CN103096382B

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Publication number: CN103096382B
Application number: CN201310030579.1A
Authority: CN
Inventors: 李红艳; 李建东; 韩涛; 王玺钧; 黄鹏宇; 马英红; 刘伟; 李钊; 杨春刚; 赵林靖; 侯蓉晖
Original assignee: Xidian University
Current assignee: Xidian University
Priority date: 2013-01-25
Filing date: 2013-01-25
Publication date: 2015-04-08
Anticipated expiration: 2033-01-25
Also published as: CN103096382A

Abstract

本发明公开了一种泛在网络中非相邻异构小区之间的负载均衡方法，主要解决现有技术中当相邻小区负载过重不能接收本小区待转移负载时无法进行负载均衡的问题。其实现步骤是：由无线接入点AP周期性收集本小区、相邻小区和两跳小区的负载信息，根据本小区归一化负载是否超过负载均衡启动门限判断是否进行负载均衡；根据相邻小区和两跳小区的负载信息判断向相邻小区转移负载还是向两跳小区转移负载；选择切换对象，根据切换对象的切换代价最小选择最佳负载转移小区；指示切换对象切换到相应小区中完成负载均衡。本发明实现了非相邻异构小区之间的负载均衡，扩大了负载均衡的范围，提高了网络性能和资源利用率，可用于异构通信环境中的资源优化。

The invention discloses a load balancing method among non-adjacent heterogeneous cells in a ubiquitous network, which mainly solves the problem in the prior art that load balancing cannot be performed when adjacent cells are overloaded and cannot receive the load to be transferred in this cell . The implementation steps are: the wireless access point AP periodically collects the load information of the local cell, the adjacent cell and the two-hop cell, and judges whether to perform load balancing according to whether the normalized load of the cell exceeds the load balancing start threshold; The load information of the cell and the two-hop cell judges whether to transfer the load to the adjacent cell or to the two-hop cell; select the switching object, and select the best load transfer cell according to the switching cost of the switching object; instruct the switching object to switch to the corresponding cell to complete Load balancing. The invention realizes the load balancing between non-adjacent heterogeneous cells, expands the range of load balancing, improves network performance and resource utilization rate, and can be used for resource optimization in heterogeneous communication environments.

Description

Translated fromChinese

泛在网络中非相邻异构小区之间的负载均衡方法A load balancing method between non-adjacent heterogeneous cells in ubiquitous networks

技术领域technical field

本发明属于通信技术领域，更进一步涉及一种泛在网络中非相邻异构小区之间的负载均衡方法。本发明可以实现异构小区之间，特别是在相邻小区负载过重无法接收待转移负载的情况下，实现非相邻异构小区之间负载的转移，避免由于小区间负载不均衡造成的通信质量差和资源浪费等现象。The invention belongs to the technical field of communication, and further relates to a load balancing method among non-adjacent heterogeneous cells in a ubiquitous network. The present invention can realize load transfer between heterogeneous cells, especially when adjacent cells are too heavily loaded to receive the load to be transferred, and realize load transfer between non-adjacent heterogeneous cells, avoiding problems caused by unbalanced loads among cells Phenomena such as poor communication quality and waste of resources.

背景技术Background technique

随着微电子和无线通信技术的快速发展，任何人在任何时候、任何地点都能进行通信的泛在网络时代逐渐成为一种可能。泛在网络更多涉及多种异构网络同时存在且相互重叠、互为补充的网络架构，在这种网络架构下，用户可使用多种网络资源，但是同时也使得不同网络资源的协调变得更加困难。例如，某一网络资源的过度使用会造成该网络的负荷过重，使得用户通信质量变差；而在某些网络负荷过重情况下，某些网络资源却可能未得到充分利用。因此，泛在网络中异构网络之间的负载均衡成为亟待解决的重要问题。With the rapid development of microelectronics and wireless communication technology, the ubiquitous network era in which anyone can communicate at any time and any place has gradually become a possibility. The ubiquitous network involves a network architecture in which multiple heterogeneous networks coexist and overlap and complement each other. Under this network architecture, users can use a variety of network resources, but at the same time it also makes the coordination of different network resources easier. more difficult. For example, the excessive use of a certain network resource will cause the network to be overloaded, making the user's communication quality deteriorate; while some network resources may not be fully utilized when the network is overloaded. Therefore, load balancing between heterogeneous networks in ubiquitous networks has become an important problem to be solved urgently.

与同构网络不同，异构网络之间进行负载均衡需要新的准则。由于不同网络中用户的信号强度、资源利用率以及用户服务质量QoS的评价标准均不相同，不能像同构网络中单纯的使用信号强度RSS或信干噪比SINR作为切换标准，因此在进行负载均衡时是否可以将一个用户切换至另一个网络需要新的准则。Unlike homogeneous networks, load balancing between heterogeneous networks requires new guidelines. Since the signal strength, resource utilization rate, and QoS evaluation criteria of users in different networks are different, it is not possible to simply use signal strength RSS or signal-to-interference-noise ratio (SINR) as handover criteria in homogeneous networks. Whether it is possible to handover a user to another network during equalization requires new criteria.

