WO2012083666A1

WO2012083666A1 - Method and device for optimizing load balance

Info

Publication number: WO2012083666A1
Application number: PCT/CN2011/076395
Authority: WO
Inventors: 卫建国; 朱永升
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-12-23
Filing date: 2011-06-27
Publication date: 2012-06-28
Also published as: CN102572948A

Abstract

A method and device for optimizing load balance are provided in the present invention, and said method includes that: when judging that load balance is required to be performed in the cell managed by eNB itself, the eNB selects all the UEs or some UEs in said cell, adjusts the threshold parameter of the handover event, and transmits said threshold parameter to the selected UEs; said eNB selects one or more UEs for handover based on the measure report reported by UE and the load state of said cell.

Description

Method and device for optimizing load balancing

Technical field

The present invention relates to the field of communications, and in particular to a method and apparatus for optimizing load balancing in an LTE (Long Term Evolution) system.

Background technique

Load balancing is a method to prevent excessive load on individual cells. It can distribute the load as evenly as possible among the geographically related cells, and reduce the load concentration in a certain cell in the area, thereby effectively improving the overall performance of the system. Improve the security, stability and capacity of the system to achieve an overall optimal state.

The process of load balancing generally consists of three phases: the measurement phase, the judgment phase, and the execution phase. The measurement phase is mainly to measure the load situation in the cell, and obtain the load information of the neighboring area (including the coverage and the inclusion relationship) through the interface between the eNBs (base stations); the judgment stage is to determine whether the community needs to perform the load according to the measured value. Equilibrium, if load balancing needs to be performed, then the third phase operation is performed, otherwise the cell will repeat the first two phases to perform real-time monitoring on the system; in the execution phase, the high-load cell should select the appropriate UE (user equipment) to switch to The low-load cell makes the load of each cell in the area equivalent.

The measurement phase is to measure the resource status of the cell, such as the PRB (physical resource block) occupancy rate, and to exchange load information through the X2 port and the neighboring cell on the neighboring base station.

In the implementation phase, the UE is selected to switch to the neighboring cell according to the service priority of the UE. However, there is a problem. For a cell with the coverage or inclusion relationship, the cell with high load is generally because of its good signal quality and the number of users accessing it, and the high load is achieved. The low-load cell in the same geographical location often The signal quality is worse than the high load cell. Then, in order to achieve load balancing, after the UE selected by the service priority switches to the low-load cell, it is likely that the signal quality is poor, and it is necessary to switch back to the high-load cell immediately, that is, ping-pong switching occurs. Summary of the invention

The technical problem to be solved by the present invention proposes a method and apparatus for optimizing load balancing to avoid ping-pong switching.

In order to solve the above problem, the present invention provides a method for optimizing load balancing, including: when an eNB determines that a cell under its jurisdiction needs to perform load balancing, select all the cells in the cell.

The UE or a part of the UE, and adjusting the threshold parameter of the handover event, and sending the threshold parameter to the selected UE;

The eNB selects one or more UEs to perform handover according to the measurement report reported by the UE and the load condition of the cell.

Optionally, the step of selecting all UEs or part of UEs in the cell includes: selecting, by the eNB, part of UEs in the cell according to service priority.

Optionally, the step of the eNB adjusting a threshold parameter of the handover event includes: the eNB reducing a threshold parameter of the handover event.

Optionally, the step of sending the threshold parameter to the selected UE includes: sending, by the eNB, the adjusted threshold parameter to the selected UE by using a reconfiguration message.

Optionally, the method further includes:

After the eNB sends the threshold parameter to the selected UE, if the UE that meets the handover condition is not selected, the selected UE is added, and a reconfiguration message is sent to the added UE, or the RRC is adjusted again. The threshold parameter of the handover event is resent to the selected UE.

Optionally, the handover event includes one or more of an A3 event, an A4 event, and an A5 event. When the handover event is an A3 event, the threshold parameter adjusted by the eNB is an individual frequency offset of the serving cell or Hysteresis threshold.

