Design of turbo-coded modulation for the AWGN channel with Tikhonov phase error

We design 1-b/symbol/Hz parallel concatenated turbo-coded modulation (PCTCM) for the additive white Gaussian noise (AWGN) channel with Tikhonov phase error. Constituent recursive convolutional codes are optimized so that the turbo codes have low error floors and low convergence thresholds. The pairwise error probability based on the maximum-likelihood decoding metric is used to select codes with low error floors. We also present a Gaussian approximation method that accurately predicts convergence thresholds for PCTCM codes on the AWGN/Tikhonov channel. Simulation results show that the selected codes perform within 0.6 dB of constellation constrained capacity, and have no detectable error floor down to bit-error rates of 10/sup -6/.     

AWGN信道中超窄带调制VMSK的最佳解调性能

以甚小移键控(VMSK)为例,针对加性白高斯噪声(AWGN)信道中的解调性能进行研究,基于信号接收的分类器模型,从最基本的概率方法出发,利用最小错误率贝叶斯准则,得到最低误比特率的接收方式及其性能.并从相关检测一致性、最佳性能以及可推广性的角度进行了详细阐述.分析结果表明,VMSK调制方式中表示1和0的信号波形中相同部分的能量并不能提高误码率性能.若要获得相同的误码性能,VMSK需要比BPSK更高的信噪比.此结论可以推广到其他UNB调制.     

M-ary phase coding for the noncoherent AWGN channel

This work considers coded M-ary phase-shift keying (MPSK) schemes with noncoherent detection. A class of block codes called module-phase codes is described. The algebraic framework used for describing these codes relies on elements from module theory which are discussed along with a method for constructing such codes for noncoherent detection. It is shown that differential encoding may be viewed as a specific code from a particular class of module-phase codes. Two classes of codes that achieve significant coding gain with respect to coherent detection of uncoded MPSK are presented. In the first class of module-phase codes, the coding gain is achieved at the expense of bandwidth expansion. In the second class, however, the coding gain is achieved at the expense of signal constellation expansion without expanding bandwidth. Finally, an integrated demodulation/decoding technique based on a modification of information set decoding is presented. It Is shown that this reduced-complexity, suboptimal decoding strategy performs nearly as well as maximum-likelihood decoding     

Lattice codes can achieve capacity on the AWGN channel

It is shown that lattice codes can achieve capacity on the additive white Gaussian noise channel. More precisely, for any rate R less than capacity and e>0, there exists a lattice code with rate no less than R and average error probability upper-bounded by e. These lattice codes include all points of the (translated) lattice within the spherical bounding region (not just the ones inside a thin spherical shell)     

利用决策树和神经网络对AWGN信道下的综合调制识别

针对现有数字调制中多种调制类型混合时的调制识别问题,结合目前对单一调制类型识别各种方法,提出一种综合分类器来完成AWGN环境中的通信信号调制识别。该方法综合使用决策树和RBF神经网络,利用神经网络可以同时对多个特征参数进行非线性优化组合,得到的超曲面能够对整个特征空间进行较精细的分割,从而提高调制识别的整体性能。识别时以决策树为主,以RBF神经网络为辅,其识别效果良好。结果表明,复杂类型调制识别通过合理选择信号特征和分类器,优化识别方法,在一定程度上可以达到相应的识别要求。     

极化码在AWGN信道下的性能分析

首先介绍了信道编码技术对于5G各方面的重要性,其次对极化码的基本原理进行阐述,尤其对信道极化部分进行了详细阐述,对编译码方法进行阐述,重点阐述使用SC(连续消除)译码算法编写程序在AWGN(高斯信道)中进行仿真,最后对仿真结果进行分析,得出信噪比对误码率的影响,通过这些仿真结果可见信道编码可以提高信道的可靠性和网络性能,而这正是在未来5G通信中需要达到的效果。     

Exact evaluation of bit- and symbol-error rates for arbitrary 2-D modulation and nonuniform signaling in AWGN channel

Exact evaluation of bit- and symbol-error rates in a 2-D constellation is a fundamental problem of digital communications, which only for particular modulations and/or bits-to-symbol mapping has closed-form solutions. Here, we propose a general, numerically efficient algorithmic method, which yields the exact results for arbitrary modulation symbols' set and arbitrary bits-to-symbol mapping, and which deals with the case of nonuniform signaling. These three conditions define any digital transmission using memoryless modulation, so the proposed method is a general tool solving all problems tackled in the literature under constraints imposed on one or more of the parameters defining the modulation or signaling type. Such an evaluation tool is of practical importance during the design of the modulation. Our analysis and numerical simulations show the advantages offered by the new method when compared with the bounding techniques.     

The lowest-possible BER and FER for any discrete memoryless channel with given capacity

We investigate properties of a channel coding scheme leading to the minimum-possible frame error ratio when transmitting over a memoryless channel with rate R > C. The results are compared to the well-known properties of a channel coding scheme leading to minimum bit error ratio. It is concluded that these two optimization requests are contradicting. A valuable application of the derived results is presented.     

