一种TD-SCDMA动态信道分配的改进方案

在TD-SCDMA系统中,由于对上下行不对称业务的需求,使得不同小区间的上下行切换点不同,因此会产生严重的小区间干扰(基站和基站间干扰)。提出一种基于移动台位置的抗基站间干扰的动态信道分配(DCA)的改进方案,它通过增大交叉时隙的空间隔离度和减少交叉时隙的使用机率来改善基站间的相互干扰,同时使每个时隙的用户空间分布更加均匀,最大化提高系统容量,改善非对称业务下系统的整体性能。     

TD-SCDMA系统动态信道分配的改进方案

在时分同步码分多址(TD-SCDMA)系统中由于对上下行不对称业务的需求,不同小区间的上下行切换点不同,因此会产生严重的小区间干扰(基站和基站间干扰)。文章提出了一种基于移动台位置的抗基站间干扰的动态信道分配(DCA)的改进方案,它通过增大交叉时隙的空间隔离度和减少交叉时隙的使用机率来改善基站间的相互干扰,同时使每个时隙的用户空间分布更加均匀,最大化提高系统容量,改善非对称业务下系统的整体性能。     

全双工信息与能量同传系统的鲁棒性预编码及高能效时隙分配方案

最近全双工信息与能量同传系统（FD-SWIPT）受到高度重视,区别于现有研究,本文在最大化多天线FD-SWIPT系统的和速率的同时,考虑了其鲁棒性和能量效率,并提出了一种FD-SWIPT系统的鲁棒性预编码及高能效时隙分配方案.由于优化涉及的因素很多,这是一个多个变量的非凸优化问题,在数学上很难求解.首先,为减少全双工系统中自干扰对和速率造成的影响,基于奇异值分解及最小均方误差算法对系统自干扰进行消除;然后,固定时隙分配因子,在自干扰信道存在估计误差的情况下,基于一阶泰勒凸逼近对原优化问题进行鲁棒预编码设计,并给出相应的迭代算法;进一步,提出了不同约束条件下的时隙分配方案,并推导了不同方案下的时隙分配因子的最优解.最后,通过仿真实验与现有结果比较,验证了本文方案的性能优势.     

一种基于自适应资源分配的干扰协调方案

在宏基站和微微基站(Macro-Pico)的异构网络中,资源分配可以有效地抑制基站间的干扰。基于降低用户的干扰和提高系统的吞吐量,提出一种自适应的频率资源分配方案。考虑分配给宏基站的每个资源块,如果距离宏基站较近的微微基站用户所受到的干扰高于最高限,采用不给宏基站分配这个资源块的方法,从而降低其对邻近微微基站用户的干扰,保证微微基站用户一定Qo S(Quality-of-Service)。系统仿真结果表明,与正交频率资源分配方案和共信道频率资源分配方案相比较,所提出的自适应频率资源分配方案降低了干扰和提高了系统的吞吐量。     

5G双工演进技术研究

5G新型双工演进技术将在TDD频谱上引入基站侧子带不重叠全双工制式,以迎合万物智联和工业互联网对低时延和大上行吞吐量同时提出的更高要求,同时还需要进一步研究并解决基站间交叉时隙干扰问题,使能公网和专网采用不同的TDD上下行时隙配比的组网方式。为满足5G新型双工演进技术的未来部署需求,对TDD宏微异时隙组网和子带不重叠全双工制式的潜在部署场景和相关干扰特征进行了分析和研究,提出潜在可行的干扰抑制方案,并通过链路预算、仿真评估和样机验证等形式论证了技术可行性。     

TD-SCDMA系统中1588v2时间同步技术探讨

1背景 同步网是通信网必不可少的组成部分,是保证网络定时性能的关键。由于TD-SCDMA标准采用了TDD模式,对时钟同步和时间同步提出了更高的要求。TD-SCDMA支持同频组网,前提是时隙必须对齐。如果相邻基站之间空中接口不同步,会产生时隙间干扰和上下行时隙干扰。     

基于智能天线和资源预留的抗基站间干扰DCA分配算法

本文针对TD-SCDMA系统在次叉时隙间快速动态信道分配算法的不足,提出了一种基于智能天线和优级信道预留的快速动态信道分配算法。该算法在进行资源整合的基础上将信道条件较好的用户分配于交叉时隙,同时尽量分配多址干扰小的时隙给用户,从而达到减少交叉时隙干扰,提高频谱效率的目的,仿真结果表明该算法能够有效增加系统容量,改善系统性能。     

适应低信干噪比的认知无线电双向中继方案及其最优功率和时隙分配

认知无线电和协同通信是两种改善频谱利用率的新技术.本文研究中继辅助的潜伏式认知无线电双向通信的可达速率.为了更有效地使用认知无线电可用而不丰富的频谱资源,本文针对一种结合逐级干扰消除和网络编码的双时隙双向中继方案,考虑公平性以最大化双向通信均可达到的端到端速率为目标,给出了其最优功率和时隙分配方法.仿真结果表明采用所提出的功率和时隙分配的双向中继方案在实际资源严格受限的认知无线电环境中优于现有的双向中继方案.     

