基于DSP的空时编码盲识别设计和实现

提出了一种基于TigerSHARC TS201S实现的MIMO系统空时编码盲识别方法的设计与实现,该设计能够在非合作条件下,利用空时编码在时间分集和空间分集下,所表现出的不同时滞相关性,实现盲识别空时编码方式。天线接收信号经过预白化,时滞相关度计算,最终利用码字表判决输出。经验证,该系统性能稳定,易于实现,且对空时编码方式具有较高的盲识别精度。     

Performance analysis of dual-hop fixed-gain AF relaying systems with OSTBC over Nakagami-m fading channels

In this paper, we present outage probability and symbol error rate (SER) performance analyses of a dual-hop transmission using fixed-gain amplify-and-forward relaying in flat Nakagami-m fading channels. The system under consideration is equipped with multiple antennas at source and destination adopting orthogonal space-time block coding to provide transmit diversity and maximum ratio combining to provide receive diversity, respectively. For integer and half-integer m values, closed forms of exact outage probability and moment generating function (MGF) expressions are derived through cumulative distribution function (CDF) of the overall system signal-to-noise ratio. Closed-form exact SER expressions based on the overall CDF are obtained for binary phase shift keying, binary frequency shift keying and M-ary pulse amplitude modulation. Exact SER expressions based on the MGF method are also obtained for binary differential phase shift keying, M-ary phase shift keying and M-ary quadrature amplitude modulation. Moreover, the asymptotic diversity order analysis is performed through derivations of asymptotic outage probability and SER. Theoretical analyses are validated by Monte Carlo simulations showing perfect match between each other.     

分层空时编码及应用研究

分层空时编码是应用于多输入多输出系统中的一种空时编码,具有结构简单、易于实现且频带利用率随着发射天线数目的增加而线性增加等优点。针对分层空时编码传输速率高、无法获得最大分集增益以及系统抗衰落性能差等缺点,提出了一种结合空时分组码的混合结构模型——分层空时混合码。同时,介绍了分层空时编码检测算法的最新进展以及分层空时编码在自由空间光通信、OFDM系统中的研究成果及应用。     

分布式残余频偏信道中STBC-OFDM的发射功率优化

在分布式残余频偏信道中,考虑多径瑞利衰落,针对采用判决反馈检测的两发射天线STBC-OFDM链路,提出了一种发射功率优化方法:根据平均信道功率增益、残余频偏方差以及噪声方差的大小,以最小化平均误比特率下界为目标,设置两分布发射天线的发射功率,仿真结果表明:相比于传统的各天线满功率发射方法,所提方法能够在节省发射功率的同...     

Diversity order analysis of orthogonal space–time block coding over keyhole fading channels with antenna selection

Although there are many research results for the keyhole fading channels in the current literature, fewer results have investigated the antenna selection scheme and quantified the diversity order. In this letter, we first derive some simple statistics of the output signal‐to‐noise ratio for the orthogonal space–time block coding over keyhole fading channels. On the basis of these results, we derive an approximate BER expression for the keyhole MIMO channels with receive antenna selection scheme. Results show that the diversity order with receive antenna selection is min{n_R,n_T}for n_R ≠ n_T, which means that the full diversity order with antenna selection is maintained. Finally, numerical results demonstrate the accuracy of our analytical expressions and the tightness of approximate formulas. Copyright © 2012 John Wiley & Sons, Ltd.     

一种空时块编码OFDM系统中的自适应均衡算法

该文提出了一种适用于Alamouti块编码的多天线发射的OFDM系统的自适应均衡算法。该算法充分利用了Alamouti编码的正交特性和多发射天线的OFDM系统特点,通过灵活的变换对接收信号进行等价的表示;通过对П矩阵求逆的研究使块最小二乘递推算法(BRLS)中的2K2K的矩阵求逆分解为K个22矩阵的求逆,从而降低了运算量和接收机的复杂度。计算机仿真结果证明了该自适应均衡算法的有效性和快速收敛性。     

基于块空时分组编码DFT-S-OFDM虚拟MIMO传输方案

该文提出了一种基于块空时分组编码的DFT-S-OFDM上行链路虚拟MIMO传输方案,并给出一种低复杂度的虚拟MIMO系统接收机检测算法。仿真研究表明:基于块空时分组编码的DFT-S-OFDM虚拟MIMO传输方案可保持原DFT-S-OFDM系统低峰均比的特性,显著降低虚拟MIMO系统接收机检测门限,提高上行链路虚拟MIMO系统传输可靠性。     

一种自适应线性分散码方案的性能研究

针对线性分散码复杂度较高的问题,提出一种自适应线性分散码(ALDC),并将其应用于协作通信网络.该码可以根据当前信道状态,自适应地选择不同的调制阶数和分散矩阵,以在不同信噪比下获得最优的误码率性能,同时降低译码复杂度.分析了该码在协作系统中的编码与译码,并在误比特率性能上与传统空时分组码和LDC进行了仿真对比.结果表明,ALDC的误码率性能要优于传统的正交空时分组码和LDC,且译码复杂度较低.     

SFBC-OFDM系统在快衰落信道下的性能分析

在STBC—OFDM系统的基础上介绍了SFBC—OFDM系统的原理、编译码方案，并通过仿真做出了SFBC—OFDM系统在快衰落信道下的性能，同时与STBC—OFDM系统的性能进行比较。结果表明：SFBC—OFDM系统在室内环境即时间延迟缓慢的情况下性能与STBC—OFDM基本上达到一致，在室外环境快衰落情况下性能要比STBC—OFDM系统要好。     

移动通信中基于交互差错的协作发射性能研究

未来移动通信系统中相互独立的多个手机通过协作发射可以获得协作分集的好处。同时,发射端信息交互差错会影响协作发射性能。考虑瑞利衰落信道及基于空时分组码的协作发射方案,该文研究了信息交互差错对分集性能的影响。理论分析及仿真结果表明,当信噪比较高时发射端信息交互差错成为影响接收性能的主要因素,发射端协作手机数大于2时,接收端增加接收天线数可在一定程度上提高接收性能极限。