WO2009039757A1

WO2009039757A1 - Method and apparatus for implementing a hard handover in boundary area

Info

Publication number: WO2009039757A1
Application number: PCT/CN2008/072305
Authority: WO
Inventors: Haofeng Qi; Yayong Chen; Yaobing Wang; Yunjuan Xie
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-20
Filing date: 2008-09-09
Publication date: 2009-04-02
Also published as: CN101232713B; CN101232713A

Abstract

A method and apparatus for implementing a hard handover in boundary area are provided, and the method includes: when a mobile terminal which is on a basic frequency of the border cell of the first BSC (Base Station Controller) is moving from coverage area of the basic frequency of the border cell of the first BSC towards the coverage area of basic frequency of the border cell of the second BSC, determining whether a first predetermined handover condition is satisfied, if the first predetermined handover condition is satisfied, then performing an inter-frequency hard handover and handing over the mobile terminal to an interim frequency provided by the first BSC which is different from the basic frequency of the first BSC. Another method for implementing a hard handover in boundary area and a BSC capable of implementing a hard handover in boundary area are also disclosed. The present invention employs the wide coverage characteristic of the interim frequency and avoids the phenomenon of ping-pong hard handover that easily occurs in intra-frequency hard handover area.

Description

Method and device for realizing hard switching of boundary area The present application claims to be submitted to the Chinese Patent Office on September 20, 2007, and the application number is 200710151929.4, and the invention title is "a method and device for realizing hard switching of boundary areas". Priority of the application, the entire contents of which are incorporated herein by reference. Technical field

The present invention relates to the field of mobile communication technologies, and in particular, to a method and apparatus for implementing hard handover of a border area. Background technique

Soft handoff is generally possible between two intra-frequency cells within the base station controller (BSC). The A3/A7 interface between the BSCs ensures that the intra-frequency neighbors between different BSCs can be soft-switched. However, it is difficult to connect A3/A7 interfaces between BSCs of different manufacturers. Currently, there is no successful case of A3/A7 interconnection between different vendors. At present, cell switching between BSCs of different manufacturers generally adopts the same frequency hard switching mode. Hard Handoff (HHO) refers to the way in which the connection to the old traffic channel is disconnected before establishing a connection with the new service channel. For example, there is no A3/A7 interface between BSC1 and BSC2. Then, the same-frequency cell that is switched from the cell of the BSC1 to the BSC2 cannot implement the soft handover. In this case, it can be configured to perform the same-frequency hard handover, and cut the pilot of the target BSC2 in a hard handover manner.

In the process of relocation of equipment from different vendors or after the relocation is completed, the scene of BSC coexistence of different vendors as shown in Figure 1 will appear. Because the signal strengths of the two parties are basically the same in the boundary area of the heterogeneous device, the same frequency pilots that are not added to the soft handover active set are interfered with before the same frequency hard handover, and the pilot of the current serving cell is interference; after the same frequency hard handover The original serving cell is excluded from the active set, and its signal is also interfered with the current carrier frequency. Therefore, it is easy to cause a ping-pong hard handoff at the boundary.

The inventor found in the creation process of the present invention that the existing co-frequency hard switching technology requires very careful planning of hard switching boundaries, setting relevant trigger parameters, and after careful testing, can minimize the switching process. The ping-pong switching that is prone to occur, the switching success rate is also unstable. If it is a relocation scenario, it needs to be provided by the relocating party. This solution is difficult to meet the border area Requirements for hard switching: Set up a single order, which can be quickly optimized or not optimized, requiring less cooperation from the other party.

Summary of the invention

The embodiment of the invention provides a method and a device for implementing hard handover in a border area, which can reduce ping-pong switching which is relatively easy to occur in a hard handover process of a border cell of a heterogeneous vendor BSC.

The method for implementing hard handover of a boundary area includes:

When the mobile terminal on the basic carrier frequency of the boundary cell of the first base station controller BSC moves from the boundary cell basic carrier frequency coverage area of the first BSC to the boundary cell basic carrier frequency coverage area of the second BSC, it is determined whether the advance is satisfied. Setting a first switching condition, if yes, performing an inter-frequency hard handover, switching the mobile terminal to a transition carrier frequency that is different from a basic carrier frequency provided by the first BSC, and the coverage of the transition carrier frequency is at least greater than The coverage of the basic carrier frequency of the first BSC boundary cell.

