WO2015127665A1

WO2015127665A1 - Soft handoff method and related device

Info

Publication number: WO2015127665A1
Application number: PCT/CN2014/072746
Authority: WO
Inventors: 谭小洪; 屈建平; 姬岩鹏
Original assignee: 华为技术有限公司
Priority date: 2014-02-28
Filing date: 2014-02-28
Publication date: 2015-09-03
Also published as: CN105191410A

Abstract

Provided are a soft handoff method and device. The method comprises: determining same-frequency cells around a cell which is currently connected to a user equipment (UE) as a same-frequency neighbour cell set; receiving a same-frequency event report which is reported by the UE after the same-frequency neighbour cell set is detected, the same-frequency event report comprising a target primary scrambling code (PSC) and an observation time difference of an air interface between the cell which is currently connected and each of the same-frequency cells in the same-frequency neighbour cell set; taking the same-frequency cells, the PSCs of which are the same as the target PSC, as cells to be determined; when the cells to be determined are multiple cells, respectively calculating the differences between the observation time differences and a theoretical time difference; and when the difference satisfies a preset threshold value, determining that a corresponding cell to be determined is a target cell. It can be seen that, when the cells to be determined are multiple cells, a target cell which can be used for a soft handoff can be effectively determined therefrom according to the difference, thereby reducing the failure rate of the soft handoff and eliminating same-frequency interferences.

Description

Soft switching method and related device

Technical field

The present invention relates to the field of communications technologies, and in particular, to a soft handover method and related apparatus. Background technique

In the wireless communication system, as the user equipment (UE) moves, the wireless signal around the UE generates a dynamically changing interference signal. In order to ensure the communication quality of the UE, the signal must be determined according to the current mobile location of the UE. The cell, and the wireless connection between the UE and the original cell is switched to the wireless connection with the cell with the strong current signal, which is the concept of handover in the cellular mobile communication system. Soft handover is one of a variety of handover types. It is characterized in that the UE establishes another wireless connection with another cell (even with the same cell) without disconnecting the existing wireless connection, and simultaneously uses two The wireless connection communicates, and the UE does not disconnect from the Radio Access Network (RAN) in the process. The advantage of soft handover over other handover types is that the UE moves from one cell to another. During the process, the service can be smoothed and the quality of the ongoing communication is not affected.

The soft handover is performed in the prior art, and is generally performed by a radio network controller (RNC), that is, a target primary scrambling code (primary synchronization code, PSC) that satisfies the condition of the soft handover signal reported by the UE after detecting the neighboring cell information. And determining, by the RNC, the target cell from the neighboring cells of the UE according to the PSC, and performing soft handover on the target cell by the UE.

However, in many cases, according to the target PSC reported by the UE, multiple to-be-determined cells having the same PSC as the target PSC are determined, but there is currently no effective method for accurately determining the determined cells from multiple to-be-determined cells. The target cell that completes the soft handover operation often has a situation in which the target cell cannot be determined or erroneously determined, so that the failure rate of the soft handover is relatively high. Summary of the invention

The technical problem to be solved by the present invention is to provide a soft handover method and related apparatus.

In order to solve the above technical problems, the technical solution adopted by the present invention is: In a first aspect, the present invention provides a soft handover method, in which a radio network controller RNC determines a surrounding frequency-frequency cell of a cell to which a user equipment UE is currently connected as a set of intra-frequency neighboring cells, and the method includes:

Receiving, by the RNC, an intra-frequency event report reported by the UE after detecting the same-frequency neighboring cell set, where the intra-frequency event report includes a target primary scrambling code PSC, and a currently connected cell and the same-frequency neighboring cell. The observation time difference of the air interface between each co-frequency cell in the set;

And the RNC matches the acquired PSCs with the PSCs of the same-frequency cells in the same-frequency neighboring cell set, and uses the same-frequency cell that is the same as the target PSC as the to-be-determined cell;

When the to-be-determined cell is a plurality of cells having different cell IDs, the RNC calculates the observed time difference corresponding to the to-be-determined cell, and the currently connected cell and the corresponding to-be-determined cell. The difference in the theoretical time difference between the air gaps;

When the difference meets a preset threshold, the RNC determines that the to-be-determined cell corresponding to the difference is a target cell that performs soft handover for the UE.