除此之外，目前的负载均衡方法均是将负载转移到待转移负载小区的相邻小区中，若此时待转移负载小区的所有相邻负载均不满足接收负载的条件，负载均衡将无法执行。此时如何实现负载的转移是另一重要问题。In addition, the current load balancing method is to transfer the load to the adjacent cells of the cell to be transferred. If all the adjacent loads of the cell to be transferred do not meet the conditions for receiving the load, the load balancing will not be possible. implement. How to achieve load transfer at this time is another important issue.

为了解决这一问题，中兴通讯股份有限公司的专利申请文件“一种异构网络中小区的切换方法与装置”（公开号：CN102625368A，申请号：CN201210065333.3，申请日期：20120801）提出了一种异构网络中小区的切换方法。在这种方法中，基站通过异构网络节点负载率对比器确定负载均衡的负载率选择区间；基站根据信号干扰噪声比SINR阈值确定正在为UE服务的网络节点的首选分组；基站的切换激活与确认器根据UE反馈的小区信息，按照所述首选分组和负载率选择区间对UE进行小区切换。In order to solve this problem, ZTE Corporation’s patent application document "A Cell Handover Method and Device in a Heterogeneous Network" (publication number: CN102625368A, application number: CN201210065333.3, application date: 20120801) proposed a A cell handover method in a heterogeneous network. In this method, the base station determines the load rate selection interval of load balancing through the load rate comparator of heterogeneous network nodes; the base station determines the preferred grouping of the network node serving the UE according to the signal-to-interference and noise ratio SINR threshold; the handover activation of the base station and The confirmer performs cell handover for the UE according to the preferred group and load rate selection interval according to the cell information fed back by the UE.

经过分析，可发现上述方案存在以下不足：首先，在为UE选择服务网络节点时单纯以信号干扰噪声比SINR作为标准，没有考虑到异构网络中不同网络之间的差异，也没有考虑到其他因素的影响；其次，负载均衡的实现是通过在不同网络之间切换用户实现，但是当某一用户所在位置可接入的所有网络负载均过重时，将无法通过切换用户实现负载的转移。After analysis, it can be found that the above scheme has the following deficiencies: First, when selecting the serving network node for the UE, the signal-to-interference-noise ratio (SINR) is simply used as the standard, and the differences between different networks in the heterogeneous network are not considered, nor are other factors considered. Second, load balancing is achieved by switching users between different networks, but when all the networks that a certain user can access are overloaded, it will not be possible to transfer the load by switching users.

发明内容Contents of the invention

本发明的目的在于针对上述已有技术的不足，提出一种在非相邻异构小区之间进行负载转移的方法，以实现异构小区之间的负载均衡，提高资源利用率和系统性能。The object of the present invention is to address the shortcomings of the above prior art, and propose a method for load transfer between non-adjacent heterogeneous cells, so as to realize load balancing between heterogeneous cells, and improve resource utilization and system performance.

本发明实现上述目的的技术思路是：当某一小区负载超过负载均衡启动门限时，首先考虑向相邻小区切换用户将负载转移到相邻异构小区中；当相邻小区由于负载过重均不满足接收本小区待转移负载的条件时，考虑以相邻小区作为中介通过两步切换将待转移负载转移到与本小区不相邻但与本小区的相邻小区相邻的两跳小区中。在切换至两跳小区的过程中，首先从本小区的相邻小区中选择用户切换至两跳小区，再从本小区中选择用户切换至本小区的相邻小区。The technical idea of the present invention to achieve the above purpose is: when the load of a certain cell exceeds the load balancing start threshold, first consider switching the user to the adjacent cell to transfer the load to the adjacent heterogeneous cell; When the conditions for receiving the load to be transferred in the own cell are not satisfied, consider using the adjacent cell as an intermediary to transfer the load to be transferred to a two-hop cell that is not adjacent to the current cell but adjacent to the adjacent cell of the current cell through two-step handover . In the process of handing over to a two-hop cell, first select users from the adjacent cells of the current cell to switch to the two-hop cell, and then select users from the current cell to switch to the adjacent cells of the current cell.

当存在多个相邻小区满足接收本小区负载的条件时或存在多个两跳小区满足通过两步切换接收本小区负载的条件时，通过同时考虑选择不同小区时用户的接收信号信噪比、切换时延和该接收负载小区的当前负载等因素给出了选择最佳相邻负载转移小区的评价准则。When there are multiple adjacent cells that meet the conditions for receiving the load of the local cell or multiple two-hop cells that meet the conditions for receiving the load of the local cell through two-step handover, by simultaneously considering the user's received signal-to-noise ratio when selecting different cells, Factors such as handover delay and the current load of the receiving load cell provide the evaluation criteria for selecting the best adjacent load transfer cell.

