Analyzing speech of patients with vocal polyps based on channel parameters and fuzzy logic systems

In this paper, the spectrum map of speech samples is used to identify patients with vocal polypus. Comparing the spectrum map with impulse response in wireless communication channels, statistical characteristic root-mean square-delay spread (RMSD) and standard deviation (SD) are employed to describe the speech frequency domain characteristics. Fuzzy logic system (FLS) is used to make polypus patients diagnosis. RMSD and SD are used as two antecedents and fuzzy rules are designed based on the data we collected from polypus patients and normal people. Based on the real data, we demonstrate that the FLS could be used in polypus patients’ diagnosis with very low probability of miss detection and 0% false alarm rate.     

中继增强型蜂窝网络接入选择策略的研究

主要考虑中继接入选择策略对基于OFDMA的中继增强型蜂窝网络带来的系统性能影响.分别针对集中式和分布式控制两种情景,以最大化用户吞吐量为目标设计了基于信干噪比的接入选择策略.并通过搭建基于802.16j的系统级动态仿真平台对其性能进行仿真分析.与传统的接入方案相比.该方案在用户吞吐量分布,以及不同中继位置下的系统频谱效率指标下,均可获得更好的系统性能增益.     

Quality of service aware admission control in cognitive device-to-device network

A hybrid system of cellular mode and device-to-device(D2D)mode is considered in this paper,where the cellular resource is reused by the D2D transmission.With the objective of capacity maximization,the power optimization of D2D sub-system is considered,taking into account quality of service(QoS)requirement.The power optimization problem is divided into two stages:The first stage is the admission control scheme design based on the QoS requirement of D2D users,and the second is power allocation to maximize agg...     

Enhancing secrecy capacity of multi‐relay wiretap systems with partial channel state information

Distributed precoding has provento be capable of enhancing the secrecy capacity of the multi‐relay wiretap system. An iterative distributed precoding and channel state information (CSI) sharing scheme can be used to reduce the CSI overhead at each relay node. However, in practical applications, the CSI of each relay node cannot be perfectly known to themselves, especially that of the relay‐eavesdropper channels. Thus, partial CSI for the relay‐eavesdropper links is assumed, and the corresponding distributed precoding and CSI sharing schemes are investigated. Under the assumption that the average value of the relay‐eavesdropper channel is known at each relay node, an extended iterative distributed precoding and CSI sharing scheme is proposed. Simulation results demonstrate that with the increase of the power ratio of the constant part to the random part of the relay‐eavesdropper channels, the proposed scheme with partial CSI performs increasingly close to the one with perfect CSI in secrecy capacity. Copyright © 2014 John Wiley & Sons, Ltd.     

Distributed spatial–temporal precoding with limited feedback in MIMO multi‐relay systems

Precoding techniques can be introduced into multi‐relay systems due to the similarity between cooperative communication systems and traditional multi‐input–multi‐output (MIMO) systems. In this paper, a channel state information (CSI) feedback scheme based on the zero‐forcing (ZF) relaying protocol is proposed at first, where the information of relaying channel and noise related to each relay node can be compressed into two positive real parameters. Then, based on the proposed feedback scheme, the singular‐vector‐based local temporal precoder is presented at the source node through two continuous transmitted vectors, which is termed as distributed spatial–temporal precoding (DSTP). Moreover, various spatial data rates can be conveniently supported by DSTP. Based on the analysis on DSTP, it is better that the number of data streams is not larger than the number of antennas equipped at the source node. The unitary DSTP with the proposed feedback scheme outperforms not only the close‐loop direct transmission but also the simple ZF relaying method. Copyright © 2010 John Wiley & Sons, Ltd.     

基于软判决的MMSE-OSIC接收机

串行干扰相消接收机是广泛应用于多输入多输出系统中的一种接收端信号处理与检测技术。在串行干扰相消接收机中,先检测的层的判决准确性会对后续层的检测产生影响。检测过程中产生的判决误差,将对后续层的检测引入残留干扰,进而影响后续层检测的正确性,造成差错传播。本文提出一种基于软判决的最小均方误差检测带排序串行干扰相消接收机,可以有效减轻基于硬判决方法的带排序串行干扰相消接收机的差错传播问题。在重构干扰信号时,该接收机使用根据软判决信息得到的符号期望,替代硬判决方法,能够有效降低干扰相消时各层之间由判决误差引起的残留干扰;该接收机还可以精确估计残留干扰的功率以及各层数据流的后处理信干噪比,改善了基于硬判决方法的串行干扰相消接收机存在的各层后处理信干噪比估计值偏大的问题。可靠性更高的软判决结果有效降低了残留干扰,更精确的各层后处理信干噪比抑制了残留干扰对后续数据流检测的影响,提高了判决结果和排序过程的准确性。仿真结果证明,基于软判决的最小均方误差检测带排序串行干扰相消接收机可以有效避免差错传播的产生,因而获得较大的性能提升。      

GPP-Based Soft Base Station Designing and Optimization

It is generally acknowledged that mobile communication base stations are composed of hardware components such as Field Programming Gate Array (FPGA), Digital Signal Processor (DSP), which promise reliable and fluent services for the mobile users. However, with the increasing demand for energy-efficiency, approaches of low power-consumption and high-flexibility are needed urgently. In this circumstance, General Purpose Processor (GPP) attracts people’s attention for its low-cost and flexibility. Benefited from the development of modern GPP in multi-core, Single Instruction Multiple Data (SIMD) instructions, larger cache, etc., GPPs are capable of performing high-density digital processing. In this paper, we compare several software-defined radio (SDR) prototypes and propose the general architecture of GPP-based soft base stations. Then, the schematic design of resource allocation and algorithm optimization in soft base station implementation are studied. As an application example, a prototype of GPP-based soft base station referring to the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is realized and evaluated. To the best of our knowledge, it is the first Soft-LTE prototype ever reported. In the end, we evaluate the timing performance of the LTE soft base station and a packet loss ratio of less than 0.003 is obtained.     

基于动态帧结构的多跳中继链路的资源分配

在基于TDMA传输方式的多跳再生中继链路中,通过引入动态的帧结构设计使该链路上的每一跳传输所占用的时间可以进行调整。提出了在这种帧结构下多跳再生中继链路的资源分配算法,目的是在保证用户QoS需求的前提下使整个链路总的发射功率达到最小。仿真结果表明,相对于采用固定帧结构的资源分配算法,该算法能够降低总发射功率,同时能够降低用户不满意的概率。     

无线Ad hoc网络中基于SWAN模型的QoS改进机制

为提高无状态无线Ad hoc网络模型SWAN的QoS性能,对其接纳控制机制和路由机制分别进行改进。对802.11 DCF协议的饱和吞吐量和流内干扰模型进行了分析,提出一种节点可用带宽和业务流占用带宽的估计方法,以提高接纳控制的准确性;同时,将网络负载信息用于路由发现过程,以获得资源相对充足的传输路径。仿真结果表明:采用上述改进机制的SWAN模型中,实时业务的时延性能显著提高,非实时业务的吞吐量也得到增加。