Another embodiment of the present invention further discloses a method for implementing hard handover of a border area, where the method includes: when a mobile terminal on a basic carrier frequency of a second BSC border cell moves from a basic carrier frequency coverage area of a second BSC boundary cell When the basic carrier frequency coverage area of the first BSC boundary cell moves, it is determined whether the preset second handover condition is met, and if yes, the inter-frequency hard handover is performed, and the mobile terminal is switched to the frequency and basic provided by the first BSC. The transition carrier frequency of the carrier carrier is different, and the coverage of the transition carrier frequency is at least greater than the coverage of the basic carrier frequency of the first BSC boundary cell.

Correspondingly, the present invention also discloses a base station controller (BSC) capable of realizing hard handover of a border area, and includes the following modules:

a transition carrier frequency module, configured to set a transition carrier frequency different from a basic carrier frequency, and the coverage of the transition carrier frequency is greater than a coverage of the basic carrier frequency;

The hard handover module is configured to determine whether the mobile terminal in the basic carrier coverage area of the BSC meets a handover condition for switching to a transition carrier frequency, and if yes, to switch the mobile terminal to the transition carrier frequency.

It can be seen from the above technical solution that the transition carrier frequency provided by the first BSC is configured as a hard handover target of the first BSC basic carrier frequency or the second BSC basic carrier frequency, and the transition carrier frequency is completely free of co-channel interference, and the pilot strength is used. The good feature can reduce the ping-pong switching that is more likely to occur during the hard handover process of the border cell of the hetero-vendor BSC. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in the claims Other drawings may also be obtained from these drawings without the use of creative labor.

Figure 1 is a schematic diagram of the boundary formed between BSCs of different manufacturers;

2 is a schematic diagram of a transition carrier and a basic carrier coverage according to an embodiment of the present invention;

3 is a schematic diagram of a handover of a mobile terminal from a BSC1 coverage area to a BSC2 coverage area according to an embodiment of the present invention;

4 is a schematic diagram of a handover of a mobile terminal from a coverage area of a BSC2 to a coverage area of a BSC1 according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an algorithm for implementing handover of a mobile terminal from a transition carrier frequency to a basic carrier frequency according to an embodiment of the present invention; FIG.

6 is a schematic diagram of an algorithm implementation of a load control hard handover of a mobile terminal from a basic carrier frequency of a BSC1 to a transition carrier frequency according to an embodiment of the invention;

7 is a schematic diagram of an algorithm implementation of a load control hard handover of a mobile terminal from a basic carrier frequency of a BSC2 to a transition carrier frequency according to an embodiment of the invention;

8 is a schematic diagram of an algorithm implementation of load control hard handover of a mobile terminal from a transition carrier frequency to a basic carrier frequency of a BSC according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an algorithm for performing load control hard handover from a transition carrier frequency to a basic carrier frequency of a BSC1 according to an embodiment of the present invention; FIG.

FIG. 10 is a schematic structural diagram of a BSC1 for implementing hard handover according to an embodiment of the present invention. detailed description

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

The embodiment of the present invention is directed to the boundary of the currently incompatible BSC (mainly the A3/A7 interface between the BSCs cannot be docked) (transient boundary, or the steady state boundary under the permission of the resource), and the switching success rate is low, which is difficult. It is necessary to cooperate with many problems, and a transition carrier frequency solution with high switching success rate, easy implementation of the single-sheet, and less cooperation between the two parties is given. In this program, just The primary party provides a wide enough transition carrier frequency in the BSC boundary area of both parties, and uses the transition carrier frequency to achieve hard handover between incompatible BSCs. Incompatible BSCs are usually BSCs produced by different vendors.

2 is a schematic diagram of a transition carrier frequency scheme in accordance with an embodiment of the present invention, wherein a rectangle represents a coverage area of a carrier frequency. The A3/A7 interface between BSC1 and BSC2 cannot be connected. The mobile terminal needs to perform the same frequency hard handover when moving between the two BSCs. BSC1 has the basic carrier frequency of the cell: carrier frequency F1 and carrier frequency F2; BSC2 also has the basic carrier frequency of the cell: carrier frequency F1 and carrier frequency F2. BSC1 also provides another transition carrier frequency F3. The frequency of the carrier frequency is different from the frequency of the existing basic carrier frequency and will not be interfered by the basic carrier frequencies of BSC1 and BSC2, so it can be in the boundary area between BSC1 and BSC2. Cover a transition strip that is wide enough. For the hard handover procedure of the embodiment of the present invention, BSC1 is called a dominant BSC; BSC2 is an existing BSC, which is called a cooperative BSC.

The resident strategy of the mobile terminal idle state is as follows:

(1) The mobile terminal in the idle state can adopt the prior art resident strategy in the cell of the BSC2.

