This paper presents prior determination of soft handover probability considering new direction of motion of mobile station (MS) coinciding with gravitation point of cells. Our simulation results for 3-cell scenario an...This paper presents prior determination of soft handover probability considering new direction of motion of mobile station (MS) coinciding with gravitation point of cells. Our simulation results for 3-cell scenario and considered new direction of MS motion can be potentially used as advance input to soft handover algorithms to minimize number of handovers.展开更多
The LTE and LTE-Advanced systems are supposed to be the most popular cellular network in 4Gnetworks. Relay technology is one of the most preferred technologies proposed in LTE-Advanced standardization to improve the c...The LTE and LTE-Advanced systems are supposed to be the most popular cellular network in 4Gnetworks. Relay technology is one of the most preferred technologies proposed in LTE-Advanced standardization to improve the capacity and coverage. This paper analyses the handover outage probability through relay deployment, and proposes some proofs and suggestions for relay deployment to minimize the handover outage probability in high speed scenarios.展开更多
A novel Cooperative Directional inter-cell Handover Scheme(CDHS) for High Altitude Platform(HAP) communications systems is proposed,in which the handover target cell and the two cells adjacent to this handover target ...A novel Cooperative Directional inter-cell Handover Scheme(CDHS) for High Altitude Platform(HAP) communications systems is proposed,in which the handover target cell and the two cells adjacent to this handover target cell work cooperatively to exploit the traffic fluctuation to improve handover performance.Users in the overlap area of the overloaded handover target cell will be forced to handover directionally before their optimal handover boundary in order to free up resources for the handover calls which would otherwise be dropped due to the shortage of resources and queue time out.Simulation results show that the handover call dropping probability is greatly reduced(at least 60%) compared with the general queue handover scheme,with little performance reduction to the call blocking probability,and the Not in the Best Cell(NBC) average time is only increased moderately.Moreover,an optimal cell radius can be achieved for a specific platform speed by minimizing the unified system performance,which is the linear combination of the handover call dropping probability and the NBC average time.展开更多
A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of th...A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.展开更多
随着高速铁路的不断发展和列车速度的不断提高,高铁场景下车地通信的可靠性和高效性引起广泛关注。列车速度的提升导致更加频繁的越区切换,使系统的可靠性得不到保障,因此列车速度的提升对高铁通信网络的安全性和可靠性产生严重影响。...随着高速铁路的不断发展和列车速度的不断提高,高铁场景下车地通信的可靠性和高效性引起广泛关注。列车速度的提升导致更加频繁的越区切换,使系统的可靠性得不到保障,因此列车速度的提升对高铁通信网络的安全性和可靠性产生严重影响。本文提出1种将LTE-A(Long Term Evolution-Advanced)网络应用到高速铁路场景并基于协同多点传输/接收CoMP(Coordinated Multi-Point transmission/reception)技术的切换优化方案模型,方案参考协作集加入模型。对系统切换成功率等进行性能分析,并与传统切换方案进行性能对比。分析表明:本文基于CoMP的切换方案可有效提升高移动性下网络的切换成功概率,明显改善系统的可靠性和效率。展开更多
GSM-R(GSM for Railway)网是铁路运输所专用的GSM无线通信网络。与普通GSM网中移动台的低速移动不同,GSM-R网中列车的高速移动会使接收信号产生严重的多普勒频移,另外接收信号还会受到电力牵引等其他干扰。因此对这些质量不佳的信号进...GSM-R(GSM for Railway)网是铁路运输所专用的GSM无线通信网络。与普通GSM网中移动台的低速移动不同,GSM-R网中列车的高速移动会使接收信号产生严重的多普勒频移,另外接收信号还会受到电力牵引等其他干扰。因此对这些质量不佳的信号进行检测将导致移动台的切换误判,造成列车越区切换成功率较低,从而削弱GSM-R网的安全性和可靠性。本文对GSM-R网传统切换策略进行建模,并且分析其切换中断率。为减小GSM-R网切换中断率,提出一种利用中继站辅助列车进行越区切换的策略。在该策略中,移动台在切换时不仅要检测相邻基站的信号,还将对重叠区中的中继站信号进行检测。仿真结果表明:本文提出切换策略的切换中断率明显小于未使用中继站时的情况,能够提高列车越区切换的成功率。展开更多
GSM-R(GSM for Railway)的可靠性和高效性引起人们的关注。列车速度的提升导致多普勒效应更严重、切换触发位置更靠后、越区切换更频繁。多普勒效应恶化接收信号质量使中断率增加;切换触发位置靠后变相缩小重叠区覆盖范围使越区切换失...GSM-R(GSM for Railway)的可靠性和高效性引起人们的关注。列车速度的提升导致多普勒效应更严重、切换触发位置更靠后、越区切换更频繁。多普勒效应恶化接收信号质量使中断率增加;切换触发位置靠后变相缩小重叠区覆盖范围使越区切换失败率增加;频繁的越区切换进一步降低系统可靠性。因此列车速度的提升对GSM-R网络的安全性和可靠性产生重要影响。同时,我国铁路网络的不断扩展对GSM-R系统的容量提出更高的要求。本文首先对GSM-R网络传统切换策略进行建模和性能分析。随后,提出一种利用列车位置信息和中继功率控制技术的切换优化方案。在该方案中,列车到达切换位置前,利用中继站获得分集增益,提升信道容量和链路可靠性;处于切换位置时,通过中继的功率控制,保证本小区的信号满足最低通信要求,变相扩大重叠区覆盖范围的同时有利于触发切换提升切换成功率。仿真结果表明:本文提出的方案有效地提升切换成功概率和信道容量,明显改善了GSM-R系统的性能。展开更多
进一步提升高铁的信道切换性能具有重要的现实意义.基于信号功率和车载数据库协同触发机制提出了应用于高速铁路下一代通信专网LTE-R(long term evolution for railway)的新型切换算法,将数据库基站信息和信号功率实测信息的比对结果作...进一步提升高铁的信道切换性能具有重要的现实意义.基于信号功率和车载数据库协同触发机制提出了应用于高速铁路下一代通信专网LTE-R(long term evolution for railway)的新型切换算法,将数据库基站信息和信号功率实测信息的比对结果作为切换触发的判据,能实现中断快速重连和切换锁定等功能.仿真结果表明,该新型切换算法能有效提升LTE-R的信道切换性能,在重叠区关键位置点的触发效率比传统算法提升43.7%,切换成功率达到了99.5%.该协同触发切换算法在LTE-R高铁通信专网上具有广阔的应用前景.展开更多
文摘This paper presents prior determination of soft handover probability considering new direction of motion of mobile station (MS) coinciding with gravitation point of cells. Our simulation results for 3-cell scenario and considered new direction of MS motion can be potentially used as advance input to soft handover algorithms to minimize number of handovers.
