WO2008011808A1 - A method and an access network for active state access terminal hand-off - Google Patents

Abstract

A method and an access network for active state access terminal hand-off are provided, wherein the method for active state access terminal hand-off among access networks includes the following steps: the current access network receives the message sent by the access terminal, and compares the pilot strength of the sector which has the highest pilot strength in the current access network and the sector which has the highest pilot strength in the neighboring access network, according to the information carried by the message; when the highest pilot strength in the neighboring access network is larger than the highest pilot strength in the current access network for predetermined threshold, the current access network sends a message to the access terminal to release the wireless interface connection in order to switch the access terminal to the idle state and switch to the sector which has the highest pilot strength in the neighboring access network from the idle state. The technical solution can reduce the affect to the performance of transmission due to the hand-off. The similar method can also be adapted to the hand-off of active state access terminal among missed neighboring sectors matching the serving sector.

Description

 Method and access network for switching active access terminal

 The present invention relates to a method and an access network for an active mobile access terminal to switch between access networks or between sectors. Background technique

 CDMA2000 is a new generation of cellular mobile communication systems, including CDMA2000 lx systems for voice services and CDMA2000 lx EV-DO systems for data services only. The CDMA2000 mobile communication system provides voice or data services for the Access Terminal (AT) through a Base Station Controller (BSC) and its Base Transceiver System (BTS). In a CDMA2000 system, a BSC and a Base Transceiver System (BTS) connected to it are collectively referred to as an Access Network (AN), each access network having multiple sectors covering different areas. Provide services for access terminals in different locations.

 When the access terminal moves between different sectors, the CDMA2000 system uses sector switching to ensure that the access terminal always gets the appropriate sector to serve it, so that no dropped calls or data service interruptions occur. When the target sector and the source sector of the handover belong to different access networks (or base station controllers), the handover is called access network handover.

 The CDMA2000 lx system is mainly designed to support voice services, and has high requirements for real-time communication. Therefore, the system protocol defines a soft handover method between different access networks (or base station controllers), so that the handover results in The communication interruption duration is eliminated. If soft handoff is not possible, the system protocol also defines a method of hard handoff between different access networks (or base station controllers), so that the communication interruption time caused by the handover is controlled to a very short range.

The CDMA2000 lx EV-DO system (hereinafter referred to as EV-DO system) is mainly designed to support data services. The real-time requirements for communication are not high, and the main focus is on the average data transmission rate. Therefore, in the CDMA2000 lx EV-DO protocol, only the method of switching between idle access terminals in different access networks is defined. The essence of this handover is: the target access network passes through the access network The A13 interface obtains high-rate packet data (HRPD) session information from the source access network to implement session migration, thereby saving the establishment of a session and configuration negotiation with the access terminal on the target access network side. process.

 To simplify the design, the EV-DO system protocol does not define a method for soft-switching between active access terminals in different access networks. Moreover, the hard handover method is not defined in the EV-DO system protocol, so that the active access terminal cannot perform hard handover between different access networks.

 In the above description, the active state of the access terminal means that the access terminal establishes a wireless interface connection with the access network, and the access terminal can upload or download data through the wireless interface. Correspondingly, the idle state of the access terminal means that the wireless interface connection is not currently established between the access terminal and the access network, but the packet control function (PCF) of the access terminal and the packet data service node (Packet) There is a peer-to-peer protocol (PPP) connection between Data Serving Nodes, PDSNs.

 In the EV-DO system, the triggering method for the idle access terminal to switch between different access networks is: when the idle state access terminal detects that the pilot strength of the sector in the new access network is higher than that of the current service When the strongest sector pilot strength of the access network is higher than a certain threshold, the UATIRequest message is reported through the access channel of the sector in the new access network, and the access network switching of the idle state access terminal is triggered. The threshold described above is determined by the chip of the access terminal.

 An access network switching method for an idle state access terminal in an EV-DO system will be specifically described below with reference to Figs. 1 and 2.