In a first possible implementation manner of the first aspect, the RNC separately calculates the observed time difference corresponding to the to-be-determined cell, and the air interface between the currently connected cell and the corresponding to-be-determined cell. The difference in theoretical time difference, including:

X=ABS(((OFFa+Tma)-(OFFb+Tmb)) mod 256 - ((Diffa-Tcella)-(Diffb-Tcellb)) mod 256)

among them,

a represents a cell currently connected; b represents any one of the cells to be determined;

The values of OFFa and Tma are obtained from the RNC from the saved FrameOffset and ChipOffset of the Radio Link link of the UE;

The values of OFFb and Tmb are transmitted from the air interface and the standard interface IUB interface between the currently connected cell and the intra-frequency cell in the same-frequency neighboring cell set included in the measurement report on the UE. Obtained in time difference;

The values of Diffa and Diffb are obtained from the NodeB-level payload broadcast, where Diffa and Diffb represent the NodeB common frame number counters of the CELLa and CELLb cells, respectively, and the RNC. Using the frame number counter RFN difference;

Tcella and Tcellb are obtained from the cell level load;

ABS stands for absolute value.

In a second possible implementation manner of the first aspect, when the plurality of the differences meet the preset threshold, the RNC determines a minimum of the plurality of the differences to be determined. The cell is a target cell for soft handover of the UE.

In a third possible implementation manner of the first aspect, a cell currently connected by the UE is specifically a cell with the best signal quality currently connected by the UE.

In conjunction with the first aspect or the first or second or third possible implementation of the first aspect, in a fourth possible implementation,

The set of intra-frequency neighboring cells includes a co-frequency neighboring cell of a cell to which the UE is currently connected, and a cell set having different cell IDs in the same-frequency neighboring cell of the same-frequency neighboring cell.

In a second aspect, the present invention provides a soft switching device, the device comprising:

a setting unit, configured to determine a surrounding intra-frequency cell of a cell currently connected by the user equipment UE as a set of co-frequency neighboring cells;

a receiving unit, configured to receive an intra-frequency event report reported by the UE after detecting the same-frequency neighboring cell set, where the intra-frequency event report includes a target primary scrambling code PSC and a currently connected cell and the same-frequency The observation time difference of the air interface between each co-frequency cell in the set of neighboring cells;

a matching unit, configured to match the obtained target PSC with the PSC of each of the same-frequency cells in the same-frequency neighboring cell set, and use the same-frequency cell that is the same as the target PSC as the to-be-determined cell ;

a difference calculation unit, configured to calculate, when the matching result of the matching unit is a plurality of cells having different cell IDs, the observed time difference corresponding to the to-be-determined cell and the current connection The difference between the theoretical time difference of the air interface between one cell and the corresponding cell to be determined;

And a determining unit, configured to determine, when the difference meets a preset threshold, the target cell that is to be determined by the difference to be the target cell for performing soft handover by the UE.

In a first possible implementation manner of the second aspect, the difference calculation unit is further configured to use The formula calculates the difference:

among them,

The values of Diffa and Diffb are obtained from the NodeB level load broadcast, where Diffa and Diffb represent the NodeB common frame number counter BFN of the CELLa and CELLb cells and the RNC common frame number counter RFN difference;

Tcella and Tcellb are obtained from the cell level load;

ABS stands for absolute value.

In a second possible implementation of the second aspect,

The determining unit is further configured to: when a plurality of the differences meet the preset threshold, determine that the smallest one of the plurality of the differences is to be soft-switched for the UE Target cell.

In a third possible implementation of the second aspect,

A cell currently connected by the UE is specifically a cell with the best signal quality currently connected by the UE.

With reference to the second aspect or the first or second or third possible implementation manner of the second aspect, in a fourth possible implementation manner,

It can be seen from the foregoing technical solution that when the UE uploads the same-frequency event report, the air interface between the cell currently connected by the UE and the same-frequency cell in the same-frequency neighboring cell set is observed. a difference, such that when a plurality of cells to be determined having the same PSC are determined during a soft handover operation, a difference between the observed time difference corresponding to the to-be-determined cell and a known theoretical time difference is calculated, if If the difference is less than the preset threshold, the RCH may be determined to be the target cell to which the UE is to be soft-switched according to the difference, and the RNC according to the cell and the current UE connected by the UE. Observing an observation time difference of an air interface between each intra-frequency cell in the same-frequency neighboring cell set, and a theoretical time difference between the saved air cell between the currently connected cell and the same-frequency cell in the same-frequency neighboring cell set The difference between the two, when the number of cells to be determined is multiple, can effectively determine the target cell that can be used for soft handover, improve the accuracy of determining the target cell, reduce the failure rate of soft handover and eliminate the same frequency. interference.