(2) When the mobile terminal is in the boundary area covered by BSC1, the basic carrier frequencies F1 and F2 are camped through the hash (HASH) mode or any other idle state, and do not reside in the transition carrier frequency F3.

(3) The cells in the border area of the two parties can complete the idle state handover by mutually configuring the other party as an idle neighboring area.

The access policy of the mobile terminal is as follows:

(1) The mobile terminal can adopt the prior art access strategy in the cell of the BSC2 and the non-boundary cell of the BSC1;

(2) The mobile terminal in the BSC1 border cell only allows it to access on the basic carrier frequency, does not allow it to access on the transition carrier frequency, and is not allowed to be assigned to the transition carrier frequency.

The service state switching strategy of the mobile terminal in the border area includes the following aspects:

(1) The service state of the mobile terminal when moving from the border cell of BSC1 to the border cell of BSC2, as shown in Figure 3:

When the mobile terminal moves from the border cell of the BSC1 to the border cell of the BSC2, the pseudo-pilot hard handover, the Handdown hard handover, the inter-frequency neighbor search hard handover, and the direct hard handover may be used to switch to F3. Due to the good pilot strength of F3 and wide coverage, the success rate must be very high. For example, the handover process of pseudo pilot hard handover is implemented as follows:

The BSC2 boundary cell base carrier is configured in the system as an external pseudo pilot of BSC1, and the pseudo pilot target is configured as a transition carrier frequency. Configuring a single-side neighboring area of the basic carrier frequency and pseudo-pilot of the BSC1 boundary cell System, the pseudo pilot hard switch of the basic carrier frequency of the BSCl boundary cell is turned on and the corresponding hard handover parameter is configured. When the mobile terminal moves to the boundary area of the BSC, the strength of the basic carrier frequency F1 (F2) will decrease, while the strength of the transition carrier frequency F3 is still very good. When the strength of Fl (F2) is poor, the intensity of the pseudo pilot is better. When it is good, the mobile terminal is switched to the target carrier frequency F3 pre-configured in the database.

Since the coverage of F3 is large enough, even if the mobile terminal enters the coverage area of BSC2, the call can be completed at F3 for most calls, and no call will be dropped.

If the user moves to a very large range, whether to switch to the cell under BSC2, you can use any of the following solutions according to the situation:

1) According to the user's mobility statistics, only a very small number of users will have a large range of movements in the call state, and most users have a relatively small mobile range, so they can choose to let the mobile terminal stay at the transition carrier frequency F3. . If the terminal moves beyond the coverage boundary of F3, it can be dropped. Because of this, there is very little, so it is a solution that is easy to implement and has a small impact on call drop rate.

2) For a very small number of users with a particularly large mobile range, if the coverage boundary of F3 is exceeded, let the terminal use the hard handover mode of RTD combined with Eclo decision or the hard handover mode of inter-frequency neighbor search to hardly switch to the basic load of BSC2. Compared with the existing intra-frequency hard switching, the success rate of this switching mode is greatly improved and relatively stable.

(2) The service state switching when the mobile terminal moves from the border cell of BSC2 to the border cell of BSC1, as shown in Fig. 4:

When the mobile terminal moves from the border cell of the BSC2 to the border cell of the BSC1, it is only necessary to configure the same-frequency hard handover relationship between the basic carrier frequency of the BSC2 boundary cell and the basic carrier frequency of the boundary cell of the BSC1, and trigger the basic carrier frequency to the BSC1 boundary cell. After the hard handover, the BSC1 receives the handover request from the BSC2 to the basic carrier hard handover of the border cell, and instructs the mobile terminal to switch to the transition carrier frequency F3 of the BSC1. Since F3 has good pilot strength and wide coverage, this handover success rate is high and ping-pong switching does not occur.

Certainly, when the mobile terminal moves from the border cell of the BSC2 to the border cell of the BSC1, the inter-frequency hard handover triggered by the RTD and the pilot strength or the inter-frequency neighbor search may be used to switch to the boundary carrier F3 of the boundary cell configuration of the BSC1. .

When the mobile terminal further moves to the basic carrier coverage area of the BSC1, the intra-cell inter-frequency hard handover (Handdown) or the inter-frequency neighbor search hard handover triggered by the loop delay (RTD) combined with the pilot strength (Eclo) may be employed. To the basic carrier frequency of BSC1, ensure that the transition carrier frequency F3 does not carry too much traffic. If the load on the transition carrier frequency is not high and the user mobility is not too large, it may be considered not to the basic carrier. Do the switching.

