基于Polar码的速率兼容调制方案设计

提出了一种基于Polar码的速率兼容调制（rate compatible modulation,RCM）联合设计方案,用于提高无线通信频谱利用率.相应地设计了基于置信度传播（belief propagation,BP）和软抵消（soft cancellation,SCAN）的接收端高效联合迭代译码算法.根据该算法可通过优化变量节点对数似然比（log-likelihood ratio,LLR）信息迭代方式以及采用限制译码符号上限的改进措施,提高译码过程的稳定性与时效性.与距离优化的级联低密度奇偶校验（low-density parity-check codes,LDPC）码RCM方案对比结果表明,提出的高效联合迭代译码算法在低信噪比（signal noise ratio,SNR）下有更低的译码复杂度,并且具有更优的吞吐量和误码率性能.因此,本文所提方案适合在恶劣信道条件下的无线传输.     

双硬限幅器异步光码分多址系统误码性能分析

针对基于单硬限幅器（OHL）异步光码分多址（OCDMA）系统的解码器不能完全消除信道串扰产生的误码，提出了具有双OHL的解码器结构来优化系统传输性能。通过数值分析给出了地址码（光正交码，OOC）的码长、码重、用户数与系统误码率的关系，结果表明：双OHL异步OCDMA系统误码率相对于单OHL系统误码率下降明显，系统传输性能得到改善。     

关于秩距离BCH码的校验矩阵及其秩距离

本文基于秩距离码提出了秩距离BCH码,给出了其校验矩阵的形式,并讨论了所给秩距离BCH码为最大秩距离HCH码时,码的生成多项式的根应满足的条件。     

秩距离BCH码的进一步研究

本文作者在“关于秩距离BCH码的校验矩阵及其秩距离”一文中提出了秩距离BCH码的概念，讨论了所给秩距离BCH码为最大秩距离BCH码时，码的生成多项式的根应满足的条件。本文在此基础上，讨论当线性秩距离码的生成多项式具有广义连续根时，它能构成秩距离BCH码的充分条件并给出了此充分条件。     

一种准静态平坦衰落信道下空时编码设计的新方法

空时码在准静态平坦瑞利衰落信道下的设计准则被广泛采用的是秩准则和行列式准则,但这些准则并不是很紧的。为此,提出了准静态平坦瑞利衰落信道下一种新的更紧的设计准则,采用这种准则还大大降低了穷举搜索空时好码的复杂度,仿真结果表明,搜索得到的空时好码性能优于现有的其它好码。     

基于改进遗传算法的STSK系统色散矩阵和3D星座的联合优化

空时移位键控（space-time shift keying,STSK）是一种用于多输入多输出（multi-input multi-output, MIMO）通信系统的调制方案,通过预先设计的色散矩阵集（dispersion matrix set,DMS）以实现系统在复用与分集之间的灵活设计。提出了改进的遗传算法（genetic algorithm,GA）辅助DMS和3D星座的联合优化,即将DMS和3D星座联合编码作为GA的染色体,并采用秩与行列式准则对应的编码增益作为总体适应度值。通过高效的选择以及改进的变异和交叉策略,可以获得低误码率（bit error rate,BER）的DMS和3D星座,同时利用3D星座的对称性,大幅度降低了编码增益对应的适应度值的计算复杂度。推导了3D STSK方案的理论平均成对差错概率（ABEP）。仿真结果表明,与传统的 GA 和随机搜索方案相比,本文提出的改进 GA在保证BER性能前提下可以显著降低系统实现的复杂度。     

线性码编码的MSK调制

本文研究了线性码编码的MSK调制系统。指出在插入一个简单差分编码网络后,线性码的优化问题在汉明距离与在欧氏距离上是一致的,从而解决了线性码编码的MSK调制问题。由于插入网络简单、便于实现,因此在MSK上使用最优线性码调制在实践上是可行的。     

基于伽罗华域高斯列消元法的RS码盲识别

为解决高码率RS(Reed Solomon)码盲识别问题,提出了一种基于伽罗华域高斯列消元法的RS码盲识别方法。先利用矩阵秩的差值函数识别符号数及码长;再遍历此时符号数对应的本原多项式,对矩阵进行伽罗华域高斯列消元,并引入熵函数差值来识别本原多项式;最后求码字多项式的根,其中连续根即为生成多项式的根。该方法可以较好地识别RS码码长、生成多项式及本原多项式,并且避免了遍历符号数时多次进行伽罗华域傅里叶变换的繁琐过程。仿真结果表明,在误码率为3×10-3的情况下,对RS码的识别概率高于90%。     