DRAWINGS

1 is a flow chart of a method for a soft handover method according to the present invention;

2 is a schematic diagram of actual operation of performing soft handover;

3 is a structural diagram of a device of a soft switching device according to the present invention. detailed description

The embodiment of the present invention provides a soft handover method and related device. In the process of performing soft handover, a cell concept is involved, and the cell is classified according to the connection relationship between the cell and the UE and the strength of the signal. It can be divided into three categories: activity sets, monitoring sets, and test sets. During the soft handover process, the UE establishes a connection with one or more cells or establishes a service link, and the active set (also called an active set) is a set of all cells currently establishing a connection with the UE. During the process of the UE, the signal strength of the cell in the original active set will definitely change, and the signal quality of the cell in the active set and the UE may become worse and worse and is no longer suitable. The UE remains connected, so the cells in the monitoring set (also called the candidate set) are all sets of cells that originally belong to the active set but are currently disconnected from the UE, and the UE can also measure. The detection set is a set of cells in the neighbor list of the cell that is currently detectable by the UE, but has no connection with the UE or does not belong to the cell with the best connection of the UE.

The above three sets can be transformed into each other, and reasonable network planning and software implementation can make three sets. Coordinating cooperation, the cells in the active set are removed from the active set when the signal condition is not met, and the cells in the monitoring set and the detection set can establish a connection with the UE when the signal condition is met, thereby adding the active set to enable the UE and The wireless environment in which it is obtained obtains the best gain on the signal. When the UE is in the coverage area of a certain cell, and the signal of the cell satisfies the condition, the neighboring cell in the Wideband Code Division Multiple Access (WCDMA) system can be planned as the same-frequency cell, and the network side The same-frequency cell can be added to the active set to realize merging or frame selection of multiple wireless signals to bring the gain of the uplink and downlink signals, but conversely, when the cell satisfying the signal condition cannot join the active set, it will cause In the same frequency interference, in order to obtain signal gain and avoid co-channel interference, the network side needs to accurately identify which intra-frequency cells can join the active set, or establish a connection with the UE. In the prior art, the UE generally detects the cell information and reports the scrambling code information of the target cell in the detection set that satisfies the signal condition, and the system determines the target cell according to the scrambling code information, and performs soft handover on the target cell. The target cell joins the activity set.

RNC is a key network element for emerging 3G networks. It is part of the access network and is used to provide mobility management, call processing, link management and switching mechanisms. Since the RNC in the prior art determines or corresponds to a plurality of cells to be determined having the same PSC as the target PSC according to the target PSC reported by the UE, there is no effective method for multiple waiting It is determined that the target cell in the cell that can perform the soft handover operation is accurately determined, and the situation that the target cell cannot be determined or erroneously determined often occurs, so that the failure rate of the soft handover is relatively high. Therefore, in the technical solution of the present invention, the RNC is configured according to an observed time difference between a cell currently connected by the UE and an air interface between the same-frequency cells in the same-frequency neighboring cell set, and the saved current The difference between the theoretical time difference of the air interface between the connected cell and the same-frequency cell in the same-frequency neighboring cell set, when the number of cells to be determined is multiple, can effectively determine the available soft-switching The target cell improves the accuracy of determining the target cell, reduces the failure rate of soft handover and eliminates co-channel interference.

At present, the set of selectable cells that determine the UE to perform soft handover is mainly the same-frequency neighboring cell of the cell that is currently connected with the UE, that is, the same-frequency neighboring cell of the active centralized cell, and the selectable range is small, which will be disguised. For the technical problem, the technical solution of the present invention further provides a preferred set of selectable cells: a set of co-frequency neighboring cells, and further increases the probability of occurrence of a situation in which a target cell that does not perform soft handover is added. Defined as the active set of the UE and the monitor set a cell set having different cell IDs in the same-frequency neighboring cell, because the cell in the monitoring set is actually part of the same-frequency neighboring cell of the cell to which the UE is connected, so that the same-frequency neighboring cell of the monitoring set can be used as the UE The possibility of soft handover of the target cell is also very large, thereby performing a reasonable and effective expansion on the selection range of the target cell, further reducing the failure rate of the soft handover.

The embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

Embodiment 1

Please refer to FIG. 1, which is a flowchart of a method for a soft handover method according to the present invention. The method includes the following steps:

S100: The radio network controller determines, by the RNC, a co-frequency cell of a cell currently connected by the user equipment UE as a co-frequency neighboring cell set.