In order to ensure the wide coverage characteristics of the F3 carrier, the load on F3 must be controlled. First, F3 only acts as a handover carrier to bear the handover traffic, and the mobile terminal is not allowed to access on the carrier frequency F3.

In addition, an algorithm can be used to control the switching behavior of the mobile terminal, and reduce traffic on the transition carrier frequency. At least one of the following methods is included:

1) Using the load control algorithm of the transition carrier frequency, the mobile terminal with small mobility on the transition carrier frequency and in the area with better basic carrier coverage is switched to the basic carrier frequency as soon as possible;

2) Using the hard handover hysteresis algorithm in the basic carrier frequency, after switching from the transition carrier to the base carrier, the delay timer is started, and the transition to the transition carrier frequency is not triggered even if the handover condition is met before the delay timer expires. This can reduce the chance of switching to the transition carrier frequency F3 and avoid overloading the F3.

3) For mobile phones with high mobility, the load-control algorithm of the transition carrier frequency is used to switch to the basic carrier frequency of the BSC2 in the edge region covered by F3, the switching success rate is high, and the transition carrier load can be reduced.

4) The user on the transition carrier frequency F3 can also switch to the basic carrier frequency through other switching methods, such as inter-frequency neighbor search hard switching or other hard switching modes;

The load control hard handoff algorithm for implementing the transition carrier frequency mentioned above is described below.

The algorithm related parameters are shown in Table 1:

Description of algorithm related parameters:

RTD_NEAR: The RTD threshold that triggers a hard handoff at a near point;

RTD_FAR: RTD threshold that triggers hard handover from a far point;

The above two thresholds are related to the coverage of the carrier frequency. Generally, the RTD_NEAR is smaller than the RTD_FAR. If the current RTD of the mobile terminal is less than or equal to the RTD_NEAR, the terminal is located in the area closer to the base station; if the current RTD of the mobile terminal is greater than or equal to the RTD_FAR, The terminal is located in the area i or far from the base station.

EcIo_NEAR: The Eclo threshold that triggers a hard handoff at a near point;

EcIo_FAR: Eclo threshold that triggers hard handoff from a far point; The above two thresholds are related to the signal strength of the carrier frequency. Generally, EcIo_NEAR is greater than EcIo_FAR. If the current Eclo of the mobile terminal is greater than or equal to EcIo_NEAR, it indicates that the signal of the mobile terminal is strong; if the current Eclo of the mobile terminal is less than or equal to EcIo_FAR , indicating that the signal in the area where the mobile terminal is located is weak.

RTD: current loop delay of the mobile terminal;

Eclo: The current pilot strength of the mobile terminal.

Algorithm trigger condition:

(RTD>=RTD—FAR && EcIo<= EcIo_FAR )11 (RTD<=RTD_NEAR && EcIo>=EcIo_NEAR ), the text is expressed as satisfying any of the following conditions:

If the actual RTD is greater than or equal to RTD_FAR and the actual Eclo is less than or equal to EcIo_FAR, the source carrier frequency (transition carrier frequency) is switched to the target carrier frequency (the basic carrier frequency of the BSC2);

If the actual RTD is less than or equal to RTD_NEAR and the actual Eclo is greater than or equal to EcIo_NEAR, the source carrier frequency (transition carrier frequency) is switched to the target carrier frequency (basic carrier frequency of BSC1).

In practical applications, it is also possible to switch only according to the threshold value of the RTD, or only according to the threshold value of the Eclo, and only need to set another threshold of the above algorithm to an inoperative extreme value.

The trigger diagram of the transition carrier frequency load control algorithm is shown in Figure 5. The mobile terminal resides on the transition carrier frequency provided by BSC1, and the pilot strength of the transition carrier frequency gradually decreases in the direction of the cell coverage area away from BSC1. It is assumed that the mobile terminal moves from the area covered by the BSC1 cell to the cell coverage area of BSC2 to point B, and the point B is located at the critical point of RTD=RTD_FAR and Eclo=EcIo_FAR, so the mobile terminal moves to point B and then according to the above trigger condition 1 The transition carrier frequency is hard switched to the basic carrier frequency of the BSC2. In practical applications, the critical point of RTD=RTD_FAR and the critical point of EcIo=EcIo_FAR may not coincide. Similarly, the mobile terminal moves from the far point of the transition carrier frequency to the near-point region of the transition carrier frequency, and the point A is RTD=RTD_NEAR And the critical point of EcIo=EcIo_NEAR, so after the mobile terminal moves to point A, it will hardly switch from the transition carrier frequency to the basic carrier frequency of BSC1 according to the above trigger condition 2.