文摘The LTE and LTE-Advanced systems are supposed to be the most popular cellular network in 4Gnetworks. Relay technology is one of the most preferred technologies proposed in LTE-Advanced standardization to improve the capacity and coverage. This paper analyses the handover outage probability through relay deployment, and proposes some proofs and suggestions for relay deployment to minimize the handover outage probability in high speed scenarios.
基金Supported by the China Scholarship Council (2008611011)Doctoral Fund of Ministry of Education of China(20094307110004)
文摘A novel Cooperative Directional inter-cell Handover Scheme(CDHS) for High Altitude Platform(HAP) communications systems is proposed,in which the handover target cell and the two cells adjacent to this handover target cell work cooperatively to exploit the traffic fluctuation to improve handover performance.Users in the overlap area of the overloaded handover target cell will be forced to handover directionally before their optimal handover boundary in order to free up resources for the handover calls which would otherwise be dropped due to the shortage of resources and queue time out.Simulation results show that the handover call dropping probability is greatly reduced(at least 60%) compared with the general queue handover scheme,with little performance reduction to the call blocking probability,and the Not in the Best Cell(NBC) average time is only increased moderately.Moreover,an optimal cell radius can be achieved for a specific platform speed by minimizing the unified system performance,which is the linear combination of the handover call dropping probability and the NBC average time.
文摘A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.
文摘随着高速铁路的不断发展和列车速度的不断提高,高铁场景下车地通信的可靠性和高效性引起广泛关注。列车速度的提升导致更加频繁的越区切换,使系统的可靠性得不到保障,因此列车速度的提升对高铁通信网络的安全性和可靠性产生严重影响。本文提出1种将LTE-A(Long Term Evolution-Advanced)网络应用到高速铁路场景并基于协同多点传输/接收CoMP(Coordinated Multi-Point transmission/reception)技术的切换优化方案模型,方案参考协作集加入模型。对系统切换成功率等进行性能分析,并与传统切换方案进行性能对比。分析表明:本文基于CoMP的切换方案可有效提升高移动性下网络的切换成功概率,明显改善系统的可靠性和效率。
文摘GSM-R(GSM for Railway)网是铁路运输所专用的GSM无线通信网络。与普通GSM网中移动台的低速移动不同,GSM-R网中列车的高速移动会使接收信号产生严重的多普勒频移,另外接收信号还会受到电力牵引等其他干扰。因此对这些质量不佳的信号进行检测将导致移动台的切换误判,造成列车越区切换成功率较低,从而削弱GSM-R网的安全性和可靠性。本文对GSM-R网传统切换策略进行建模,并且分析其切换中断率。为减小GSM-R网切换中断率,提出一种利用中继站辅助列车进行越区切换的策略。在该策略中,移动台在切换时不仅要检测相邻基站的信号,还将对重叠区中的中继站信号进行检测。仿真结果表明:本文提出切换策略的切换中断率明显小于未使用中继站时的情况,能够提高列车越区切换的成功率。
文摘GSM-R(GSM for Railway)的可靠性和高效性引起人们的关注。列车速度的提升导致多普勒效应更严重、切换触发位置更靠后、越区切换更频繁。多普勒效应恶化接收信号质量使中断率增加;切换触发位置靠后变相缩小重叠区覆盖范围使越区切换失败率增加;频繁的越区切换进一步降低系统可靠性。因此列车速度的提升对GSM-R网络的安全性和可靠性产生重要影响。同时,我国铁路网络的不断扩展对GSM-R系统的容量提出更高的要求。本文首先对GSM-R网络传统切换策略进行建模和性能分析。随后,提出一种利用列车位置信息和中继功率控制技术的切换优化方案。在该方案中,列车到达切换位置前,利用中继站获得分集增益,提升信道容量和链路可靠性;处于切换位置时,通过中继的功率控制,保证本小区的信号满足最低通信要求,变相扩大重叠区覆盖范围的同时有利于触发切换提升切换成功率。仿真结果表明:本文提出的方案有效地提升切换成功概率和信道容量,明显改善了GSM-R系统的性能。
文摘进一步提升高铁的信道切换性能具有重要的现实意义.基于信号功率和车载数据库协同触发机制提出了应用于高速铁路下一代通信专网LTE-R(long term evolution for railway)的新型切换算法,将数据库基站信息和信号功率实测信息的比对结果作为切换触发的判据,能实现中断快速重连和切换锁定等功能.仿真结果表明,该新型切换算法能有效提升LTE-R的信道切换性能,在重叠区关键位置点的触发效率比传统算法提升43.7%,切换成功率达到了99.5%.该协同触发切换算法在LTE-R高铁通信专网上具有广阔的应用前景.