 In Fig. 1, sectors A, B, and C of the access network 10 and sectors D and E of the access network 20 are respectively distributed along the direction of the X-axis of the coordinate axis. It is assumed that an access terminal 30 having an idle state is in a session state with the access network 10 and is moving from sectors A, B, C of the access network 10 to sectors D, E of the access network 20. The access terminal 30 continuously detects the pilot strength of each access sector during the move (step 100).

At this time, the pilot strengths of the sectors D and E of the access network 20 gradually increase with the movement of the access terminal 30, and the pilot strengths of the sectors A, B, and C of the access network 10 gradually decrease. . Moreover, the access terminal 30 determines whether the difference between the pilot strength of the sector of the other access network (including the access network 20) and the pilot strength of the sector of the current access network 10 exceeds the handover determined by the access terminal chip. Difference threshold (step 110).

 When the access terminal 30 reaches the geographic location 1, the difference between the pilot strength of the sector D of the access network 20 and the pilot strength of the strongest sector C of the current access network 10 exceeds the handover difference determined by the access terminal chip. The value threshold, therefore, the access terminal 30 reports the UATIRequest message to the access network 20 via the access channel of the sector D in the access network 20 (step 120).

 Then, after receiving the UATIRequest message reported by the access terminal 30, the access network 20 obtains high-rate packet data (HRPD) session information from the access network 10 through the A13 interface between the access networks, and establishes with the access terminal 30. The session (step 130), thereby realizing the migration of the session between the access networks, that is, the access network switching of the idle state access terminal.

 When the access terminal is in an idle state, if the access terminal has data to upload, or the packet data service node has data to be transmitted to the access terminal, a wireless interface connection is established between the access terminal and the access network to complete the data. Transmission, the access terminal goes from idle to active.

 After the data transmission is completed, the connection release may be initiated by the access terminal, the access network or the packet data serving node, and the access terminal transits from the active state to the idle state.

 However, the EV-DO system protocol does not define a method in which an active access terminal performs soft handover or hard handover between different access networks.

 An existing technical solution for implementing soft handover between access terminals in different access networks is to implement an active access terminal to perform soft connection between different access networks through a customized access network interface message. Switch. However, this is a non-standard interface message and cannot be coordinated between access networks of different vendors, so that the scope of use of this solution is limited.

 Another prior art solution is: an access network switching method based on connection release initiated by an access terminal. In this scheme, when an access terminal moves from a sector of the current access network to a sector of another access network, the pilot signal strength obtained from the current access network sector becomes weaker and weaker until it The data from the current access network sector cannot be received correctly. At this time, the access terminal will actively release the wireless connection, from the active state to the idle state.

When the access terminal is in the idle state, it continuously detects the pilot signals transmitted from the surrounding sectors. in case When the access terminal detects that the pilot strength of the sector in the new access network is higher than the sector pilot strength of the current access network, the access terminal initiates an idle inter-network handover. Switch to the sector of the new access network.

 After the access terminal completes the idle state access network switching, since the data transmission task is not completed, the initiator of the task, the access terminal or the packet data serving node initiates the connection establishment again through the sector of the new access network. After the connection is established, the access terminal changes from the idle state to the active state, thereby finally completing the process of the active access terminal switching between different access networks.

 An access network switching method of an active state access terminal in an EV-DO system according to the prior art will be specifically described below with reference to Figs. 3 and 4.

 In Fig. 3, as in Fig. 1, the sectors, B, C of the access network 10 and the sectors D, E of the access network 20 are distributed along the X-axis of the coordinate axis. It is assumed that an active access terminal 30 is in a data communication state with a packet data serving node (not shown) through the access network 10 and is moving from the sectors A, B, C of the access network 10 to the access network 20 The sectors D, E move. The access terminal 30 continuously detects the pilot strength of each sector during the move (step 200) and determines whether the data can be correctly received (step 210).

 At this time, the pilot strength of the sectors D and E of the access network 20 gradually increases with the movement of the access terminal 30, and the pilot strengths of the sectors A, B, and C of the current access network 10 gradually increase. Weakened.