本发明的技术方案包括如下步骤：Technical scheme of the present invention comprises the steps:

（1）负载信息收集：(1) Load information collection:

每个小区的无线接入点AP周期性地收集负载信息，并更新负载信息列表，The wireless access point AP of each cell periodically collects load information and updates the load information list,

所述负载信息包括：本小区i的当前负载Li、容量Ci、本小区i与相邻小区j的重叠区域用户负载OLij、与本小区i相邻的小区j的识别码IDj、当前负载Lj、容量Cj、本小区i的两跳小区k的识别码IDk、当前负载Lk、容量Ck和两跳小区k与相邻小区j的重叠区域用户负载OLjk，The load information includes: the current load Li and capacity Ci of the cell i, the user load OLij in the overlapping area between the cell i and the adjacent cell j, the identification code IDj of the cell j adjacent to the cell i, the current load Lj, Capacity Cj, the identification code IDk of the two-hop cell k of the current cell i, the current load Lk, the capacity Ck, and the user load OLjk in the overlapping area between the two-hop cell k and the adjacent cell j,

所述负载信息列表包括：本小区负载信息列表，相邻小区负载信息列表和两跳小区负载信息列表；The load information list includes: a list of load information of this cell, a list of load information of adjacent cells and a list of load information of two-hop cells;

（2）设置负载均衡启动门限Th，比较本小区归一化负载Ti与负载均衡启动门限Th的大小，若归一化负载大于负载均衡启动门限，即：Ti＞Th，执行步骤（3）；否则，返回步骤（1），等待负载信息更新，其中，本小区归一化负载Ti是本小区的当前负载Li与容量Ci之比，即：Ti＝Li/Ci；(2) Set the load balancing start threshold Th, compare the normalized load Ti of the community with the load balancing start threshold Th, if the normalized load is greater than the load balancing start threshold, that is: Ti>Th, perform step (3); Otherwise, return to step (1) and wait for the load information to be updated, where the normalized load Ti of the cell is the ratio of the current load Li to the capacity Ci of the cell, namely: Ti=Li/Ci;

（3）设置小区最大可接收负载门限Tl，判断是否向相邻小区转移负载：搜索满足min{(Cj*Tl-Lj),OLij}≥(Ci*Th-Li)的相邻小区j的集合L，若集合L不为空，则判断可以向相邻小区转移负载，执行步骤（5a）；否则，执行步骤（4）；(3) Set the maximum acceptable load threshold Tl of the cell, and judge whether to transfer the load to the adjacent cell: search for the set of adjacent cell j that satisfies min{(Cj*Tl-Lj), OLij}≥(Ci*Th-Li) L, if the set L is not empty, it is judged that the load can be transferred to the adjacent cell, and the step (5a) is executed; otherwise, the step (4) is executed;

（4）判断是否向两跳小区转移负载：(4) Determine whether to transfer the load to the two-hop cell:

搜索满足min{(Ck*Tl-Lk),OLij,OLjk}≥(Ci*Th-Li)的两跳小区k的集合T，若集合T不为空，则判断可以向两跳小区转移负载，执行步骤（5b）；否则，返回步骤（1），等待负载信息更新；Search for the set T of the two-hop cell k that satisfies min{(Ck*Tl-Lk), OLij, OLjk}≥(Ci*Th-Li), if the set T is not empty, it is judged that the load can be transferred to the two-hop cell, Execute step (5b); otherwise, return to step (1) and wait for the load information to be updated;

（5）选择切换对象：(5) Select the switching object:

（5a）在本小区与相邻小区的重叠区域内选择用户负载之和等于本小区待转移负载的用户作为切换对象，执行步骤（6a）；(5a) In the overlapping area between the current cell and the adjacent cell, select the user whose sum of user load is equal to the load to be transferred in this cell as the handover object, and perform step (6a);

（5b）在相邻小区与两跳小区的重叠区域内选择负载之和等于本小区待转移负载的用户作为第一步切换的切换对象，在本小区与相邻小区的重叠区域内选择负载之和等于本小区待转移负载的用户作为第二步切换的切换对象，执行步骤（6b）；(5b) In the overlapping area between the adjacent cell and the two-hop cell, select the user whose load sum is equal to the load to be transferred in this cell as the handover object in the first step, and select the user whose load is in the overlapping area between the adjacent cell and the adjacent cell. and the users equal to the load to be transferred in this cell are used as the handover objects of the second step handover, and step (6b) is performed;

（6）计算切换代价，选择最佳负载转移小区：(6) Calculate the switching cost and select the best load transfer cell:

（6a）无线接入点AP按下式计算切换至满足条件的相邻小区的切换代价Pj：(6a) The wireless access point AP calculates the switching cost Pj of switching to a neighboring cell that meets the conditions according to the following formula:

$Pj Pj = = {Σ Σ}_{u u = = 11}^{n no} ((((11 - - Sju Sju)) + + Dju Dju)) + + Tj Tj,,$

其中，Sju表示用户u切换至小区j可获得的平均信噪比增益，它是用户u切换至小区j可获得的信噪比SNRau与用户切换信噪比门限SNRt之差的归一化值，即：Sju＝(SNRau-SNRt)/SNRt；Dju表示用户u切换至小区j的时延代价，它是用户u切换至小区j的切换时延Du与时延门限Dt的归一化值，即：Dju＝(Du-Dt)/Dt；Among them, Sju represents the average SNR gain obtained by switching user u to cell j, which is the normalized value of the difference between the SNR au obtained by user u switching to cell j and the user switching signal-to-noise ratio threshold SNRt, That is: Sju=(SNRau-SNRt)/SNRt; Dju represents the delay cost of user u switching to cell j, which is the normalized value of switching delay Du and delay threshold Dt of user u switching to cell j, namely : Dju=(Du-Dt)/Dt;