Optionally, the method further includes:

The eNB determines whether the cell under its jurisdiction needs to perform load balancing according to the load condition of the cell under its jurisdiction and the neighboring area load information carried in the neighboring resource status report information sent by the neighboring base station.

The present invention also provides an apparatus for optimizing load balancing, which is applied to an eNB, where the apparatus includes Number adjustment module and switching selection module, wherein

The parameter adjustment module is configured to: when it is determined that the cell managed by the eNB needs to perform load balancing, select all user equipments (UEs) or partial UEs in the cell, and adjust threshold parameters of the handover event, where the The threshold parameter is sent to the selected UE;

The handover selection module is configured to: select one or more UEs to perform handover according to the measurement report reported by the UE and the load condition of the cell.

Optionally, the parameter adjustment module is configured to adjust a threshold parameter of the handover event in the following manner: lowering a threshold parameter of the handover event.

Optionally, the parameter adjustment module is configured to send the threshold parameter to the selected UE in the following manner: sending the threshold parameter to the selected UE by using a reconfiguration message.

Optionally, the switching selection module is further configured to notify the parameter adjustment module if the UE that meets the handover condition is not selected;

The parameter adjustment module is further configured to: if the notification sent by the handover selection module that does not select the UE that meets the handover condition is received, add the selected UE, and send a reconfiguration message to the added UE, or Adjusting the threshold parameter of the handover event, and resending the reconfiguration message to the selected UE.

The above solution can reduce the signal quality of the UE after handover to the target cell while reducing the load of the source cell, thereby avoiding the occurrence of ping-pong handover, and does not necessarily have to switch to the same coverage or the cell containing the relationship. BRIEF abstract

1 is a flow chart of load balancing according to Embodiment 1 of the present invention;

2 is a schematic diagram of a request and response message for acquiring a neighbor resource status in an embodiment of the present invention;

4 is a schematic diagram of an air interface RRC connection reconfiguration process according to an embodiment of the present invention; FIG. 5 is a schematic diagram of a UE transmitting a measurement report to an eNB according to an embodiment of the present invention.

Preferred embodiment of the invention

In the embodiment of the present invention, the eNB adjusts the threshold parameter of the handover event in the load balancing process to select a more suitable UE to switch to the neighboring cell.

Specifically, when the eNB determines that the cell under its jurisdiction needs to perform load balancing, the UE selects all the UEs or part of the UEs in the cell, and adjusts the threshold parameter of the handover event, and sends the threshold parameter to the selected UE. The eNB selects one or more UEs to perform handover according to the measurement report reported by the UE and the load condition of the cell. The eNB determines whether the cell under its jurisdiction needs to perform load balancing according to the load condition of the cell under its jurisdiction and the neighboring area load information carried in the neighboring cell resource status report information sent by the neighboring base station.

The eNB may select a part of the UEs in the cell to send the threshold parameter according to the service priority.

The handover event may include an A3 event, an A4 event, an A5 event, and the like.

Wherein, the quality of service (RSRP (Reference Signal Received Power) / RSRQ (Reference Signal Received Quality)) of the neighboring cell is higher than the serving cell by an absolute threshold, triggering A3 event switching; when the quality of service of the neighboring cell is higher than an absolute threshold, Triggering A4 event switching; When the serving quality of the serving cell is lower than an absolute threshold of 1, the quality of service of the neighboring cell is higher than an absolute threshold of 2, triggering the A5 event switching.

The eNB may reduce the threshold parameter of the A3/A4/A5 event, so that the condition of the handover is more easily satisfied (such as reducing the individual frequency offset or the hysteresis threshold of the serving cell of the A3 event), and the adjusted threshold parameter is passed under the reconfiguration message. Send to the selected UE.

After receiving the reconfiguration message, the UE performs measurement. If the handover condition is met, the UE reports the measurement report to the eNB, and the eNB selects an appropriate UE to perform handover.

