WO2010124502A1

WO2010124502A1 - Cell hard handoff method and system for establishing forward supplemental channel

Info

Publication number: WO2010124502A1
Application number: PCT/CN2009/075926
Authority: WO
Inventors: 马甄; 韩桂鲁; 卢晓
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-04-30
Filing date: 2009-12-24
Publication date: 2010-11-04
Also published as: CN101547489B; CN101547489A

Abstract

A cell hard handoff method and system for establishing a Forward Supplemental Channel (FSCH) are disclosed in the present invention, wherein a hard handoff judgement condition comprising a hard handoff threshold parameter is preset in the method. The method includes the following steps of: judging whether a FSCH effective set currently exists, if the FSCH effective set exists, reselecting a pilot frequency establishing FSCH by a base station according to the speed of the currently established SCH, the pilot frequency intensity of the FSCH effective set and the hard handoff judgement condition, thus completing the process of the cell hard handoff; and if the FSCH effective set does not exist, performing a judgement by the base station according to the pilot frequency intensity of a FSCH candidate set and the hard handoff judgement condition, and selecting one pilot frequency from the FSCH candidate set to establish FSCH, thus completing the process of the cell hard handoff. The method and the system of the present invention can optimally use the wireless resource of a base station system, and also can switch FSCH to the most appropriate cell in the most appropriate time according to the actual condition of the wireless environment, thus realizing the establishment of the igh-speed and stable FSCH.

Description

Cell hard handover method and system for establishing forward supplemental channel

The present invention relates to a handover technique in a communication system, and in particular to a cell hard handover method and system for establishing a forward supplemental channel. Background technique

The current system not only provides traditional voice services, but also provides data services. With the increasing number of data service users, low-speed data services can no longer meet the needs of users, so it is necessary to provide high-speed data services. The high-speed data download service is implemented by establishing a FSCH (Forward Supplemental Channel) with different rates between the mobile terminal and the base station system. FSCH is a physical traffic channel that allows a base station system to deliver high-speed data to mobile terminals by allocating a large amount of radio resources to each user, including WalshCode, CE (Channel Element), and power resources. . The higher the FSCH rate, the more WalshCode, CE, and power resources are occupied.

When the mobile terminal is in the handover area where multiple pilots are located, the cell handover can be performed by using a soft handover mode or a hard handover mode. The FSCH, that is, the soft handover mode, is established between the mobile terminal and multiple cells of the base station system. By adopting the soft handover mode to establish the FSCH, the mobile terminal can simultaneously demodulate multiple wireless signals, effectively improving the signal demodulation gain of the mobile terminal, and still can establish a higher rate FSCH in a place with poor wireless environment.

However, the soft handover mode establishes the radio resources required by the FSCH, but the FSCH is always established on one cell, that is, the hard handover mode, and the required radio resources are multiplied. In contrast, the establishment of FSCH by hard handover can not only effectively utilize the limited radio resources of the base station system, but also manage the management of radio resources and reduce the overall system complexity.

However, when the mobile terminal is located in the switching area where the multi-pilot is located or the area where the wireless signal is unstable In the case that the FSCH is established on only one cell in the hard handover mode, the base station system may construct the FSCH in order to reselect a more suitable cell, and may repeatedly construct the FSCH, which is easy to generate a ping-pong effect. However, if the FSCH switching is not performed in time, it may be interfered by other pilot signals, resulting in a poor link quality and a high frame error rate, which affects the download of data. Summary of the invention

The technical problem to be solved by the present invention is to provide a cell hard handover method and system for establishing an FSCH, which can optimally use the radio resources of the base station system, and can also switch the FSCH at the most suitable time according to the actual situation of the radio environment. To the most suitable cell, the establishment of high-speed stable FSCH.

In order to solve the above technical problem, the technical solution of the present invention is implemented as follows:

A cell hard handover method for establishing a forward supplemental channel, which presets a hard handover determination condition including a hard handover threshold parameter; the method includes:

Determining whether there is an active set of the FSCH, if there is an active set of the FSCH, the base station reselects the pilot for establishing the FSCH according to the rate of the currently established FSCH, the pilot strength of the FSCH active set, and the hard handover determination condition, and completes the cell. Hard switching process

If the FSCH active set does not exist, the base station determines according to the pilot strength of the FSCH candidate set and the hard handover determination condition, selects one pilot from the FSCH candidate set to establish the FSCH, and completes the hard handover procedure.

The process of establishing the FSCH includes:

The FSCH is established by selecting pilots in the FSCH candidate set that are stronger than the pilots that are added to the FSCH active set pilot strength threshold.