（6b）选择切换代价Pj最小的相邻小区作为最佳负载转移小区，执行步骤（7a）；(6b) Select the adjacent cell with the smallest handover cost Pj as the best load transfer cell, and perform step (7a);

（6c）无线接入点AP按下式计算两步切换至满足条件的两跳小区的切换代价Pjk：(6c) The wireless access point AP calculates the handover cost Pjk of the two-step handover to the two-hop cell that meets the conditions according to the following formula:

$Pjk Pjk = = {Σ Σ}_{u u 11 = = 11}^{m m} ((((11 - - Sju Sju 11)) + + Dju Dju 11 + + Tj Tj)) + + {Σ Σ}_{u u 22 = = 11}^{n no} ((((11 - - Sku Sku 22)) + + Dku Dku 22)) + + Tk Tk)),,$

其中，Sju1表示用户u1切换至小区j可获得的平均信噪比增益，它是用户u1切换至小区j可获得的信噪比SNRau1与用户切换信噪比门限SNRt之差的归一化值，即：Sju1＝(SNRau1-SNRt)/SNRt；Dju1表示用户u1切换至小区j的时延代价，它是用户u1切换至小区j的切换时延Du1与时延门限Dt的归一化值，Dju1＝(Du1-Dt)/Dt；Sku2表示用户u2切换至小区k可获得的平均信噪比增益，它是用户u2切换至小区k可获得的信噪比与用户切换信噪比门限SNR之差的归一化值，即：Dku2表示用户u2切换至小区k的时延代价，它是用户u2切换至小区k的切换时延Du2与时延门限Dt的归一化值，即：Dku2＝(Du2-Dt)/Dt；Among them, Sju1 represents the average SNR gain that user u1 can obtain when switching to cell j, which is the normalized value of the difference between SNR au1 that user u1 can obtain when switching to cell j and the user switching signal-to-noise ratio threshold SNRt, That is: Sju1=(SNRau1-SNRt)/SNRt; Dju1 represents the delay cost of user u1 switching to cell j, which is the normalized value of switching delay Du1 and delay threshold Dt of user u1 switching to cell j, Dju1 =(Du1-Dt)/Dt; Sku2 represents the average signal-to-noise ratio gain that user u2 can obtain when switching to cell k, which is the signal-to-noise ratio that user u2 can obtain when switching to cell k The normalized value of the difference between the SNR threshold and the user switching signal-to-noise ratio, namely: Dku2 represents the delay cost of user u2 switching to cell k, which is the normalized value of switching delay Du2 and delay threshold Dt of user u2 switching to cell k, that is: Dku2=(Du2-Dt)/Dt;

（6d）选择切换代价Pjk最小的两跳小区作为最佳负载转移小区，执行步骤（7b）；(6d) Select the two-hop cell with the smallest handover cost Pjk as the best load transfer cell, and perform step (7b);

（7）执行切换：(7) Execute switching:

（7a）所选最佳负载转移小区中的切换对象在本小区无线接入点的指示下切换到最佳负载转移小区；(7a) The handover object in the selected best load transfer cell is switched to the best load transfer cell under the instruction of the wireless access point of the cell;

（7b）两步切换完成负载转移：(7b) Two-step switching completes the load transfer:

（7b1）第一步切换：本小区无线接入点AP向相邻小区无线接入点AP发送执行切换信息，要求相邻小区无线接入点AP向所选最佳负载转移小区与相邻小区之间的切换对象发送切换指示；该切换对象根据相邻小区无线接入点AP发送的切换指示切换到所选最佳负载转移小区；切换完成后相邻小区无线接入点AP向本小区无线接入点AP回复切换完成信息；(7b1) The first step of handover: the wireless access point AP of this cell sends the execution handover information to the wireless access point AP of the adjacent cell, and requires the wireless access point AP of the adjacent cell to transfer the selected optimal load between the cell and the adjacent cell The handover object between them sends a handover instruction; the handover object switches to the selected best load transfer cell according to the handover instruction sent by the wireless access point AP of the adjacent cell; after the handover is completed, the wireless access point AP of the adjacent cell wirelessly communicates The access point AP replies with handover completion information;

（7b2）第二步切换：收到相邻小区的切换完成信息后，本小区无线接入点AP向本小区与相邻小区之间的切换对象发送切换指示，该切换对象根据收到的切换指示切换到相邻小区。(7b2) The second step of handover: After receiving the handover completion information of the adjacent cell, the wireless access point AP of the local cell sends a handover instruction to the handover object between the local cell and the adjacent cell, and the handover object is based on the received handover Indicates handover to an adjacent cell.

