An improved Quasi Cyclic Low Density Parity Check code (QC-LDPC) is proposed to reduce the complexity of the Low Density Parity Check code (LDPC) while obtaining the similar performance. The proposed QC-LDPC presents an improved construction at high SNR with circulant sub-matrices. The proposed construction yields a performance gain of about 1 dB at a 0.0003 bit error rate (BER) and it is teste...

In this paper, we investigate the application of nonbinary low density parity check (LDPC) codes over Galois field GF(q) for both single-input single-output (SISO) and multipleinput multiple-output (MIMO) fading channels using higher order modulations. As opposed to the widely studied binary systems that employ joint detection and channel decoding, we propose a nonbinary system where optimal si...

This paper considers the application of low-density parity check (LDPC) error correcting codes to code division multiple access (CDMA) systems over satellite links. The adapted LDPC codes are selected from a special class of semi-random (SR) constructions characterized by low encoder complexity, and their performance is optimized by removing short cycles from the code bipartite graphs. Relative...

In this paper Hard Decision and Soft Decision decoding techniques for Quasi-Cyclic-Low Density Parity Check (QC-LDPC) code and Low Density Parity Check (LDPC) code is introduced. QC-LDPC code is proposed to reduce the complexity of the Low Density Parity Check code while obtaining the similar performance. The decoding processes of these codes are easy to simplify and implement. The algorithms u...

Abstract — Density evolution (DE) is one of the most powerful analytical tools for low-density parity-check (LDPC) codes on memoryless binaryinput/symmetric-output channels. The case of nonsymmetric channels is tackled either by the LDPC coset code ensemble (a channel symmetrizing argument) or by the generalized DE for linear codes on non-symmetric channels. Existing simulations show that the b...

Density evolution (DE) is one of the most powerful analytical tools for low-density parity-check (LDPC) codes on memoryless binary-input/symmetric-output channels. The case of non-symmetric channels is tackled either by the LDPC coset code ensemble (a channel symmetrizing argument) or by the generalized DE for linear codes on non-symmetric channels. Existing simulations show that the performanc...

In this paper, we have investigated the application of non-binary LDPC codes to spatial multiplexing MIMO systems with a large number of low power antennas. We demonstrate that such large MIMO systems incorporating with low-complexity MMSE detector and non-binary LDPC codes can achieve low probability of bit error at near MIMO capacity. The new proposed non-binary LDPC coded system also perform...

-In this paper, we propose iterative soft-input soft-output (SISO) multi-carrier detection (inter-carrier interference cancellation) and LDPC decoding of the OFDM system in the mobile channel. The proposed SISO multi-carrier detection and sum-product decoding of the LDPC-coded OFDM system can achieve better error rate performance than previous SISO multi-carrier detection and BCJR decoding of c...

Low Density Parity Check (LDPC) codes have become very popular now-a-days because of their shannon limit approaching error correcting capability and hence have been used in many applications. This paper demonstrates a flexible Low Density Parity Check (LDPC) decoder which is an improve ment over other existing work on a general LDPC decoder. In this paper we have presented a fully flexible LDPC...

In this paper the low density party check (LDPC) codes used in the IEEE 802.16 standard physical layer are studied, and two novel techniques to enhance the performance of such codes are introduced. In the first technique, a novel parity check matrix for LDPC codes over GF(4) with the non-zero entries chosen to maximize the entropy is proposed, the parity check matrix is based on the binary pari...