It should be noted that this step belongs to the setting step. After setting, unless the definition or range of the same-frequency neighboring cell set needs to be modified, it is not necessary to perform this step again during the soft switching operation.

The cell currently connected by the UE may refer to any one of the one or more cells that have established a connection with the UE. In order to be able to determine a cell to be determined with better relative signal quality, the technical solution of the present invention further A preferred embodiment is given, that is, selecting a cell to which the UE is currently connected is specifically selecting a cell with the best signal quality currently connected by the UE, and determining the same frequency by using the cell with the best signal quality as a reference. The range of neighborhood collections.

At present, the set of selectable cells that determine the UE to perform soft handover is mainly the same-frequency neighboring cell of the cell that is currently connected with the UE, that is, the same-frequency neighboring cell of the active centralized cell, and the selectable range is small, which will be disguised. The probability of occurrence of a situation in which a target cell that does not perform soft handover is added is increased. The same-frequency neighboring cell set in this step refers to a cell set of a co-frequency cell around a cell connected to the selected UE, for example, a cell closer to the cell, in order to determine a relative signal. A better quality cell to be determined, the technical solution of the present invention also provides a preferred implementation manner, that is, the surrounding intra-frequency cell is further defined as the selected cell set of the different cell ID. Moreover, when the selected one cell currently connected by the UE is specifically a cell with the best signal quality in the cell currently connected to the UE, the surrounding same frequency The cell is equivalent to a set including cells of the UE, a cell in the monitoring set, and a cell having different cell IDs in the same-frequency neighboring cell of the active set and the monitoring set, because the cell in the monitoring set is actually connected with the UE. The part of the same-frequency neighboring cell of a cell, so the possibility that the same-frequency neighboring cell of the monitoring set can be used as the target cell for soft handover of the UE is also very large, thereby making reasonable selection on the target cell range. Effective expansion further reduces the failure rate of soft handover.

S101: The RNC receives an intra-frequency event report reported by the UE after detecting the same-frequency neighboring cell set, where the intra-frequency event report includes a target primary scrambling code PSC and a currently connected cell and the same frequency. The observation time difference of the air interface between each co-frequency cell in the set of neighboring cells;

It should be noted that, according to step S100, the UE detects each cell included in the same-frequency neighboring cell set, determines a PSC that can perform soft handover, and according to data transmission in the process of detection, Determining an observation time difference between the intra-frequency cells in the same-frequency neighboring cell set and the selected one of the cells currently connected to the UE, for use in step S103.

S102: The RNC matches the acquired target PSC with the PSC of each intra-frequency cell in the same-frequency neighboring cell set, and uses the same-frequency cell with the PSC and the target PSC as the to-be-determined cell. ;

It should be noted that the RSC has already stored the PSC of each cell when the network is set up. Therefore, the PSC of each intra-frequency cell in the same-frequency neighboring cell set is that the RNC selects from the saved PSC. It belongs to the prior art and will not be described here.

In the process of performing matching, all the cells in the same-frequency neighboring cell set may be matched at one time, or the cells in the same-frequency neighboring cell set may be divided into several parts to be matched in sequence, and the basis of the dividing The distance of a currently connected cell selected by the same frequency neighboring cell distance. This matching method can quickly and accurately determine the cell to be determined.

Matching in the same-frequency neighboring cell of the currently connected cell in the same-frequency neighboring cell set, if the matching cell with the same target PSC is matched, the cell does not continue after matching the cell. If it matches, the process proceeds to step S103. If the matching is unsuccessful, the matching is further performed from the same-frequency neighboring cell of the other cell in the active set of the same-frequency neighboring cell set. If the cell with the same PSC is matched, the cell is no longer matched after the cell is matched. The matching is continued, and the process proceeds to step S103.

If the matching is unsuccessful, the cell remaining in the same-frequency neighboring cell set is removed from the cell after the two-part cell is removed. If the cell with the same PSC is matched, the cell is matched. S103.

S103: When the to-be-determined cell is a plurality of cells having different cell IDs, the RNC respectively calculates the observed time difference corresponding to the to-be-determined cell and the saved one of the currently connected cells and the corresponding one. The difference in the theoretical time difference of the air gap between the cells to be determined;

It should be noted that the theoretical time difference is obtained and saved by the configuration data of each cell in the networking. When the RNC calculates the difference, the theoretical time difference is directly saved from the RNC. Obtained in the data. When performing the calculation, the technical solution of the present invention provides a preferred calculation method for calculating the difference, in addition to other calculation manners in which the difference can be calculated:

X=ABS(((OFFa+Tma)-(OFFb+Tmb)) mod 256 - ((Diffa-Tcella)-(Diffb-Tcellb)) mod 256);

among them,

a represents one cell of the current connection; b represents any one of the cells to be determined. The values of OFFa and Tma are obtained from the RNC from the saved FrameOffset and ChipOffset of the Radio Link link of the UE.