本发明与现有技术相比具有以下优点：Compared with the prior art, the present invention has the following advantages:

第一，本发明针对现有技术中当相邻小区负载过重不满足接收本小区待转移负载的条件时无法进行负载均衡的问题，提出了非相邻小区之间的负载均衡方法，即当相邻小区均负载过重不能接收本小区的待转移负载时，首先将相邻小区中的负载转移到可接收负载的两跳小区中，然后将本小区中的待转移负载转移到相邻小区中，通过两步切换实现了非相邻异构小区之间的负载均衡，这种方法扩大了负载均衡的范围，实现了更大范围内的负载均衡。First, the present invention aims at the problem in the prior art that load balancing cannot be performed when the adjacent cell load is too heavy and does not meet the conditions for receiving the load to be transferred in this cell, and proposes a load balancing method between non-adjacent cells, that is, when When the adjacent cells are too heavily loaded and cannot receive the load to be transferred in this cell, first transfer the load in the adjacent cell to the two-hop cell that can receive the load, and then transfer the load to be transferred in this cell to the adjacent cell In this method, the load balancing between non-adjacent heterogeneous cells is realized by two-step handover, which expands the scope of load balancing and realizes load balancing in a larger range.

第二，本发明针对泛在网络中的小区异构特性，给出了异构小区之间负载均衡过程中，存在多个相邻小区满足接收本小区待转移负载的条件时或存在多个两跳小区满足通过两步切换接收本小区待转移负载的条件时，选择最佳负载转移小区的准则，该准则同时考虑了选择不同小区时用户可获得的接收信号强度增益、用户的切换时延代价和该小区的当前负载，使用该准则可以在异构小区之间实现负载均衡的同时使得切换代价最小，并且使得用户能获得更好的通信质量。Second, aiming at the heterogeneous characteristics of cells in the ubiquitous network, the present invention provides that in the process of load balancing between heterogeneous cells, when there are multiple adjacent cells that meet the conditions for receiving the load to be transferred from this cell or there are multiple two When the hopping cell meets the condition of receiving the load to be transferred in this cell through two-step handover, the criterion for selecting the best load transfer cell, this criterion also takes into account the received signal strength gain that the user can obtain when selecting a different cell, and the handover delay cost of the user and the current load of the cell, using this criterion can achieve load balancing among heterogeneous cells while minimizing handover costs and enabling users to obtain better communication quality.

附图说明Description of drawings

图1为本发明的场景图；Fig. 1 is a scene diagram of the present invention;

图2为本发明的流程图。Fig. 2 is a flowchart of the present invention.

具体实施方式：Detailed ways:

下面结合附图对本发明做进一步的描述。The present invention will be further described below in conjunction with the accompanying drawings.

本发明的应用场景如图1所示，其中，图1(a)是一步切换场景图，它描述了存在满足接收本小区待转移负载条件的相邻小区时，将待转移负载由本小区转移到相邻小区的场景；图1（b）是两步切换场景图，它描述了在相邻小区负载过重不满足接收本小区待转移负载的条件时，首先将相邻小区中的部分负载转移到可接收负载的两跳小区中，然后将本小区中的待转移负载转移到相邻小区中的场景。The application scenario of the present invention is shown in Figure 1, wherein, Figure 1 (a) is a one-step handover scene diagram, and it has described that when there is an adjacent cell that meets the condition of receiving the load to be transferred in the cell, the load to be transferred is transferred from the cell to the The scene of adjacent cells; Figure 1(b) is a two-step handover scenario diagram, which describes that when the load of the adjacent cell is too heavy to meet the conditions for receiving the load to be transferred from the current cell, first transfer part of the load in the adjacent cell The scenario where the load is transferred to a two-hop cell that can receive the load, and then the load to be transferred in this cell is transferred to an adjacent cell.

参照图2，本发明在上述场景中进行非相邻异构小区之间的负载均衡的步骤如下：Referring to Fig. 2, the present invention performs the steps of load balancing between non-adjacent heterogeneous cells in the above scenario as follows:

步骤1，周期性收集负载信息：Step 1, periodically collect load information:

（1a）小区i内的所有用户设备UEu周期性扫描相邻小区信号，并向小区i的无线接入点AP报告扫描到的相邻小区信号信噪比信息，所述相邻小区信号信噪比信息包括：用户设备识别码UEIDu、相邻小区j的识别码IDj、接收到的相邻小区j信号信噪比SNRju；(1a) All user equipment UEu in the cell i periodically scan the adjacent cell signals, and report the scanned signal-to-noise ratio information of the adjacent cell signals to the wireless access point AP of the cell i, and the signal-to-noise ratio of the adjacent cell signals The ratio information includes: user equipment identification code UEIDu, identification code IDj of neighboring cell j, received signal-to-noise ratio SNRju of neighboring cell j signal;

（1b）小区i的无线接入点AP根据用户设备UE报告的相邻小区信号信噪比信息，统计重叠区域用户负载OLij，该重叠区域用户负载OLij，是指接收到相邻小区j的信号信噪比SNRju大于正确接收信号的信噪比门限SNRt的所有用户负载之和；(1b) The wireless access point AP of cell i calculates the user load OLij in the overlapping area according to the signal-to-noise ratio information of the adjacent cell reported by the user equipment UE. The user load OLij in the overlapping area refers to the signal received from the adjacent cell j The sum of all user loads whose signal-to-noise ratio SNRju is greater than the signal-to-noise ratio threshold SNRt of the correctly received signal;