In addition, after the eNB sends the threshold parameter to the selected UE, if the UE that meets the handover condition is not selected, the selected UE may be added, and the reconfiguration message may be sent to the added UE, or may be adjusted again. The threshold parameter of the handover event is used to resend the reconfiguration message to the selected UE.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that In the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other. Embodiment 1

As shown in FIG. 1, the embodiment of the present invention includes the following steps:

Step 101: The eNB determines whether the load balancing period is reached. If yes, the next step is performed. Step 102: The eNB obtains the load of the cell under its jurisdiction (hereinafter referred to as the local cell) through the measurement module; and sends the packet through the neighboring base station. The neighboring resource status report information, and obtain the load information of the neighboring area;

As shown in FIG. 2 and FIG. 3, the neighbor cell load information is acquired through the X2 port.

Referring to FIG. 2, the eNB1 sends a resource status request message (RESOURCE STATUS REQUEST) to the base station eNB2 to which the neighboring cell belongs;

eNB2 returns a resource status response message to eNB1 (RESOURECE STATUS RESPONSE)

Referring to FIG. 3, the eNB2 sends a resource status update message (RESOURCE STATUS UPATE) (ie, neighbor cell resource status report information) to the eNB1, where the load information of the cell under the jurisdiction of the eNB2 is carried.

Step 103, determining whether the cell is the highest load cell, and if yes, performing the next step, if not, executing step 109;

Step 104, determining whether the load of the local cell exceeds the startup threshold of the load balancing, and if yes, performing the next step, otherwise, performing step 109;

The cell load is based on the PRB utilization of the GBR (Guest Guaranteed Bit Rate) service, the PRB utilization of the GBR service in the uplink, and the Non-Guaranteed Bit Rate (NGBR) service. a load value calculated by the PRB utilization rate, the PRB utilization rate of the NGBR service, the total PRB usage rate of the cell downlink, the total PRB usage rate of the cell uplink, the downlink system bandwidth of the cell, and the uplink system bandwidth of the cell, If it is greater than a certain threshold (which can be set by the background), the load balancing process is performed.

Step 105: Reduce a threshold parameter of the handover event (referred to as a handover threshold); For example, for an A3 event,

The conditions for entering the A3 event are: Mn + Ofn + Ocn-Hys >Ms + Ofs + Ocs + Off ,

Where Μη is the measured value of the neighboring area RSRP (reference signal received power) or RSRQ (reference signal received quality), 0 is the adjacent area frequency offset, Ocn is the adjacent area frequency offset, and Ms is the serving cell RSRP (reference signal received power) ) or RSRQ (reference signal reception quality) measured value, Ofs is the serving cell frequency offset, Ocs is the serving cell individual frequency offset, Hys is the hysteresis, and Off is the deviation of the judgment condition.

In addition to the measured values, other parameters are available. For example, for this conditional formula, the value of Ocs (individual frequency offset of the serving cell) or Hys (hysteresis threshold) can be lowered, so that the A3 event is easily satisfied, and switching occurs.

Step 106: Reconfigure the measurement task for all UEs in the cell (the measured neighboring cell is the neighboring cell with the lowest load)

As shown in FIG. 4, the eNB sends a reconfiguration message (RRC Connection Reconfiguration, RRC Connection Reconfiguration message) to the UE, and carries the handover threshold.

The UE returns a reconfiguration complete message to the eNB (RRC Connection Reconfiguration)

Complete, the RRC connection reconfiguration complete message).

Step 107: After receiving the reconfiguration message, the UE performs measurement, and if the handover condition is met, the measurement report is measured on the eNB, as shown in FIG. 5;

Step 108: The eNB selects a UE to perform handover according to the measurement report reported by the UE and the load condition of the cell.

Step 109: Wait for the next load balancing execution period to arrive.

Embodiment 2

Steps 201 to 205 are the same as steps 101 to 105 of the first embodiment.

Step 206: The first embodiment is modified, and part of the UE is selected according to the service priority, and the measurement task is re-allocated to the selected UE.

Steps 207 to 209 are the same as steps 107 to 109 of the first embodiment. Embodiment 3

In the second example, since the number of UEs selected according to the service priority is limited, even if the handover threshold is lowered, there is a possibility that no UE can satisfy the handover condition. Example 3 is an improvement of the second example.

Steps 301 to 305 are the same as steps 101 to 105 of the first embodiment.

