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This document provides ETRI's response to a question about the comparison between Space-Time Block Code (STBC) and Space-Frequency Block Code (SFBC) in WLAN systems. It includes an explanation of STBC, the assumptions of STBC, and the suitability of STBC in WLAN environments with low Doppler frequency and high frequency selectivity.
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ETRI’s response to question - STBC vs SFBC Heejung Yu, Taehyun Jeon, and Sok-kyu Lee ETRI Next Generation Wireless LAN Research Team heejung@etri.re.kr Heejung Yu, ETRI
Q from Joseph Levy, P.E. • For Heejung Yu, ETRI: • Regarding document:11-04-0923-00-000n-etri-proposal-specification.doc • 1)Have you looked at SFBC rather than STBC? Heejung Yu, ETRI
STBC(Space-Time Block Code) • Simplest and well-known STBC : Alamouti code • An assumption of STBC • Two channel coefficients, h1 and h2, are constant over 2 symbol transmission. Heejung Yu, ETRI
subcarrier OFDM symbol ST(F)BC in MIMO-OFDM • To apply STBC, channel variation between two OFDM symbols should be low. • To apply SFBC, channel variation between two subcarriers should be low. Heejung Yu, ETRI
STBC VS. SFBC • WLAN environments have relatively low Doppler frequency and high frequency selectivity. • high channel variation between two consecutive subcarriers. • low channel variation between two consecutive OFDM symbols • STBC would be a better solution for WLAN systems Heejung Yu, ETRI