Volume 28, Issue 1, November 2014

Wide range CFO estimation for TDS-OFDM [Full Text]

Hamada Esmaiel and Danchi Jiang

Abstract— An improved carrier frequency offset (CFO) estimation scheme is proposed in this short paper, for time domain synchronization orthogonal frequency division multiplexing (TDS-OFDM) system over multi-path fading channel with significant tap delay. Equalized processing method is proposed based on the frequency-domain pseudorandom noise (FDPN) of TDS- OFDM to estimate the carrier frequency offset. Time reversal is proposed to improve the estimation accuracy. 


White Space Technology AS A Tool For Bridging Digital Divide [Full Text]

L. Oborkhale and R. Akomodi

Abstract— Over the years, Broadband has become increasingly central to the lives of consumers and the success of businesses. Since through broadband connections, consumers are able to access and interact with a wide range of content, services and businesses to exploit new market opportunities. There is growing need for wireless internet communication all over. Due to some of the limitations of the current and dominant wireless internet communication technology which is the Wi-Fi a vast regions of different countries are underserviced which are mainly rural areas with bad terrains, low population density or non-commercial places. This paper is primarily aimed at looking at the viability of the TV White space technology as a new possibility for rural broadband connection. 


Performance Analysis of Variable Block-Size Motion Estimation in H.264/AVC [Full Text]

S. M. Shamsul Alam and Sehrish Khan

Abstract— Motion estimation by using variable macro block size in H.264 plays a vital role to enhance the coding efficiency over a scheme that exploited the fixed macro block size motion compensation. However, searching the motion vectors using variable macro block sizes requires different computational complexities. This paper describes the different motion estimation algorithms by applying variable macro-block size and multiple frame differences. The extensive simulation results show that exhaustive search with lower macro block size outperforms compared to other search techniques. But the computational complexities of exhaustive search is very high than three step search (TSS), new three step search (NTSS), four step search (FSS) and diamond search (DS) techniques. To make an optimum solution, this paper depicts a comparison between different motion estimation techniques for diverse picture sequences. Based on this comparison, DS shows very low computational complexities with low search parameters. Based on these observations, an optimization technique is required to select the mode of macro block (MB), search parameter (SP) size, and block matching algorithm technique. To get this adaptation technique, Affine transformation based motion prediction is applied. On the other hand, the PSNR (Peak Signal to Noise Ratio) is plotted by using multiple frame differences. Simulation results portray that PSNR depends on how many similar sequences are present in the reference picture frames. This simulation is very useful to design new motion estimation algorithms by using multiple reference frames.