CN101626590B

CN101626590B - Method for preventing conflict between moving load balance and moving robustness optimization function

Info

Publication number: CN101626590B
Application number: CN2009100902813A
Authority: CN
Inventors: 薛开平; 彭敏; 洪佩琳; 刘志强; 叶浩
Original assignee: University of Science and Technology of China USTC
Current assignee: University of Science and Technology of China USTC
Priority date: 2009-08-04
Filing date: 2009-08-04
Publication date: 2012-07-04
Anticipated expiration: 2029-08-04
Also published as: CN101626590A

Abstract

The invention provides a method for preventing a conflict between moving load balance and moving robustness optimization function, which adopts the main idea that when the moving load balance operation is carried out in an LTE-Advanced network, the adjustment of the moving load balance to a switching threshold needs to be limited in the tolerance range of the moving robustness optimization so as to prevent various switching problems caused by inaccurately adjusting the switching parameter by the moving load balance.

Description

A kind of method of avoiding moving load equilibrium and mobile robustness optimization function conflict

Technical field

The present invention relates to the mobile communication technology field; Be particularly related to a kind of LTE of being used for (Long-term Evolution; The 3GPP Long Term Evolution) solves mobile robustness optimization (MRO in the network; Mobility Robustness Optimization) with the method for balanced (MLB, the Mobility Load Balance) function conflict of moving load, belongs to moving communicating field.

Background technology

In the 3GPP long evolving system,, excessive to the configuration employing human configuration and the administration overhead of parameter because the number of network parameter is doted on big and complexity is higher.In order to improve the operation and maintenance performance of network; Reduce configuration and management of base station (3GPP has proposed self-organizing network (Self-Organizing Networks for enhanced Node B, the manual work intervention in the time of eNB) as far as possible; SON), its effective means with complexity that is considered to reduce cost.

Self-organizing network is divided into self-configuring (Self-Configuration), self-optimizing (Self-Optimization) and cures (Self-Healing) three parts certainly.Self-configuring is meant that newly deployed node independently knows necessary fundamental system operative configuration through " autoinstall procedure ", thereby realizes configuration automatically; Self-optimizing is meant and utilizes subscriber equipment (User Equipment UE) measures with eNB and the result of performance measurement adjusts network automatically; Can detect and locate most of problematic places automatically from curing, and solve these problems through certain mechanism.

(Mobility Robustness Optimization, MRO) (MobilityLoad Balancing MLB) is two important use-cases (Use Case) of self-optimizing process among the self-organizing network SON to mobile robustness optimization with the moving load equilibrium.

Between eNB handoff parameter the position that has determined handoff threshold is set, incorrect if handoff threshold is provided with, can cause UE that inappropriate switching takes place and Radio Link lost efficacy.As the too early switching (Too EarlyHO) of switching of rattling (Ping-Pong HO) and UE, spend evening and switch (Too Late HO) with switch to the Radio Link inefficacy that wrong cell (HO To A Wrong Cell) brings (Radio Link Failure, RLF).The MRO function; Be meant switching problem through statistics UE, thereby to corresponding handoff parameter, like sub-district individual offsets amount (Cell Individual Offset; CIO); (Time To Triger TTT) waited and to adjust, thereby avoids or reduce inappropriate switching and Radio Link inefficacy triggered time.

In the coverage of eNB, reason can cause the load too high of eNB owing to traffic carrying capacity is more etc., thereby can have influence on the service quality of UE.The MLB function is meant through the adjustment handoff parameter, waits like cell specific offset amount (Cell Specific Offset) to change handoff threshold, makes the part UE of high capacity eNB switch to the neighbours eNB that hangs down load, thus the load between balanced eNB.

At present, MRO and MLB function are separate, the collision problem between consideration and the other side.For example, the MRO function switches according to detected table tennis and Radio Link lost efficacy, and handoff threshold is adjusted accordingly, thereby reduced the generation that table tennis switches and Radio Link lost efficacy; Meanwhile, the MLB function for the UE that makes high capacity eNB switches to the neighbours eNB that hangs down load, possibly is transferred to the origin-location with handoff threshold again from the consideration of load between balanced eNB, causes table tennis switching and Radio Link to lose efficacy and occurs again.The MRO function is switched according to detected table tennis and the Radio Link inefficacy afterwards, can adjust accordingly handoff threshold once more, but the MLB function possibly is transferred to the origin-location with handoff threshold again once more.Such two functions will get into a circulation, during can cause UE to produce that table tennis switches and problems such as Radio Link inefficacy.

