WO2006069545A1

WO2006069545A1 - Soft handoff method

Info

Publication number: WO2006069545A1
Application number: PCT/CN2005/002398
Authority: WO
Inventors: Bing Xu; Jiayi Zhang; Sihong Zhou; Xingang Liang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-12-30
Filing date: 2005-12-30
Publication date: 2006-07-06
Also published as: CN100387097C; CN1798440A

Abstract

A method of soft handoff is disclosed. In which, the evolved original cell base station deletes the radio interface protocol stack example established for user terminal of soft handoff, then the radio network gateway establishes radio interface protocol stack example in its own that corresponding to said user terminal. The evolved original cell base station sends the wireless signal received to the radio network gateway, the no-evolved object cell base station establishes radio connection with said user terminal, and transmits the received wireless signal of user terminal to the radio network gateway via radio network controller of its own. The radio network gateway performs combination of macro-diversity to said received wireless signal transmitted from original and object cell base station. By using the method of present invention, it can simplify the flowchart for user terminal handing over from the evolved radio access network to no-evolved radio access network, decrease the occupation of radio transmission resource, and reduce the delay of data transmission in radio access network.

Description

Soft switching method

The present invention relates to a radio access network technology in a communication network, and in particular to a soft handover method. Background of the invention

The currently widely used wireless network is generally composed of a radio access network and a core network. The radio access network usually consists of one or several radio network subsystems (RNS Radio Network Subsystem), and the RNS includes a radio network controller (RNC). ), one or several base stations NodeB. A radio access network system in a wireless network is shown in FIG. 1. FIG. 1 is a diagram of a radio access network system in a wireless network in the prior art.

Among them, R C has established a wireless interface protocol stack, namely Packet Data Convergence Protocol (PDCP) / Broadcast, Multicast Control (BMC) / Radio Link Control (RLC) / Media Access Control (MAC) and other wireless interface protocol stacks. This allows the RC to perform functions such as system broadcast, paging, radio resource control and management, Radio Access Network Application Protocol (RANAP) / Radio Network Subsystem Application Protocol (RNSAP) message forwarding; NodeB does not have the radio interface The protocol stack, that is, the radio interface protocol stack such as PDCP/BMC/RLC/MAC. Therefore, NodeB can perform functions such as spreading, modulation, coding, and exchange of baseband signals and RF signals for wireless signals.

The RC 101 is connected to the CN 100 through an Iu interface, and the RNC 101 is connected to the NodeB 102 and the NodeB 103 through an Iub interface. In this radio access network structure, one NodeB is connected to only one RNC, and there is a control and management-based affiliation relationship between different RNCs and different NodeBs, that is, the NodeB 102 and the NodeB 103 are only connected to the RNC 101, respectively. It is managed by the RNC 101. With the development of wireless communication, people are evolving the radio access network. One of the radio access networks that are being evolved by theoretical research is shown in Figure 2. Figure 2 is another wireless technology in the prior art. A diagram of the radio access network system in the network. The radio access network system includes a wireless network gateway (RG) and a NodeB+. The RG 201 is a functional entity after the RNC 101 in FIG. 1 is evolved, and the NodeB+ 202 and the NodeB+ 203 are functional entities after the NodeB 102 and the NodeB 103 in FIG. 1 are evolved. The "+" in the above NodeB+ represents that the NodeB+ has completed the evolution.

The evolved RG 201 no longer has a radio interface protocol stack such as PDCP/BMC/RLC/MAC, and the RNG 201 can only perform functions such as system broadcast, paging, and RANAP/RNSAP message forwarding, and no longer controls the radio resources. And management operations; relatively speaking, the evolved NodeB+ has a radio interface protocol stack such as PDCP/BMC/RLC/MAC, which enables the NodeB+ to complete the wireless signal spreading, modulation, coding, baseband number and radio frequency signal mutual In addition, it can also complete functions such as control and management of wireless resources.

It can be seen that the evolved NodeB+ has enhanced functions compared to the unevolved NodeB in FIG. 1, and the function of the evolved RNG is weaker than that of the unevolved RNC in FIG. 1, which is mainly for the purpose of making NodeB+ The closest node of the user equipment (UE) can perform operations such as control and management of radio resources as much as possible, thereby reducing the workload of the RNG, thereby effectively reducing the resource occupancy rate and the probability of failure of the RNG.

In Figure 2, RNG 201 is connected to CN 200 via an Iu interface.