 For example, when the access terminal 30 reaches the geographic location 2, the pilot strength of the sector D of the access network 20 exceeds the threshold Pilot_Add, and the access terminal 30 notifies the access network 10 by using a route update message (RouteUpdate message). Sector D of access network 20 is added to the active set. However, since there is no access network soft handoff, the access network 10 cannot add the sector D of the access network 20 to the active set. As the pilot strength of the current access network 10 sector A, B, C continues to weaken and the pilot strength of the sector D of the access network 20 continues to increase, the access terminal 30 continues to report the routing update message, attempting Sector D of access network 20 is added to the active set.

For example, when the access terminal 30 reaches the geographic location 3, the sector D with the strongest pilot strength in the access network 20 is stronger than the sector C with the strongest pilot strength in the access network 10, and the strongest pilot strength. The difference between the two exceeds the handover difference threshold determined by the access terminal chip. However, since the active state access terminal is not defined In the inter-network soft handover, the active access terminal 30 cannot switch from the access network 10 to the access network 20.

 When the access terminal 30 reaches the geographic location 4, the pilot strength of the sector C with the strongest pilot strength of the access network 10 is already lower than the pilot join threshold Pilot_Add, and although the connection rate may be decreased, it may still be received. The communication data, therefore, the active access terminal 10 is still communicating with the access network 10 with weak pilot strength, rather than the access network 20 with strong pilot strength.

 Until the access terminal 30 reaches the geographic location 5, the access terminal 30 cannot correctly accept the communication data, thereby actively releasing the wireless connection from the active state to the idle state (step 220).

 Therefore, in the geographical location 5, since the access terminal 30 is in the idle state, and the pilot strength of the sector E with the strongest pilot strength of the access network 20 and the pilot strength of the access network 10 are the strongest, the sector C The difference between the pilot strengths is already greater than the handover difference threshold determined by the access terminal chip, so the idle state access terminal 30 will complete the access inter-network handover (step 230).

 After the idle state access network switching is completed, since the data transmission task is not completed, the initiator of the task, the access terminal 30 or the packet data serving node initiates the connection establishment connection through the sector of the new access network 20, thereby The access terminal 30 transitions from the idle state to the active state (step 240), and finally completes the process of the active state access terminal 30 switching between different access networks.

 The shortcomings of this technology are mainly reflected in the impact on single-user throughput, sector throughput, and timeliness of handover.

First, the impact on single-user throughput is discussed. Consider the following situation: that is, as the access terminal moves from the sector of the current access network to the sector of other access networks, the access terminal is away from the current access network. The center of the sector is already far away, and the center of the sector from the new access network is already very close. Since soft handover cannot be performed between different access networks, the sectors of the new access network cannot be added to the active set of the access terminal, and the active set of the access terminal is the sector of the current access network. Since the pilot strength of these sectors is already weak, the data transmission quality on the wireless link can be kept below a certain packet error rate only at a lower data transmission rate. However, reducing the data transmission rate will not degrade the quality of the data transmission on the wireless link to the extent that the wireless interface connection is released. Thus, the access terminal continues to reside on the current access network at a lower data transmission rate. In this case, the user's data throughput Obviously it was depressed.

 Second, this method affects sector throughput. For sectors at different access network boundaries, the throughput of users across the boundary of the access network is depressed, and the data throughput of the sector is clearly degraded. If the user's distribution is more concentrated on the access network boundary, the extent to which the sector throughput is depressed will be greater.

 Finally, this method will affect the timeliness of the handover. There may be an imbalance in the front-end of the wireless link, so that when the quality of the forward-facing wireless link deteriorates to cause the access terminal to initiate the release of the wireless interface connection, the quality of the reverse wireless link may be deteriorated, resulting in The incoming network cannot correctly receive the message reported by the access terminal. In this way, the release of the wireless interface connection is initiated by the access network only after the release-to-idle state timer set by the access network side expires. In addition to the delay in accessing the inter-network handover caused by the access terminal releasing the radio interface connection, this phenomenon may cause further delays in inter-network handover and further impact on single-user throughput and sector throughput. .

