CDMA2000 1X系统反向功率控制性能分析

本文主要分析了CDMA2000 1X蜂窝系统反向链路的功率控制性能，在分析过程中假设无线信道为独立的瑞利衰落信道，分别从功率调节步长、移动台移动速度、功控比特的BER以及信道参数几个功控参数来加以分析研究，并由此得出提高功率控制性能的一些方法。     

LTE系统PRACH详解

PRACH(Physical Random Access Channel),物理随机接入信道,作为非同步用户和LTE无线接入的正交传输方案的接口,主要用于网络接入的初始化,为未得到上行同步或已经失去上行同步的用户实现上行定时同步。本文首先对LTE系统PRACH进行了简单介绍,然后分别从PRACH的初始参数、触发事件、消息流程以及检测等几个方面进行了详解。     

一种CDMA系统反向功率控制的算法

本文简要介绍了基于ＩＳ－９５的ＣＤＭＡ系统反向信道功率控制的原理及其算法实现，从理论上分析了理想的精确功率控制和非精确功率控制对反向信道爱尔兰容量的影响，并对反向闭环功控算法和外环功率控制算法进行了仿真，得到爱尔兰容量最大的仿真算法。     

Ⅲ代功控参数优化研究

主要讨论了某设备中,三代功控原理及针对功控原理和网络现状对功控参数进行优化设置,再分别针对上行和下行干扰情况,进行优化调整,以达到整体降低网络噪声,提升网络质量。最后以一个应用实例举证了该理论的实际可操作性应用效果。对GSM网络优化中提升网络质量和后期网络优化具有很大的借鉴意义。     

一种基于惩罚因子的LTE上行调度算法研究

针对LTE系统无线信道的复杂性和用户上行信道估计的不准确性,结合上行信道的实际情况,对经典PF调度算法进行改进,提出一种基于惩罚因子的LTE上行调度算法,并采用该算法对GBR业务进行上行调度仿真。实验结果表明,该算法在仿真网络环境下能有效提升LTE网络的上行业务量,提高网络资源的利用率。     

基于PSO的D2D蜂窝网络联合信道分配和功率控制

为解决蜂窝用户(Cellular Users, CU)和终端直通(Device to Device, D2D)用户之间的干扰管理问题,提高无线蜂窝网络吞吐量,提出了一种基于粒子群优化的联合信道分配和功率控制方案。提出了具有不同约束条件的2个联合信道分配和功率控制问题,并将离散信道和连续功率联合分配给CU和D2D对,允许任意数量的D2D对与一个CU共享同一信道。通过设计适应度值避免算法陷入局部最优或产生不可行的解决方案,并使算法收敛到全局最优。通过搭建仿真网络模型进行测试验证,并与随机粒子群优化算法进行对比分析。实验结果表明,所提方法可有效提高蜂窝网络中的D2D通信网络吞吐量,且与随机粒子群优化算法相比,所提方法在D2D吞吐量、蜂窝吞吐量以及整体网络吞吐量方面具有明显优势。     

认知网络中基于中继的频谱资源分配

根据无线认知中继网络上、下行链路子载波的信道特性,研究认知网络的频谱资源分配,提出一种上、下行链路子载波联合优化的分配算法。该算法根据子信道增益差值因子的大小分配下行链路子载波,以源节点和中继节点功率最小化为优化目标配对上行链路子载波,以用户的实时需求分配子载波的比特和功率,有效降低了系统的发射功率,提高了系统吞吐量。仿真结果表明,与启发—集中式和分布式辅助反馈传输功率分配算法比较,该联合优化算法的单位比特功耗降低了1.5~3 dBμW,误比特率性能提高了1个数量级左右。     

基于非合作博弈的OFDMA无线多跳中继网络上行链路资源分配算法

研究了基于OFDMA多址技术的无线多跳中继网络上行链路资源分配问题。首先,在最大发射功率等约束条件下,建立了多小区OFDMA无线多跳中继网络上行链路的资源分配优化模型。将非合作博弈论和定价机制引入后,该优化问题可转化为在每个子信道上独立地进行功率分配。基于非合作博弈的功率分配模型中的纳什均衡点的存在性和唯一性得到了证明,并给出了具体的分布式求解算法。仿真结果表明,所提算法能在大幅减少系统总发射功率的情况下,有效地提升系统吞吐量,达到较高的能效比。     