The values of OFFb and Tmb are transmitted from the air interface and the standard interface IUB interface between the currently connected cell and the intra-frequency cell in the same-frequency neighboring cell set included in the measurement report on the UE. Obtained in the time difference.

That is to say, the data in (OFFa+Tma)-(OFFb+Tmb) belongs to the data related to the air interface.

The values of Diffa and Diffb are obtained from the NODEB-level load broadcast, where Diffa and Diffb represent the difference between BFN and RFN of the CELLa and CELLb cells, respectively, where BFN is the common frame number counter in the NodeB, which is called Node B Frame Number, and the numerical range. 0 to The 4095frameso RFN is a general frame number counter of the RNC, which is called RNC Frame Number and has a value range of 0 to 4095 fmmes.

Tcella and Tcellb are obtained from the cell-level load, where Tcell is a supplemental channel (SCH), a common pilot channel (CPICH), and a time offset of the downlink scrambling code relative to the BFN. 0 to 9, in 256 chips.

That is to say, the data in (Diffa-Tcella)-(Diffb-Tcellb) belongs to the data related to the standard interface IUB interface.

ABS stands for absolute value.

S104: When the difference meets a preset threshold, the RNC determines that the to-be-determined cell corresponding to the difference is a target cell that performs soft handover for the UE.

That is, when the UE detects that the current one of the observed time differences is closer to the saved theoretical time difference, that is, the smaller the value of the obtained X is, the more suitable the cell corresponding to the observed time difference is. It becomes the target cell for the UE to perform soft handover.

The preset threshold may be adaptively increased or decreased according to the network environment of the network area where the current UE is located, so as to minimize the occurrence of the final determination of the target cell, and minimize the determination of multiple to-be-determined cells. The value of X can meet the preset threshold.

In order to effectively maintain the handover process, define a N-space data of a corresponding cell: When a cell is used as a BestCell, an N-space data structure associated with it is described as follows: There are N records with the same data structure (the number of records can be arbitrarily added) ), each record includes: a PSC, the number of CELLIDs corresponding to the PSC (0, 1 or more), the cell to be determined, the number of consecutive handover failures of the cell to be determined, and a flag for whether the record needs to be periodically cleared. Bit

According to step S103, the Xi (i=l, 2, . . . m) of each cell in the cell to be determined corresponding to the cell is respectively calculated, and the cell whose Xi is less than or equal to the preset threshold is added to the set Y;

If the number of sets is equal to 0, the "number of cells to be determined" of the PSC is marked as "equal to 0" to exit the algorithm; If the number of sets Y is greater than 1, only the "number of cells to be determined" is recorded as "greater than 1", and the corresponding cell ID to be determined in which the Xi value is the smallest is selected for soft handover;

If the number of sets Y is equal to 1, the corresponding CELLID is counted in the N space, and the cell ID to be determined is selected for soft handover;

After the soft handover is initiated, the RNC confirms whether the handover succeeds or fails according to whether the RL_Restore_Ind is received, and maintains data such as "the number of consecutive handover failures of the candidate cell" in the N space, so as to facilitate efficient processing of the subsequent detection set report.

That is, when there are a plurality of the differences that meet the preset threshold, the RNC determines that the smallest one of the plurality of the differences is the target for the UE to perform soft handover. Community. Said. Please refer to FIG. 2 , which is a schematic diagram of actual operation of soft handover according to the present invention. In this embodiment, the currently connected cell of the UE is further defined as a cell with the best signal quality currently connected by the UE, and the same frequency of the cell with the best signal quality currently connected by the UE is co-frequency The cell is further defined as a co-frequency neighboring cell of the cell with the best signal quality currently connected by the UE, and a cell set having different cell IDs in the co-frequency neighboring cell of the co-frequency neighboring cell.

C1 is the optimal cell to which the UE is currently connected (that is, the cell with the best signal quality currently connected)

Cll, C12, C13, C14, C15 are the same-frequency neighbors of C1.

The C11 and the C12 belong to the active set cell of the UE, that is, the connection is also established with the UE.

