller than the MAC layer version of the terminal If the version of the access control layer is not used, a handover failure message is returned to the serving base station. 2. The method according to claim 1, wherein the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically: The serving base station sends a first message to the target base station to be subjected to hard handover, where the first message carries the medium access control layer version of the terminal. 3. The method according to claim 1, wherein the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically: The serving base station sends a second message to the target base station to perform hard handover when waiting for the handover instruction message sent by the terminal for more than a predetermined time, the second message carrying the medium access control layer version of the terminal. 4. The method according to claim 1, wherein the serving base station sends the medium access control layer version of the terminal to the target base station to be subjected to hard handover, specifically: After receiving the terminal information acquisition message sent by the target base station, the serving base station sends the MAC layer context information of the terminal to the target base station, and the MAC layer context information carries the MAC layer version of the terminal. 5. The method according to any one of claims 1-4, characterized in that: The target base station sends the MAC layer version of the terminal to the target base station of the next hard handover during the next hard handover process. 6. A communication system comprising a plurality of base stations and terminals, characterized in that: The serving base station is used to send the medium access control layer version of the terminal to the target base station to be hard handed over; The target base station is configured to compare the MAC layer version of the terminal with the MAC layer version of the target base station after receiving the MAC layer version of the terminal, and if the MAC layer version of the target base station is less than The medium access control layer version of the terminal returns a handover failure message to the serving base station. 7. The communication system of claim 6, wherein: The serving base station is specifically configured to send a first message to a target base station to be subjected to hard handover, where the first message carries a medium access control layer version of the terminal. 8. The communication system of claim 6, wherein: The serving base station is specifically configured to send a second message to the target base station to perform hard handover when waiting for the terminal to send a handover indication message for more than a predetermined time, the second message carrying the medium access control layer version of the terminal. 9. The communication system of claim 6, wherein: The serving base station is specifically configured to send the medium access control layer context information of the terminal to the target base station after receiving the terminal information acquisition message sent by the target base station, and the medium access control layer context information carries the medium access control layer context information of the terminal Enter the version of the control layer. 10. The communication system according to any one of claims 6-9, characterized in that, The target base station is further configured to send the MAC layer version of the terminal to the target base station of the next hard handover during the next hard handover. 11. A base station, characterized in that, It is used to compare the MAC layer version of the terminal with its own MAC layer version after receiving the MAC layer version of the terminal issued by the currently serving base station, if its own MAC layer version If the version is smaller than the MAC layer version of the terminal, a handover failure message is returned to the currently serving serving base station.

Images