Rate-compatible Punctured Research Articles

An Efficient Construction of Rate-Compatible Punctured Polar (RCPP) Codes Using Hierarchical Puncturing

In this paper, we present an efficient method to construct a good rate-compatible punctured polar (RCPP) code for incremental redundancy hybrid automatic repeat request schemes. One of the major challenges on the construction of a RCPP code is to optimize a common information set which is good for all the (punctured) polar codes in the family. Unfortunately, there is no efficient way to solve the above problem. In the proposed construction, a common information set is simply optimized for the highest-rate code in the family and then it is updated to yield an effective information set for each other code, by keeping the condition that information bits are unchanged during retransmissions. This is enabled by presenting a novel hierarchical (or reciprocal ) puncturing and information-copy technique. Specifically, some information bits are copied to frozen-bit channels whose locations are carefully determined according to rate-compatible puncturing patterns. This yields an information-dependent frozen vector in the encoding part. Also, in the decoding part, the effective information sets are obtained by properly combining the common information set and the information-dependent frozen vector. More importantly, the impact of unknown frozen bits are avoided due to the special structure of the proposed hierarchical (or reciprocal) puncturing. Simulation results verify that the proposed RCPP code can yield a significant performance gain (about 2 dB) over a benchmark RCPP code where both codes use the same rate-compatible puncturing patterns but the latter uses the conventional all-zero frozen vector. Therefore, the proposed method would be crucial to construct a good RCPP code efficiently.

Practical network-coding scheme for two-way relay channels employing a rate-compatible punctured code

A cooperative communication in a two-way relay channel is a bidirectional communication between two terminals with the aid of a common relay. In order to improve the performance of the cooperative communication in a two-way relay channel, a network coding can be used to exploit the broadcasting nature of wireless transmission. In [8], it was shown that each individual link can achieve its own capacity when the length of the codewords is the same. However, the length of the codewords can be different in practical systems since the two-way relay channel is naturally asymmetric. Thus, in this paper, we show a practical network coding scheme with a given modulation and coding set by employing a rate-compatible puncturing technique. Simulation results show that the proposed scheme can provide at least as good performance as that obtained in individual link without using special encoder/decoder.

Rate-compatible punctured low-density parity-check codes with short block lengths

We consider the problem of rate-compatible puncturing of low-density parity-check (LDPC) codes over additive white Gaussian noise (AWGN) channels. In previous work, it was shown that puncturing distributions exist for LDPC codes but the code length was large. In this correspondence, we give a procedure for determining the puncturing distributions for LDPC codes with short block lengths (a few thousand bits) and show that careful puncturing can produce good performance. We compare the performance of the rate-compatible punctured LDPC codes with dedicated LDPC codes across a range of rates and see that the rate-compatible codes have a favorable complexity/performance tradeoff.

Efficient rate allocation for progressive image transmission via unequal error protection over finite-state Markov channels

This paper proposes a unified framework for addressing progressive image transmission over noisy channels based on the finite-state Markov channel (FSMC) model. FSMC models are simple yet general enough to model binary symmetric, Gilbert-Elliott, and fading channels. They allow error sequence analysis that facilitates quantifying the statistical characteristics of the embedded bitstreams transmitted over FSMC in closed form. Using a concatenation of rate-compatible puncturing convolutional code and cyclic redundancy check code for error protection, we use a concatenation of rate-compatible punctured convolutional code and cyclic redundancy check code for error protection, which results in an unequal error protection (UEP) system, and find (sub-)optimal rate allocation solutions for our setup. By mapping fading channels to FSMCs, the JSCC problem is thus solved without the burden of simulations using an image-dependent lookup table. Fast algorithms are proposed to search for the optimal UEP. Experiments on embedded image bitstreams over FSMCs confirm our analytical results.

On Rate-Compatible Punctured Turbo Codes Design

We propose and compare some design criteria for the search of good systematic rate-compatible punctured turbo code (RCPTC) families. The considerations presented by S. Benedetto et al. (1998) to find the best component encoders for turbo code construction are extended to find good rate-compatible puncturing patterns for a given interleaver length N. This approach is shown to lead to codes that improve over previous ones, both in the maximum-likelihood sense (using transfer function bounds) and in the iterative decoding sense (through simulation results). To find simulation and analytical results, the coded bits are transmitted over an additive white Gaussian noise (AWGN) channel using an antipodal binary modulation. The two main applications of this technique are its use in hybrid incremental ARQ/FEC schemes and its use to achieve unequal error protection of an information sequence.

Some Notes on Rate-Compatible Punctured Turbo Codes (RCPTC) Design

In this letter, we propose and compare some design criteria for the search of good rate-compatible systematic turbo codes (RCPTC) families. The considerations presented by Benedetto et al. to find "best" component encoders for turbo-code construction are extended to find good rate-compatible puncturing patterns leading to codes with promising performances.

Rate-compatible convolutional codes for multirate DS-CDMA systems

New rate-compatible convolutional (RCC) codes with high constraint lengths and a wide range of code rates are presented. These new codes originate from rate 1/4 optimum distance spectrum (ODS) convolutional parent encoders with constraint lengths 7-10. Low rate encoders (rates 115 down to 1/10) are found by a nested search, and high rate encoders (rates above 1/4) are found by rate-compatible puncturing. The new codes form rate-compatible code families more powerful and flexible than those previously presented. It is shown that these codes are almost as good as the existing optimum convolutional codes of the same fates. The effects of varying the design parameters of the rate-compatible punctured convolutional (RCPC) codes, i.e., the parent encoder rate, the puncturing period, and the constraint length, are also examined. The new codes are then applied to a multicode direct-sequence code-division multiple-access (DS-CDMA) system and are shown to provide good performance and rate-matching capabilities. The results, which are evaluated in terms of the efficiency for Gaussian and Rayleigh fading channels, show that the system efficiency increases with decreasing code rate.