In addition, there is a many-to-many connection between NodeB+ and RNG in Figure 2. There is no longer a fixed management and connection relationship between NodeB+ and RNG, that is: Any NodeB+ can be connected to any one or more RNGs. In FIG. 2, NodeB+ 202, NodeB+ 203 and RNG 201 are connected through an Im'/Iu interface; between NodeB+ 202 and NodeB+ 203, there is usually an Iur interface.

In practical applications, there are often UEs moving from the evolved radio access network shown in FIG. 2. In the un-evolved radio access network soft handover shown in FIG. 1, a functional entity in the radio access network also performs a corresponding macro-division and (MDC) operation, and the radio access network involved in the UE soft handover As shown in FIG. 3, FIG. 3 is a network structure diagram of a prior art user equipment during soft handover.

In FIG. 3, RNG 301 and RNC 302 are respectively connected to CN 300 through an Iu interface, R G

301 and RNC 302 are connected through a lur interface; RNG 301 and NodeB+ 303 are connected through a lur/Iu interface, RNC 302 and NodeB 304 are connected through a lub interface; and NodeB+ 303 and NodeB 304 can communicate with UE 305 through a wireless link, respectively.

The UE 305 initially only maintains a wireless connection with the NodeB+ 303, and the NodeB+ 303 transmits the received UE 305 wireless signal to the CN 300 via the RNG 301. After receiving the wireless signal of the UE 305, the CN 300 performs corresponding processing on the signal. For example, the signal is a service request, and the CN 300 allocates corresponding radio resources according to the signal and performs subsequent corresponding operations. At the same time, the UE 305 periodically receives the pilot signals of all the cells it can receive, and transmits a pilot measurement message containing the above pilot signals to the odeB+ 303.

Then, with the movement of the UE 305, when the pilot signal of the NodeB 304 reaches a certain strength in the pilot measurement message sent by the UE 305 to the NodeB+ 303, the NodeB+303 transmits the radio link establishment to the NodeB 304 via the RNG 301 and the RNC 302. request.

The method for the NodeB+ 303 to know whether the pilot signal reaches a certain strength is generally: a pilot signal strength threshold is preset in the NodeB+ 303. If the strength of the pilot signal exceeds the threshold, the NodeB+303 It is considered that the pilot signal reaches a certain intensity; otherwise, the NodeB+303 considers that the pilot signal does not reach a certain intensity.

The NodeB 304 that received the radio link setup request newly assigns a radio channel to the UE 305, and the UE 305 accesses the channel. Thus, the NodeB 304 establishes a wireless link with the UE 305. Thereafter, the NodeB 304 transmits the received radio signal of the UE 305 to the NodeB+ 303 via the RC 302, RG 301. NodeB+ 303 will receive the UE 305 itself The wireless signal is MDC operated with the wireless signal from the UE 305 of the NodeB 304 to increase the wireless signal strength of the UE 305 received by the NodeB+ 303. Next, the NodeB+ 303 transmits the radio signal of the UE 305 that completes the MDC operation to the RNG 301; the RG 301 then transmits the received radio signal of the UE 305 that has completed the merging to the CN 300. After receiving the wireless signal of the UE 305, the CN 300 performs corresponding processing on the signal.

In an actual soft handover application, a base station such as NodeB+ 303 that initially maintains a wireless connection with the UE 305 is generally referred to as a source cell base station, and the radio signal coverage of the base station is referred to as a source cell; and a UE 305 such as the NodeB 304 is used. The newly accessed base station at the time of handover is referred to as a target cell base station, and the wireless signal coverage of the base station is referred to as a target cell.

FIG. 4 is a flow chart of the MDC when the UE is soft-switched in the network structure shown in FIG. 3, and FIG. 4 is a flowchart of the MDC when the user equipment is soft-switched in the prior art. The process includes the following steps: Step 401: The UE periodically A pilot signal of all cells that it can receive is received, and a pilot measurement message including the pilot signal is transmitted to the NodeB+ as the source cell base station. When the pilot signal of a certain NodeB included in the pilot measurement message reaches a certain strength, the NodeB+ uses the NodeB as the target cell, and sends a radio link establishment request to the RNC to which the NodeB belongs via the RG connected to the NodeB. The request includes channel parameters such as a wireless configuration of the wireless channel allocated by the NodeB+ to the UE.

, NodeB+ knows whether the pilot signal reaches a certain strength ^; usually: a pilot signal strength threshold is preset in the NodeB+, and if the strength of the pilot signal exceeds the threshold, the NodeB+ considers the The pilot signal reaches a certain intensity; otherwise, NodeB+ considers that the pilot signal does not reach a certain intensity.