 In addition, CDMA2000 lx and CDMA2000 lx EV-DO dual-mode access terminals can switch between CDMA2000 lx and CDMA2000 lx EV-DO systems when performing data services, that is, switching from the access network of CDMA2000 lx system. To the access network of the CDMA2000 lx EV-DO system, or to the access network of the CDMA2000 lx EV-DO system to the access network of the CDMA2000 lx system. For these two types of switching, there is currently no suitable switching method.

 In addition, in an access network using a CDMA2000 lx EV-DO system or an access network using a CDMA2000 lx system, when an active mobile phone (access terminal) performing a data service performs handover between sectors, the handover generally needs to be Inter-sectoralization is performed with neighbor relationships (adjacent relationships are important network planning and optimization parameters). In the case of missing the neighbor relationship, that is, the difference between the pilot strengths of the adjacent sector and the current serving sector has met the handover requirement, but the neighboring sector is not configured in the neighboring sector list of the access terminal. Time will affect the timeliness of the switch. Summary of the invention

Therefore, an object of the embodiments of the present invention is to provide a method for switching an active access terminal between access networks and an access network, so as to implement an active access terminal to switch between different access networks, After the switch is completed, the connection can still exist, and the data transfer task being executed can still continue, and the impact of the switch on the data transmission performance is reduced as much as possible.

 The technical solution of the embodiment of the present invention may be applicable to the access terminal switching between different access networks of the CDMA lx EV-DO system, or switching from the access network of the CDMA2000 lx system to the access of the CDMA lx EV-DO system. Network, or switch from the access network of the CDMA lx EV-DO system to the access network of the CDMA2000 lx system.

 Another object of the embodiments of the present invention is to provide a method for switching an active access terminal between sectors that missed a neighbor relationship and an access network, and avoiding the mismatch of adjacent sectors for timeliness of handover. influences. The technical solution can be applied to an access network using a CDMA2000 lx EV-DO system or an access network using a CDMA2000 lx system, and an access terminal performing data services switches between sectors in which no adjacent relationship is configured.

 According to the embodiment of the present invention, a method for switching an active access terminal between access networks mainly includes the following steps:

 The current access network receives the message sent by the access terminal, and compares the sector with the strongest pilot strength in the current access network and the sector with the strongest pilot strength in the adjacent access network according to the information carried in the message. Pilot strength; when the strongest pilot strength in the neighboring access network is higher than the strongest pilot strength of the current access network by a predetermined threshold, the current access network sends a message to the access terminal, releasing the radio interface connection. The access terminal is migrated to an idle state, so that the idle state access terminal switches to the sector with the strongest pilot strength in the adjacent access network.

 An access network in the embodiment of the present invention includes:

 a receiving module, configured to receive a message sent by the access terminal and output the message;

 a first determining module, configured to compare pilot strength between a sector with strongest pilot strength in the access network and a sector with strongest pilot strength in a neighboring access network according to information carried by the message And output the comparison result;

a first processing module, configured to send a message to the access terminal when the comparison result is that the strongest pilot strength in the neighboring access network is higher than the strongest pilot strength of the access network by a predetermined threshold , release the wireless interface connection, and make the access terminal migrate to the idle state. In addition, a similar technical solution of the technical solution for switching the active access terminal between the access networks may be applicable to switching the active access terminal between the sectors that are missing the adjacent relationship, so that timely switching can be avoided. Due to the influence of the missed pairing switching of adjacent sectors.

 According to one form of embodiment of the present invention, a method for switching an active state access terminal between sectors that miss a neighbor relationship includes the following steps:

 The current access network receives the message sent by the access terminal, and compares the pilot strength between the neighboring sector with the strongest pilot strength and the current serving sector; the pilot strength in the adjacent sector is greater than the current pilot strength When the pilot strength of the strongest serving sector is higher than a predetermined threshold, and the neighboring sector is the sector of the current serving sector that misses the adjacent relationship, the message is sent to the access terminal, and the wireless interface connection is released. The access terminal is migrated to an idle state to cause the idle state access terminal to switch to the neighboring sector.