In the transition carrier frequency solution of the embodiment of the present invention, for the transition carrier frequency, the mobile terminal on the transition carrier frequency can be switched to the basic carrier frequency in time by the above algorithm, thereby effectively alleviating the load on the transition carrier frequency. For the basic carrier frequency, the parameters for the basic carrier frequency can also be flexibly set according to the above algorithm, so that the mobile terminal on the basic carrier frequency can switch to the transition carrier frequency in time to avoid the same frequency switching.

The parameters set for the basic carrier frequency include:

1. Switching from the basic carrier frequency of the BSC1 boundary cell to the transition carrier frequency: As shown in FIG. 6, the basic carrier frequency switching configuration of the BSC1 is: the above-mentioned load control hard handover algorithm is started in the boundary cell of the BSC1, and RTD_NEAR=0, EcIo_NEAR=0, RTD_FAR and EcIo_FAR are set according to actual conditions to ensure the movement of the BSC1 boundary cell. When the terminal moves to the cell coverage area of the BSC 2 to the loop delay RTD is greater than or equal to the RTD_FAR and/or the pilot strength Eclo is less than or equal to EcIo_FAR, the mobile terminal switches to the transition carrier frequency.

2. Switching from the basic carrier frequency of the BSC2 boundary cell to the transition carrier frequency

As shown in Figure 7, the BSC2 basic carrier frequency switching configuration: the above-mentioned load control hard handover algorithm is enabled in the boundary cell of the BSC2, and RTD_NEAR=0, EcIo_NEAR=0, RTD_FAR and EcIo_FAR are set according to actual conditions to ensure the movement of the BSC2 boundary cell. When the terminal moves to the cell coverage area of the BSC1 until the actual loop delay RTD is greater than or equal to RTD_FAR and/or the actual pilot strength Eclo is less than or equal to EcIo_FAR, the mobile terminal switches to the transition carrier frequency.

3. Switching from the transition carrier frequency to the basic carrier frequency

As shown in FIG. 8, the load control hard handover algorithm is started at the transition carrier frequency, and the handover target and handover parameters of the transition carrier frequency are configured, and when the mobile terminal on the transition carrier frequency moves to the boundary cell of the BSC2, the transition to the transition carrier is performed. When the frequency covers the edge region, the system instructs the mobile terminal to switch to the basic carrier frequency of the BSC2 cell by determining that the actual loop delay RTD is greater than or equal to RTD_FAR and/or the actual pilot strength Eclo is less than or equal to EcIo_FAR.

As shown in FIG. 9, when the mobile terminal on the transition carrier frequency moves to the BSC1 coverage cell, when moving to the BSC1 basic carrier frequency coverage,

The system determines that the actual loop delay RTD that satisfies the transition carrier frequency is less than or equal to RTD_NEAR and/or the actual pilot strength Eclo is greater than or equal to EcIo_NEAR, indicating that the mobile terminal switches to the basic carrier frequency of BSC1.

The parameter configuration of the transition carrier frequency should satisfy the following relationship:

RTD—NEAR <RTD_FAR

EcIo_NEAR > EcIo_FAR

RTD_NEAR (Transition Carrier Frequency) < RTD_FAR (Basic Carrier Frequency)

EcIo_NEAR (transition carrier frequency) > EcIo_FAR (basic carrier frequency)

Switching from the transition carrier frequency to the basic carrier frequency The above-mentioned load control hard handover algorithm is only a feasible hard handover scheme when it is necessary to reduce the transient carrier frequency load, and is not the only hard handover scheme. For example, a hard handover of an inter-frequency neighbor search may also be used when switching from a transition carrier frequency to a basic carrier frequency of the BSC2. The transition from the basic carrier frequency of the BSC1 to the BSC1 carrier frequency switching using the above-mentioned load control hard handover algorithm is only an alternative, for example, pseudo pilot hard handover, hard handover of different frequency neighbor search, direct Hard switching, etc.

The transition from the basic carrier frequency of the BSC2 to the BSC1 carrier frequency switching using the above-mentioned load control hard handover algorithm is only an alternative. For example, the most simple solution is to directly configure the basic carrier frequency between BSC2 and BSC1. In the frequency hard handover relationship, when BSC2 initiates a hard handover to the basic carrier frequency of BSC1, BSC1 directs it to switch to the transition carrier of BSC1. In addition, pseudo-pilot hard handover, hard handover of inter-frequency neighbor search, and direct hard handover are optional hard handover algorithms.

