TD-LTE系统中下行控制信道容量分析

本文主要针对TD-LTE系统中下行控制信道,特别是能够影响小区用户数的PHICH信道和PDCCH信道,分析影响其信道容量的因素,并给出信道容量的计算公式,为将来进行TD-LTE网络规划与网络参数配置提供技术参考.     

LTE-A空口监测仪PDCCH盲检测的研究与实现

针对LTE-A网络结构以及运行机制复杂造成通信网络测试优化困难,以及国内LTE-A网络监测分析的设备的短缺问题,基于此进行了LTE-A空口监测分析仪表的研发。下行控制信道(PDCCH)承载了下行控制信息(DCI),是LTE-A系统资源调度的核心。根据PDCCH信道发送流程,设计下行控制信道盲检方法,为空口监测分析仪表快速准确获取下行控制信息提供支持。盲检流程包括解速率匹配、Viterbi译码、RNTI解扰、CRC校验,使仪表在当前PDCCH承载的下行控制信息格式及位置的未知的情况下,盲检出属于自己的DCI信息。     

VoLTE容量性能研究

研究了VoLTE的业务模型、容量相关的关键技术以及容量受限因素,对控制信道和业务信道资源调度机制作了细致的研究。根据资源调度机制研究了VoLTE容量性能评估方法,最终在一定配置下应用该方法对控制信道可调度用户数及业务信道可承载用户数进行理论推算,并对理想蜂窝网络结构下的用户容量进行仿真。此外在不同厂家设备条件下,针对VoLTE实验网,对实际业务信道可承载的用户数进行测试。最终确定了实际场景下,VoLTE单小区最大承载用户数可达200个左右,证实了VoLTE可以提供比2G/3G系统更大的承载能力。     

基于I/Q数据的5G控制信道盲检

为了研究真实环境5G下行I/Q解码流程,构建"5G核心网+5G基站+测试终端+I/Q数字采集系统"的测试环境,采集基站下行空口信号I/Q数据,并基于3GPP第15版本标准,开展5G下行控制信道PDCCH盲检流程研究,包括候选PDCCH时频域位置确定、信道估计与相关检测,PDCCH比特序列解码流程(含解扰,解速率匹配,极...     

Massive MIMO小区PDCCH控制信道容量提升技术研究

5G大带宽业务信道资源多,但是随着用户增多,控制信道资源提前成为瓶颈,Massive MIMO的大容量能力很难发挥出来.特别是大话务场景用户数多、用户信号质量差、用户做小包业务等均会导致PDCCH CCE受限严重.针对上述不足,重点分析了重载场景控制信道受限对MM性能的影响,保障重载场景MM小区的调度能力.所提PDCC...     

LTE物理下行控制信道盲检过程研究

LIE物理下行控制信道为整个系统上下行传输分配各种资源,对系统起着非常关键的调度作用.基于PDCCH信道发送与接收流程,根据PDCCH信道结构,详细分析了信道的调度过程、专用搜索空间和公共搜索空间,为终端PDCCH信道接收制定了一种详细的盲检方法,为LIE系统的实际实现提供了理论依据.     

合理配置PDCCH提升4G网平均速率

通过对UE端PDCCH信道的研究理解,结合LTE系统下行链路的特性及FDD-LTE建网初期用户量的特点,通过合理配置PDCCH信道中CFI达到降低系统开销,提升速率,提高用户体验的目的.     

LTE-A系统DCI盲检测方法的实现过程研究

LTE-A物理下行控制信道为整个系统上下行传输分配各种资源,介绍了PDCCH在系统中占有的资源数量和载波聚合在盲检测中的调度方式。根据PDCCH信道结构,设计了一种DCI盲检测发送和接收流程,详细介绍了其具体调度过程和盲检测方法,并提出了一些减少盲检次数和减少误检或漏检的改进思路,为LTE-A系统的实际实现提供理论依据。     

LTE-A系统DCI盲检测方法及实现过程研究

LTE-A物理下行控制信道为整个系统上下行传输分配各种资源,介绍了PDCCH在系统中占有的资源数量和载波聚合在盲检测中的调度方式。根据PDCCH信道结构,设计了一种DCI盲检测发送和接收流程,详细介绍了其具体调度过程和盲检测方法,并提出了一些减少盲检次数和减少误检或漏检的改进思路,为LTE-A系统的实际实现提供理论依据。     

TD-HSPA控制信道空分复用技术创新应用

TD-SCDMA系统对于要支持4倍空分复用功能需至少配置相应4对数的HS-SCCH/HS-SICH控制信道,这使得HSPA带宽降低或接入用户数下降,影响HSPA业务信道空分复用的效果容量.为此,提出了控制信道空分复用技术,它有效的解决了该问题.     

