A Novel Constellation Shaping Technique for Bit-Interleaved Coded Modulation

We present a new and simple method which consists to apply constellation shaping to bit-interleaved turbo-coded modulation (BICTM) over additive white Gaussian noise channels. By assuming the example of a 3-bit/dim 16-PAM BITCM, it is shown that this technique can provide shaping gain of 0.79 dB.     

具有不均匀保护特性的Turbo码多级编码调制方案

本文提出一种新型多级编码调制方法,即将Turbo码和卷积码组合起来,然后按照Ungerboeck集分割的方法,与各级编码层对应,实现编码调制,由于Turbo码具有很高的渐进编码增益。将它与卷积码组合成多级码时,系统就具有很好的不均匀保护特性（UEP）,同时可以提高频带效率。     

调频编码频率信号

针对步进频率信号存在的距离－多普勒耦合的和速度利用率低的缺点，提出一种新信号形式，可同时解决这两方面的问题，改善了信号的性能。     

Bit-Interleaved Coded Modulation With Iterative Decoding Using Constellation Shaping

We investigate the association between constellation shaping and bit-interleaved coded modulation with iterative decoding (BICM-ID). To this end, we consider a technique which consists of inserting shaping block codes between mapping and channel coding functions in order to achieve constellation shaping. By assuming the example of a 2-b/s/Hz 16-quadrature amplitude modulation BICM-ID, it is demonstrated using computer simulations that this technique can improve the performance of BICM-ID schemes by a few tenths of a decibel.     

多层叠加LDPC码编码调制技术

 本文提出了一种多层叠加LDPC码编码调制系统.与传统的基于速率分配的多层编码调制技术相比,多层叠加编码调制系统具有很好的对称性和可扩展性.通过分析比较Turbo码译码算法与LDPC码的译码算法的复杂度,本文指出了多层叠加LDPC码编码调制系统具有译码简单,易于实现的优点.实验结果表明,多层叠加LDPC码编码调制系统可以在不牺牲带宽的同时获得较好的性能.     

Constellation Rearrangement: Enhancement for Multilevel Modulation Formats and Transmit Diversity

Radio link adaptivity will be a key feature of the air interfaces of future mobile communication systems. This adaptivity includes techniques such as fast scheduling, hybrid ARQ, transmit diversity and adaptive modulation and coding. The performance of adaptive modulation generally suffers from the power inefficiencies of multilevel modulation formats. This is due to the variations in bit reliabilities caused by the bit-mapping onto the signal constellation. This article presents a concept, called constellation rearrangement (CoRe), which improves the multilevel modulation power efficiency by the joint application with transmit diversity schemes. It is shown by a theoretical analysis for 16-QAM that the presented concept can equalize variations in bit reliabilities by employing different mapping rules for the transmission over the diversity branches. This significantly improves the receiver block error rate performance and, hence, the performance of the adaptive modulation and coding. This is proven by simulations at link-level in a multicarrier CDMA system for AWGN and fading channels employing turbo coded transmission.     

一种二相编码信号调制特征分析方法

二相编码信号的调制特征对于信号的分选和识别是很重要的参数。在利用小波变换提取二相编码信号的调制特征时,尺度参数的设置很重要,他影响到小波脊线提取。通过正弦波频率估计的综合方法来精确地估计出信号的载频,并得到合适的尺度参数,再得到小波脊线。利用小波变换的模值来得到二相编码信号的调制特征。仿真试验验证了此方法的有效性。     

Rayleigh衰落信道中多级编码调制的不等错误保护

本文研究了Rayleigh衰落信道中以信道容量规则为设计准则的多级编码调制系统的不等错误保护性能的实现及其改进.在详细分析了多级编码调制的不等错误保护原理的基础上,设计了一种针对8ASK调制的非均匀信号星座.理论分析与计算机仿真均表明,非均匀信号星座的设计能够增强多级编码调制系统的不等错误保护能力,在不展宽频带的前提下有效地提高Rayleigh衰落环境下数字通信系统的传输质量.     

On the Use of Hexagonal Constellation for Peak-to-Average Power Ratio Reduction of an ODFM Signal

One of the main drawbacks of orthogonal frequency division multiplexing (OFDM) is the high peak-to-average power ratio (PAPR) of the OFDM signal. In this paper, we propose the use of hexagonal constellation for PAPR reduction of an OFDM signal. Because hexagonal constellation is the densest packing of regularly spaced points in two dimensions, we can have more signal points in a given area with hexagonal constellation than with quadrature amplitude modulation (QAM) constellation. We can exploit these extra degrees of freedom provided by the hexagonal constellation for PAPR reduction of an OFDM signal. We will apply the proposed technique to eliminate data rate loss due to the side information in partial transmit sequence (PTS) technique and selected mapping (SLM) technique.     

多相编码雷达信号参数快速估计方法

针对Wigner-Ville分布、Radon-Wigner变换估计多相编码雷达信号参数存在运算量大、估计精度低等问题,本文提出了基于Radon-ambiguity变换和分数阶傅里叶变换(FRFT)联合分析的参数快速估计方法。该方法采用Radon-ambiguity变换估计信号调制斜率,采用分数阶傅里叶变换估计载频、周期等,通过两次一维搜索峰值来估计信号的参数,与Wigner变换、Radon-Wigner变换的二维搜索峰值相比,运算量大大降低,且提高了参数估计精度。仿真结果证明了该方法的有效性。     

Blind Signal Modulation Recognition through Density Spread of Constellation Signature

Wireless Personal Communications - Cluster analysis is a commonly used technique by investors to create a diversified portfolio. The approach aims at maximizing returns for a tolerable degree of...     