基于接收SINR的LTE上行闭环功率控制算法研究

功率控制是无线通信系统资源控制的一项重要内容。LTE的上行功率控制方案采用了一种开环和闭环相结合的方式,主要用于补偿路径损耗和信道衰落,以及降低小区间干扰。为了提升小区边缘用户性能,文章提出了一种基于接收SINR的闭环功率控制算法。仿真结果表明,在保证小区整体性能的基础上,与开环功控相比,此闭环功控算法在小区边缘用户性能上最多有53%的提升。     

LTE网络容量优化方法研究

介绍了LTE网络无线帧结构,对LTE网络覆盖与容量优化的目的、优化参数以及优化流程进行了详细阐述。针对小区间干扰问题,使用有效的频率复用结构和合理的实时调度算法来提高整个 LTE 小区总的吞吐量。LTE网络容量优化可以有效地提高了LTE网络系统的容量以及覆盖能力。     

基于GSIC的上行链路毫米波大规模MIMO-NOMA系统低功耗传输方法

非正交多址接入（non-orthogonal multiple access,NOMA）和毫米波大规模多输入多输出（multiple-input multiple-output,MIMO）的结合能够支持未来无线通信网络的巨流量大连接需求。研究了上行链路毫米波大规模MIMO-NOMA系统中的功率最小化问题，提出了基于群体串行干扰消除（group-levelsuccessiveinterference cancellation,GSIC）的混合波束成形毫米波MIMO-NOMA上行传输系统新架构。具体来说，根据信道增益对用户进行群体划分，不同群体用户由NOMA服务，群体内用户采用空分多址区分。通过给不同群体设计模拟波束成形矩阵，对数字波束成形和功率控制进行联合优化，提出了一种并行迭代算法来解决优化问题。仿真结果表明，所提出的新架构在总功率方面优于传统的基于分簇和用户级串行干扰消除的毫米波大规模MIMO-NOMA。     

LTE系统上行链路质量提升的方法研究

随着VoLTE业务的商用以及4G用户大规模增加，4G网络不仅承担数据业务，还承担着语音业务，这对上行链路质量提出了更高的要求。在网络结构和无线环境日趋复杂的情况下，LTE链路质量在很大程度上制约着LTE网络性能的发挥，LTE网络受干扰、覆盖或容量受限程度直接影响了通话质量、上传下载速率、业务时延等用户的实际感知，还会引起无法接通、掉话、切换失败等一系列问题事件。本文利用功率余量值PH表征LTE上行链路质量，通过挖掘并调整上行性能参数来快速的提升上行链路质量。结合上海核心城区低功率余量TOP小区的实际情况，探究上海低PHR小区占比高的主要原因，提出一套区别于传统优化方式的参数优化方案以实现低PHR小区占比降低，达到上行链路质量提升的目的。通过试点验证可知，目前核心城区上行低PHR问题小区占比已由3.94%降至1.48%。     

认知型飞蜂窝网络中的子信道分配与功率控制

为了解决宏蜂窝与飞蜂窝构成的两层异构网络上行干扰与资源分配问题,提出了一种在认知型飞蜂窝的双层异构网中结合子信道分配和功率控制进行资源分配的框架。通过对异构网中跨层干扰问题进行分析与建模,将求解最优子信道分配矩阵和用户发射功率矩阵作为干扰管理问题的解决方法。模型中认知型飞蜂窝网络子信道和飞蜂窝网络用户构成非合作博弈,双方利用效用函数最优值进行匹配,构成初始信道分配矩阵;再由接入控制器根据接入条件从初始信道分配矩阵中筛选用户,并优化接入用户的发射功率矩阵,得到最优子信道分配矩阵和功率矩阵。仿真结果表明,优化框架提高了双层异构网络中飞蜂窝网络用户的吞吐量和接入率,降低了异构网中跨层干扰。     

LTE混合网络异频空闲重选参数优化研究

LTE混合网络的无线网络环境,在LTE网络空闲状态,涉及LTE系统同频、异频及异系统空闲重选。首先介绍了LTE无线网络空闲重选原理,其次通过LTE混合网络的无线网络环境中异频空闲重选参数优化分析,提出LTE混合网络的无线网络空闲重选参数优化方案,并结合实际LTE混合网络的无线网络环境,进一步验证了空闲重选参数优化方案能够提高LTE混合网络的无线网络覆盖效果。     

Uplink scheduling scheme for cloud service based on software-defined wireless network

A LTE uplink scheduling scheme matching the features of wireless cloud services was proposed for the SDWN (software-defined wireless network). The scheme first solved the resource allocation problem by using the binary integer programming method, and then calculated the optimal transmission rate of cloud services in each time slot using the method of dynamic programming, finally adjusted the transmission rate of cloud services proportional to the current channel status using QoS control method in the framework of SDWN. The proposed scheme minimizes the energy con-sumption of cloud services while ensuring the transmission rate demand of multiple services. The performance of the al-gorithm is verified by simulation.     