Step 402: Receive an R C of the radio link setup request, and send the request to the NodeB, where the NodeB newly allocates a radio channel to the UE according to a channel parameter such as a radio configuration included in the request;

After NodeB establishes the wireless link and feeds the channel configuration back to NodeB+, NodeB+ Sending an active set update message to the UE, after receiving the message, the UE updates the active set saved by the UE, that is, adds the wireless channel allocated by the NodeB to the UE to the active set, and accesses the NodeB to newly allocate the wireless for the UE. channel.

In this way, the NodeB establishes a wireless link with the UE. Then, the NodeB sends the received UE radio signal to the NodeB+ via the RNC and the RNG to which the NodeB belongs.

Step 403: The NodeB+ performs an MDC operation on the UE radio signal received by itself and the UE radio signal sent from the NodeB, so that the radio signal strength of the UE is improved.

Steps 404 to 405: The NodeB+ sends the UE radio signal of the MDC operation to the R G, and the RNG performs the upper layer protocol processing such as MAC and RLC on the received UE radio signal. The protocol processing of the MAC layer is used for parameter control of the data transmission channel, and the protocol processing of the RLC layer is used for data transmission control of the logical channel.

In the case of the residence, the RNG sends a signal processed by the upper layer protocol such as MAC and RLC to the CN.

After receiving the UE wireless signal, the CN performs corresponding processing on the signal. For example, if the signal is a signal requested by the service, the CN allocates the corresponding resource according to the signal and performs subsequent corresponding operations.

If the above related MDC operation is integrated into the radio access network, as shown in FIG. 5, FIG. 5 is a schematic diagram of the MDC in the prior art radio access network. In FIG. 5, when the UE 505 accesses the NodeB 504, it maintains a wireless connection with the NodeB+ 503 and the NodeB 504, respectively. At this time, the MDC operation is divided into the following steps:

Step a: The NodeB 504 sends the received UE 505 radio signal to the R C 502 to which the ^odeB 504 belongs.

Step b: The RNC 502 sends the received UE 505 radio signal to the RNG 501 connected to the NodeB+ 503.

Step c: The RNG 501 transmits the received UE 505 radio signal sent from the RNC 502 to the NodeB+ 503. Step d: The NodeB+ 503 performs the MDC operation on the UE 504 wireless signal received by itself and the UE 505 wireless signal received from the RG 501, and sends the completed UE 505 wireless signal to the RNG 501.

Step e: The RNG 501 sends the received UE 505 wireless signal that has been merged to the CN 500.

It can be seen from the process illustrated in FIG. 5 that when applying the prior art for soft handover, the MDC operation must be performed by the NodeB+ as the source cell base station, which causes excessive system link transmission resources to be occupied, thereby aggravating the base station as the source cell. The transmission link load between the NodeB+ and the RNG connected to it, and causes the radio access network to generate a data transmission delay; and since the link accounts for a large proportion of the entire network, the transmission link load The increase is a huge investment for operators. SUMMARY OF THE INVENTION In view of this, the main object of the present invention is to provide a soft handover method, which reduces the wireless transmission when the user equipment is soft-switched from the evolved radio access network to the unevolved radio access network. The occupancy rate of resources reduces the data transmission delay in the radio access network.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The invention discloses a soft handover method, which is applied to a network in which a user terminal enters a soft handover from a source cell base station to a target cell, where the network includes at least a wireless network gateway and a radio network controller, and the radio network gateway belongs to the source. The cell base station, the radio network controller belongs to the target cell base station, and the method includes the following steps:

a source cell base station sends a macro diversity set corresponding to the user terminal to the wireless network gateway and uploads the request, and after receiving the uplink request, the wireless network gateway establishes an instance of the wireless interface protocol stack for the user terminal;

b. The source cell base station sends a wireless signal from the user terminal that is received by itself to the a wireless network gateway, the target cell base station transmits the received user terminal wireless signal to the wireless network gateway via the radio network controller to which the target cell belongs;

C. The wireless network gateway performs macro-division of the received wireless signals from the user terminal.

In step a, before the source cell base station sends the macro diversity set and uploads the request, the method further includes:

The source cell base station determines whether the received cell pilot signal included in the pilot measurement message of the user terminal reaches a preset strength threshold. If yes, the cell is used as the target cell, and the macro is sent to the wireless network gateway. Divide and move up requests „

After step a, and before performing step b, the method further includes: a0, the wireless network gateway sends a macro diversity set to the source cell base station and uplinks the response, and the source cell base station deletes or stops after receiving the uplink response. An instance of a wireless interface protocol stack that it has established for the user terminal.