（1c）小区i的无线接入点AP测量上一周期内资源的使用情况，作为当前负载Li，以保证小区内用户服务质量的小区负载最大值作为容量Ci；(1c) The wireless access point AP of cell i measures the usage of resources in the previous cycle as the current load Li, and the maximum cell load to ensure the quality of service of users in the cell is taken as the capacity Ci;

（1d）小区i的无线接入点AP向相邻小区无线接入点AP请求相邻小区负载信息，即小区i的无线接入点AP向相邻小区j的无线接入点AP发送负载信息请求信息，相邻小区j的无线接入点AP收到该信息后回复负载信息应答信息，该负载信息应答信息包括：小区j的识别码IDj、当前负载Lj、容量Cj、小区j的相邻小区w的识别码IDw、当前负载Lw、容量Cw和小区j与其相邻小区w的重叠区域用户负载OLjw，该重叠区域用户负载OLjw，是指接收到相邻小区w的信号信噪比SNRwu大于正确接收信号的信噪比门限SNRt的所有用户负载之和；(1d) The wireless access point AP of cell i requests the adjacent cell load information from the wireless access point AP of the adjacent cell, that is, the wireless access point AP of the cell i sends the load information to the wireless access point AP of the adjacent cell j Request information, the wireless access point AP of adjacent cell j will reply the load information response information after receiving the information, the load information response information includes: identification code IDj of cell j, current load Lj, capacity Cj, neighbors of cell j The identification code IDw of the cell w, the current load Lw, the capacity Cw, and the user load OLjw in the overlapping area between the cell j and its adjacent cell w. The sum of all user loads of the signal-to-noise ratio threshold SNRt of the correctly received signal;

（1e）小区i的无线接入点AP在小区j的相邻小区w中选择与小区i不相邻的小区标记为小区i的两跳小区。(1e) The wireless access point AP of cell i selects a cell that is not adjacent to cell i in the neighboring cell w of cell j, which is marked as a two-hop cell of cell i.

步骤2，更新负载信息列表：Step 2, update the load information list:

小区i的无线接入点AP根据步骤1中收集到的负载信息更新负载信息列表中的对应项，即用新获得的负载信息替换负载信息列表中的对应项的原有值，该负载信息列表包括：本小区负载信息列表，相邻小区负载信息列表和两跳小区负载信息列表，其中：The wireless access point AP of cell i updates the corresponding item in the load information list according to the load information collected in step 1, that is, replaces the original value of the corresponding item in the load information list with the newly obtained load information, and the load information list Including: the load information list of this cell, the load information list of adjacent cells and the load information list of two-hop cells, where:

本小区负载信息列表包括：本小区i的识别码IDi、当前负载Li、容量Ci、本小区i与相邻小区j的重叠区域用户负载OLij；The load information list of the current cell includes: the identification code IDi of the current cell i, the current load Li, the capacity Ci, the user load OLij in the overlapping area between the current cell i and the adjacent cell j;

相邻小区负载信息列表包括：相邻小区j的识别码IDj、当前负载Lj、容量Cj和相邻小区j与两跳小区k的重叠区域用户负载OLjk；The adjacent cell load information list includes: the identification code IDj of the adjacent cell j, the current load Lj, the capacity Cj, and the user load OLjk in the overlapping area between the adjacent cell j and the two-hop cell k;

两跳小区负载信息列表包括：两跳小区k的识别码IDk、当前负载Lk和容量Ck。The two-hop cell load information list includes: the identification code IDk of the two-hop cell k, the current load Lk and the capacity Ck.

步骤3，设置负载均衡启动门限Th，小区i的无线接入点AP比较本小区归一化负载Ti与负载均衡启动门限Th的大小，若归一化负载大于负载均衡启动门限，即：Ti＞Th，执行步骤4；否则，返回步骤1，其中：Step 3: Set the load balancing start threshold Th. The wireless access point AP of cell i compares the normalized load Ti of the cell with the load balancing start threshold Th. If the normalized load is greater than the load balancing start threshold, that is: Ti> Th, execute step 4; otherwise, return to step 1, where:

所述本小区归一化负载Ti是本小区i的当前负载Li与容量Ci之比，即：Ti＝Li/Ci；The normalized load Ti of the cell is the ratio of the current load Li of the cell i to the capacity Ci, that is: Ti=Li/Ci;

所述负载均衡启动门限Th，是指小区需要进行负载均衡的小区负载最小值Lupi与小区容量Ci之比，即：Th＝Lupi/Ci，该门限的设置与小区的通信模式、资源分配方法和用户服务质量要求有关。The load balancing starting threshold Th refers to the ratio of the cell load minimum value Lupi and the cell capacity Ci that the cell needs to load balance, that is: Th=Lupi/Ci, the setting of the threshold is related to the communication mode, resource allocation method and related to user service quality requirements.