The process of selecting the pilot includes:

When the rate of the established FSCH reaches the rate requirement, and the pilot strength of the FSCH active set is weaker than the FSCH hard handover absolute pilot strength threshold, the pilot whose pilot strength in the FSCH candidate set is stronger than the pilot strength of the FSCH active set is selected; When the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is greater than the pilot of the FSCH hard handover pilot strength difference threshold.

The process of selecting the pilot includes:

When the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is smaller than the FSCH hard handover pilot strength difference threshold, and the difference between the two is poor. The value is continuously greater than the pilot of the FSCH hard handoff to avoid the ping-pong effect of the pilot strength difference threshold exceeding the set threshold.

The process of selecting the pilot includes: selecting the strongest pilot among the pilots that can be used to establish the FSCH in the FSCH candidate set.

The method further includes: reconstructing the FSCH active set and the FSCH candidate set, the constructing process comprising:

The base station updates the FCH active set according to the pilot measurement data fed back by the mobile terminal, and reconstructs the FSCH active set and the FSCH candidate set according to the updated FCH active set.

A cell hard handover system for establishing a forward supplemental channel includes: a mobile terminal and a base station system, where the base station system includes:

a measurement unit, configured to measure a rate of a currently established FSCH, and a pilot strength of an FSCH active set; a switching threshold setting unit, configured to set a hard handover determination condition including a hard handover threshold parameter; and a handover control unit, configured to switch according to the The hard handover determination condition of the threshold setting unit and the measurement result of the measurement unit complete the pilot selection, establish the FSCH, and complete the hard handover process.

The manner in which the handover control unit completes the pilot selection is: when there is no FSCH active set, the pilot strength of the FSCH candidate set is stronger than the pilot that is added to the FSCH effective set pilot strength threshold.

When there is an active set of FSCH, the manner in which the handover control unit completes the pilot selection is: When the rate of the established FSCH reaches the rate requirement, and the pilot strength of the FSCH active set is weaker than the FSCH hard handover absolute pilot strength threshold, the pilot whose pilot strength in the FSCH candidate set is stronger than the pilot strength of the FSCH active set is selected;

When the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is greater than the pilot of the FSCH hard handover pilot strength difference threshold.

When the rate of the established FSCH does not meet the rate requirement, the handover control unit completes the pilot selection by: selecting a pilot strength of the FSCH candidate set that is stronger than the pilot strength of the FSCH active set, and the difference between the two The pilot that is smaller than the FSCH hard handover pilot strength difference threshold, and whose difference is continuously greater than the pilot strength difference threshold of the FSCH hard handover avoiding the ping-pong effect exceeds the pilot of the set threshold.

The handover control unit is further configured to select a pilot with the strongest strength among pilots that can be used to establish an FSCH in the FSCH candidate set to establish an FSCH, and complete a hard handover procedure.

The measuring unit is further configured to periodically send a pilot measurement report request message to the mobile terminal, and receive a pilot measurement report message reported by the mobile terminal;

The handover control unit is further configured to update the FCH active set according to the pilot measurement report message received by the measurement unit, and reconstruct the FSCH active set and the FSCH candidate set.

Compared with the prior art, the present invention mainly adopts a hard handover manner to establish an FSCH, and selects a cell that is most suitable for establishing an FSCH on the basis of optimally utilizing the radio resources of the base station system and maximally ensuring the download performance of the data service. With the present invention, the following advantages are obtained:

First, in order to make reasonable and effective use and maximum savings of the limited radio resources of the base station system, the FSCH is established by using a hard handover manner;

Second, in order to prevent the ping-pong effect in the area with poor wireless environment, a solution to limit the occurrence of FSCH hard handover is proposed.

Third, on the basis of preventing the ping-pong effect, in order to make the FSCH hard in time if necessary Switching, also proposed a solution to the switch. DRAWINGS

1 is a flowchart of Embodiment 1 of a cell hard handover method for establishing a forward supplemental channel according to the present invention; FIG. 2 is a schematic diagram of an embodiment of a cell hard handover system for establishing a forward supplemental channel according to the present invention; Embodiment 2 of the cell hard handover method of the channel. detailed description

The present invention mainly determines the cell in which the FSCH should be established according to the cell pilot strength reported by the mobile terminal and the relevant threshold for establishing the FSCH set by the base station system, using the following control principle.

The method proposed by the present invention will be described in detail below with reference to the embodiment in Fig. 1. It is first necessary to set the hard handoff threshold parameters in the system, and construct the hard handoff judgment conditions from these threshold parameters. Figure 1 includes the following steps:

Step 101: Establish a data service call connection between the mobile terminal and the base station, and perform data transmission through the basic service channel.

Step 102: When the base station finds that the data in the data buffer exceeds the FSCH demand threshold, the base station starts to establish the FSCH.

