Digital signal processing issues for wireless communication systems in Line of Sight(LOS) and Non Line of Sight (NLOS) environments

This paper is written to convey the digital signal processing (DSP) issues experienced by wireless communication systems which are the limiting factors for enhanced spectral efficiency, link reliability and data rate, with respect to physical (PHY) layer and network throughput, latency and propagation delay pertaining to network layer for future wireless related applications. Normally, a wireless communication system has radio frequency (RF) sector as the front end and digital signal processing sector as the back end. Issues in the RF section are addressed at the fabrication level by consideration of suitable chip fabrication technologies. Whereas digital signal processing section, forming the baseband sector after analog to digital converter (ADC) is concerned with prime issue of channel estimation which is essential for data detection in a wireless communication system performance. Though, other issues of DSP in a wireless communication system exist such as time-frequency synchronization, power control, and interference minimization, this paper considers the issue of channel estimation because of its aforementioned significance. In this paper, channel estimation issue of DSP is performed under multipath fading scenarios which are normally Non Line of Sight (NLOS) environments modeled by distributions such as Rayleigh distribution, Nakagami and Line of Sight (LOS) environment by Ricean distribution. Simulation results are performed to evaluate the metric of mean square error (MSE) against signal to noise ratio (SNR) for channel estimation algorithms in LOS and NLOS environments. Based on obtained wireless channel values bit error rate (BER) performance is also analyzed.