Maximum-likelihood differential detection of uncoded and trelliscoded amplitude phase modulation over AWGN and fading channels-metricsand performance

This paper derives metrics for maximum-likelihood differential detection of uncoded and trellis coded MPSK and QAM transmitted over Rayleigh and Rician fading channels. Receiver structures based on these metrics are proposed and their error probability performance analyzed and/or simulated. The results represent a generalization of the notion of multiple symbol differential detection, previously introduced by the authors for MPSK over an AWGN, to the fading channel and other modulations. For the coded cases, ideal interleaving/deinterleaving is assumed and furthermore the presence or absence of channel state information. An interesting side result is that for a constant envelope modulation transmitted over a fading channel with unknown but rapidly-varying phase error (the other extreme to the slowly-varying phase error case normally assumed for differential detection), under certain practical assumptions, it is shown that the optimum receiver is of the limiter-discriminator type     

On the capacity region of the discrete additive multiple-accessarbitrarily varying channel

The discrete additive multiple-access arbitrarily varying channel (AVC) with two senders and one receiver is considered. Necessary and sufficient conditions are given for its deterministic-code average-probability-of-error capacity region under a state constraint to have a nonempty interior. In the case that no state constraint is present, the capacity region is characterized exactly. In the case of the noiseless mod-2 adder AVC using state constraint function l(s)=s and subject to a state constraint L less than or equal to 0.13616917, the capacity region is shown to be a 45-degree triangle whose legs have length 1-h(L), where h denotes the binary entropy function     

Analysis of random access channel in UTRA‐TDD on AWGN channel

The random access channel (RACH) in UTRA‐TDD systems is an uplink contention‐based transport channel that is mainly used to carry control information from mobile stations to base stations. In this paper, we study the performance of RACH on an additive white Gaussian noise (AWGN) channel whereby successful transmission of a burst requires the spreading code chosen to be collision‐free and the burst is error‐free after convolutional decoding. Based on this model, the code‐collision probability, the data bit error probability and the RACH channel capacity are derived. The random retransmission delay mechanism is not specified in UTRA‐TDD. We therefore choose an access mechanism with binary exponential backoff delay procedure similar to that in IEEE 802.11. Based on that mechanism, the blocking probability and the first two moments of the delay are also derived. Compared with the mean, the standard deviation is found to be very high. Copyright © 2004 John Wiley & Sons, Ltd.     

Capacity of blockwise noncoherent M-APSK/AWGN channel

Capacity-achieving input distribution for the blockwise noncoherent M-APSK/AWGN channel is characterised. Upper and lower bounds on the normalised capacity, with and without the use of differential encoding, are derived. They show that the coherent channel capacity is approached with increasing channel coherence interval. Moreover, they indicate that the coherent capacity is approximated faster with differential encoding.     

Analysis of blind data hiding using discrete cosine transform phase modulation

This paper presents an analysis for data embedding in two-dimensional signals based on DCT phase modulation. A communication system model for this data embedding scheme is developed. Closed form expressions for estimating the number of bits that can be embedded given a specific distortion measure and the probability of bit error are developed. The data embedding process is viewed as transmitting data through a binary symmetric channel with crossover error probabilities, which depends only on the power in the selected coefficients and the noise created by the signal processing operations undergone by the image.     

The capacity region of the discrete memoryless interference channel with strong interference (Corresp.)

The capacity region of the discrete memoryless interference channel with strong interference is established.     

A combinatorial approach to finding the capacity of the discrete noiseless channel

Shannon defined the capacity of the discrete noiseless channel (DNC) and considered a finite-state model from which the capacity can be calculated. Alternatively, the DNC may be (and often is) represented by a finite list of forbidden strings. In this correspondence, we demonstrate the application of combinatorial techniques to finding the Shannon capacity of the DNC directly from the forbidden list. In our derivations, the case of noninteger symbol durations, as introduced by Csiszar, is considered.     

Diversity codes for differential phase modulation in a correlatedRayleigh fading channel

This paper proposes a simple diversity scheme that makes use of nonlinear block coding, symbol interleaving, and differential phase modulation. The resultant signaling mechanism merits intrinsic time diversity within each codeword, which is resistant to correlated fading. The maximum-likelihood noncoherent receiver which operates over correlated Rayleigh fading is developed. Exact and approximate upper bounds are derived to assess the codeword-error probability characteristics of the proposed system     

AWGN信道下PSK信号幅度与信噪比的估计

研究了AWGN信道下PSK信号幅度和信噪比的估计问题，提出了一种基于迭代的直接判决反馈估计算法，并对其性能进行了分析和仿真。仿真结果表明：低信噪比下经过多次迭代后，由于误码导致的估计偏差可得到较大程度的补偿，估计器的性能接近有数据辅助时的性能，明显优于直接判决反馈时的性能。     

加性高斯信道中不等保护系数帧同步

针时以信道容量为设计目标的现代通信系统,提出一种具有动态自适应性的不等错误率准则下变化保护系数帧同步算法,能够提高数字图像通信系统中帧同步算法的误码率适应性问题。仿真结果表明,该算法在低信噪比下具有较好性能。     

The capacity region of a multiple-access discrete memoryless channel can increase with feedback (Corresp.)

The capacity of a single-input single-output discrete memoryless channel is not increased by the use of a noiseless feedback link. It is shown, by example, that this is not the case for a multiple-access discrete memoryless channel. That is, it is shown that the capacity region for such a channel is enlarged if a noiseless feedback link is utilized.     

基于数据辅助的AWGN信道下QPSK信号信噪比估计

提出了一种以噪声功率为主导的新的信噪比估计算法,仿真结果表明,该算法比现有的基于DA的最大似然估计方法具有更好的性能,尤其在低信噪比条件下,可以同时具有更好的精度和更高的可信度,而且不受接收机相位误差的影响.最后分析了本算法的误差来源,并给出了应用建议.