 An access network in the embodiment of the present invention includes:

 a receiving module, configured to receive a message sent by the access terminal and output the message;

 a second determining module, configured to compare pilot strength between a neighboring sector and a current serving sector with the strongest pilot strength according to the information carried by the message, and output a comparison result;

 a second processing module, configured to: when the comparison result is that a pilot strength of a neighboring sector is higher than a pilot strength of a serving sector with a strongest pilot strength, and the neighboring sector is current When the serving sector misses the sector of the adjacent relationship, the message is sent to the access terminal, and the wireless interface connection is released, so that the access terminal migrates to the idle state.

 In the technical solution of the embodiment of the present invention, the access network selects an appropriate timing to actively release the wireless interface connection, so as to implement the switching between the access networks, thereby ensuring that the connection can still exist after the handover is completed, and the data transmission task is being executed. Under the condition that it can continue, the impact of switching on data transmission performance indicators such as single-user throughput and sector throughput can be reduced as much as possible. DRAWINGS

 1 is a diagram showing an example of switching an idle state access terminal between access networks according to the definition of the CDMA2000 lx EV-DO protocol;

2 is a flow chart showing the process of implementing an access network switching between an idle state access terminal in the example of FIG. Figure

 3 is a schematic diagram showing an example of switching an active access terminal between access networks according to a prior art method;

 4 is a flow chart showing a process of implementing an access network switching between an active state access terminal in the example of FIG. 3;

 5 is a schematic diagram illustrating an example of switching an active access terminal between access networks according to an embodiment of the present invention;

 6 is a flow chart showing a process of implementing an access network switching between an active state access terminal in the example of FIG. 5;

 7 is a block diagram of an access network in an embodiment of the present invention;

 FIG. 8 is a block diagram of another access network in the embodiment of the present invention. detailed description

 Different from the prior art, the embodiment of the present invention does not wait for the access signal obtained by the access terminal in the current access network sector to become weaker and weaker until it cannot correctly receive the data transmitted by the current access network sector. When the wireless interface connection is actively released to implement the switching between the access networks, the access network selects an appropriate timing to actively release the wireless interface connection to implement the switching between the access networks.

 That is, in the embodiment of the present invention, when the access terminal moves from the current access network sector to other access network sectors, the pilot strength of the new access network sector is gradually increased, and the current access network fan is gradually added. The pilot strength of the zone will gradually weaken, and the pilot strength of the target access network sector will exceed the pilot strength of the current access network sector from a certain geographical area. In the case that the current access network learns the information from the routing update message reported by the access terminal, the pilot strength difference between the new access network sector and the current access network sector may exceed a set threshold. , actively releasing the wireless interface connection, so that the call is timely migrated to the target access network through the idle state switching between the access networks.

 Fig. 5 shows a specific embodiment of the method for switching an active access terminal between access networks according to the present invention. The flowchart of Fig. 6 is specifically described as follows.

In FIG. 5, as in FIG. 1 and FIG. 3, the access network 10 is respectively distributed along the direction of the X-axis of the coordinate axis. Sectors A, B, C and sectors D, E of access network 20. It is assumed that an active access terminal 30 is transmitting data through the access network 10 with a data packet serving node (not shown) and from the sectors A, B, C of the access network 10 to the access network 20. Sectors D, E move. During the mobile process, the access terminal 30 continuously detects the pilot strength of each access sector and reports the detection result to the access network 10 through a route update message (step 300).

 At this time, the pilot strengths of the sectors D and E of the access network 20 gradually increase with the movement of the access terminal 30, and the pilot strengths of the sectors A, B, and C of the access network 10 gradually decrease. .

 For example, when the access terminal 30 reaches the geographic location 2, the pilot strength of the sector D of the access network 20 exceeds the threshold Pilot_Add, and the access terminal 30 notifies the access network 10 of the access network by a routing update message. Sector D of 20 is added to the active set. However, since there is no access network soft handoff, the access network 10 cannot add the sector D of the access network 20 to the active set. As the pilot strength of the current access network 10 sector A, B, C continues to weaken and the pilot strength of the sector D of the access network 20 continues to increase, the access terminal 30 continues to report the routing update message, attempting Sector D of access network 20 is added to the active set.

