TD-SCDMA分层小区切换算法研究
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摘要
TD-SCDMA是我国提出的第三代移动通信标准,也是目前国际三大主流3G标准之一。目前,TD-SCDMA在我国已经进入大规模商用阶段,发展前景十分光明。在现实生活中,尤其是在大城市,由于地铁公交等各种交通工具的存在,使得用户终端经常会在高速与低速中不断变换。这种频繁切换往往会导致用户在使用手机时通信质量下降,严重时还会有掉话发生。只有解决这个问题,才能提高TD-SCDMA网络质量,使其能在竞争激烈的通信市场占据主导地位。
分层小区结构的概念,简单地说,就是采用宏小区覆盖多个微小区,形成分层结构。而分层小区切换算法就是网络布局采用分层小区结构,并根据用户终端‘(UE)移动速度,当UE高速移动时,将其切换至宏小区；当UE低速移动时,将其切换至微小区。这样可以兼顾网络的容量与质量,提高网络性能。
本论文对分层小区切换算法的原理和实现过程进行了详细介绍。在该算法中,如何确定UE的移动速度,从而选择将其切换至对应的小区是算法的关键。目前已有的判决方法有如下几种：根据UE在小区中驻留的时间进行判定；或者根据UE在单位时间内发生的同层小区切换次数进行判定；或者根据单位时间内最好信号质量的微小区基站的变换次数进行判定。这些方法都存在一定的局限性,可能会导致速度判定的不准确性。本文的创新处在于在分层小区切换算法中引入滑窗概念,计算一定时间内的滑窗中的有效切换事件数目,与设定的高速和低速门限进行比较,从而实时判断用户终端当时的移动速度,并根据该移动速度选择其对应的处理流程,将其切换至宏小区或微小区。为了验证算法,我们采用了外场测试的方法,在世博园区内对算法的功能和性能进行了详细验证。测试结果证明,采用滑窗机制的分层小区切换算法能够达到提高网络性能的要求。
TD-SCDMA which was proposed by China is one of the three mainstream 3rd mobile communication standards. Currently, TD-SCDMA in china has entered a phase of large-scale commercial and it has a promising future.In real life, especially in large cities, as the existing of transportation such as underground, UE often change its speed to high speed or low speed. Such continually handover often leads to serious decline in quality of communication when user use their mobile telephone, sometimes may the drop-call happens in bad condition. Only by addressing this issue in order to improve the quality of TD-SCDMA network, it can be in the highly competitive communications market dominance.
In brief, the concept of hierarchical cell structures is macro-cell override several micro-cells and form hierarchical structure. The handover algorithms of hierarchical cell structures use hierarchical cell structures in network topology, and it gives the verdict by the movement velocity of UE.When UE moves at high speed, it makes a handover to macro-cell and when UE moves at low speed, it makes a handover to micro-cell.Using this method, it can give consideration to both network capacity and quality, and it can improve network performance.
This discourse recommends the principle and implementation process of the handover algorithms of hierarchical cell structures in detail.In the algorithm, how to determine the movement velocity and handover UE to the opposite cell is a key of the algorithms. At present, there are several decision methods:judged by the residence time of UE in the cell;or judged by times of UE handover between cells with the same level in unit time; or judged by change times of the micro-cell with best signal quality in unit time. These methods have some limitations which may cause inaccuracy of the speed judge. The innovation of this paper is that we lead in the concept of slide window into the handover algorithms of hierarchical cell structures. We calculate the valid handover event number within a certain period of time, and we compare it with a located threshold of high speed or low speed and then verdict the movement speed of UE.Based on its movement velocity, we choose the opposite processing procedures, handover the UE to the macro-cell or micro-cell.To validate the algorithm,we used the method of field test and amply tested the function and capability of the algorithm in the Expo Site.The test results prove that the handover algorithms of hierarchical cell structures used slide window can improve the performance of network.
分层小区结构的概念,简单地说,就是采用宏小区覆盖多个微小区,形成分层结构。而分层小区切换算法就是网络布局采用分层小区结构,并根据用户终端‘(UE)移动速度,当UE高速移动时,将其切换至宏小区；当UE低速移动时,将其切换至微小区。这样可以兼顾网络的容量与质量,提高网络性能。
本论文对分层小区切换算法的原理和实现过程进行了详细介绍。在该算法中,如何确定UE的移动速度,从而选择将其切换至对应的小区是算法的关键。目前已有的判决方法有如下几种：根据UE在小区中驻留的时间进行判定；或者根据UE在单位时间内发生的同层小区切换次数进行判定；或者根据单位时间内最好信号质量的微小区基站的变换次数进行判定。这些方法都存在一定的局限性,可能会导致速度判定的不准确性。本文的创新处在于在分层小区切换算法中引入滑窗概念,计算一定时间内的滑窗中的有效切换事件数目,与设定的高速和低速门限进行比较,从而实时判断用户终端当时的移动速度,并根据该移动速度选择其对应的处理流程,将其切换至宏小区或微小区。为了验证算法,我们采用了外场测试的方法,在世博园区内对算法的功能和性能进行了详细验证。测试结果证明,采用滑窗机制的分层小区切换算法能够达到提高网络性能的要求。
TD-SCDMA which was proposed by China is one of the three mainstream 3rd mobile communication standards. Currently, TD-SCDMA in china has entered a phase of large-scale commercial and it has a promising future.In real life, especially in large cities, as the existing of transportation such as underground, UE often change its speed to high speed or low speed. Such continually handover often leads to serious decline in quality of communication when user use their mobile telephone, sometimes may the drop-call happens in bad condition. Only by addressing this issue in order to improve the quality of TD-SCDMA network, it can be in the highly competitive communications market dominance.