无线多跳网络下基于干扰管理的高容量跨层优化策略

在多跳多基站无线网络环境下,设计了一种基于干扰管理的高容量跨层优化策略。算法的物理层采用串行干扰消除实现干扰管理,在上层首先通过Voronoi图实现区域划分,然后基于节点的最小跳数建立每个节点到基站的初始链路分配和多跳路由方案,之后通过多时间片分配或多跳路由的节点选取对方案进行优化,并通过迭代的方式寻找吞吐量更大的优化策略。理论分析证明了该方案具有多项式时间复杂度,仿真结果显示引入了干扰管理相关技术后,整个网络的吞吐率有2到5倍的提升。     

TD-SCDMA系统中的动态时隙分配过程研究

在TD—SCDMA系统中由于上下行不对称业务的需求，使得不同小区的上下行切换点不同，出现交叉时隙，因此会产生严重的小区间干扰，需要使用动态信道分配算法以解决小区间的上下行时隙分配，小区内各种用户对时隙的选择等，使小区间干扰最小、系统容量最大，同时用户QoS最好。先介绍了TD—SCDMA系统中的资源和干扰情况，再重点介绍动态时隙分配全过程，分析了各部分所要完成的功能，并给出了慢速动态时隙分配的2种方案、快速动态时隙分配的4个过程以及各个过程的方案。     

VLC网络中兼具功率与时隙分配的自适应干扰管理机制

为了更好解决目前可见光通信（visible light communication,VLC）中干扰管理方案存在的动态优化问题,提出了一种兼具优化功率分配与时隙分配的自适应干扰管理机制。首先,在每个时隙依据用户的位置建立每个用户的接入点（access point,AP）协作集,寻找所有由最多数量互不干扰用户组成的极大独立集,以此自适应地避免同频干扰;在每个时隙为每个极大独立集采用改进的线性注水功率分配算法为信道自适应地分配发送功率,以此优化每个极大独立集的用户和速率;基于用户和速率、速率公平性及时延公平性的归一化优先因子,选出具有最大优先因子的候选极大独立集,其中包含的用户在该时隙被调用。通过仿真且与代表性文献中的算法比较可得,本文提出的自适应干扰管理与优化资源分配方案在网络频谱利用率、能效、用户速率公平性与时延公平性方面具有明显优势。      

Ordered array processing for space-time coded systems

The zero-forcing interference suppression and cancellation scheme proposed by Tarokh et al., in 1999, for grouped space time coded system suffers performance loss due to limited diversity gains for the first detected antenna groups, and power allocation was suggested to overcome this problem. In this letter, we propose an ordered detection algorithm which compensates the diversity loss by always detecting the group with the strongest post-ing signal-to-noise ratio. Compared with the power allocation scheme, our proposed scheme is more robust to varying channel conditions and when used with iterative interference cancellation, a performance gain of 2.4 dB can be obtained at a frame-error rate rate of 10/sup -2/.     

V-BLAST系统中一种简单的发射功率分配方案

采用发射功率分配方案可以有效地提高V-BLAST系统的性能。一方面,采用注水发射功率分配方案,可以有效地提高系统容量,另一方面,采用合理的发射功率分配方案,可以在固定数据速率时,改善误码率性能。本文针对第二种应用,给出了一种基于等信干噪比的发射功率分配方案,计算复杂度低,需要的反馈信令少,而且该功率分配方案与调制方式和检测算法无关。通过对MMSE串行干扰抵消和MMSE软干扰抵消检测算法仿真验证,其性能远好于不采用发射功率分配方案,同时接近基于拉格朗日极值法的功率分配方案性能。     

Joint power allocation and beamforming with users selection for cognitive radio networks via discrete stochastic optimization