The embodiment of the present invention utilizes the characteristics that the transition carrier frequency has no co-channel interference, the pilot strength is good, and the coverage is wide, and the ping-pong switching which is relatively easy to occur in the hard-switching process of the border cell of the different vendor BSC is reduced, and the device can be set. Quick optimization or no optimization is required, and the other party needs to cooperate less.

As shown in FIG. 10, the BSC1 for implementing the solution of the embodiment of the present invention includes the following modules: a transition carrier module 1010, configured to set a transition carrier frequency different from a basic carrier frequency, and the transition carrier frequency The coverage is greater than the coverage of the basic carrier frequency;

The hard handover module 1020 is configured to determine whether the mobile terminal in the basic carrier coverage area of the BSC1 meets a handover condition for switching to the transition carrier frequency, and if yes, the mobile terminal is switched to the transition carrier module 1010. Transition carrier frequency; or determining whether the mobile terminal at the transition carrier frequency satisfies a condition for switching to a basic carrier frequency of the BSC1, and if so, switching the mobile terminal to a basic carrier frequency; or determining the transition Whether the mobile terminal of the carrier frequency satisfies the condition of switching to the basic carrier frequency of the adjacent BSC, and if so, instructs the mobile terminal to switch to the basic carrier frequency of the adjacent BSC.

The hard switching module 1020 includes:

a first switching unit 1021, configured to set an RTD_FAR and/or an EcIo_FAR of a basic carrier frequency of the BSC1, and determine whether an actual loop delay of the mobile terminal on the BSC basic carrier frequency is greater than or equal to the RTD_FAR, and/or Whether the actual pilot strength of the mobile terminal is less than or equal to the EcIo_FAR, and if yes, instructing the mobile terminal to perform an inter-frequency hard handover to the transition carrier frequency.

The second switching unit 1022 is configured to set the RTD_NEAR and/or EcIo_NEAR of the transition carrier frequency, and determine whether the actual loop delay of the mobile terminal on the transition carrier frequency is less than or equal to RTD_NEAR, and/or determine the transition carrier frequency. Whether the actual pilot strength of the mobile terminal is greater than or equal to EcIo_NEAR, if yes, instructing the mobile terminal to perform inter-frequency hard handover, switching to the basic carrier frequency of the BSC1; and the second switching unit further setting the RTD_FAR of the transition carrier frequency and / or EcIo_FAR, and judge Whether the actual loop delay of the mobile terminal on the transition carrier frequency is greater than or equal to RTD_FAR, and/or determining whether the actual pilot strength of the mobile terminal on the transition carrier frequency is less than or equal to EcIo_FAR, and if yes, indicating the mobile terminal Performing an inter-frequency hard handover, switching to the basic carrier frequency of the adjacent BSC 2 of the BSC1.

The transition carrier module 1010 further includes:

The transition carrier frequency information sending unit 1011 is configured to: when the neighboring vendor BSC2 initiates a hard handover to the BSC1, the BSC1 allocates resources on the transition carrier frequency, and feeds back the transition carrier frequency as the target carrier frequency through the handover request response message. Describe the manufacturer BSC. In this way, the heterogeneous BSC can preferentially switch the mobile terminal to the transition carrier frequency.

It should be noted that the adjacent BSC2 of the BSC1 also has the same structure and function as the BSC1, and can implement the handover of the mobile terminal in the BSC2 to the adjacent BSC of the BSC2.

The solution of the embodiment of the present invention requires less cooperation from different vendors, and most of the configurations are completed in the single-side BSC device: The other party only needs to configure the same-frequency hard-switching relationship with the same single-chip, and there is no other matching requirement. With the transition carrier frequency, there is no co-channel interference at all, and the pilot strength is good. Only the other side BSC supports the hardest single hard handover algorithm, which can improve the hard handover success rate of the BSC boundary. By utilizing the characteristics of the wide coverage of the transition carrier frequency and combining the user mobility characteristics, the probability of the hard handover of the dominant BSC to the BSC direction is reduced, thereby improving the success rate of the hard handover. Combining the above characteristics, the solution of the present invention utilizes the wide coverage characteristic of the transition carrier frequency, and reduces the situation that the conventional intra-frequency hard handover region is prone to ping-pong hard handover, and the handover success rate is unstable.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary hardware platform, and of course, can also be implemented entirely by hardware. Based on such understanding, all or part of the technical solution of the present invention contributing to the background art may be embodied in the form of a software product, which may be stored in a storage medium such as a ROM/RAM, a magnetic disk, an optical disk, or the like. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention or portions of the embodiments.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

Rights request

A method for implementing hard handover in a border area, comprising: the following steps: when a mobile terminal on a basic carrier frequency of a boundary cell of a first base station controller BSC covers a basic carrier frequency from a boundary cell of a first BSC When the area moves to the basic carrier frequency coverage area of the boundary cell of the second BSC, it is determined whether the preset first handover condition is met, and if yes, the inter-frequency hard handover is performed, and the mobile terminal is switched to the frequency provided by the first BSC. The transition carrier frequency is different from the basic carrier frequency, and the coverage of the transition carrier frequency is at least greater than the coverage of the basic carrier frequency of the first BSC boundary cell.