In brief, the concept of hierarchical cell structures is macro-cell override several micro-cells and form hierarchical structure. The handover algorithms of hierarchical cell structures use hierarchical cell structures in network topology, and it gives the verdict by the movement velocity of UE.When UE moves at high speed, it makes a handover to macro-cell and when UE moves at low speed, it makes a handover to micro-cell.Using this method, it can give consideration to both network capacity and quality, and it can improve network performance.
This discourse recommends the principle and implementation process of the handover algorithms of hierarchical cell structures in detail.In the algorithm, how to determine the movement velocity and handover UE to the opposite cell is a key of the algorithms. At present, there are several decision methods:judged by the residence time of UE in the cell;or judged by times of UE handover between cells with the same level in unit time; or judged by change times of the micro-cell with best signal quality in unit time. These methods have some limitations which may cause inaccuracy of the speed judge. The innovation of this paper is that we lead in the concept of slide window into the handover algorithms of hierarchical cell structures. We calculate the valid handover event number within a certain period of time, and we compare it with a located threshold of high speed or low speed and then verdict the movement speed of UE.Based on its movement velocity, we choose the opposite processing procedures, handover the UE to the macro-cell or micro-cell.To validate the algorithm,we used the method of field test and amply tested the function and capability of the algorithm in the Expo Site.The test results prove that the handover algorithms of hierarchical cell structures used slide window can improve the performance of network.
引文
1、段红光,毕敏,罗一静.第三代移动通信系统协议体系与信令流程[M].北京：人民邮电出版社,2007：1-10.
2、段玉宏,夏国忠,胡剑,黄萍等.TD-SCDMA无线网络设计与规划[M].北京：人民邮电出版社,2007：1-10.
3、李世鹤,杨运年.TD-SCDMA第三代移动通信系统[M].北京：人民邮电出版社.2009：1-10.
4、李世鹤.TD-SCDMA第三代移动通信系统标准[M].北京：人民邮电出版社,2003：5-17.
5、张楠.TD-SCDMA系统的RRM算法研究[D].北京：北京邮电大学,2007：8-10.
6、邹翔.TD-SCDMA无线资源管理算法仿真平台的研究与设计[D].西安：西安电子科技大学,2004：11-12
7、李春滨.TD-SCDMA移动通信系统的网络仿真[D].西安：西北工业大学,2006：14-16.
8、李晓东.应用HSDPA的TD-SCDMA系统快速DCA算法研究.北京：北京邮电大学,2007：5-13
9、秦健.TD-SCDMA关键技术和特点分析[J].企业家天地,2009,2：249-251。
10、钱李.TD-SCDMA关键技术浅析-联合检测[J].信息科学,2010,6：73.
11、秦夏鸿.移动通信系统中的切换技术研究[D].北京：北京邮电大学,2007：7-8.
12、葛莉纬.3G系统中的切换技术研究[D].南京：东南大学,2003：12-17.
13、3GPP TS 25.212,Multiplexing and channel coding (FDD) [S].
14、3GPP TS 25.101,User Equipment (UE) radio transmission and reception (FDD)[S].
15、李红林,赵亮.TD系统中小区间切换控制算法的研究[J].电信交换,2008,5(4)：11-13
16、谢鹰.分层小区技术在GSM网络中的应用[J],邮电设计技术,2007,4：24-26
17、侯晓明.分层网_移动通信高层覆盖的又一解决之道[J],中国无线电管理,2001,5：28-29
18、3GPP TS 25.331,Radio resource control(FDD)[S].
19、于翠波,李道本.分层蜂窝结构(HCS)的性能分析[C],2003年无线及移动通信委员会学术年会论文集,2003,355-358
20、古挺锋.TD-SCDMA系统接入控制策略研究.成都：西南交通大学,2007：24-26.
21、Richardson T, Urbanke R.The capacity of low-density parity check codes under message-passing decoding[J].IEEE Trans.Inform.Theory (S0018-9448),2000, 47(2):599-618.