Cognitive radio is a promising technique to dynamic utilize the spectrum resource and improve spectrum efficiency. In this paper, we study the problem of mutual interference cancellation among secondary users (SUs) and interference control to primary users (PUs) in spectrum sharing underlay cognitive radio networks. Multiple antennas are used at the secondary base station to form multiple beams towards individual SUs, and a set of SUs are selected to adapt to the beams. For the interference control to PUs, we study power allocation among SUs to guarantee the interference to PUs below a tolerable level while maximizing SUs?? QoS. Based on these conditions, the problem of joint power allocation and beamforming with SUs selection is studied. Specifically, we emphasize on the condition of imperfect channel sensing due to hardware limitation, short sensing time and network connectivity issues, which means that only the noisy estimate of channel information for SUs can be obtained. We formulate the optimization problem to maximize the sum rate as a discrete stochastic optimization problem, then an efficient algorithm based on a discrete stochastic optimization method is proposed to solve the joint power allocation and beamforming with SUs selection problem. We verify that the proposed algorithm has fast convergence rate, low computation complexity and good tracking capability in time-varying radio environment. Finally, extensive simulation results are presented to demonstrate the performance of the proposed scheme.     

Joint resource optimization for nonorthogonal multiple access-enhanced scalable video coding multicast in unmanned aerial vehicle-assisted radio-access networks

A joint resource-optimization scheme is investigated for nonorthogonal multiple access (NOMA)-enhanced scalable video coding (SVC) multicast in unmanned aerial vehicle (UAV)-assisted radio-access networks (RANs). This scheme allows a ground base station and UAVs to simultaneously multicast successive video layers in SVC with successive interference cancellation in NOMA. A video quality-maximization problem is formulated as a mixed-integer nonlinear programming problem to determine the UAV deployment and association, RAN spectrum allocation for multicast groups, and UAV transmit power. The optimization problem is decoupled into the UAV deployment–association, spectrum-partition, and UAV transmit-power–control subproblems. A heuristic strategy is designed to determine the UAV deployment and association patterns. An upgraded knapsack algorithm is developed to solve spectrum partition, followed by fast UAV power fine-tuning to further boost the performance. The simulation results confirm that the proposed scheme improves the average peak signal-to-noise ratio, aggregate video-reception rate, and spectrum utilization over various baselines.     

激光跨介质通信中跳时隙的编解码方法

跨介质无线光信道环境下散射吸收效应的出现会产生光强闪烁和光束漂移,造成激光光束传输性能下降,对数据传输产生干扰。为降低信息传输丢失概率、实现快速帧同步,提出一种跳时隙的脉冲位置调制编解码方法,通过研究跳时隙PPM编解码、信息组帧和传输技术,探讨系统实现方案。测试结果表明,采用跳时隙PPM字节组帧的信息传输技术,可进一步提升无线光信号传输抗干扰能力,收发双方依据约定的跳时隙通信规则,包括时隙类型组合、帧同步方式,有利于减小系统信息传输中被截获破译的机率,从而实现快速可靠通信。     

混合干扰抵消技术在导航接收机中的应用

在扩频体制的无线电导航系统中,接收机同时会收到多个导航台发射的地波和天波信号,这样接收点同时存在天波干扰和远近效应问题。提出基于天地波识别的远近效应判定算法和混合干扰抵消方法,在捕获结果都为地波的前提下,判断是否存在远近效应,利用串行干扰抵消跟踪获得较准确的初始数据估计,在此基础上用并行干扰抵消使信息数据更加精确。分析了干扰的因素,建立了实现原理框图,从而得出系统性能。仿真结果表明,利用改进的干扰抵消技术不仅可以提高系统的识别能力,还可以提高对于导航电文的接收性能。     

A co-channel interference cancellation technique using orthogonalconvolutional codes on multipath Rayleigh fading channel

This paper proposes and evaluates a new co-channel interference cancellation technique that utilizes orthogonal convolutional codes on a multipath Raleigh fading channel. In a spread spectrum multiple access environment co-channel interference (CCI) limits the performance of the communication link. To remove this interference, several CCI cancellation techniques have been proposed, including a technique that does not require the receiver to have knowledge of the cross-correlation between user sequences. This method leaves residual interference after the cancellation caused by errors in the initial decisions. To reduce the residual interference and improve the initial decisions, the proposed scheme utilizes the error-correcting capability of orthogonal convolutional codes. This paper evaluates the performance of this scheme. Our results show that the proposed CCI canceller offers an improvement in capacity of a factor of 1.5~3 as compared with a conventional canceller on a multipath Rayleigh fading channel. The proposed canceller works in the presence of residual interference due to imperfect cancellation. The proposed canceller also has a capacity improvement with the use of soft handoff in a multicell configuration