C13, C14 and C15 belong to the monitoring set cell of the UE.

Clll, C112, C113, C121, C122, C131, C132, C141, C142, C151, C152, C153 and C888 belong to the detection set cell of the UE, wherein:

Clll, C112 and C113 are Cron's co-frequency neighbors, C121, C122 and C888 are C12 co-frequency neighbors, C131, C132 and C888 are C13 co-frequency neighbors, C141, C142 and C888 are C14 co-frequency neighbors Zones, C151, C152, C153 and C888 are C15's co-frequency neighbors.

The PSCs of C113, C121, C131, C142, and C152 are set to be the same, and all are PSC=100, but the respective cell IDs are different. The PSCs of Clll, C122, C141, and C153 are set to be the same, both of which are PSC=200, but the respective cell IDs are different.

C888 is the same '', zone, which belongs to the same-frequency neighboring areas of C12, C13, and C15, respectively. The UE currently camps on C1, and C1 belongs to the cell with the best signal quality connected to the UE, and the obtained co-frequency neighboring cell set is:

Clll, C112, C113, C121, C122, C888 (C888 repeat, only record once), C131, C132, C141, C142, C151, C152 and C153

The UE is detected by the detection of the uplink detection, wherein the target PSC=100, then the cell distribution corresponding to the threshold in the same-frequency neighboring cell set is:

C113, C121, C131, C142 and C152.

The following equations are used for each of the above cells:

X=ABS(((OFFa+Tma)-(OFFb+Tmb)) mod 256 - ((Diffa-Tcella)-(Diffb-Tcellb)) mod 256).

Finally, it can be concluded that the X value corresponding to C131 is the closest to 0, that is, the preset threshold is met and is the smallest, so that the C131 cell can be confirmed as the target cell for which the current UE performs soft handover. It can be seen that, by using the foregoing embodiment, the RNC is configured according to an observed time difference between a cell currently connected by the UE and an air interface between the same-frequency cells in the same-frequency neighboring cell set, and the saved current connection. The difference between the theoretical time difference between the air cell and the air channel between each cell in the same-frequency neighboring cell set, when the number of cells to be determined is multiple, the target that can be used for soft handover can be effectively determined. The cell improves the accuracy of determining the target cell, reduces the failure rate of soft handover, and eliminates co-channel interference.

At present, the set of selectable cells that determine the UE to perform soft handover is mainly the same-frequency neighboring cell of the cell that is currently connected with the UE, that is, the same-frequency neighboring cell of the active centralized cell, and the selectable range is small, which will be disguised. For the technical problem, the technical solution of the present invention further provides a preferred set of selectable cells: a set of co-frequency neighboring cells, and further increases the probability of occurrence of a situation in which a target cell that does not perform soft handover is added. Defined as the active set of the UE and the set of cells with different cell IDs in the same-frequency neighbor of the monitoring set, because the cells in the monitoring set are actually A part of the same-frequency neighboring cell of the cell to which the UE is connected, so that the same-frequency neighboring cell of the monitoring set can be used as the target cell for the soft handover of the UE, and thus the target cell is selected. A reasonable and effective expansion is performed, and there is no need to increase the neighboring cell configuration, and there is no negative gain in the CCH state PS user call drop rate deterioration, and the soft handover failure rate is further reduced. Embodiment 2

This embodiment is a device embodiment corresponding to the first embodiment. Referring to FIG. 3, it is a structural diagram of a device of a soft switching device according to the present invention, including:

The setting unit 300 is configured to determine, as a set of co-frequency neighboring cells, a surrounding intra-frequency cell of a cell to which the user equipment UE is currently connected;

It should be noted that, after the setting unit 300 is set, the setting unit 300 does not need to be triggered again during the soft switching operation unless the definition or range of the same frequency neighbor set needs to be modified.

The receiving unit 301 is configured to receive an intra-frequency event report reported by the UE after detecting the same-frequency neighboring cell set, where the intra-frequency event report includes a target primary scrambling code PSC and a currently connected cell and the same The observation time difference of the air interface between each co-frequency cell in the set of frequency neighboring cells;

It should be noted that, according to the setting unit 300, the UE detects each cell included in the same-frequency neighboring cell set, determines a PSC that can perform soft handover, and performs data transmission according to the detection process. And determining, by the triggering difference calculation unit 303, the subsequent use time of the air interface between the same-frequency cell in the same-frequency neighboring cell set and the selected cell currently connected to the UE.