TD-LTE网络中PDCCH配置对网络的影响分析

TD-LTE系统中PDCCH的配置对网络的覆盖和容量都有一定的影响,本文主要通过对PDCCH聚合度的改变测试,从中找出PDCCH聚合度和覆盖距离以及容量之间的内在联系,为今后网络配置提供一定的依据。     

Joint Admission Control and Channel Selection Based on Multi Response Learning Automata (MRLA) in Cognitive Radio Networks

We use multi response learning automata (MRLA) to control how secondary users should access the licensed primary channels in cognitive radio networks. We seek two aims in this paper: (1) estimating the availability probability of each primary channel and (2) admission control of secondary users to decrease the rate of collisions between them. We consider single and multiple secondary user scenarios. In the first scenario, the secondary user deploys learning automata to estimate the primary channel availability probability for efficient exploitation. In the second scenario, each secondary user deploys an algorithm based on MRLA to estimate primary traffic as well as the behavior of other secondary users in order to control the rate of collisions. Then, to have a better control on the rate of secondary collisions, when the number of secondary users is greater than the number of primary channels, we proposed an admission control scheme. In this scheme, some of secondary users are blocked in each time slot and do not have any interaction with the environment. The convergence of the proposed algorithms with and without admission schemes is analyzed. Simulation results are provided to show the improvement in the secondary users’ total throughput and switching cost while maintaining the fairness between them.     

Research on the interference control and resource allocation in D2D communication

In order to solve the problem of interference caused by D2D users reuse cellular resources in cellular network,an algorithm of interference control and resource allocation of D2D communication in single cell cellular system was proposed.Firstly,an interference graph was constructed according to the interference between users in the system to find the reusable channel resource for D2D users.Then,the channel resource pre-allocation and the channel switching policy were performed for D2D users in sequence according to the preset D2D user priority.The simulation results show that the proposed algorithm can significantly improve the system throughput and the access rate of D2D users so that the system can achieve better performance in the presence of small or large number of D2D users.     

Performance analysis of an opportunistic multi‐user cognitive network with multiple primary users

Consider a multi‐user underlay cognitive network where multiple cognitive users concurrently share the spectrum with a primary network with multiple users. The channel between the secondary network is assumed to have independent but not identical Nakagami‐m fading. The interference channel between the secondary users (SUs) and the primary users is assumed to have Rayleigh fading. A power allocation based on the instantaneous channel state information is derived when a peak interference power constraint is imposed on the secondary network in addition to the limited peak transmit power of each SU. The uplink scenario is considered where a single SU is selected for transmission. This opportunistic selection depends on the transmission channel power gain and the interference channel power gain as well as the power allocation policy adopted at the users. Exact closed form expressions for the moment‐generating function, outage performance, symbol error rate performance, and the ergodic capacity are derived. Numerical results corroborate the derived analytical results. The performance is also studied in the asymptotic regimes, and the generalized diversity gain of this scheduling scheme is derived. It is shown that when the interference channel is deeply faded and the peak transmit power constraint is relaxed, the scheduling scheme achieves full diversity and that increasing the number of primary users does not impact the diversity order. Copyright © 2014 John Wiley & Sons, Ltd.     

LTE基站中PDSCH高效并行计算的FPGA实现

提出一种第三代合作伙伴(3GPP)长期演进(LTE)基站中下行共享信道(PDSCH)中比特级信号处理并行计算方案,其并行运算是基于现场可编程门阵列(FPGA)的。由于下行控制信道中数据流量相对下行共享信道偏少,为了保证控制信道与共享信道下行数据的时序对齐,并且最大程度上节省硬件资源,以满足LTE系统测试要求,必须采用并行计算的处理方式。采用VHDL语言在Xilinx公司的Virtex-6系列FPGA芯片内成功对该方案进行了验证,并对其进行优化。     

4G网络的资源瓶颈分析

分析了LTE网络的技术能力,包括小区吞吐量,PDCCH、PHICH和PUCCH信道容量,接入容量,寻呼容量等,并基于技术能力分析了各种典型业务的PRB、PDCCH CCE、PUCCH、PRACH、寻呼、RRC连接等网络资源的消耗和占用情况,最后推导了限制LTE网络提供更多用户服务的瓶颈资源,提出了建设和运营优化时重点考察的瓶颈指标建议.     

User-level performance of channel-aware scheduling algorithms in wireless data networks

Channel-aware scheduling strategies, such as the Proportional Fair algorithm for the CDMA 1xEV-DO system, provide an effective mechanism for improving throughput performance in wireless data networks by exploiting channel fluctuations. The performance of channel-aware scheduling algorithms has mostly been explored at the packet level for a static user population, often assuming infinite backlogs. In the present paper, we focus on the performance at the flow level in a dynamic setting with random finite-size service demands. We show that in certain cases the user-level performance may be evaluated by means of a multiclass Processor-Sharing model where the total service rate varies with the total number of users. The latter model provides explicit formulas for the distribution of the number of active users of the various classes, the mean response times, the blocking probabilities, and the throughput. In addition we show that, in the presence of channel variations, greedy, myopic strategies which maximize throughput in a static scenario, may result in sub-optimal throughput performance for a dynamic user configuration and cause potential instability effects.