Before the step 1), the method further includes: i establishing a wireless connection between the user terminal and the target cell base station, establishing a first transmission link between the source cell base station and the wireless network gateway; establishing the target cell base station and its a second transmission link between the radio network controllers, the radio network controller and the radio network gateway;

The source cell base station sends a wireless signal to the wireless network gateway by using the first transmission link between the source cell base station and the wireless network gateway in step b; the target cell is wireless to the wireless connection and the second transmission link. The network gateway sends a wireless signal.

A method for establishing a first transmission link between a source cell base station and a wireless network gateway by establishing a wireless connection between the user terminal and the standard cell base station includes:

Al. The wireless network gateway sends a transmission link setup request to the source cell base station, and also sends a radio link setup request to the target cell base station; the source cell base station receives the transmission link establishment After the request, establishing a first transmission link with the wireless network gateway; after receiving the wireless link establishment request, the target cell base station allocates a wireless channel to the user terminal;

A2. After the target cell base station allocates a wireless channel to the user terminal, sends a radio link setup response to the radio network gateway by the radio network controller to which the UE is located; after receiving the response, the radio network gateway receives the response via the source '·) The base station sends an activation set update command to the user terminal. After receiving the activation set update command, the user terminal updates the activated set saved by itself and accesses the wireless channel allocated by the target cell base station to the user terminal.

The step of establishing a second transmission link between the target cell base station and the radio network controller to which it belongs, and between the radio network controller and the radio network gateway includes:

The wireless network gateway sends a link establishment request to the radio network controller to which the target cell base station belongs; after receiving the request, the radio network controller establishes a transmission link between itself and the radio network gateway and the base station of the target cell .

If the soft handover user terminal performs softer handover in the source cell and/or the target cell, the method for the source and target cell base stations to send the user terminal wireless signal to the wireless network gateway is:

The source cell base station softens and combines the wireless signals received by the user terminal from the user terminal, and then transmits the wireless signal of the user terminal that completes the softer combining to the wireless network gateway; and/or the user terminal received by the target cell base station from the user terminal. The wireless signal is soft-combined, and the wireless signal of the user terminal that completes the softer combination is sent to the radio network controller to which it belongs, and the radio network controller sends the radio signal of the user terminal to the wireless network gateway.

If the soft handover user terminal performs softer handover in the source cell and/or the target cell, the method for the source and target cell base station to send the user terminal wireless signal to the wireless network gateway is:

The source cell base station directly transmits the wireless signal received by the user terminal to the user terminal. Line network gateway;

And/or, the target cell base station directly transmits the wireless signal received from the user terminal to the wireless network gateway via the radio network controller to which the target cell belongs.

After completing the macro diversity set, the wireless network gateway further performs upper layer protocol processing on the completed user terminal wireless signal, and then sends the signal to the core network.

In step b, if the pilot signal received by the wireless network gateway is less than the set threshold, the method further includes: - the wireless network gateway sends an activation to the user terminal Set an update request, and the user terminal performs its own activation set update after receiving the request;

The wireless network gateway also sends a link release request to the cell base station; after receiving the front-end request, the cell base station releases the radio resource allocated to the user terminal.

If the cell base station releases the radio resource allocated to the user terminal, the user terminal only maintains a wireless connection with the source cell base station, the method further includes:

The wireless network gateway sends a macro diversity set to the cell base station currently maintaining a wireless connection with the user terminal and moves the request down;

After receiving the request, the cell base station establishes, for the user terminal, an instance of the radio interface protocol stack that processes the subsequent communication operation, and returns a macro diversity set to the wireless network gateway and moves the response downward;

After receiving the macro diversity set and moving the response down, the wireless network gateway deletes the wireless interface protocol stack instance that it has established for the user terminal.

Compared with the prior art, the soft handover method provided by the present invention deletes the evolved source 'J, the base station when the user terminal performs soft handover from the evolved radio access network to the unevolved radio access network. For the wireless interface protocol stack instance established by the soft handover user terminal, the wireless network gateway establishes the wireless interface protocol stack instance corresponding to the user terminal, and the evolved source and area base station sends the received wireless signal to the wireless network gateway. , undemocratic target small The regional base station establishes a wireless connection with the user terminal, and then sends the received wireless signal of the user terminal to the wireless network gateway via the wireless network controller to which it belongs, and the wireless network gateway receives the received source and target from the wireless network gateway. The wireless signal of the cell base station performs macro diversity combining, which simplifies the process of soft handover of the user equipment from the evolved radio access network to the unevolved radio access network, reduces the occupancy rate of the wireless transmission resource, and reduces the occupation rate. Data transmission delay in the radio access network. BRIEF DESCRIPTION OF THE DRAWINGS