2. The method for implementing hard handover of a border area according to claim 1, wherein the inter-frequency hard handover comprises: using load control hard handover, or pseudo pilot hard handover, or hard handover of inter-frequency neighbor search. , or direct hard switching to achieve different frequency hard switching.

The method for implementing hard handover of a boundary area according to claim 1, wherein the loop delay remote handover threshold RTD_FAR1 of the basic carrier frequency of the first BSC and/or the basic carrier frequency of the first BSC are set. The frequency strength remotely switches the threshold EcIo_FAR1, and the determining whether the first switching condition is set in advance includes at least one of the following steps:

Determining whether the actual loop delay of the mobile terminal on the first BSC basic carrier frequency is greater than or equal to the RTD_FAR1, and if yes, satisfying the preset first handover condition;

Determining whether the actual pilot strength of the mobile terminal on the first BSC basic carrier frequency is less than or equal to the EcIo_FAR1, and if so, satisfying the preset first handover condition.

The method for implementing hard handover of a boundary region according to claim 3, wherein: setting a loop delay remote handover threshold RTD_FAR2 of the transition carrier frequency and/or a pilot strength remote handover threshold EcIo_FAR2 of the transition carrier frequency, After the mobile terminal switches to the transition carrier frequency provided by the first BSC, the method further includes: determining whether at least one of the following conditions is met:

The actual loop delay of the mobile terminal is greater than or equal to RTD_FAR2;

The actual pilot strength of the mobile terminal is less than or equal to EcIo_FAR2;

If yes, the mobile terminal performs an inter-frequency hard handover to the cell base carrier frequency of the second BSC.

The method for implementing hard handover of a boundary region according to claim 3, wherein a loop delay near-point handover threshold RTD_NEAR of the transition carrier frequency and/or a pilot strength near-point handover threshold EcIo_NEAR of the transition carrier frequency are set, After the mobile terminal switches to the transition carrier frequency provided by the first BSC, the method further includes: determining whether at least one of the following conditions is met:

The actual loop delay of the mobile terminal is less than or equal to RTD_NEAR;

The actual pilot strength of the mobile terminal is greater than or equal to EcIo_NEAR;

If so, intra-cell inter-frequency hard handoff is performed to switch the mobile terminal to the cell base carrier frequency of the first BSC.

The method for implementing the hard handover of the border area according to claim 1 or 2, wherein after the hard handover in the cell of the mobile terminal, the method further includes:

The delay timer is started, and the inter-frequency hard switching is prohibited until the delay timer expires.

7. A method for implementing hard handover of a border area, the method comprising:

When the mobile terminal on the basic carrier frequency of the second BSC border cell moves from the basic carrier frequency coverage area of the second BSC boundary cell to the basic carrier frequency coverage area of the first BSC boundary cell, the second BSC is configured according to the second The same-frequency hard handover relationship between the BSC and the basic carrier frequency of the first BSC triggers a hard handover to the basic carrier frequency of the boundary cell of the first BSC;

After receiving the handover request of the second BSC to the basic carrier hard handover of the border cell, the first BSC instructs the mobile terminal to switch to a transition carrier frequency that is different from the basic carrier frequency provided by the first BSC, and the transition carrier The coverage of the frequency is at least greater than the coverage of the basic carrier frequency of the first BSC boundary cell.

8. A method for implementing hard handover of a border area, the method comprising:

When the mobile terminal on the basic carrier frequency of the second BSC border cell moves from the basic carrier frequency coverage area of the second BSC boundary cell to the basic carrier frequency coverage area of the first BSC boundary cell, it is determined whether the preset number is satisfied. a handover condition, if yes, performing an inter-frequency hard handover, switching the mobile terminal to a transition carrier frequency that is different from a basic carrier frequency provided by the first BSC, and the coverage of the transition carrier frequency is at least greater than the first BSC The coverage of the basic carrier frequency of the boundary cell.

9. The method for implementing hard handover of a boundary area according to claim 8, wherein the difference is The frequency hard handover includes: load control hard handover, or pseudo pilot hard handover, or hard handover of inter-frequency neighbor search, or direct hard handover.