A Unified Bit-to-Symbol Mapping for Generalized Constellation Modulation

Gray mapping is a well-known way to improve the performance of regular constellation modulation, but it is challenging to be applied directly for irregular alternative. To address this issue, in this paper,a unified bit-to-symbol mapping method is designed for generalized constellation modulation(i.e., regular and irregular shaping). The objective of the proposed approach is to minimize the average bit error probability by reducing the hamming distance(HD) of symbols with larger values of pairwi...     

A Coded Modulation Scheme for Deep-Space Optical Communications

A coded modulation scheme for deep-space optical communications is studied, which is a serial concatenation of an outer low-density parity-check (LDPC) code, an interleaver, a bit-accumulator, and pulse-position modulation (PPM). It is referred as LDPC-APPM. It is decoded with an iterative demodulator-decoder using standard turbo-decoding techniques. Simulation results show that the LDPC-APPM with an outer LDPC code of medium code length suffers a loss of about 0.7 dB at a bit-error rate of relative to the serially concatenated PPM (SCPPM) of similar parameters, which consists of the serial concatenation of an outer convolutional code, an interleaver, a bit-accumulator, and PPM; however, it has better code rate flexibility especially for high rates and simpler implementation structure than SCPPM. Further, it can achieve better performance than the LDPC-PPM of the same rate and length, which consists of the serial concatenation of an LDPC code and PPM.     

级联卷积编码调制的研究

Turbo码与格状编码调制相结合可以取得大的编码增益和高的带宽效率。本文在Turbo码的基础上,综述了级联卷积编码调制,包括基本结构、设计准则等。     

一种性能更优的差分酉空时码正交旋转信号星座

由于差分酉空时码信号星座点之间的分集乘积是影响系统的重要因素.本文利用代数理论构造出一种正交旋转的差分酉空时码的信号星座集,使得原循环群星座成为新正交旋转星座的一个搜索子集,以扩大信号星座点之间的分集乘积,其误码率性能将比原循环群星座差分酉空时码有2dB多的增益.     

基于脉冲位置调制的无线光通信多级编码调制及其多阶段解调译码算法

针对无线光通信脉冲位置调制(PPM)与信道编码的结合应用,提出了一种多级编码调制方案,利用多级编码的多级标签结构,将PPM符号所对应的分组比特分拆到不同子码通道的码字中,同时结合PPM的信号集分割和极大似然检测解调方法,推导了方案的多阶段解调译码算法。在弱湍流大气条件下的仿真分析表明,PPM多级编码调制相对单级编码调制在误码率10-6下获得0.85 dB以上的增益,且可实现对不同重要程度信息段的不等差错保护。在分量码码型给定的条件下,按纠错能力逐级配置分量码并采用所推导的多阶段解调译码,可为系统提供更好差错性能,优于直接的并行译码方法。     

基于联合迭代算法的多层编码超宽带通信系统

该文提出一种多层编码的超宽带通信系统,给出接收端脉冲解映射器和译码器之间联合迭代处理算法。三层编码的超宽带系统的误码性能仿真表明：比较未编码系统,误码性能得到明显的改善;AWGN信道下,多级迭代算法和并行迭代算法分别需要3次和4次迭代收敛到最佳性能;而在室内信道环境中,多级迭代算法和并行迭代算法各自需要2次和3次迭代收敛到最佳性能;最佳迭代次数下,两种算法的性能相当,但并行迭代算法的时延约为多级迭代算法时延的1/3。     

Turbo Coded Modulation for Unequal Error Protection

A major concern in designing communication systems is to maintain quality of service for a wide range of channel conditions. This is an important issue particularly for the applications where precise characterization of the channel is impossible. For such applications, the source data can be classified into several classes and Unequal Error Protection (UEP) can be used to effectively protect the more important classes even in poor receiving conditions. This paper is focused on the study, design, and performance evaluation of unequal error protecting turbo coded modulation schemes. We first propose several schemes for unequal error protecting using turbo coded modulation. All these schemes provide high performance gains for more important classes that can hardly be achieved using conventional coded modulation schemes. We then study unequal error protecting turbo coded modulation schemes by deriving channel capacity and cutoff rates for different protection levels. We show that for more important classes more room is available for improvement.     

Simple Unified Approach to Develop a Time-Domain Modulation Strategy for Single-Phase Multilevel Converters

Single-phase power converters are widely used in power applications as photovoltaics and fuel-cell power conditioners. In addition, multilevel converters are a well-known solution in order to achieve high-quality output waveforms in power systems. In this paper, a time-domain duty-cycle computation technique for single-phase multilevel converters named 1DM is presented. The proposed technique is based on geometrical calculations with outstanding simplicity and generality. The proposed modulation technique can be easily applied to any multilevel converter topology carrying out the necessary calculations. The most common multilevel converter topologies have been studied in this paper as examples to introduce the proposed modulation strategy. Any other multilevel converter topology could be studied, and the corresponding 1DM could be easily developed. In addition, the well-known optimized voltage balance strategy for voltage capacitor control using the redundant switching states of the system is applied working with the proposed 1DM method, showing that both techniques are compatible. Experimental and simulation results for several single-phase multilevel converters are shown to validate the proposed modulation technique.      

一种8VSB Turbo格状编码调制方案

本文阐述这了一种适用于带限信道的８ＶＳＢ Ｔｕｒｂｏ格状编码制方案,它把纠错极强的Ｔｕｒｔｏ码和频带效率极高的格状编码调制结合,具有极强的信道传输能力。同时给出了相应的迭代译码算法及其误码率曲线。