 In addition, the access network 10 determines whether the pilot strength of the sector with the highest pilot strength of the other access network is higher than a sector with the highest pilot strength by a set threshold (step 310).

 Then, when the geographic location 6 is reached, the sector D with the strongest pilot strength in the access network 20 is stronger than the sector C with the strongest pilot strength in the access network 10, and the difference between the strongest pilot strengths The set threshold Dormant- Threshold is exceeded (the set threshold is not less than the idle state switching threshold determined by the access terminal chip). The access network 10 detects the situation in the routing update message continuously reported by the access terminal 30, and then sends a connection close message to the access terminal 30, releasing the wireless interface connection, and causing the access terminal 30 to migrate to the idle state (step 320). ).

Therefore, in the geographic location 6, since the access terminal 30 is in an idle state, and the pilot strength of the sector D of the access network 20 is the strongest with the pilot strength of the access network 10, the pilot strength of the sector C is strongest. The difference is already greater than the handover difference threshold determined by the access terminal chip, so the access terminal 30 will complete the idle state handover (step 330). Thereafter, the access terminal 30 or the packet data serving node is the same as the case where the access terminal initiated by the access terminal described above with reference to FIG. 3 and FIG. 4 releases the active state access inter-network handover. It is shown that the connection establishment process is initiated actively, so that the access terminal returns to the active state (step 340). Thus, the active state access terminal 30 switches from the access network 10 to the access network 20.

 Setting the Threshold Dormant_ Threshold value in the embodiment of the present invention has an important impact on system performance, and the specific requirements are as follows:

 a. setting the threshold Dormant_ Threshold value equal to or greater than the pilot strength difference threshold that triggers the idle state access network switching determined by the internal chip of the access terminal (eg, mobile phone), so that the access terminal migrates to After the idle state, the idle mode access network switching is triggered, and the connection establishment is not initiated on the current access network.

 b. Under the premise of satisfying condition a, setting the threshold Dormant_Threshold can also be adjusted according to the slow fading and fast fading of the pilot signals at the interface of each access network. The slow fading of the pilot signal reflects the effect of the distance from the base station on the pilot strength, reflecting the effect of the distance from the base station on the data transmission rate. The fast fading of the pilot signal reflects the extent to which the pilot strength fluctuates, reflecting whether it is likely to cause a ping-pong switch. By reasonably adjusting the value of the threshold Dormant-Threshold, on the one hand, it can trigger the access network switching in time to maximize the system performance indicators such as single-user throughput and sector throughput; on the other hand, it can be minimized. Ping-pong switching between access networks reduces the impact of pilot strength fluctuations on system performance. Since the system may include multiple access networks, each access network includes multiple sectors, so the system will include multiple access network interfaces, and each access network interface includes multiple sector boundaries. At the office. The slow fading and fast fading conditions of the pilot signals at the intersection of the various sectors are different, and therefore, different switching thresholds Dormant_Threshold can be set at different sector boundaries at different access network interfaces.

 The technical solution of the embodiment of the present invention can effectively avoid the problems that may occur in the prior art, that is, when there is a sector with better pilot strength in the adjacent access network, the access terminal still stays at the current pilot. In the less powerful sectors, the data transmission rate is kept low, so that the system performance is not fully utilized.

Although the technical solution of the embodiment of the present invention is directed to the problem that the active access terminal switches between different access networks of the CDMA 2000 lx EV-DO system, the embodiment of the present invention passes The technical solution that the network device initiates the connection release to implement the handover is also applicable to the switching between the active mode dual mode access terminal performing the data service between the access networks of the CDMA2000 lx and the CDMA2000 lx EV-DO system, and is also applicable to the use of CDMA2000. In the access network of the lx EV-DO system or the access network using the CDMA2000 lx system, the active access terminal performing the data service performs the inter-sector handover in time when the adjacent relationship is missed.

