Introduction: The goal of this Letter is to investigate the possibility of achieving spatial diversity without the use of physically connected antenna arrays by examining the simple case of a two-node network. We consider a pair of nodes that are connected via a communication channel that has relatively benign characteristics. Typically, these two nodes are in close proximity. For simplicity, w...

Symbol flipping-based hard decision decoding for non-binary low-density parity check (LDPC) codes has attracted much attention due to low decoding complexity even though the error performance of the symbol flipping decoder is inferior to that of the soft decision decoders. Standard symbol flipping decoding involves two steps, selection of the symbol position to be flipped and selection of the f...

In this paper, we propose a normalized a posteriori probability (APP) based algorithm for the decoding of low-density parity check (LDPC) codes. The normalized APP-based algorithm utilizes normalization to improve the accuracy of the soft values delivered by the simplified APP-based algorithm from one iteration to another during the iterative decoding, and can achieve very good tradeoff between...

The low density parity check codes whose performance is closest to the Shan-non limit arèGallager codes' based on irregular graphs. We compare alternative methods for constructing these graphs and present two results. First, we nd a `super{Poisson' construction which gives a small improvement in empirical performance over a random construction. Second, whereas Gallager codes normally take N 2 t...

Let C be a Z2Z4-additive code of length n > 3. We prove that if the binary Gray image of C, C = Φ(C), is a 1-perfect nonlinear code, then C cannot be a Z2Z4-cyclic code except for one case of length n = 15. Moreover, we give a parity check matrix for this cyclic code. Adding an even parity check coordinate to a Z2Z4-additive 1-perfect code gives an extended 1-perfect code. We also prove that an...

We investigate algebraic constructions for a class of iteratively encodable low-density parity-check codes suitable for high rate applications. The iterative encoding technique, which is based upon the graphical representation of the code, allows the decoder circuit to be also used for encoding, thus saving circuit area. A method for constructing a (3,6)-regular class of such codes is already k...

This paper presents a new class of q-ary erasure-correcting codes based on Latin and Sudoku squares of order q, and an iterative decoding algorithm similar to the one used for the Low Density Parity Check code. The algorithm works by assigning binary variables to the q-ary values, and by generalizing the definition of parity check operation to represent the constraints that define the Latin and...

Based on the ideas of cyclotomic cosets, idempotents and Mattson-Solomon polynomials, we present a new method to construct GF(2m ), where m > 0 cyclic low-density paritycheck codes. The construction method produces the dual code idempotent which is used to define the parity-check matrix of the low-density parity-check code. An interesting feature of this construction method is the ability to in...

The evaluation of the minimum distance of low-density parity-check (LDPC) codes remains an open problem due to the rather large dimension of the parity check matrix H associated with any practical code. In this article, we propose an effective modification of the error impulse (EI) technique for computation of the minimum distance of the LDPC codes. The EI method is successfully applied to sub-...