The matching unit 302 is configured to match the acquired target PSC with the PSC of each intra-frequency cell in the same-frequency neighboring cell set, and use the same-frequency cell with the PSC and the target PSC as the to-be determined. Community

It should be noted that, the matching unit 302 has already saved the PSC of each cell when networking, so the PSC of each intra-frequency cell in the same-frequency neighboring cell set here is that the matching unit 302 has been saved. The selected ones in the PSC belong to the prior art and will not be described here.

Matching in the same-frequency neighboring cell of the currently connected cell in the same-frequency neighboring cell set, if the matching cell with the same target PSC is matched, the cell does not continue after matching the cell. Matching, trigger difference calculation unit 303.

If the matching is unsuccessful, further from the active set other cells in the same-frequency neighboring cell set The matching is performed in the same-frequency neighboring cell. If the matching cell has the same cell as the target PSC, the matching does not continue after matching the partial cell, and the difference calculating unit 303 is triggered.

If the matching is unsuccessful, the cell remaining in the same-frequency neighboring cell set is removed from the cell after the two-part cell is removed. If the cell with the same PSC is matched, the triggering difference is performed after the cell is matched. Value calculation unit 303.

The difference calculation unit 303 is configured to: when the matching result of the matching unit is that the to-be-determined cell is a plurality of cells having different cell IDs, calculate the observed time difference corresponding to the to-be-determined cell, and the current The difference between the theoretical time difference of the air interface between the connected cell and the corresponding air cell to be determined;

It should be noted that the theoretical time difference is obtained and saved by the configuration data of each cell in the networking, and the difference calculation unit 303 calculates the difference, the theoretical time difference is the difference. The value calculation unit 303 directly acquires from the saved data. When performing the calculation, the technical solution of the present invention provides a preferred calculation method for calculating the difference, in addition to other calculation manners in which the difference can be calculated:

among them,

The values of Diffa and Diffb are obtained from the NODEB-level load broadcast, where Diffa and Diffb represent the difference between BFN and RFN of the CELLa and CELLb cells, respectively, where BFN is the common frame number counter in the NodeB, which is called Node B Frame Number, and the numerical range. 0 to 4095frames o RFN is the general frame number counter of RNC, which is called RNC Frame Number, and the value range is 0 to 4095fmmes.

Tcella and Tcellb are obtained from the cell-level load, where Tcell is a supplemental channel (SCH), a common pilot channel (CPICH), and a time offset of the downlink scrambling code relative to the BFN. 0 to 9 in 256 chips.

ABS stands for absolute value.

The determining unit 304 is configured to determine, when the difference value meets a preset threshold, the target cell that performs the soft handover by using the to-be-determined cell corresponding to the difference.

That is, when the determining unit 304 detects that the determined current observation time difference is closer to the saved theoretical time difference, that is, the smaller the value of the obtained X is, the observation time difference corresponds to The more suitable the cell is, the target cell for which the UE performs soft handover.

Preferably,

The determining unit 304 is further configured to: when a plurality of the differences meet the preset threshold, determine that the smallest one of the plurality of the differences is to be soft-switched for the UE Target cell. It can be clearly understood by those skilled in the art that all or part of the steps in the foregoing embodiment may be implemented by means of software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, can be embodied in the form of a software product that can be stored in the storage. In the medium, such as ROM/RAM, disk, optical disk, etc., includes instructions for causing a computer device (which may be a personal computer, a server, or a network communication device such as a media gateway, etc.) to perform various embodiments of the present invention Or the method described in some parts of the examples.

It should be noted that the various embodiments in the present specification are described in a progressive manner, and the same similar parts between the various embodiments may be referred to each other, and each embodiment focuses on different embodiments from other embodiments. At the office. In particular, for the device and system embodiments, since they are substantially similar to the method embodiments, they are described in a relatively simple manner, and the relevant portions of the method embodiments can be referred to. The apparatus and system embodiments described above are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, ie may be located One place, or it can be distributed to multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment. Those of ordinary skill in the art can understand and implement without any creative effort.

The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It should be noted that a number of modifications and refinements can be made by those skilled in the art without departing from the spirit of the invention, and such modifications and refinements are also considered to be within the scope of the invention.