 First, it illustrates the case where the active state of the CDMA2000 lx and the CDMA2000 Ix EV-DO dual-mode handset (access terminal) are switched between the access networks of the CDMA2000 lx and CDMA2000 lx EV-DO systems. At this point, both the CDMA2000 lx system and the Ix EV-DO system are connected to the same packet data service node. When performing the data service, if the dual-mode mobile phone works in the CDMA2000 lx EV-DO mode, it can simultaneously monitor the pilot signal strength of the CDMA2000 lx system and report it to the access network through the routing update message, which can be implemented by using the present invention. The technical solution of the example realizes the active state switching of the mobile phone from the CDMA2000 Ix EV-DO system to the CDMA2000 lx system.

 That is, when the pilot strength of the sector of the CDMA2000 lx access network exceeds the pilot strength of the sector with the highest pilot strength of the current CDMA2000 lx EV-DO access network, the CDMA2000 lx access network sends a connection. Close the message to the dual mode phone to release the wireless interface. The dual-mode handset can then be switched to the CDMA2000 lx access network.

 If the mobile phone works in the CDMA2000 lx mode, if the dual-mode mobile phone can simultaneously monitor and monitor the pilot signal strength of the CDMA2000 Ix EV-DO system, the technical solution of the embodiment of the present invention can also be utilized. Here, it should be noted that when the mobile phone works in CDMA2000 1x mode, the dual-mode mobile phone will report each sector (including CDMA2000 lx EV- by reporting the pilot strength measurement message (corresponding to the routing update message of the CDMA2000 Ix EV-DO mode). The pilot strength of the sector of the DO access network and the sector of the CDMA2000 lx access network is reported to the CDMA2000 lx access network.

Therefore, when the pilot strength of the sector of the CDMA2000 lx EV-DO access network exceeds the specified threshold of the sector with the highest pilot strength of the current CDMA2000 lx access network, the CDMA2000 lx access network sends a call. Release the message (corresponding to the connection close message in CDMA2000 Ix EV-DO mode) to the dual mode handset to release the wireless interface. Then the dual-mode phone can switch to CDMA2000 lx EV-DO Access Network.

 In addition, in an access network using a CDMA2000 lx EV-DO system or an access network using a CDMA2000 lx system, when an active mobile phone (access terminal) performing a data service performs handover between sectors, the handover generally needs to be Inter-sectoralization is performed with neighbor relationships (adjacent relationships are important network planning and optimization parameters). In the case of missing the adjacent relationship, the timeliness of the handover is affected. According to the method of the embodiment of the present invention, even if the neighbor relationship is missed, the mobile phone can report the signal strength of the pilot of the sector not allocated to the neighboring cell to the access network by monitoring the remaining pilot set. If the sector that misses the adjacent relationship actually has better coverage (the difference between the pilot strength of the sector that misses the neighbor relationship and the pilot strength of the current serving sector exceeds the set handover threshold), the access network The network device can initiate the connection release actively, and the mobile phone can be switched to the idle state, so that the data can be switched to the better covered sector to continue the data service.

 In the above method, the handover threshold must also be greater than or equal to the access terminal idle state handover threshold. Moreover, since the slow fading and fast fading of the pilot signals at the boundary of each sector of the access network are different, different switching thresholds can be set for different sector boundaries in the access network.

 An access network in the embodiment of the present invention, as shown in FIG. 7, includes:

 a receiving module, configured to receive a message sent by the access terminal and output the message;

 a first determining module, configured to compare, according to information carried in the message, a pilot strength between a sector with the strongest pilot strength in the access network and a sector with the strongest pilot strength in the adjacent access network, and output Comparing result; the first processing module is configured to send a message to the access when the comparison result is that the strongest pilot strength in the neighboring access network is higher than the strongest pilot strength of the access network by a predetermined threshold The terminal releases the wireless interface connection, and the access terminal is migrated to the idle state.

 The access network may be an access network using a CDMA2000 lx EV-DO system or an access network using a CDMA2000 lx system.