广义正交码索引调制系统的性能分析

摘 要：为了提高码索引调制（code index modulation，CIM）系统的传输效率，提出了一种具有更低复杂度的单输入单输出（single input single output，SISO）的广义正交码索引调制（generalized orthogonal code index modulation，GQCIM）系统。CIM 系统使用扩频码和星座符号传输信息，但只能激活两个扩频码索引和一个调制符号。而 GQCIM 系统以一种新颖的方式克服了只激活一个调制符号的限制，同时充分利用了调制符号的正交性，增加扩频码索引以传输更多的额外信息位，提高了系统的传输效率。此外，分析了GQCIM系统的理论性能，推导了误码率性能的上界。通过蒙特卡罗仿真验证了GQCIM系统的性能，对比发现GQCIM系统的理论和仿真性能一致。而且在相同的传输效率下，结果显示GQCIM系统的性能优于同样具有正交性的调制系统，如广义码索引调制（generalized code index modulation，GCIM）系统、CIM系统、码索引调制-正交空间调制（code index modulation aided quadrature spatial modulation，CIM-QSM）系统、码索引调制-正交空间调制（code index modulation aided spatial modulation，CIM-SM）系统、脉冲索引调制（pulse index modulation，PIM）系统。     

基于LS码的MC—CDMA通信系统的设计与仿真

LS码是一种相关性能优良且具有正交互补性质的多址码,将其应用于多载波码分多址（MC—CDMA）系统中,仿真此系统证明了此设计的可行性,得到其误码率性能图,结果表明：基于LS码的MC—CDMA系统误码率随着信噪比的增大而下降速度很快,LS码的实用性较强。     

On the optimum design of unitary cyclic group space-time codes

In this letter, based on the exact pairwise-error probability, we derive the union bound on the symbol-error probability (SEP) of the differential unitary space-time (DUST) modulation employing group codes. Instead of using the rank-and-determinant or Euclidean distance criteria, we optimize the cyclic group codes such that the union bound on the SEP is minimized for a predetermined scenario, taking into account the number of transmit and receive antennas and the operating signal-to-noise ratio (SNR). Our simulation results show that for a wide range of SNRs, the codes with the minimum union bound for a particular SNR outperform the codes designed based on rank-and-determinant or Euclidean distance criteria.     

一种多符号网格码与差分空时分组码级连方法

我们提出了一种多符号网格码(MTCM)与差分空时分组码级连的传输方法,研究了在传输信道是慢时变平坦瑞利衰变的条件下,并采用理想交织时系统的性能。导出了这个级连系统的成对错误概率上限表达式,分析表明,系统的性能主要受到不同信号序列间的最小汉明矩离和信号星座间的平方欧几里德矩离的影响。仿真结果表明,在相同的频谱有效性和信号星座条件下,这种级连的系统比非级连差分空时编码系统有更好的性能。     

非正交多址中继系统复数域网络编码优化设计

无线中继与网络编码是提高通信系统数据可靠性和吞吐率的重要技术手段,重点研究了单中继非正交多址系统复数域网络编码的优化设计问题.首先,在限制源节点和中继节点的总发送功率并假设各个源节点发送功率相同的条件下,证明了当源节点与中继节点发送功率相等时基于复数域网络编码的单中继非正交多址系统误符号率(SEP)性能最佳.其次,以编码增益为目标函数,提出了一种复数域网络编码的优化设计方法.与已有的复数域网络编码系数设计方法相比,此方法能满足任意源节点个数条件下复数域网络编码系数的优化设计要求,同时可以有效地避免因为网络编码系数选择不当造成信号重叠的现象,提升和改进系统的SEP性能.     