Step 103: The base station determines the cell that establishes the FSCH, establishes the FSCH rate, allocates the radio resource that establishes the FSCH, and the like, and sends the extended supplementary channel assignment message to the mobile terminal, and the FSCH establishment is completed.

Step 104: The base station starts to transmit data to the mobile terminal on the FSCH.

As shown in FIG. 2, the cell hard handover system for establishing a forward supplemental channel is mainly modified in a base station system, and the base station system adds several functional units, including: a measurement unit, configured to periodically transmit pilot measurements to the mobile terminal. Reporting the request message, and receiving the pilot measurement report message reported by the mobile terminal; and the rate of the currently established FSCH and the pilot strength of the FSCH active set. Cut The threshold setting unit is configured to set a hard handover threshold parameter, and construct a hard handover judgment condition, where the threshold parameters include: an FSCH active set pilot strength threshold, an FSCH hard handover pilot strength absolute threshold, and an FSCH hard handover pilot strength difference threshold. The FSCH hard handoff avoids the pilot strength difference threshold of the ping-pong effect. a handover control unit, configured to update an FCH active set according to the mobile terminal pilot measurement report reported by the measurement unit, reconstruct an FSCH active set and a candidate set; and complete pilot selection according to the hard handover determination condition of the handover threshold setting unit, Establish FSCH and complete cell hard handover.

Next, in conjunction with the second embodiment of Fig. 3, the setting of the threshold parameter, the configuration of the hard switching condition, and the like of the present invention will be described in detail. The hard handover judgment conditions of this embodiment include:

(1) If the FSCH active set does not currently exist, the pilot of the FSCH candidate set is stronger than the pilot that is added to the FSCH active set pilot strength threshold to establish the FSCH;

(2) If there is currently an active set of FSCH, and

The rate of the established FSCH reaches the rate requirement, and the pilot strength of the FSCH active set is weaker than the FSCH hard handover absolute pilot strength threshold, and the pilot of the pilot strength of the FSCH candidate set is stronger than the pilot of the FSCH active set to establish the FSCH. ;

The rate of the established FSCH is not the rate requirement, and the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is greater than the pilot of the FSCH hard handover pilot strength difference threshold to establish the FSCH;

(3) If there is currently a valid set of FSCH, and the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is smaller than the FSCH hard handover pilot. The strength difference threshold, and the difference between the two is continuously greater than the pilot of the FSCH hard handover avoiding the ping-pong effect pilot strength difference threshold exceeding the set threshold to establish the FSCH;

(4) The pilot with the strongest selection strength among the pilots that can be used to establish the FSCH in the FSCH candidate set is used as the pilot for establishing the FSCH. The judgment condition (1) is a judgment condition in the case where the effective set does not exist; (2) the judgment condition in the case where the effective set exists; (3) the judgment condition in the case of avoiding the ping-pong effect; (4) is the most The judgment condition of the pilot selection.

In this embodiment, the base station sends a periodic pilot measurement report request message to the mobile terminal, so that the mobile terminal periodically reports the pilot measurement report message to the base station. After receiving the pilot measurement report message, the base station updates the FCH active set according to the pilot strength of each cell reported in the message. The main processing flow shown in Figure 3:

Step 301: The base station sets the relevant threshold of the FSCH in the hard handover manner, including: T_SCH_ADD (adding the FSCH effective set pilot strength threshold), T_SCH_HARD_ABSOLUTE (the FSCH hard handover pilot strength absolute threshold), T_SCH_HARD_GAP (the FSCH hard handover pilot strength difference) Threshold), T_SCH_HARD_COMP (FSCH hard handoff avoids the pilot strength difference threshold of ping-pong effect).

Step 302: Divide the pilot in the current FCH active set into two sets of an FSCH active set and an FSCH candidate set. The FSCH active set is a subset of the FCH active set, so the base station needs to reconstruct the FSCH active set based on the updated FCH active set. The FSCH active set is the pilot that currently establishes the FSCH, and the FSCH candidate set is the pilot that does not currently establish the FSCH but is effectively concentrated in the FCH.

Step 303: Determine whether the current FSCH active set exists. If yes, go to step 304; if not, go to step 314.

Step 304: Determine whether the current rate of establishing the FSCH meets the existing rate requirement, and if yes, go to step 305; if no, go to step 309.

Step 305: Determine whether the pilot strength of the current FSCH active set is weaker than the threshold T_SCH_HARD_ABSOLUTE, and if yes, proceed to step 306.

Step 306: Determine whether the pilot strength of the current FSCH active set is weaker than the strength of the strongest pilot in the FSCH candidate set. If yes, go to step 307; if no, go to step 308. In step 307, the FSCH active set is switched to the strongest pilot in the FSCH candidate set.

