TY - JOUR
T1 - Low-complexity multipath diversity through fractional sampling in OFDM
AU - Tepedelenlioglu, Cihan
AU - Challagulla, Ravikanth
N1 - Funding Information:
Mr. Challagulla received the Kishore Vaigyanik Protsahan Yojana (a scholarship from the Department of Science and Technology, Government of India) during his undergraduate years.
Funding Information:
Manuscript received January 14, 2003; revised October 30, 2003. This work was supported by the National Science Foundation under Career Grant CCR-0133841. Portions of this work were presented at the International Symposium on Wireless Communications, September 2002, and the Asilomar Conference on Signals, Systems, and Computers, November 2002. The associate editor co-ordinating the review of this paper and approving it for publication was Dr. Dennis R. Morgan.
PY - 2004/11
Y1 - 2004/11
N2 - Orthogonal frequency division multiplexing (OFDM) enables low-complexity equalization and has been adopted in several wireless standards. However, OFDM cannot exploit multipath diversity without computationally complex coding and decoding. We show here that by sampling at a rate higher than the symbol rate, which is also known as fractional sampling (FS), one can improve the diversity that the wireless channel can provide in an OFDM system. We propose maximal ratio combining at each subcarrier for the FS-OFDM system, argue that the diversity gains acquired through this approach are related to the spectral shape of the pulse and its excess bandwidth, and derive analytical bit error and symbol error rate expressions for our scheme. We also explore extensions to differentially encoded systems that do not require channel status information at the receiver, multiple-input multiple-output (MIMO) systems that exploit space diversity, and low peak-to-average (PAR) options such as zero-padded (ZP) and cyclic-prefix only (CP-only) transmissions. We corroborate our approach with simulations.
AB - Orthogonal frequency division multiplexing (OFDM) enables low-complexity equalization and has been adopted in several wireless standards. However, OFDM cannot exploit multipath diversity without computationally complex coding and decoding. We show here that by sampling at a rate higher than the symbol rate, which is also known as fractional sampling (FS), one can improve the diversity that the wireless channel can provide in an OFDM system. We propose maximal ratio combining at each subcarrier for the FS-OFDM system, argue that the diversity gains acquired through this approach are related to the spectral shape of the pulse and its excess bandwidth, and derive analytical bit error and symbol error rate expressions for our scheme. We also explore extensions to differentially encoded systems that do not require channel status information at the receiver, multiple-input multiple-output (MIMO) systems that exploit space diversity, and low peak-to-average (PAR) options such as zero-padded (ZP) and cyclic-prefix only (CP-only) transmissions. We corroborate our approach with simulations.
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U2 - 10.1109/TSP.2004.836452
DO - 10.1109/TSP.2004.836452
M3 - Article
AN - SCOPUS:7544222881
SN - 1053-587X
VL - 52
SP - 3104
EP - 3116
JO - IEEE Transactions on Signal Processing
JF - IEEE Transactions on Signal Processing
IS - 11
ER -