1 is a system diagram of a radio access network in a wireless network in the prior art;

2 is a system diagram of a radio access network system in another wireless network in the prior art;

3 is a network structure diagram of a prior art user equipment during soft handover;

4 is a flow chart of an MDC when a user equipment of the prior art is soft-switched;

5 is a schematic diagram of an MDC in a prior art radio access network;

6 is a flowchart of an MDC when a user equipment is soft-switched according to the present invention;

Figure 7 is a schematic diagram of an MDC in a radio access network of the present invention. Mode for carrying out the invention

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

In the soft handover method provided by the present invention, the source cell base station sends a macro diversity set corresponding to the soft handover user terminal to the wireless network gateway and uploads the request, and after receiving the uplink request, the wireless network gateway establishes the soft handover user terminal. An example of a radio interface protocol stack; the source cell base station sends a radio signal from the user terminal that is received by itself to the radio network gateway, and the target cell base station sends the received radio signal of the user terminal to the radio network controller to which the UE belongs. The wireless network gateway; the wireless network gateway performs macro diversity combining on the received wireless signals from the user terminal. ' Further, after the wireless network gateway establishes the wireless interface protocol stack instance, the method may further send a macro diversity set to the source cell base station and uplink the response, and after receiving the uplink response, the source cell base station deletes or stops itself as the user terminal. An established wireless interface protocol stack instance for soft handoff. In this way, if the signal strength of the cell of the NodeB+ is detected to be greater than a certain threshold during the soft handover process, the instance of the radio interface protocol stack may be re-established for the user terminal in the NodeB+, or the user terminal is started. Established wireless interface protocol stack.

The RNG in the radio access network system of the present invention can perform functions such as system wide, paging, and RANAP/RNSAP message forwarding, and can also perform operations such as control and management of radio resources when the UE performs soft handover, so that RNG During the soft handover of the UE, the related MDC operation can still be performed according to the corresponding request.

Referring to FIG. 6, FIG. 6 is a flowchart of an MDC when a user equipment is soft-switched according to the present invention, and the process includes the following steps:

Step 601: The UE periodically receives the pilot signals of all the cells that it can receive, and transmits a pilot measurement message including the pilot signal strength to the NodeB+ that is the source cell base station. When the pilot signal of a certain NodeB included in the pilot measurement message reaches a certain strength, the NodeB+ uses the NodeB as the target cell, and sends an MDC uplink request to the RNG connected to the NodeB+. ;

The method for the NodeB+ to know whether the pilot signal reaches a certain strength is usually: a pilot signal strength threshold is preset in the NodeB+, and if the strength of the pilot signal exceeds the threshold, the NodeB+ considers the pilot. The signal reaches a certain strength; No. ¹ J, NodeB+ considers that the pilot signal does not reach a certain intensity.

The uplink request includes the radio interface protocol stack configuration information about the soft handover of the UE in the NodeB+, such as: a data transmission format, a data transmission rate, a retransmission when the data transmission error occurs, and the like; the uplink request further includes a NodeB+ allocated for the UE. Wireless configuration of the wireless channel Road parameters.

Step 602: After receiving the MDC upload request, the RNG creates a new radio interface protocol stack instance corresponding to the soft handover of the UE according to the configuration information included in the request, to process the radio resource control in the subsequent soft handover process of the UE. , management, etc. After that, the RNG sends an MDC upshift response to NodeB+.

When receiving the MDC uplink request, the RNG also sends a link establishment request to the NodeB+ and the RNC to which the NodeB belongs, requesting the NodeB+ to establish a transmission link to the RNG; and requesting the RC to establish a transmission link with the RNG and the NodeB. And the RNG further sends a radio link setup request including a radio channel parameter allocated by the NodeB+ to the UE to the NodeB via the RNC, and requests the NodeB to establish a radio connection with the UE.

Step 603: After receiving the MDC uplink response, the NodeB+ deletes or stops the wireless interface protocol stack instance that has been established for the UE to perform soft handover, so that the NodeB+ does not process the radio resource control and management during the subsequent soft handover of the UE. :

After receiving the radio link setup request, the NodeB allocates a radio channel to the UE, and returns a radio link setup response to the RNG according to the response. The RNG sends an activation set update to the UE by using the NodeB+ according to the response. After receiving the command, the UE accesses the NodeB to the newly allocated radio channel of the UE, and updates the active set saved by the UE, that is, adds the wireless channel allocated by the NodeB to the UE to the active set.