Therefore, how to make MRO and MLB function unite and carry out, clash when avoiding both to adjust parameter, become the problem of needing solution at present badly.

Summary of the invention

The technical problem that the present invention will solve: the deficiency that overcomes prior art; A kind of method that mobile robustness optimization conflicts with the moving load equalization function that solves is proposed; It realizes simple; Under the situation that MRO and MLB function are launched simultaneously, two functional modules all can operate as normal, and parameter adjustment each other can not cause the another one module to optimize the inefficacy of effect.

MLB changes handoff threshold through adjustment handoff parameter (Cell Specific Offset etc.), makes the part UE of high capacity eNB switch to its neighbours eNB, thus the load between the balanced eNB; MRO is through adjustment switching-related parameters (CellIndividual Offset; Timer to Triger etc.); Carry out handover optimization with changing the isoparametric mode of handoff threshold; Avoid or reduce incorrect switching (Ping-Pong HO, Too Early HO, Too Late HO and HO to A Wrong Cell) and Radio Link lost efficacy (Radio Link Failure, appearance RLF).Because MLB and MRO operate through the mode that changes handoff threshold, when the both adjusts switching-related parameters, may produce conflict.For example, the MRO function is adjusted handoff threshold according to detected incorrect switching, switches and RLF thereby reduce Ping-Pong; Simultaneously, MLB possibly be transferred to original state with handoff threshold again from the consideration of load balancing, causes incorrect switching before this to occur again.

The present invention proposes a kind of method that mobile robustness optimization conflicts with the moving load equalization function that solves.In this method, after incorrect switching took place, MRO was known the switching problem of generation through the UE feedback, mutual through between the eNB, and MRO can be known the handoff threshold that all kinds of incorrect switchings take place.MRO gives the MLB functional module these Threshold Notify, MLB in the adjustment handoff threshold, as long as be not transferred to the thresholding place that incorrect switching takes place, just can avoid with MRO between conflict.

Description of drawings

Fig. 1 is the overlapping sketch map that causes Ping-Pong HO of handoff threshold;

Fig. 2 is a MLB adjustment thresholding sketch map of avoiding Ping-Pong HO;

Fig. 3 is a MLB adjustment thresholding sketch map of avoiding Too Early HO;

Fig. 4 is a MLB adjustment thresholding sketch map of avoiding Too Late HO.

Embodiment

Illustrate implementation method of the present invention below in conjunction with accompanying drawing and three specific embodiments of the present invention.

Embodiment 1

In the embodiment of the invention because inappropriate handoff parameter causes the Ping-Pong HO of UE between adjacent eNB.Fig. 1 has provided the sketch map of the overlapping Ping-Pong of the causing HO of handoff threshold.

Present embodiment provide a kind of avoid carrying out Ping-Pong HO robustness optimization after, the method for MLB and MRO function conflict.The practical implementation step is following:

1) neighbours' eNB 1 and 2 MRO module are detecting after Ping-Pong HO takes place in the switching of the other side eNB each other, and the critical handoff threshold when according to formula 1 record Ping-Pong HO taking place is designated as T at interval _{1,2, PingPong}Change step 2 over to if the relevant parameter of eNB 1 or eNB 2 has renewal, otherwise change step 3 over to;

T _1,2=(H ₁-CIO _1,2)+(H ₂-CIO _2,1) H in (1) formula 1 ₁Be the hysteresis (Hysteresis) of eNB i, CIO _{I, j}Be the side-play amount (CellIndividual Offset) of eNB i for eNB j maintenance

2) eNB notifies the eNB to the other side neighbours with own updated H and CIO value through the X2 interface between eNB;

3) according to T _{1,2, PingPong}Calculate the threshold value of carrying out the MLB adjustment, like formula 2;

Threshold _{1，2，PingPong}＝T _{1，2，PingPong}-H ₂+CIO _2，1 (2)

4) when overload takes place in eNB 1, use the MLB function to carry out load balancing, be constraints with formula 3, guarantee that MLB to being adjusted within the MRO allowed band of eNB handoff parameter, avoids causing Ping-Pong HO again, as shown in Figure 2.