步骤4，设置小区最大可接收负载门限Tl，小区i的无线接入点AP判断其是否向相邻小区转移负载：搜索满足min{(Cj*Tl-Lj),OLij}≥(Ci*Th-Li)的相邻小区j的集合L，若集合L不为空，则小区i的无线接入点AP判断可以向相邻小区转移负载，执行步骤（6a）；否则，执行步骤5；Step 4, set the maximum acceptable load threshold T1 of the cell, and the wireless access point AP of cell i judges whether it transfers the load to the adjacent cell: the search satisfies min{(Cj*Tl-Lj), OLij}≥(Ci*Th- The set L of the adjacent cell j of Li), if the set L is not empty, the wireless access point AP of the cell i judges that the load can be transferred to the adjacent cell, and executes step (6a); otherwise, executes step 5;

所述小区最大可接收负载门限Tl，是指允许小区接收负载均衡转移负载的小区负载最大值Llowi与小区容量Ci之比，即：Tl＝Llowi/Ci；其中，允许小区接收负载均衡转移负载的小区负载最大值Llowi是小区需要进行负载均衡的小区负载最小值Lupi与为防止“乒乓切换”预留的负载Lbuf之差；为防止“乒乓切换”预留的负载Lbuf，是指为了防止由于本小区内的突发业务或移动至本小区的切换业务导致本小区负载突然增加而引起的“乒乓切换”所预留的负载，该预留的负载Lbuf的设置与小区内用户业务的突发特性和用户移动性有关。The maximum acceptable load threshold T1 of the cell refers to the ratio of the maximum cell load Llowi and the cell capacity Ci that allow the cell to receive the load balancing transfer load, that is: T1=Llowi/Ci; where the cell is allowed to receive the load balancing transfer load. The maximum cell load Llowi is the difference between the minimum cell load Lupi that needs to be load balanced in the cell and the load Lbuf reserved for preventing "ping-pong handover"; the load Lbuf reserved for preventing "ping-pong handover" is to prevent The load reserved by the "ping-pong handover" caused by the sudden increase in the load of the cell due to the sudden increase in the load of the cell or the handover service that moves to the cell, the setting of the reserved load Lbuf is related to the burst characteristics of the user traffic in the cell related to user mobility.

步骤5，小区i的无线接入点AP判断是否向两跳小区转移负载：搜索满足min{(Ck*Tl-Lk),OLij,OLjk}≥(Ci*Th-Li)的两跳小区k的集合T，若集合T不为空，则小区i的无线接入点AP判断可以向两跳小区转移负载，执行步骤（6b）；否则，返回步骤1。Step 5, the wireless access point AP of cell i judges whether to transfer the load to the two-hop cell: search for the two-hop cell k that satisfies min{(Ck*Tl-Lk), OLij, OLjk}≥(Ci*Th-Li) Set T, if the set T is not empty, the wireless access point AP of cell i judges that the load can be transferred to the two-hop cell, and executes step (6b); otherwise, returns to step 1.

步骤6，选择切换对象：Step 6, select the switching object:

（6a）选择一步切换的切换对象：(6a) Select the switching object for one-step switching:

（6a1）小区i的无线接入点AP在相邻小区负载信息列表中筛选出本小区i与相邻小区j重叠区域的所有用户；(6a1) The wireless access point AP of cell i screens out all users in the overlapping area between this cell i and adjacent cell j in the adjacent cell load information list;

（6a2）小区i的无线接入点AP根据用户u接收到相邻小区j的信号信噪比SNRau由大到小逐一选择用户，直到增加一个用户后，所选用户负载之和等于或大于本小区待转移负载，此时所选用户即为一步切换的切换对象；(6a2) The wireless access point AP of cell i selects users one by one according to the signal-to-noise ratio SNRau received by user u from adjacent cell j from large to small, until after adding a user, the sum of the selected user loads is equal to or greater than this The load of the cell is to be transferred, and the selected user at this time is the handover object of one-step handover;

（6b）选择两步切换的切换对象：(6b) Select the switching object for the two-step switching:

（6b1）小区i的无线接入点AP向相邻小区j的无线接入点AP发送选择切换对象请求信息，要求相邻小区无线接入点按照步骤（6a）中的方法选择切换对象；(6b1) The wireless access point AP of cell i sends a request message for selecting a handover object to the wireless access point AP of adjacent cell j, requesting the wireless access point of the adjacent cell to select a handover object according to the method in step (6a);

（6b2）相邻小区j的无线接入点AP将所选切换对象信息发送给本小区无线接入点AP，该切换对象信息包括：用户设备识别码UEIDu、接收到的两跳小区k的信号信噪比SNRku和用户业务类型TCu；(6b2) The wireless access point AP of the adjacent cell j sends the selected handover object information to the local cell wireless access point AP. The handover object information includes: the user equipment identification code UEIDu, the received signal of the two-hop cell k Signal-to-noise ratio SNRku and user traffic type TCu;

（6b3）小区i的无线接入点AP收到相邻小区j的无线接入点AP发送的切换对象信息后，将该信息中的包含的用户作为第一步切换的切换对象；(6b3) After receiving the handover object information sent by the wireless access point AP of the adjacent cell j, the wireless access point AP of cell i takes the user included in the information as the handover object of the first handover;