Step 306: Select a partial UE according to the service priority, and re-assign the measurement task to the selected UE. Step 307: If the measurement report is not received within the predetermined time, then expand the step 306 to select the UE according to the service priority. , or lower the handover threshold again, resend the measurement task, repeat step 307 until the UE that meets the handover condition is selected, and performs handover;

Step 308, waiting for the next load balancing execution period to arrive.

The following needs to be noted in this embodiment:

1. The switching threshold cannot be lowered too low to avoid unreasonable switching.

Second, in order to avoid excessive signaling overhead, the degree of expanding the selected UE set or lowering the handover threshold may be appropriately larger to avoid step 307 looping multiple times.

The apparatus for optimizing load balancing according to the embodiment of the present invention is applied to an eNB, and includes a parameter adjustment module and a handover selection module, where

The parameter adjustment module is configured to: when it is determined that the cell under the control of the eNB needs to perform load balancing, select all UEs or part of the UEs in the cell, and adjust a threshold parameter of the handover event, and send the threshold parameter Give the selected UE;

Optionally, the parameter adjustment module is configured to: when adjusting a threshold parameter of the handover event, reduce a threshold parameter of the handover event.

Optionally, the handover selection module is further configured to: if the parameter adjustment module sends the adjusted threshold parameter to the selected UE by using a reconfiguration message, if the UE that meets the handover condition is not selected, The parameter adjustment module; the parameter adjustment module is further configured to: If the module does not select the UE that meets the handover condition, the selected UE is added, and the reconfiguration message is sent to the added UE, or the threshold parameter of the handover event is adjusted again, and the reconfiguration message is resent to the selected UE. .

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Optionally, all or part of the steps of the foregoing embodiments may also be implemented by using one or more integrated circuits. Accordingly, each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may use software functions. The form of the module is implemented. The invention is not limited to any specific form of combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

The above-mentioned embodiments of the present invention can reduce the signal quality of the UE after handover to the target cell while reducing the load of the source cell, thereby avoiding the occurrence of ping-pong handover, and does not necessarily have to switch to the cell with the coverage or the inclusion relationship.

Claims

Claim

1. A method for optimizing load balancing, comprising:

When the base station (eNB) determines that the cell under its jurisdiction needs to perform load balancing, select all user equipments (UEs) or some UEs in the cell, and adjust threshold parameters of the handover event, and send the threshold parameter to the selected one. UE;

2. The method according to claim 1, wherein the step of selecting all UEs or partial UEs in the cell comprises:

The eNB selects a part of UEs in the cell according to a service priority.

3. The method of claim 1, wherein

The step of the eNB adjusting a threshold parameter of the handover event includes: the eNB reducing a threshold parameter of the handover event.

The method of claim 1, wherein the step of sending the threshold parameter to the selected UE comprises:

And the eNB sends the adjusted threshold parameter to the selected UE by using a reconfiguration message.

5. The method of claim 4, the method further comprising:

6. The method of claim 1, wherein

The handover event includes one or more of an A3 event, an A4 event, and an A5 event. When the handover event is an A3 event, the threshold parameter adjusted by the eNB is a serving cell individual frequency offset or a hysteresis threshold.

The method according to any one of claims 1 to 6, further comprising: the eNB carrying the information according to the load condition of the cell under its jurisdiction and the neighboring resource status report information sent by the neighboring base station Neighbor load information, determine whether the cell under its jurisdiction needs to load Balanced.

8. An apparatus for optimizing load balancing, which is applied to a base station (eNB), where the apparatus includes a parameter adjustment module and a handover selection module, where

9. The apparatus according to claim 8, wherein

The parameter adjustment module is configured to adjust a threshold parameter of the handover event in the following manner: Lowering a threshold parameter of the handover event.

10. The apparatus according to claim 8, wherein

The parameter adjustment module is configured to send the threshold parameter to the selected UE in the following manner: the threshold parameter is sent to the selected UE by using a reconfiguration message.

11. The apparatus according to claim 10, wherein

The handover selection module is further configured to: notify the parameter adjustment module if the UE that meets the handover condition is not selected;