Author : R.Prabakar and Krithiga.S

The Orthogonal Frequency Division Multiple Access (OFDMA) when used in wireless networks provides high spectral efficiency with robust performance and thus been considered for 4G air interface technology. On the other hand, the MIMO technique that uses multiple antennas at the base station and the mobile station provides spatial diversity and multiplexing gain. Adaptive Resource Allocation technique has been considered for maximizing the capacity taking QoS requirements. A precoding scheme named Gram-Schmidt (GS) precoder is proposed which follows the conventional approach invoking the Singular Value Decomposition (SVD) to obtain the pre-processing and the post-processing vectors for different users through proper linear combinations of the singular vectors. In this project, two algorithms space/frequency allocation algorithm and constraint-relaxation based greedy search algorithm are to be used. These algorithms adaptively assign the subcarrier/power and select both pre-processing and post-processing vectors. This work design will be useful in minimizing the total transmit power and meet each user’s QoS requirement.

Keywords: GS (Gram-Schmidt) SVD (Singular Value Decomposition) QoS (Quality of Service)

Article published in International Journal of Current  Engineering  and Technology, Vol.4,No.2 (April- 2014)