A Noval RAR QOSTBC Scheme with Linear Decoding for M PSK Over Diverse Channels
The full rate can be attained by the conventional Quasi Orthogonal Space Time Block Codes (QO STBC) with the downside of more decoding intricacy and less diversity gain. Grammian matrix of already existing QO STBC scheme contains non diagonal elements i.e. interference terms which are responsible for more computational load at the receiver. The non diagonal elements causing interference while decoding process are eliminated from the grammian matrix by the use of RAR (reflection and rotation) operations on the detection matrix of already existing QO STBC. Reflection and rotation QO STBC (RAR QOSTBC) scheme is proposed in this paper, which results in transformation of the grammian matrix into a diagonal matrix. Corresponding to the diagonal matrix, a new RAR QOSTBC encoding matrix is generated. RAR QOSTBC scheme enables to achieve more diversity gain as well as it reduces decoding intricacy at the receiver as comparison to the already existing QO STBC method. Analysis has been performed for different levels of PSK modulation over two distinct channels (AWGN and Rayleigh) by changing the number of receive antennas. Simulation result shows a significant improvement in the BER performance because of the removal of non slanting elements from the detection matrix.
Int. J. Wirel. Inf. Networks