H ₁-CIO _1，2＞Threshold _{1，2，PingPong} (3)

Embodiment 2

In the embodiment of the invention, because eNB has used inappropriate handoff parameter will cause Too Early HO.Present embodiment provide a kind of avoid carrying out Too Early HO robustness optimization after, the method for MLB and MRO function conflict.The practical implementation step is following:

1) the MRO module of eNB 1 is detecting after Too Early HO takes place in the switching of eNB 2, and record causes the wrong hysteresis H that switches _{1, Early}And CIO _{1,2, Early.}。H wherein _{1, Early}And CIO _{1,2, Early}Be respectively that eNB 1 employed hysteresis (Hysteresis) and eNB 1 were the set sub-district side-play amount (Cell IndividualOffset) of eNB 2 when Too Early Ho took place;

2) calculate the handoff threshold that Too Early HO takes place, like formula 4;

Threshold _{1，2，Early}＝H _1，Early-CIO _{1，2，Early} (4)

3) when overload takes place in eNB 1, use the MLB function to carry out load balancing, be constraints with formula 5, guarantee that MLB to being adjusted within the MRO allowed band of eNB handoff parameter, avoids causing again Too Early HO, as shown in Figure 3.

H ₁-CIO _1，2＞Threshold _{1，2，Early} (5)

Embodiment 3

In the embodiment of the invention because inappropriate handoff parameter causes Too Late HO.Present embodiment provide a kind of avoid carrying out Too Late HO robustness optimization after, the method for MLB and MRO function conflict.The practical implementation step is following:

1) the MRO module of eNB 2 detects after Too Late HO takes place in the switching of eNB 1, the hysteresis H when Too Late HO takes place the MRO record of eNB 2 _{2, Late}And CIO _{2,1, Late.}。H wherein _{2, Late}And CIO _{2,1, Late}Be respectively that eNB 2 employed hysteresis (Hysteresis) and eNB 2 were the set sub-district side-play amount (CellIndividual Offset) of eNB 1 when Too LateHo took place;

H and CIO when 2) Too Late HO will take place the MRO module of eNB 1 and eNB 2 pass to the other side through X2 interface.The MLB module of eNB combines table tennis to switch relevant T _{1,2, PingPong}, calculate adjustable threshold range.

3) eNB 2 calculates the handoff threshold that Too Late HO takes place, like formula 6;

Threshold _2，1，Late＝H _2，Late-CIO _2，1，Late (6)

4) when overload takes place in eNB 1, use the MLB function to carry out load balancing, be constraints with formula 7, guarantee that MLB to being adjusted within the MRO allowed band of eNB handoff parameter, prevents handoff threshold is transferred to the degree that Too Late HO takes place, as shown in Figure 4.

H ₁-CIO _1，2＞T _{1，2，PingPong}-Threshold _2，1，Late (7)

Claims

1.LTE-Advanced a kind of method of avoiding mobile robustness optimization to conflict with the moving load equalization function in the network is characterized in that:

Base station eNB carries out needing the relevant threshold parameter of record after the mobile robustness optimization parameter adjustment; When carrying out the moving load equalization operation; The adjustment of moving load equilibrium to handoff threshold is limited in the scope of mobile robustness optimization permission, causes switching problem to avoid the balanced wrong adjustment handoff parameter of moving load.

2.LTE-Advanced a kind of method of avoiding mobile robustness optimization to conflict with the moving load equalization function in the network is characterized in that:

Base station eNB is being carried out the threshold parameter that mobile robustness optimization parameter adjustment postscript picture recording closes: when robustness optimization is carried out in switching to Ping-Pong, write down critical handoff threshold interval T _PingPongAnd according to neighbours eNB handoff parameter calculating Ping-Pong handoff threshold; Base station eNB is carried out moving load when balanced, is the parameter adjustable extent that constraints limits the moving load equalization operation with self eNB handoff parameter and above-mentioned Ping-Pong handoff threshold.

3.LTE-Advanced a kind of method of avoiding mobile robustness optimization to conflict with the moving load equalization function in the network is characterized in that:

Base station eNB is being carried out the threshold parameter that mobile robustness optimization parameter adjustment postscript picture recording closes: when robustness optimization was carried out in switching to Too Early, record eNB handoff parameter setting was also calculated corresponding Too Early handoff threshold; Base station eNB is carried out moving load when balanced, is the parameter adjustable extent that constraints limits the moving load equalization operation with self eNB handoff parameter and above-mentioned Too Early handoff threshold.

4.LTE-Advanced a kind of method of avoiding mobile robustness optimization to conflict with the moving load equalization function in the network is characterized in that:

Base station eNB is being carried out the threshold parameter that mobile robustness optimization parameter adjustment postscript picture recording closes: when robustness optimization is carried out in switching to Too Late, according to neighbours eNB handoff parameter the corresponding Too Late handoff threshold of calculating is set; Base station eNB is carried out moving load when balanced, with self eNB handoff parameter critical handoff threshold interval T when PingPong taking place switch _PingPongAnd above-mentioned Too Late handoff threshold is the parameter adjustable extent that constraints limits the moving load equalization operation.