Abid Yahya

Row Division Method to Generate QC-LDPC Codes

To cut down the hardware implementation cost this paper presents an efficient method to construct large girth Quasi-Cyclic low density parity check (QC-LDPC) codes. The row groups are paired two times the row weight, which has the complexity as compared to the connection of individual columns and rows. The complexity of directing within groups estimates on the transposition employed to connect rows and columns between groups. The newly obtained codes are incorporated with diversity techniques and are employed as a forward error correction codes to cater for some anti-jamming (AJ) competences in the presence of partial band noise jamming (PBNJ). The robustness of two girth-twelve QC-LDPC codes is evidenced by comparing it with randomly constructed LDPC codes and QC-LDPC codes proposed in [14].

A new Quasi-Cyclic low density parity check codes

This paper proposes a new technique for constructing the Quasi-Cyclic low density parity check (QC-LDPC) codes based on row division method. The new codes offer more flexibility in term of girth, code rates and codeword length. In this method of code construction, the rows are used to form as the distance graph. Then they are transformed to a parity-check matrix in order to acquire the desired girth. The new QC-LDPC codes show good bit-error rate performance as compared to the renowned Mackay codes for given values of Eb/No by 0.12 dB at BER of10-7 .

System Model Performance Coupled with DPSK Modulation over Flat Rayleigh Fading Channels

In this paper performance enhancement of the system has been investigated by employing large girth Quasi-Cyclic low-density parity-check (QC-LDPC) codes as forward error correction code, coupled with differential phase shift keying (DPSK) over Rayleigh fading channels. Performance of the system is evaluated by measuring bit error rate (BER) for a given value of . Simulation results at diversity level L=4 have confirmed the robustness of the system with a gain of about 1.5 dB as compared to the results of known differential detection system over Rayleigh Fading Channels at a BER of10^-5 .