After receiving the link establishment request from the RNG, the NodeB+ establishes a data transmission link to the RNG via its own Iur interface; the RNC to which the NodeB belongs receives the link establishment request sent from the RNG, and then establishes The data transmission link between itself and the RNG, itself and the NodeB. :

After completing step 603, the NodeB establishes a radio link with the UE, and there is a data transmission link via R C to R G to which it belongs.

Step 604: The NodeB sends the received UE radio signal to the RNC to which it belongs. The RNC then sends the UE radio signal to the RNG.

Similarly, while maintaining a wireless connection with the UE, the NodeB+ also establishes a data transmission link with the RNG through its own Iur interface.

After that, the NodeB+ sends the received UE radio signal to the RNG through its Iur interface.

Step 605: The RNG performs an MDC operation on the received UE radio signals sent from the NodeB+ and the NodeB.

Step 606: The RNG performs upper layer protocol processing such as MAC and RLC on the UE radio signal that completes the MDC operation. After that, the RNG sends a signal for completing the above upper layer protocol processing to the CN.

After receiving the UE wireless signal, the CN performs corresponding processing on the signal. For example, the signal is a service request, and the CN allocates corresponding resources according to the signal and performs subsequent corresponding operations.

In fact, in step 603, before the NodeB+ establishes a data transmission link to the RNG via its own Iur interface, a data transmission link established between the NodeB+ and the RNG via the Iu interface is used to The received UE wireless signal is sent to the RNG.

The reason for the new data transmission link to the RNG via the above-mentioned NodeB+ Iur interface is because the Iu interface and the Iur interface support different application protocols: The Iu interface supports the Radio Access Network Application Part (RANAP) protocol, and the Iur interface Supports the Wireless Network Self Application System Part (RNSAP) protocol. The processing after the RNG receives the UE radio signals supporting different protocols is also different: the RNG forwards the UE radio signal supporting the RANAP protocol received via the Iu interface to the CN; and supports the R SAP protocol received via the Iur interface. The UE wireless signal performs MDC operation.

If the above-mentioned MDC upshift operation is integrated into the radio access network, as shown in FIG. 7, FIG. 7 is a schematic diagram of the MDC in the radio access network of the present invention. Among them, RNG 701 and CN 700 The RNG 701 is connected to the NodeB+ 703 through the Iur/Iu interface, the RNC 702 is connected to the NodeB 704 through the Iub interface, and the RNG 701 and the RC 702 are connected through the Iur interface. The NodeB+ 703 and the NodeB 704 can communicate with the UE 705 through the wireless link. Communication.

In addition to functions such as broadcast, paging, and forwarding of RANAP/R SAP messages, the RNG 701 can also perform operations such as control and management of radio resources during soft handover of the UE 705; relatively speaking, NodeB+ 703, NodeB 704 In addition to the completion of wireless signal spread spectrum, modulation, coding, baseband signal and RF signal exchange, it can also complete the control and management of wireless resources.

As can be seen from FIG. 7, when the UE 705 accesses the NodeB 704, it maintains a wireless connection with the NodeB+ 703 and the NodeB 704, respectively. In addition, since the NodeB+ 703 has deleted the radio interface protocol stack instance that it has established for the UE 705 to correspond to the UE soft handover, the NodeB+ 703 does not process the radio resource control and management during the subsequent soft handover of the UE 705. The R G 701 can process the radio resource control, 'management, etc.' in the subsequent soft handover process of the UE 705 by creating a new radio interface protocol stack corresponding to the soft handover of the UE. first. ,

At this time, the MDC operation when the UE 705 is soft-switched is divided into the following steps:

Step a: The NodeB+ 703 sends the received wireless signal of the UE 705 to the RNG 701 via its own Iur interface; the NodeB 704 sends the wireless signal of the UE 705 received by itself to the RNC 702 to which it belongs.

Step b: 1 >^ 702 sends the received wireless signal of 1^ 705 to 1^0 701.

The RNG 701 performs the received UE radio signals from the NodeB+ 703 and the RNC 702.

MDC operation.

Step c: The RNG 701 sends the UE wireless signal that completes the MDC operation to the CN 700. As can be seen from FIG. 7, the MDC operation in the soft handover of the UE of the present invention can be completed in only three steps, in which case the UE and the NodeB+ as the source cell base station and the target cell The NodeBs of the base stations all maintain a wireless connection. In fact, the target cell base station may be one or more, that is, the UE newly accesses one or more NodeBs during the soft handover process; meanwhile, the UE also periodically receives the information that it can receive. The pilot signals of all the cells, and the pilot measurement message including the above pilot signals are sent to the RNG through the NodeB+.