Step 308: Release the currently established FSCH.

Step 309: Determine whether the pilot strength of the current FSCH active set is weaker than the strength of the strongest pilot in the FSCH candidate set, and if yes, proceed to step 310.

Step 310: Determine whether the difference between the pilot strength of the current FSCH active set and the strongest pilot of the FSCH candidate set is greater than D_8 (11_1^1 0_0 ?, if yes, go to step 311; if not, turn Proceed to step 312.

Step 311: Switch the FSCH active set to the strongest pilot in the FSCH candidate set.

Step 312: Determine whether the pilot strength of the current FSCH active set is continuously weaker than the number of times the strongest pilot strength in the FSCH candidate set is greater than the T_SCH_HARD_COMP exceeds a set threshold, and the number of times threshold may be set to 3 times, and if so, Go to step 313.

Step 313, the FSCH active set is switched to the strongest pilot in the FSCH candidate set; Step 314, determining whether there is a pilot stronger than the T_SCH_ADD in the FSCH candidate set, and if yes, proceeding to step 315;

Step 315: Select a pilot that is stronger than T_SCH_ADD in the FSCH candidate set to establish an FSCH. It is also possible to directly select the strongest pilot to establish the FSCH.

The method and system of the present invention can be applied to communication systems such as CDMA, such as CDMA2000 communication systems.

In summary, the present invention mainly adopts a hard handover manner to establish an FSCH, and selects a cell that is most suitable for establishing an FSCH on the basis of optimally utilizing radio resources of the base station system and maximally ensuring data service download performance. With the present invention, the following advantages are obtained:

Second, in order to prevent the ping-pong effect in the area with poor wireless environment, a solution to limit the occurrence of FSCH hard handover is proposed. Third, on the basis of preventing the ping-pong effect, in order to enable the FSCH to be hard-switched in time when necessary, a handover solution is also proposed.

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It is to be understood by those skilled in the art that the present invention can be delineated or replaced without departing from the spirit and scope of the invention.

Claims

Claim

A cell hard handover method for establishing a forward supplemental channel, characterized in that: a hard handover determination condition including a hard handover threshold parameter is preset; the method includes:

2. The method according to claim 1, wherein the process of establishing the FSCH comprises:

3. The method according to claim 1 or 2, wherein the process of selecting the pilot comprises:

When the rate of the established FSCH reaches the rate requirement, and the pilot strength of the FSCH active set is weaker than the FSCH hard handover absolute pilot strength threshold, the pilot whose pilot strength in the FSCH candidate set is stronger than the pilot strength of the FSCH active set is selected;

4. The method according to claim 1 or 2, wherein the process of selecting the pilot comprises:

When the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is smaller than the FSCH hard handover pilot strength. The difference threshold, and the difference between the two is continuously greater than the pilot whose FSCH hard handover avoids the pilot strength difference threshold of the ping-pong effect exceeds the set threshold.

The method according to claim 1 or 2, wherein the process of selecting the pilot comprises: selecting a pilot with the strongest strength among pilots that can be used to establish an FSCH in an FSCH candidate set.

The method according to claim 1, wherein the method further comprises: re-structuring the FSCH active set and the FSCH candidate set, the constructing process comprising:

A cell hard handover system for establishing a forward supplemental channel, comprising: a mobile terminal and a base station system, wherein the base station system includes:

The system according to claim 7, wherein the manner in which the handover control unit completes the pilot selection is: when there is no FSCH active set, selecting the pilot strength of the FSCH candidate set is stronger than adding the FSCH. A pilot that sets the pilot strength threshold.

The system according to claim 7, wherein when the FSCH active set is present, the manner in which the handover control unit completes the pilot selection is:

When the rate of the established FSCH does not meet the rate requirement, the pilot strength of the FSCH candidate set is stronger than the pilot strength of the FSCH active set, and the difference between the two is greater than the FSCH hard handover pilot strength. The pilot of the difference threshold.

The system according to claim 7, wherein when the rate of the established FSCH fails to meet the rate requirement, the manner in which the handover control unit completes the pilot selection is: selecting a pilot strength of the FSCH candidate set. Stronger than the pilot strength of the FSCH active set, and the difference between the two is less than the FSCH hard handover pilot strength difference threshold, and the difference between the two is continuously greater than the FSCH hard handover avoidance ping-pong effect pilot strength difference threshold exceeds the set The pilot of the threshold.

The system according to any one of claims 7 to 10, wherein the handover control unit is further configured to select a pilot with the strongest selection strength among the pilots that can be used to establish the FSCH in the FSCH candidate set to establish FSCH, complete the hard handover process.

12. The system of claim 7 wherein: