Physical-layer network coding in k-users MIMO-Y two-way relay channels

In order to exchange information among k users using the technology of physical-layer network coding in the multiple input multiple output Y two-way relay channels,the GSA-GSA scheme was proposed,using the technology of general signal alignment during the uplink and the downlink.The signals were exchanged between every source node align in a transformed subspace,rather than the direct subspace.This was realized by jointly designing the precoding matrices at all source nodes and the processing matrix at the relay.The constraints of the number of sending and receiving antennas and the sum rate of proposed scheme were analyzed.In simulation,it can figure out that the proposed scheme needs fewer antennas in the whole system and can improve the achievable system sum rate under the same SNR and degrees of freedom.     

一种面向新一代可伸缩视频编码的上采样设计

可伸缩视频编码属于新一代H.265/HEVC视频编码标准中的关键技术。本文分析了其相关技术,针对传统空间可伸缩视频编码中的上采样过程运算复杂、时间延迟等缺点,借鉴双边滤波器,将内容自适应嵌入到上采样过程中,提出了一种新的非线性和内容自适应设计方法。通过理论推导得出了改进后滤波器的表示公式,并设计出了新的上采样实现流程。通过仿真实验验证了理论推导的正确性,并与传统方法进行了比较,结果表明该方法可有效地提高编码效率、降低系统复杂性。     

混合蛙跳在网络编码协作系统资源分配中的应用

网络编码协作中继技术能合理分配IMT-Advanced的资源,从而提高系统性能,受到了广大学者的关注。针对基于网络编码的双向多中继协作系统,提出基于混合蛙跳的资源分配方案。以最小化系统传输功率为优化目标,在满足用户QoS下,推导每个节点的最优化功率,建立最优化资源分配模型,利用混合蛙跳算法解决系统资源分配问题。仿真结果表明,在满足单节点QoS下,所提出的基于混合蛙跳的资源分配方案能有效减小系统的总功率,提高了系统性能。     

无线中继协作中LDPC码与网络编码联合设计探讨

在研究无线协作移动通信的基础上,利用LDPC(Low Density Parity Check)码(多层LDPC码或者速率兼容LDPC码),针对多接入协作系统,讨论如何将其与网络编码(线性网络编码、随机网络编码)结合的设计方案,从而提高通信系统性能和吞吐量,具有极高的理论价值和应用前景。     

基于天线分集和空-时编码的抗舰载卫星天线指向损耗方法研究

本文针对舰载卫星天线指向损耗问题,将接收分集和空-时编码技术应用于舰艇卫星通信中。构建了舰船卫星通信信道模型,分析了舰载天线随机指向损耗特点,研究了接收分集和空-时编码技术,进行了舰船卫星MIMO通信性能仿真。研究结果表明,将MIMO技术应用于舰艇卫星通信可以有效改善舰载卫星天线指向损耗的不良影响。     

一种优化的多视点视频编码预测结构

首先分析了JMVC的参考预测结构,利用1个Go P(Group of Picture)中不同时间层上的帧与其参考帧之间的相关度不同和不同时间层上的帧数目也不同的特点,提出了去除奇数视点最高和次高时间层的视点间预测,并增加偶数视点非关键帧的最低和次低时间层的视点间预测的预测结构。实验结果表明,提出的预测结构基本不影响视频质量,且表现出了更加出色的编码效率,编码的复杂度减少幅度高达15%,输出码率也有所减少,较好地改善了编码的实时性能。     

基于物理层子信道的单频网组网优化方法*

本文针对利用物理层子信道传输多种业务的地面数字电视单频网,提出了一种基于叠加编码调制的单频网优化方法,该方法在保证公共业务覆盖要求的同时提升本地业务的接收效果,对充分利用信道资源、减少单频网分析设计周期具有重要意义。     

分布式视频编码边信息改进技术

高质量的边信息生成技术是分布式视频编码系统实现高压缩效率的关键所在.提出一种边信息的改进方法,对部分译码的Wyner-Ziv(WZ)帧中运动剧烈的区域进行空域修正,使用相邻关键帧对应块的空间预测值与实际值之间的差值来补偿当前部分译码WZ帧中空间预测的误差.仿真结果表明该方法提升了边信息的质量,进而提高了DVC系统的率失真性能.     

SAR天线监测的正交编码研究

通过分析天线内监测的原理框架图,结合SAR卫星的自身设备系统提出了SAR天线监测的数学模型,分析耦合和传输对监测带来的影响。根据监测网络编码正交性的要求给出了适用于该监测网络的相位码,提出了受T/R组件移相精度的影响而相位码码长不足的问题,给出了分块和迭代两种解决方法。最后,用计算仿真实验说明了相位码的有效性和监测模型的可行性。     

Effect of AMC on fixed‐rate traffic with hard delay constraints in mobile broadband systems

The adaptive modulation and coding (AMC) technique, which has been adopted by advanced mobile telecommunication systems, supports a flexible response to the random radio behaviour. As a result, the attained transmission rate over a wireless link is time varying. Hence, resource demands are not deterministic but fluctuating even for calls with constant bit rate service requirements. Consequently, constant bit rate calls are susceptible to a forced call termination because of insufficient resources not only in a target cell during inter‐cell handoffs but also in a serving cell during radio link deterioration. Furthermore, call blocking and dropping probabilities depend on radio propagation conditions among other factors and therefore they are dissimilar throughout a service area. The latter leads to unfairness problems. We analytically measure the impact of AMC on fixed‐rate service with hard delay constraints such as voice for different signal, mobility and traffic conditions. We consider a reference case (call requests are admitted into the system provided there are enough free resources) and two classes of admission control approaches: traditional (only inter‐cell handoffs are prioritised) and modified (all ongoing calls are prioritised). The reported results reveal conditions for which AMC affects voice call performance and can serve as guidelines on admission control design. Copyright © 2013 John Wiley & Sons, Ltd.