Claims

Rights request

1. A soft handover method, in which the controller RNC determines the surrounding same-frequency cells of a cell to which the user equipment UE is currently connected as a set of same-frequency neighbor cells. The method includes: The RNC receives the co-frequency event report reported by the UE after detecting the co-frequency neighbor cell set. The co-frequency event report includes the target primary scrambling code PSC and the currently connected cell and the co-frequency neighbor cell set. The observation time difference of the air interface between each co-frequency cell;

The RNC matches the obtained target PSC with the PSC of each same-frequency cell in the same-frequency neighbor cell set, and uses the same-frequency cell whose PSC is the same as the target PSC as the cell to be determined;

When the cells to be determined are multiple cells with different cell IDs, the RNC calculates the observation time difference corresponding to the cell to be determined and the difference between the currently connected cell and the corresponding cell to be determined. The theoretical time difference between air interfaces;

When the difference meets the preset threshold, the RNC determines that the cell to be determined corresponding to the difference is the target cell for the UE to perform soft handover.

2. The method according to claim 1, characterized in that, the RNC respectively calculates the observation time difference corresponding to the cell to be determined and the time difference between the currently connected cell and the corresponding cell to be determined. The theoretical time difference of the air interface includes:

X=ABS(((OFFa+Tma)-(OFFb+Tmb))mod 256 - ((Diffa-Tcella)-(Diffb-Tcellb)) mod 256)

in,

a represents a currently connected cell; b represents any one of the cells to be determined;

The values of OFFa and Tma are obtained from the FrameOffset and ChipOffset of the Radio Link of the UE saved by the RNC;

The values of OFFb and Tmb are obtained from the signal transmission of the air interface and standard interface IUB interface between the currently connected cell contained in the measurement report on the UE and each co-frequency cell in the co-frequency neighbor cell set. Obtained from the time difference;

The values of Diffa and Diffb are obtained from the NodeB-level load broadcast, where Diffa and Diffb represent the NodeB general frame number counter BFN and RNC communication of CELLa and CELLb cells respectively. Use the frame number counter RFN difference;

Tcella and Tcellb are obtained from cell-level load;

ABS represents absolute value.

3. The method according to claim 1, characterized in that,

When there are multiple differences that meet the preset threshold, the RNC determines that the cell to be determined corresponding to the smallest one of the multiple differences is the target cell for the UE to perform soft handover.

4. The method according to claim 1, characterized in that,

A cell to which the UE is currently connected is specifically a cell with the best signal quality to which the UE is currently connected.

5. The method according to any one of claims 1 to 4, characterized in that,

The same-frequency neighbor cell set includes the same-frequency neighbor cells of a cell to which the UE is currently connected and a set of cells with different cell IDs among the same-frequency neighbor cells of the same-frequency neighbor cell.

6. A soft switching device, characterized in that the device includes:

A setting unit configured to determine co-frequency cells surrounding a cell to which the user equipment UE is currently connected as a set of co-frequency neighbor cells;

A receiving unit configured to receive an intra-frequency event report reported by the UE after detecting the intra-frequency neighbor cell set. The intra-frequency event report includes the target primary scrambling code PSC and the currently connected cell and the intra-frequency event report. The observation time difference of the air interface between co-frequency cells in the neighboring cell set;

A matching unit, configured to match the obtained target PSC with the PSC of each same-frequency cell in the same-frequency neighbor cell set, and use the same-frequency cell whose PSC is the same as the target PSC as the cell to be determined. ;

A difference calculation unit configured to respectively calculate the observation time difference corresponding to the cell to be determined and the current connection when the matching result of the matching unit is that the cell to be determined is a plurality of cells with different cell IDs. The difference in the theoretical time difference of the air interface between a cell and the corresponding cell to be determined;

A determining unit configured to determine, when the difference meets a preset threshold, that the cell to be determined corresponding to the difference is a target cell for the UE to perform soft handover.

7. The device according to claim 6, characterized in that the difference calculation unit is also used to calculate the difference using the following formula:

X=ABS(((OFFa+Tma)-(OFFb+Tmb))mod 256 - ((Diffa-Tcella)-(Diffb-Tcellb)) mod 256)

in,

The values of Diffa and Diffb are obtained from the NodeB-level load broadcast, where Diffa and Diffb represent the difference between the NodeB general frame number counter BFN and the RNC general frame number counter RFN of the CELLa and CELLb cells respectively;

Tcella and Tcellb are obtained from cell-level load;

ABS represents absolute value.

8. The device according to claim 6, characterized in that,

The determining unit is further configured to determine, when a plurality of the differences satisfy a preset threshold, that the cell to be determined corresponding to the smallest one of the plurality of differences is the cell for soft handover of the UE. target neighborhood.

9. The device according to claim 6, characterized in that,

10. The device according to any one of claims 6 to 9, characterized in that,