相关衰落信道上广义矩形MQAM的性能

研究相关多输入多输出Nakagami衰落信道上的正交空时分组编码广义矩形M进制正交幅度调制（MQAM）方案,使用矩生成函数方法推导其平均误符号率（SEP）的精确闭合表达式。比较了独立同分布Nakagami衰落信道上和相关Nakagami衰落信道上广义矩形MQAM的平均SEP性能。数值计算结果阐明Nakagami衰落系数和天线间的相关性对正交空时分组编码广义矩形MQAM平均SEP性能的影响。     

Joint trellis coded quantization/modulation

A joint source/channel coding system constructed using trellis coded quantization (TCQ) and trellis coded modulation (TCM) is described. Identical trellises are used in the TCQ and TCM systems, and a straightforward mapping of TCQ codewords to TCM symbols is presented which guarantees that Euclidean squared distance in the channel is commensurate with quantization mean-square error (MSE). Hence, likely TCM error events of small Euclidean distance cause only a small increase in overall source coding MSE     

Rank permutation group codes based on Kendall's correlation statistic

A coding scheme based on the properties of rank vectors is presented. The new codes are based on the theory of permutation groups by introducing a new notation for the group operation that simplifies the generation and decoding of desirable rank codes. The use of group theory is made possible by the introduction of the Kendall correlation coefficient as a measure of the distance between code words. This technique provides a method for the choice of rank vector code words superior to those that have been proposed in the past. Much of the terminology used in block coding can also be used to describe rank vector codes, but the actual quantities involved are quite different. The rank vector codes discussed in the paper offer the advantage of low sensitivity of the probability of error to the noise distribution because of the nonparametric character of rank vector detection schemes. Bounds that have been verified by extensive computer simulation have been derived for the probability of error.     

The random coded modulation: performance and euclidean distance spectrum evaluation

We apply the random coding argument to coded modulation. The well-known union bound on the error probability of general signaling schemes is revisited. The random coded modulation idea is introduced and a simple bound on the average performance of coded constellations is presented. A relationship between the union bound and the cut-off rate is exhibited by introducing the concept of N-dimensional partial cut-off rate. We define finite theta series for bounded finite-dimensional constellations and their related transfer functions. Bounds on the block and symbol error probability based on the transfer function are derived. The discussion is then focused on the squared Euclidean distance distribution. The evaluation of such parameters as its first two moments (average squared distance and squared distance variance) is considered by either finite theta series or transfer function of the bounded signal set. The Euclidean distance spectra of a few multidimensional coded modulation schemes based on square/cross constituent two-dimensional constellations are presented. Their respective partial cut-off rates are computed. We discuss the asymptotic behaviour and we show that almost all very long coded constellations are good (actually, they tend to become quasi-identical in a certain sense). Finally, we examine how to extend the initial union bound to Gallager-type bounds.     

Optimum bandwidth-distance performance in full response CPM systems

The problem of minimizing the effective bandwidth of a binary full-response continuous-phase-modulation (CPM) signal with respect to the shape of the frequency pulse for a prescribed value of the minimum Euclidean distance, which is directly related to the error probability for high signal-to noise ratio, is considered. An analytical procedure is presented that allows the determination of the optimum pulse shape together with its bandwidth and the minimum-distance characteristics. The solution contains an unknown parameter that is determined by numerical of a nonlinear equation. The results are compared to some standard pulses in terms of bandwidth, spectral density, minimum Euclidean distance, and error probability. Some gain in bandwidth is obtained for high values of minimum distance     

Performance and design of space-time coding in fading channels

The pairwise-error probability upper bounds of space-time codes (STCs) in independent Rician fading channels are derived. Based on the performance analysis, novel code design criteria for slow and fast Rayleigh fading channels are developed. It is found that, in fading channels, the STC design criteria depend on the value of the possible diversity gain of the system. In slow fading channels, when the diversity gain is smaller than four, the code error performance is dominated by the minimum rank and the minimum determinant of the codeword distance matrix. However, when the diversity gain is larger than, or equal to, four, the performance is dominated by the minimum squared Euclidean distance. Based on the proposed design criteria, new codes are designed and evaluated by simulation.     

Exponential error bounds for random codes on Gaussian arbitrarily varying channels

The main objective is to develop exponential bounds to the best error probability achievable with random coding on the Gaussian arbitrarily varying channel (GAVC) in the one case where a (strong) capacity exists (i.e., with peak time-averaged power constraints on both the transmitter and interference). The GAVC models a channel corrupted by thermal noise and by an unknown interfering signal of bounded power. The upper and lower bounds to the best error probability achievable on this channel with random coding are presented. The asymptotic exponents of these bounds agree in a range of rates near capacity. The exponents are universally larger than the corresponding exponents for the discrete-time Gaussian channel with the same capacity. It is further shown that the decoder can be taken to be the minimum Euclidean distance rule at all rates less than capacity.<>