22、Tanner R M.A recursive approach to low complexity codes [J].IEEE Trans.Inform. Theory(S0018-9448),1981,27(9):533-547.
23、叶环球.一种用户终端在分层小区中切换的实现方法[P].中国专利：1859726A,2006：3-5.
24、张静荣.一种分层小区系统中移动终端调度方法[P].中国专利：1503580A,2004：5-6.
25、王德伟,唐友喜.分层小区环境中移动台运动速度的一种测量方法[J].移动通信,2003,7(3)：105-108.
26、肖琨.无线移动小区系统切换策略的分析与展望[J],移动通信,2007,7：99-103.
27、彭木根,王文博.TD-SCDMA移动通信系统切换控制算法仿真研究[J].系统仿真学报,2006,7：1912-1916.
28、董石磊,董江,陈严冬.TD-SCDMA终端外场测试问题研究[J].吉林大学学报,2008,3：330-331.
29、来志京,果敢,魏然等.TD-SCDMA终端外场测试经验分析[J].现代电信科技.2008,10：39-41.
30、吴晓蓉.TD-SCDMA系统下行链路物理层算法研究[D].武汉：华中科技大学,2005：25-30.
2、段玉宏,夏国忠,胡剑,黄萍等.TD-SCDMA无线网络设计与规划[M].北京：人民邮电出版社,2007：1-10.
3、李世鹤,杨运年.TD-SCDMA第三代移动通信系统[M].北京：人民邮电出版社.2009：1-10.
4、李世鹤.TD-SCDMA第三代移动通信系统标准[M].北京：人民邮电出版社,2003：5-17.
5、张楠.TD-SCDMA系统的RRM算法研究[D].北京：北京邮电大学,2007：8-10.
6、邹翔.TD-SCDMA无线资源管理算法仿真平台的研究与设计[D].西安：西安电子科技大学,2004：11-12
7、李春滨.TD-SCDMA移动通信系统的网络仿真[D].西安：西北工业大学,2006：14-16.
8、李晓东.应用HSDPA的TD-SCDMA系统快速DCA算法研究.北京：北京邮电大学,2007：5-13
9、秦健.TD-SCDMA关键技术和特点分析[J].企业家天地,2009,2：249-251。
10、钱李.TD-SCDMA关键技术浅析-联合检测[J].信息科学,2010,6：73.
11、秦夏鸿.移动通信系统中的切换技术研究[D].北京：北京邮电大学,2007：7-8.
12、葛莉纬.3G系统中的切换技术研究[D].南京：东南大学,2003：12-17.
13、3GPP TS 25.212,Multiplexing and channel coding (FDD) [S].
14、3GPP TS 25.101,User Equipment (UE) radio transmission and reception (FDD)[S].
15、李红林,赵亮.TD系统中小区间切换控制算法的研究[J].电信交换,2008,5(4)：11-13
16、谢鹰.分层小区技术在GSM网络中的应用[J],邮电设计技术,2007,4：24-26
17、侯晓明.分层网_移动通信高层覆盖的又一解决之道[J],中国无线电管理,2001,5：28-29
18、3GPP TS 25.331,Radio resource control(FDD)[S].
19、于翠波,李道本.分层蜂窝结构(HCS)的性能分析[C],2003年无线及移动通信委员会学术年会论文集,2003,355-358
20、古挺锋.TD-SCDMA系统接入控制策略研究.成都：西南交通大学,2007：24-26.
21、Richardson T, Urbanke R.The capacity of low-density parity check codes under message-passing decoding[J].IEEE Trans.Inform.Theory (S0018-9448),2000, 47(2):599-618.
22、Tanner R M.A recursive approach to low complexity codes [J].IEEE Trans.Inform. Theory(S0018-9448),1981,27(9):533-547.
23、叶环球.一种用户终端在分层小区中切换的实现方法[P].中国专利：1859726A,2006：3-5.
24、张静荣.一种分层小区系统中移动终端调度方法[P].中国专利：1503580A,2004：5-6.
25、王德伟,唐友喜.分层小区环境中移动台运动速度的一种测量方法[J].移动通信,2003,7(3)：105-108.
26、肖琨.无线移动小区系统切换策略的分析与展望[J],移动通信,2007,7：99-103.
27、彭木根,王文博.TD-SCDMA移动通信系统切换控制算法仿真研究[J].系统仿真学报,2006,7：1912-1916.
28、董石磊,董江,陈严冬.TD-SCDMA终端外场测试问题研究[J].吉林大学学报,2008,3：330-331.
29、来志京,果敢,魏然等.TD-SCDMA终端外场测试经验分析[J].现代电信科技.2008,10：39-41.
30、吴晓蓉.TD-SCDMA系统下行链路物理层算法研究[D].武汉：华中科技大学,2005：25-30.