As the UE moves, it is possible that the pilot signal of a certain NodeB or NodeB+ received by the UE is gradually weakening. When the RNG determines that the pilot signal strength of a certain NodeB or NodfeB+ included in the pilot measurement message is reduced to a certain extent, the RNG sends an activation set update request to the UE, and after receiving the request, the UE responds to its own active set. Update: Delete the cell identifier corresponding to the pilot signal in the active set. At the same time, the RNG also sends a link release message to the NodeB or NodeB+; after receiving the release message, the NodeB or NodeB+ releases the radio resource allocated for the UE.

The method for the RG to determine whether the pilot signal strength is reduced to a certain extent is generally: a resource release threshold is preset in the RNG. If the strength of the pilot signal is lower than the threshold, the RNG considers the The pilot signal is reduced to a certain degree; otherwise, the RNG does not consider the pilot signal to be reduced to a certain extent.

After one or more of the above-mentioned radio resource release operations, the UE may eventually maintain a wireless connection with only one cell base station that can receive the strongest pilot signal, and at this time, the activation set of the UE is only saved corresponding to one cell. The wireless link of the base station. ;

When: the RNG finds that there is only a radio link corresponding to one cell base station in the active set of the UE, and the cell base station corresponding to the radio link is a NodeB+ that has served as the source cell base station, sending an MDC drop request to the NodeB+, The MDC drop request includes configuration information included in the radio interface protocol stack instance established by the RNG for the UE, such as: data transmission format, data transmission rate, and whether retransmission is performed when the data transmission error occurs.

After receiving the MDC drop request, the NodeB+ establishes a corresponding radio interface protocol stack instance for the UE according to the configuration information included in the request, to ensure that the NodeB+ can The subsequent communication operations of the UE are normally processed. At the same time, the cell base station sends an MDC downlink response to the RNG. After receiving the MDC downlink response, the RNG deletes the corresponding wireless interface protocol stack instance that it has established for the UE.

In the soft handover procedure described above, the UE is only connected to the NodeB+, which is the source cell base station, through a radio link. However, when the UE performs a softer handover across sectors in the source cell, it remains connected to the NodeB+ over multiple wireless links. The soft handoff method at this time is somewhat different from the soft handoff method shown in the figure. The difference is: when the NodeB+ establishes a transmission link with the RNG; and the NodeB establishes a radio link with the UE, and after establishing a transmission link with the RG by the RNC to which the UE belongs, the NodeB+ first passes through multiple wireless connections with the UE. The link receives the wireless signals sent from the UE and then softens the wireless signals.

Afterwards, the NodeB+ sends the soft-combined UE radio signal to the RNG; and the NodeB sends the received UE radio signal to the RNG via the RNC to which it belongs; the RNG then completes the softer combined UE radio signal to the received NodeB+ and The UE charging signal sent from the RNC performs MDC operation.

Of course, if the UE performs a softer handover across the sector in the target cell after switching to the target cell, the NodeB serving as the target cell base station maintains a wireless connection with the UE through multiple wireless links. Then, when the NodeB+ establishes a transmission link with the RG; and the NodeB establishes a radio link with the UE, and also establishes a transmission link with the RG through the RNC to which the UE belongs, the NodeB also first passes through multiple wireless chains connected to the UE. The way receives the wireless signals sent from the UE and then softens the wireless signals.

After that, the NodeB+ sends the soft-combined UE radio signal to the RNG; and the NodeB sends the soft-combined UE radio signal to the RNG via the RNC to which the NodeB belongs; the RNG then completes the softer merge of the received NodeB+ and NodeB. The UE wireless signal performs MDC operation. It can be seen from the above that when the UE has the softer handover described above during soft handover, the NodeB+ as the source cell base station and/or the NodeB as the target cell base station may first soften the respective received UE radio signals. Then, the wireless signal of the soft-combined UE is sent to the RNG, and the RG performs the subsequent MDC operation. The specific signaling process is the same as that of the signaling process shown in FIG. 6, and details are not described herein.

In fact, the above-mentioned NodeB+ and/or NodeB may not perform softer combining on the UE wireless signals of multiple wireless links that are received by themselves, but send the UE wireless signals to the RNG separately, and the RNG directly receives them. All the UEs perform the MDC operation on the radio signals. The specific signaling procedure is the same as the signaling procedure described in Figure 6, and is not described here.

It can be seen from the above that the soft handover method provided by the present invention simplifies the process of soft handover of the user equipment from the deducted radio access network to the unevolved radio access network, and reduces the radio transmission resources. The occupancy rate reduces the data transmission delay in the radio access network.

