Successful development of Broadband over Power Lines (BPL) is obviously a potential solution for wireless communication systems with the existing infrastructure. Multi-Carrier Code Division Multiple Access (MC-CDMA) with Orthogonal Frequency Division Multiplexing (OFDM) modulation technique is a promising solution for a frequency selective fading with impulsive noises of the PLC channel. A linear iterative receiver with a Finite State Markov Channel (FSMC) model is proposed to remove Multiple Access Interference (MAI) and Inter Symbol Interferences (ISI). In this paper we focused on Maximum Likelihood (ML) feedback detection by introducing FSMC to get significant improvement in Bit Error Rate (BER). This model of the receiver is more robust against Gaussian colored and impulsive noises of the PLC channel.

This paper gives a general overview of the implementation aspects of turbo decoders. Although the parallel architecture of the turbo code is emphasized, the serial concatenated convolutional codes for the turbo decoder are discussed too. Considering the general structure of iterative decoders, the main features of the soft input and soft output algorithm, which are the heart of a turbo decoder, are observed. The efficient parallel architectures of turbo decoders are shown which allow high speed implementation. Apart from these, implementation aspects like quantization issues and stopping rules to increase the throughput as well as an evaluation of the various turbo decoders are discussed. Finally, we suggest a number of solutions to overcome the implementation issues as well as the complexities without affecting the high throughput rate.

An analytical approach is proposed to evaluate the bit error rate (BER) performance of a direct detection on-off keying (OOK) free space optical link over log-normal atmospheric turbulence-induced fading channels based on modified Alamouti code presented by Simon and Vilnrotter and maximal ratio combining (MRC) at the receiver. Simulations show that due to coding and diversity at the receiver, a significant improvement in the BER performance is obtained at a given BER. For diversity order of 2 in both transmitter and in receiver, the amount of BER improvement is 6.6dB at BER 10-5. Further increment of the receiver diversity from 2 to 4 gives additional 3dB improvement at the same BER. A drastic improvement of the BER performance is also possible for increasing number of receiver diversity which may increase hardware complexity. Simulation results are demonstrated to confirm the analytical results.Bangladesh J. Sci. Ind. Res.53(3), 205-210, 2018