Network Performance Analysis of TCP-Based 3GPP LTE Time Division Duplex Systems

This paper deals with the determination of downlink (DL) and uplink (UL) channel split ratio for time division duplex (TDD) based long term evolution (LTE) networks. In a TDD system, UL and DL transmissions are carried out at different time intervals, but share the same frequency band. The TDD framing in LTE is adaptive in the sense that the DL to UL bandwidth ratio may vary with time. This paper proposes an adaptive split ratio (ASR) scheme for LTE networks to automatically adjust the bandwidth ratio of DL to UL, according to the current traffic profile, wireless interference, and transport layer parameters. This provides the maximum aggregate throughput in LTE systems. The performance analysis shows that ASR scheme outperforms static allocation in terms of higher aggregate throughput and better adaptively to network dynamics. Further, it is also observed that the ASR scheme performs well for LTE, compared to worldwide interoperability for microwave access (WiMAX) system.     

Rate selection based medium access control for full-duplex asymmetric transmission

The realization of full-duplex wireless communication is predictable. And asymmetric transmission is a practical and low-cost application scenario, where full-duplex access point (FD_AP) can communicate with two users simultaneously to receive and send packets. While, in an asymmetric transmission, the transmit power of uplink sender decides the uplink and downlink rates because of the inter-client interference, which accordingly restricts the throughput. Besides, the size of packets in uplink and downlink is generally unequal. Therefore, a WIFI network with a FD_AP and half-duplex users is studied in this paper, and a medium access control (MAC) protocol based on power control and rate selection (PCRS) is proposed. PCRS MAC employs a received signal strength based rate selection strategy to select different rates and power for uplink and downlink transmission. Then, FD_AP can establish efficient and reliable full-duplex asymmetric transmission. Simulation results show that PCRS can improve the throughput and the probability of successful asymmetric communication as compared to the distributed coordination function (DCF) and a simple full-duplex MAC protocol without PCRS. Besides, PCRS MAC also maintains a high level of fairness.

     

Cross-Layer Antenna Beamforming and Power Control in Wireless Uplinks

We consider backlog-driven power control and antenna beamforming as a means to maximize network throughput in a wireless uplink, where a base station receives with an antenna array from single-antenna wireless users. Throughput maximization gives rise to an optimization problem which is in general non-concave. We introduce a cross-layer, alternating maximization algorithm searching for the optimal solution, and a variant of the algorithm with reduced complexity. The algorithm alternates between a power control step and a beamforming step. Simulation results illustrate the convergence of the proposed scheme to a locally optimal pair of power vector and beamforming matrix, and quantify its throughput gains in a system with stochastic arrivals.     

Coverage and capacity optimization in LTE network based on non-cooperative games

As to provide the optimal coverage and capacity performance,support high-data-rate service and decrease the capital expenditures and operational expenditures(OPEX)(CAPEX) for operator,the coverage and capacity optimization(CCO) is one of the key use cases in long term evolution(LTE) self-organization network(SON).In LTE system,some factors(e.g.load,traffic type,user distribution,uplink power setting,inter-cell interference,etc.) limit the coverage and capacity performance.From the view of single cell,it always pursuits maximize performance of coverage and capacity by optimizing the uplink power setting and intra-cell resource allocation,but it may result in decreasing the performance of its neighbor cells.Therefore,the benefit of every cell conflicts each other.In order to tradeoff the benefit of every cell and maximize the performance of the whole network,this paper proposes a multi-cell uplink power allocation scheme based on non-cooperative games.The scheme aims to make the performance of coverage and capacity balanced by the negotiation of the uplink power parameters among multi-cells.So the performance of every cell can reach the Nash equilibrium,making it feasible to reduce the inter-cell interference by setting an appropriate uplink power parameter.Finally,the simulation result shows the proposed algorithm can effectively enhance the performance of coverage and capacity in LTE network.