（6b3）小区i的无线接入点AP在相邻小区负载信息列表中筛选出本小区i与相邻小区j重叠区域的所有用户；(6b3) The wireless access point AP of cell i screens out all users in the overlapping area between this cell i and adjacent cell j in the adjacent cell load information list;

（6b4）小区i的无线接入点AP根据用户u接收到相邻小区j的信号信噪比SNRau由大到小逐一选择用户，直到增加一个用户后，所选用户负载之和等于或大于本小区待转移负载，将此时所选用户作为第二步切换的切换对象。(6b4) The wireless access point AP of cell i selects users one by one according to the signal-to-noise ratio SNRau of adjacent cell j received by user u from large to small, until after adding a user, the sum of the selected user loads is equal to or greater than this The load of the cell is to be transferred, and the user selected at this time is taken as the handover object of the second step handover.

步骤7，计算切换代价，选择最佳负载转移小区：Step 7, calculate the handover cost, and select the best load transfer cell:

（7a）无线接入点AP按下式计算切换至满足条件的相邻小区的切换代价Pj：(7a) The wireless access point AP calculates the switching cost Pj of switching to a neighboring cell that meets the conditions according to the following formula:

其中，Sju表示用户u切换至小区j可获得的平均信噪比增益，它是用户u切换至小区j可获得的信噪比SNRju与用户切换信噪比门限SNRt之差的归一化值，即：Sju＝(SNRau-SNRt)/SNRt；Dju表示用户u切换至小区j的时延代价，它是用户u切换至小区j的切换时延Du与时延门限Dt的归一化值，即：Dju＝(Du-Dt)/Dt；Among them, Sju represents the average SNR gain obtained by switching user u to cell j, which is the normalized value of the difference between SNRju obtained by switching user u to cell j and the SNR threshold SNRt for user switching, That is: Sju=(SNRau-SNRt)/SNRt; Dju represents the delay cost of user u switching to cell j, which is the normalized value of switching delay Du and delay threshold Dt of user u switching to cell j, namely : Dju=(Du-Dt)/Dt;

（7b）选择切换代价Pj最小的相邻小区作为最佳负载转移小区，执行步骤（8a）；(7b) Select the adjacent cell with the smallest handover cost Pj as the best load transfer cell, and perform step (8a);

（7c）无线接入点AP按下式计算两步切换至满足条件的两跳小区的切换代价Pjk：(7c) The wireless access point AP calculates the handover cost Pjk of the two-step handover to the two-hop cell that meets the conditions according to the following formula:

（7d）选择切换代价Pjk最小的两跳小区作为最佳负载转移小区，执行步骤（8b）。(7d) Select the two-hop cell with the smallest handover cost Pjk as the best load transfer cell, and perform step (8b).

步骤8，执行切换。Step 8, perform switching.

（8a）一步切换完成负载转移，即将所选最佳负载转移小区中的切换对象，在本小区无线接入点的指示下切换到最佳负载转移小区；(8a) One-step handover to complete the load transfer, that is, the handover object in the selected best load transfer cell is switched to the best load transfer cell under the instruction of the wireless access point of the cell;

（8b）两步切换完成负载转移：(8b) Two-step switching completes the load transfer:

（8b1）第一步切换：本小区无线接入点AP向相邻小区无线接入点AP发送执行切换信息，要求相邻小区无线接入点AP向所选最佳负载转移小区与相邻小区之间的切换对象发送切换指示；该切换对象根据相邻小区无线接入点AP发送的切换指示切换到所选最佳负载转移小区；切换完成后相邻小区无线接入点AP向本小区无线接入点AP回复切换完成信息；(8b1) The first step of handover: the wireless access point AP of this cell sends the execution handover information to the wireless access point AP of the adjacent cell, and requires the wireless access point AP of the adjacent cell to transfer the selected best load between the cell and the adjacent cell The handover object between them sends a handover instruction; the handover object switches to the selected best load transfer cell according to the handover instruction sent by the wireless access point AP of the adjacent cell; after the handover is completed, the wireless access point AP of the adjacent cell wirelessly communicates The access point AP replies with handover completion information;

（8b2）第二步切换：收到相邻小区的切换完成信息后，本小区无线接入点AP向本小区与相邻小区之间的切换对象发送切换指示，该切换对象根据收到的切换指示切换到相邻小区。(8b2) The second step of handover: After receiving the handover completion information of the adjacent cell, the wireless access point AP of the local cell sends a handover instruction to the handover object between the local cell and the adjacent cell, and the handover object is based on the received handover Indicates handover to an adjacent cell.

以上描述仅是本发明的一个具体实例，显然对于本领域的专业人员来说，在了解了本发明内容和原理后，都可能在不背离本发明原理、结构的情况下，进行形式和细节上的各种修改和改变，但是这些基于本发明思想的修正和改变仍在本发明的权利要求保护范围之内。The above description is only a specific example of the present invention. Obviously, for those skilled in the art, after understanding the content and principle of the present invention, it is possible to carry out the form and details without departing from the principle and structure of the present invention. Various amendments and changes, but these amendments and changes based on the idea of the present invention are still within the protection scope of the claims of the present invention.