TY - GEN
T1 - Adaptive time-frequency spreading of quasi-orthogonal block codes for MIMO-OFDM systems
AU - Ong, J. L.
AU - Jayalath, A. D.S.
AU - Athaudage, C. R.N.
PY - 2006
Y1 - 2006
N2 - This paper describes a novel low complexity time-frequency spreading of orthogonal block codes for MIMO-OFDM systems in highly time and frequency selective channels. The space-time codes (STC) and space-frequency codes (SFC) proposed in literature for MIMO-OFDM systems require a quasi-static channel, where the channel is assumed to be constant over a number of OFDM time symbols or OFDM subcarriers. In orthogonal block codes (OBC) this is equal to the number of transmit antennas Nt employed. For higher order space-diversity systems with Nt ≥ 4, it is likely that the assumption of constant channel within the OBC to be violated in fast fading channels resulting performance degradation. We propose an adaptive time-frequency spreading strategy that minimizes the decoding error rate in different types of fading channels. The adaptation technique incorporated is based on a fading interference matric, which is evaluated at the transmitter using channel fading statistics. Simulation results demonstrate the effectiveness of the proposed adaptive time-frequency spreading of OBCs.
AB - This paper describes a novel low complexity time-frequency spreading of orthogonal block codes for MIMO-OFDM systems in highly time and frequency selective channels. The space-time codes (STC) and space-frequency codes (SFC) proposed in literature for MIMO-OFDM systems require a quasi-static channel, where the channel is assumed to be constant over a number of OFDM time symbols or OFDM subcarriers. In orthogonal block codes (OBC) this is equal to the number of transmit antennas Nt employed. For higher order space-diversity systems with Nt ≥ 4, it is likely that the assumption of constant channel within the OBC to be violated in fast fading channels resulting performance degradation. We propose an adaptive time-frequency spreading strategy that minimizes the decoding error rate in different types of fading channels. The adaptation technique incorporated is based on a fading interference matric, which is evaluated at the transmitter using channel fading statistics. Simulation results demonstrate the effectiveness of the proposed adaptive time-frequency spreading of OBCs.
UR - http://www.scopus.com/inward/record.url?scp=46949102193&partnerID=8YFLogxK
U2 - 10.1109/ICCS.2006.301391
DO - 10.1109/ICCS.2006.301391
M3 - Conference contribution
SN - 1424404118
SN - 9781424404117
T3 - 2006 IEEE Singapore International Conference on Communication Systems, ICCS 2006
BT - 2006 IEEE Singapore International Conference on Communication Systems, ICCS 2006
T2 - 10th IEEE Singapore International Conference on Communications Systems, ICCS 2006
Y2 - 30 October 2006 through 1 November 2006
ER -