Comparison of Coded and Un-coded MC-DS-CDMA System using Linear Block Codes

Abstract

Recent advances in wireless communication have made use of MC-CDMA (Multi-carrier code division multiple access) in broadband communication to allow high data rates. In this research, the channel coding is being investigated for synchronous MC-CDMA using LBC (linear block codes) by using hamming codes with code rates 0.57 and 0.73 respectively. In the proposed approach the Walsh codes used for spreading users in time domain. In addition, the performance of concatenated error correction codes are analyzed, where BCH hamming code has been used as outer and convolution code has been used as inner code. The OFDM (Orthogonal Frequency Division Multiplexing) has been used to achieve frequency diversity gain and same signal has been sent over different carrier frequencies for testing. The carrier frequencies being adequately separated in frequency domain so they do not interfere with each other and therefore further increased in capacity. In this scheme, the MRC (Maximum Ratio Combiner) for combining the signals coming from different subcarriers were used. In addition, the MRC followed by de-correlating detectors (DD) and results for both receivers were compared and demonstrated with 16 and 32 users