The method for implementing hard handover of a border area according to claim 8, wherein the performing an inter-frequency hard handover, switching the mobile terminal from a basic carrier frequency of a second BSC boundary cell to a first BSC The transition carrier frequency includes:

The mobile terminal receives the handover indication of the transition carrier frequency of the first BSC delivered by the second BSC, and performs the inter-frequency hard handover with the transition carrier frequency as the target carrier frequency.

The method for implementing hard handover of a boundary region according to claim 10, wherein a loop delay remote handover threshold RTD_FAR2 of the second BSC basic carrier frequency and/or a pilot of the second BSC basic carrier frequency are preset The strength remote point switching threshold EcIo_FAR2, the determining whether the second switching condition that is set in advance is included at least one of the following:

Determining whether the actual loop delay of the mobile terminal on the second BSC basic carrier frequency is greater than or equal to the RTD_FAR2, and if yes, satisfying a preset second handover condition;

Determining whether the actual pilot strength of the mobile terminal on the second BSC basic carrier frequency is less than or equal to the EcIo_FAR2, and if so, satisfying the preset second handover condition.

12. The method for implementing hard handover of a boundary region according to claim 11, wherein: setting a loop delay remote handover threshold RTD_FAR1 of the transition carrier frequency and/or a pilot strength remote handover threshold EcIo_FAR1 of the transition carrier frequency, After the mobile terminal switches to the transition carrier frequency provided by the first BSC, the method further includes: determining whether at least one of the following conditions is met:

The actual loop delay of the mobile terminal is greater than or equal to RTD_FAR1;

The actual pilot strength of the mobile terminal is less than or equal to EcIo_FARl;

If so, the mobile terminal performs an inter-frequency hard handover to the cell base carrier frequency of the second BSC.

13. The method for implementing hard handover of a boundary region according to claim 11, wherein: setting a loop delay near-point handover threshold RTD_NEAR of the transition carrier frequency and/or a pilot strength near-point handover threshold EcIo_NEAR of the transition carrier frequency, After the mobile terminal switches to the transition carrier frequency provided by the first BSC, the method further includes: determining whether at least one of the following conditions is met: The actual loop delay of the mobile terminal is less than or equal to RTD_NEAR;

If yes, the intra-cell inter-frequency hard handover is performed, and the mobile terminal is switched to the cell basic carrier frequency of the first BSC.

The method for implementing hard handover of a border area according to claim 12 or 13, wherein after the hard handover of the mobile terminal, the method further includes:

A base station controller capable of hard switching a boundary area, comprising: a transition carrier frequency module, configured to set a transition carrier frequency different from a basic carrier frequency, and the coverage of the transition carrier frequency Greater than the coverage of the basic carrier frequency;

The hard handover module is configured to determine whether the mobile terminal in the basic carrier frequency coverage area of the base station controller BSC meets the handover condition for the transition carrier frequency handover, and if yes, switches the mobile terminal to the transition carrier frequency.

The base station controller capable of implementing hard handover of a border area according to claim 15, wherein the hard handover module comprises:

a first switching unit, configured to set an RTD_FAR and/or an EcIo_FAR of a basic carrier frequency of the BSC, and determine whether an actual loop delay of the mobile terminal on the BSC basic carrier frequency is greater than or equal to the RTD_FAR1, and/or Whether the actual pilot strength of the mobile terminal is less than or equal to the EcIo_FAR1, and if so, the mobile terminal performs an inter-frequency hard handover to the transition carrier frequency.

The base station controller capable of implementing hard handover of a border area according to claim 16, wherein the hard handover module further comprises:

a second switching unit, configured to set an RTD_NEAR and/or an EcIo_NEAR of the transition carrier frequency, and determine whether an actual loop delay of the mobile terminal on the transition carrier frequency is less than or equal to RTD_NEAR, and/or determine the transition carrier frequency Whether the actual pilot strength of the mobile terminal is greater than or equal to EcIo_NEAR, and if so, the mobile terminal performs intra-cell inter-frequency hard handover, and switches to the basic carrier frequency of the adjacent BSC of the BSC.

The base station controller capable of implementing hard handover of a border area according to any one of claims 15 to 17, wherein the transition carrier frequency module further comprises a transition carrier frequency information sending unit, and is not used with the BSC. When the compatible neighboring BSC initiates a hard handover to the BSC, allocate resources on the transition carrier frequency, and feed back the transition carrier frequency as the target carrier frequency to the neighboring BSC through the handover request response message.