 Another access network in the embodiment of the present invention, as shown in FIG. 8, includes:

 a receiving module, configured to receive a message sent by the access terminal and output the message;

a second determining module, configured to compare, according to the information carried by the message, a pilot strength between a neighboring sector with the strongest pilot strength and a current serving sector, and output a comparison result; a second processing module, configured to: when the comparison result is that a pilot strength of a neighboring sector is higher than a pilot strength of a serving sector with a strongest pilot strength, and the neighboring sector is currently serving When a sector of a sector is missing a sector of a neighbor relationship, a message is sent to the access terminal, and the wireless interface connection is released, so that the access terminal migrates to an idle state.

 The access network may be an access network using a CDMA2000 lx EV-DO system or an access network using a CDMA2000 lx system.

 In summary, with the technical solution provided by the embodiment of the present invention, the access network selects an appropriate timing to actively release the wireless interface connection, thereby implementing switching between access networks, thereby ensuring that the connection can still exist after the handover is completed. Under the condition that the ongoing data transmission task can continue, the impact of switching on data transmission performance indicators such as single-user throughput and sector throughput can be reduced as much as possible. The spirit and scope of the Ming. Thus, it is intended that the present invention cover the modifications and the modifications of the invention

Claims

Rights request  A method for switching an active access terminal between access networks, characterized in that the method comprises the following steps:  The current access network receives the message sent by the access terminal, and compares the sector with the strongest pilot strength in the current access network and the sector with the strongest pilot strength in the adjacent access network according to the information carried by the message. Pilot strength between  When the strongest pilot strength in the neighboring access network is higher than the strongest pilot strength of the current access network by a predetermined threshold, the current access network sends a message to the access terminal, releasing the wireless interface connection, and making the access terminal The transition to the idle state is such that the access terminal in the idle state switches to the sector with the strongest pilot strength in the neighboring access network.  2. The method according to claim 1, wherein the threshold is greater than or equal to an access terminal idle state switching threshold.  3. The method according to claim 2, wherein the threshold is set according to a slow fading and a fast fading of a pilot signal at a boundary between a neighboring access network and a current access network.  4. The method according to claim 1, wherein the message is a route update message. 5. A method for switching an active access terminal between sectors that missed an adjacent relationship, the method comprising the steps of:  The current access network receives the message sent by the access terminal, and compares the pilot strength between the neighboring sector with the strongest pilot strength and the current serving sector according to the information carried by the message;  When the pilot strength of the adjacent sector is higher than the pilot strength of the serving sector with the strongest current pilot strength by a predetermined threshold, and the neighboring sector is the sector of the current serving sector that misses the adjacent relationship And sending a message to the access terminal, releasing the wireless interface connection, and migrating the access terminal to an idle state, so that the idle state access terminal switches to the adjacent sector.  The method according to claim 5, wherein the threshold is greater than or equal to an access terminal idle state switching threshold. 7. The method according to claim 6, wherein the threshold is set according to a slow fading and a fast fading condition of a pilot signal at a junction between a sector that misses a neighbor relationship and a current serving sector boundary. 8. The method according to claim 5, wherein the message is a route update message. 9. An access network, characterized in that:  a receiving module, configured to receive a message sent by the access terminal and output the message;  a first determining module, configured to compare pilot strength between a sector with strongest pilot strength in the access network and a sector with strongest pilot strength in a neighboring access network according to information carried by the message And output the comparison result;  a first processing module, configured to send a message to the access terminal when the comparison result is that the strongest pilot strength in the neighboring access network is higher than the strongest pilot strength of the access network by a predetermined threshold , release the wireless interface connection, and make the access terminal migrate to the idle state.  10. An access network, characterized in that:  a receiving module, configured to receive a message sent by the access terminal and output the message;  a second determining module, configured to compare pilot strength between a neighboring sector and a current serving sector with the strongest pilot strength according to the information carried by the message, and output a comparison result;  a second processing module, configured to: when the comparison result is that a pilot strength of a neighboring sector is higher than a pilot strength of a serving sector with a strongest pilot strength, and the neighboring sector is current When the serving sector misses the sector of the adjacent relationship, the message is sent to the access terminal, and the wireless interface connection is released, so that the access terminal migrates to the idle state.