Binary communication over the Gaussian channel using feedback with a peak energy constraint

We consider binary communication over the additive white Gaussian noise channel with no bandwidth constraint on the channel input signals, assuming the availability of a noiseless delayless feedback link. Although the signals at timetcan depend on the noise at timestau < tand are therefore random functions, we require that the signal energy never exceed a fixed level. We show that the optimal probability of error is attainable without the use of the feedback channel by using antipodal signals.     

A coding scheme for additive noise channels with feedback--I: No bandwidth constraint

In some communication problems, it is a good assumption that the channel consists of an additive white Gaussian noise forward link and an essentially noiseless feedback link. In this paper, we study channels where no bandwidth constraint is placed on the transmitted signals. Such channels arise in space communications. It is known that the availability of the feedback link cannot increase the channel capacity of the noisy forward link, but it can considerably reduce the coding effort required to achieve a given level of performance. We present a coding scheme that exploits the feedback to achieve considerable reductions in coding and decoding complexity and delay over what would be needed for comparable performance with the best known (simplex) codes for the one-way channel. Our scheme, which was motivated by the Robbins-Monro stochastic approximation technique, can also be used over channels where the additive noise is not Gaussian but is still independent from instant to instant. An extension of the scheme for channels with limited signal bandwidth is presented in a companion paper (Part II).     

Simple coding scheme to reduce peak factor in QPSK multicarriermodulation

The authors present a simple half-rate coding scheme to limit the peak factor of QPSK multicarrier waveforms to less than one quarter that of the uncoded carrier, using Rudin-Shapiro polynomials     

Elastic bandwidth allocation scheme with softened peak interference power constraint for the dynamic cognitive radio systems

The popularity of diverse wireless communication systems has led to increased strains on the unlicensed spectrum. However, investigations have shown that vast portions of the licensed spectrum remain underutilized across frequency, space and time. To improve the utilization of the existing radio spectrum, cognitive radio (CR) allows a secondary system to access the licensed spectrum as long as the primary system’s operation is not compromised. Two main CR transmission modes, spectrum overlay and underlay have been proposed. In the spectrum overlay mode, challenges in quality-of-service (QoS) provisioning arise due to the necessity for secondary users to vacate the channels when a primary user appears. In the underlay model, interference caused to the primary system has to be carefully managed resulting in a constraint of the secondary system’s transmit power, which causes difficulty in QoS provisioning. In this paper, we propose an elastic bandwidth allocation scheme to make concurrent use of both spectrum overlay and underlay transmission modes. Different from existing hybrid transmission strategy, our scheme employ a novel softened peak interference power constraint to improve the performance of the secondary system while still granting the superior protection to the primary system transmissions. This allows the proposed scheme to achieve a superior transmission capacity in the CR network while avoiding the weaknesses of the both spectrum overlay and spectrum underlay transmission modes.     

On a hybrid beamforming/space-time coding scheme

A multiple transmit antenna system based on hybrid beamforming and space-time coding technologies is examined. The reduction factor of the required transmitted energy achievable by the use of hybrid scheme is quantified for any given outage capacity. We show that although a sole space-time coding configuration is superior asymptotically (i.e., for extremely low outage requirements), a hybrid beamforming/space-time coding configuration can be a more effective solution for modest outage requirements. It may provide a useful design guideline for wireless systems, especially for the downlink where multiple transmit antenna scheme is feasible.     

On bit-error probability of a concatenated coding scheme

This paper presents a method for evaluating the bit-error probability of a concatenated coding system for BPSK transmission over the AWGN channel. In the concatenated system, a linear binary block code is used as the inner code and is decoded with the soft-decision maximum likelihood decoding, and a maximum distance separable code (or its interleaved code) is used as the outer code and is decoded with a bounded distance decoding. The method is illustrated through a specific example in which the inner code is a binary (64.40.8) Reed-Muller subcode and the outer code is the NASA standard (255, 223, 33) Reed-Solomon code over GF(2⁸) interleaved to a depth of 5. This specific concatenated system is being considered for NASA's high-speed satellite communications. The bit-error performance is evaluated by a combination of simulation and analysis. The split weight enumerators for the maximum distance separable codes are derived and used for the analysis     

Sequential signalling under a peak power constraint

The error exponent for sequential signaling over the additive-Gaussian-white-noise channel subject to a peak power constraint is derived. This exponent is maximum under the assumption that information is transmitted in blocks.     

Strong universal source coding subject to a rate-distortion constraint

The following problem in universal source coding is explored. Some members of a class of sources have various constraints on the maximum rate at which they may be encoded, and thc remainder have various constraints on the maximum distortion that may result from encoding. It is desired to find a universal code that will adapt its performance so that whatever source in the class is encoded, the resulting performance meets the constraint and is optimal in the rate-distortion function sense for that particular source. It is shown that such codes exist when the class is totally bounded and the constraints are uniformly continuous in an appropriate sense. A key result shows that the value of any uniformly continuous function on a totally bounded class can be uniformly well estimated from observations of the output of any source in     

Regularized subband coding scheme

Two enhanced subband coding schemes using a regularized image restoration technique are proposed: the first controls the global regularity of the decompressed image; the second extends the first approach at each decomposition level. The quantization scheme incorporates scalar quantization (SQ) and pyramidal lattice vector quantization (VQ) with both optimal bit and quantizer allocation. Experimental results show that both the block effect due to VQ and the quantization noise are significantly reduced.     