Claims

Claim

A soft handover method, which is applied to a network in which a user terminal performs soft handover from a source cell base station to a target cell, where the network includes at least a wireless network gateway and a radio network controller, and the radio network gateway belongs to a source cell base station. The radio network controller belongs to the target cell base station, and the method includes the following steps:

b. The source cell base station sends a wireless signal from the user terminal that is received by itself to the wireless network gateway, and the target cell base station sends a wireless signal of the user terminal that receives the ί 'J to the wireless network via the wireless network controller to which the target cell base station belongs. Network gateway

C. The wireless network gateway performs macro-division of the received wireless signals from the user terminal. :

The method according to claim 1, wherein in the step a, before the source cell base station sends the macro diversity set and uploads the request, the method further includes:

The source cell base station determines whether the received cell pilot signal included in the pilot measurement message of the user terminal reaches a preset strength threshold. If yes, the cell is used as the target cell, and the macro is sent to the wireless network gateway. Divide and move the request up.

3. The method of claim 1, wherein after step a, and prior to performing step b, the method further comprises:

A0. The wireless network gateway sends a macro diversity set to the source cell base station and uplinks the response. After receiving the uplink response, the source cell base station deletes or stops the wireless interface protocol stack instance that it has established for the user terminal.

4. The method according to claim 1, wherein before step b, the party The law further includes:

Establishing a wireless connection between the user terminal and the target cell base station, establishing a first transmission link between the source cell base station and the wireless network gateway; establishing a wireless network control between the target cell base station and a radio network controller to which the target cell is established a second transmission link between the device and the wireless network gateway;

The method according to claim 4, wherein in step a, establishing a wireless connection between the user terminal and the target cell base station, and establishing a first transmission link between the source cell base station and the wireless network gateway Includes:

Al. The wireless network gateway sends a transmission link setup request to the source cell base station, and further sends a radio link setup request to the target cell base station; and after the source cell base station receives the transmission link setup request, establishes with the radio network gateway. a first transmission link between the target cell; after receiving the radio link setup request, the target cell base station allocates a wireless channel to the user terminal;

A2. After the target cell base station allocates a wireless channel to the user terminal, sends a radio link setup response to the radio network gateway by the radio network controller to which the UE is located; after receiving the response, the radio network gateway sends the radio base station to the user. The terminal sends an activation set update command. After receiving the activation set update command, the user terminal updates the activated set saved by itself and accesses the wireless channel allocated by the target cell base station to the user terminal.

The method according to claim 4, wherein in step a, establishing a second between the target cell base station and a radio network controller to which it belongs, and between the radio network controller and the radio network gateway The steps of the transmission link include:

The wireless network gateway sends a link establishment request to the radio network controller to which the target cell base station belongs; after receiving the request, the radio network controller establishes itself and the wireless network gateway to And a transmission link between itself and the base station of the target cell.

The method according to claim 1, wherein in step b, if the soft handover user terminal performs softer handover in the source cell and/or the target cell, the source and target cell base stations are to the wireless network gateway. The method of transmitting the wireless signal of the user terminal is:

The source cell base station performs softer combining of the wireless signals received by the user terminal from the user terminal, and then sends the wireless signal of the user terminal that completes the softer combination to the wireless network gateway;

And/or the target cell base station performs softer combining of the no-signal received from the user terminal, and then transmits the wireless signal of the user terminal that completes the softer combination to the radio network controller to which it belongs, and the radio network controller will The user terminal wireless signal is sent to the wireless network gateway.

The method according to claim 1, wherein in step b, if the soft handover user terminal performs softer handover in the source cell and/or the target cell, the source and target cell base stations are to the wireless The method for the network gateway to send the wireless signal of the user terminal is:

The source cell base station directly sends the wireless signal received by the user terminal from the user terminal to the wireless network gateway;

9. The method according to claim 1, wherein in step c, the wireless network gateway completes the macro diversity set, and further performs upper layer protocol processing on the completed user terminal radio signal, and then sends the signal to the core network. .

The method according to any one of claims 1 to 7, wherein, in step b, if the pilot signal of the cell included in the pilot measurement message received by the wireless network gateway is lower than the set gate In the case of limits, the method further comprises:

The wireless network gateway sends an activation set update request to the user terminal, and the user terminal performs its own activation set update after receiving the request; The wireless network gateway also sends a link release request to the cell base station; after receiving the release request, the cell base station releases the radio resource allocated for the user terminal.

The method according to claim 10, wherein, if the cell base station releases the radio resource allocated to the user terminal, the user terminal only maintains a wireless connection with the source cell base station, the method further includes:

Transmitting, by the wireless network gateway, a macro diversity set and a down request to a cell base station currently maintaining a wireless connection with the user terminal;