Adaptive spatial mode of space-time and spacefrequency OFDM system over fading channels

• Main Authors: Noordin, Nor K., M. Ali, Borhanuddin, Jamuar, S. S., A. Rahman, Tharek, Ismail, Mahamod
• Format: Article
• Language: English
• Published: Penerbit UTM Press 2006
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/4109/1/JTD_2005_09.pdf; http://eprints.utm.my/id/eprint/4109/; http://www.penerbit.utm.my/onlinejournal/45/D/JTDis45D04.pdf
• Institution: Universiti Teknologi Malaysia

In this paper we present a 2 transmit 1 receive (1 Tx : 1 Rx) adaptive spatial mode (ASM) of space-time (ST) and space-frequency (SF) orthogonal frequency division multiplexing (OFDM). At low signal to noise ratio (SNR) we employ ST-OFDM and switch to SF-OFDM at a certain SNR threshold. We determine this threshold from the intersection of individual performance curves. Results show a gain of 9 dB (at a bit error rate of 10-3) is achieved by employing adaptive spatial mode compared to a fixed ST-OFDM, almost 6 dB to fixed SF-OFDM, 4 dB to Coded ST-OFDM and 2 dB to a fixed coded SF-OFDM, at a delay spread of 700 ns.