Variable-rate universal block source coding subject to a fidelity constraint

Variable-rate universal source codes are data compression schemes that are optimum for the coding of a collection of sources (e.g., a source with unknown parameters) subject to a fixed average distortion constraint. Existence of variable-rate universal source codes is demonstrated for very general classes of sources and distortion measures.     

Serial concatenated coding scheme with minimum shift keying

A novel serially concatenated coding scheme for use with minimum shift keying (MSK) is proposed. The novelty is to use a mixture of recursive and non-recursive realisations for the MSK modulator. It is shown that this improves the performance of iterative demodulation and decoding of convolutionally encoded MSK signals with a slight decrease in the decoder complexity     

单天线功率受限的自适应调制V-BLAST系统

提出了一种在单天线峰值瞬时功率和总平均功率都受限条件下的改进注水法和离散调制的比特、功率分配方法,并应用于自适应调制V-BLAST系统.如果由注水法得到的分配结果中某发射天线的瞬时功率高于峰值功率限制,就修正该天线的分配比特数和功率使之满足限制要求,剩余的功率再由注水法分配到其他天线上.仿真结果表明,提出的算法很好地满足了目标要求,而且单天线功率受限使比特率有所下降.     

Robust differential chain coding scheme

In differential chain coding (DCC), the bandwidth efficient relative vector is sensitive to channel errors, resulting in error propagation and corruption of the decoding process. A robust differential chain coding scheme is presented for stopping error propagation in the relative vector without increasing its bandwidth or using an additional forward error correction code. In this scheme, the relative vector is combined with the previous absolute vector to form a new error-resistant channel codeword. Experiments showed that, compared to DCC, the new scheme notably improves subjective quality when subject to transmission errors     

基于时空多样性编码的低轮值无线传感器网络可靠传输算法

提出了适用于低轮值无线传感器网络的可靠传输算法,主要特点是发掘并利用低轮值无线传感器网络特有的时空相关性,结合编码机制以获得较高的能量效率和较低的传输时延。针对编码块在多条路径上的最优分配问题进行了建模。由于求解最优策略是NP难题,给出了近似算法,并通过仿真分析了不同参数对近似算法的影响。仿真结果表明,基于时空多样性编码的分配算法能够在较低的能量开销条件下,实现低时延的可靠传输。     

A close-to-capacity dirty paper coding scheme

The "writing on dirty paper"-channel model offers an information-theoretic framework for precoding techniques for canceling arbitrary interference known at the transmitter. It indicates that lossless precoding is theoretically possible at any signal-to-noise ratio (SNR), and thus dirty-paper coding may serve as a basic building block in both single-user and multiuser communication systems. We design an end-to-end coding realization of a system materializing a significant portion of the promised gains. We employ multidimensional quantization based on trellis shaping at the transmitter. Coset decoding is implemented at the receiver using "virtual bits." Combined with iterative decoding of capacity-approaching codes we achieve an improvement of 2dB over the best scalar quantization scheme. Code design is done using the EXIT chart technique.     

A general coding scheme for the two-way channel

A general coding scheme for the nonrestricted memoryless discrete two-way channel is presented based on the introduction of auxiliary random variables forming a stationary Markov process. The coding scheme yields an achievable rate region which exceeds the inner bound of Shannon in the general case. A finite cardinality bound for the auxiliary random variables is given, showing that the region is computable. Finally, the capacity region for the memoryless Gaussian two-way channel is established.     

VIDEO CODING SCHEME FOR ATM NETWORKS

A new variable bit rate layered coding scheme based on subband coding is given in this paper. It can make full use of the merits of ATM transmission, as well as compensation for the quality degradation caused by cell loss, which is an inherent problem of ATM networks, and thus a stable, high quality video transmission is achieved. This paper presents the coding scheme, cell construction and simulation results.     

Concatenated coding scheme for MTCM/CPFSK with Hamming code

An investigation into the burst statistics of multiple symbol trellis coded continuous phase frequency shift keying is presented. Based on this investigation, an outer linear block code with a block interleaver has been developed, and is presented to demonstrate the efficient correction of burst errors     

An adaptive coding scheme with code combining for mobile radiosystems

The authors propose and study an adaptive error-control coding scheme for binary digital FM (BFM) mobile radio transmission. The scheme employs code combining through packet retransmissions. The number of transmissions of a packet is in proportion to the channel fading/noise levels, which is in contrast to time diversity techniques where a fixed number of repetitions of a data packet is performed even in the absence of channel errors. Furthermore, the receiver uses received signal envelopes as channel state information, which significantly improves the throughput and bit error rate (BER) performance. Performance of the proposed scheme is analyzed for frequency-flat Rayleigh fading channels with additive white Gaussian noise (AWGN), co-channel interference and random FM noise     

Diversity coding scheme for wireless optical communication with direct detection

A new diversity coding scheme using four transmit apertures, one receive aperture and two detectors is proposed for wireless optical communication with direct detection. Pilot symbols are inserted to the encoding information sequence. Simulations show that the scheme can yield a signal-to-noise ratio gain of 6 dB at 10/sup -4/ error probability.