Multiplex communications – Generalized orthogonal or special mathematical techniques – Particular set of orthogonal functions
Reexamination Certificate
2006-03-28
2006-03-28
Duong, Frank (Department: 2666)
Multiplex communications
Generalized orthogonal or special mathematical techniques
Particular set of orthogonal functions
C370S343000, C455S101000
Reexamination Certificate
active
07020072
ABSTRACT:
Wireless communications for frequency-selective fading channels is realized by employing a system including orthogonal frequency division multiplexing (OFDM) in combination with an at least two antenna transmit diversity arrangement. Specifically, OFDM converts a multipath channel into a plurality of narrowband subchannels each having flat fading. Then, the signals on the same frequency subchannels of the at least two antennas are grouped together. Considering a first frequency subchannel, during a first OFDM time interval, a first signal and a second signal are transmitted on the first frequency subchannel from a first antenna (0) and from a second antenna (1), respectively. During a second OFDM time interval, a reverse sign (−) complex conjugate of the second signal and a complex conjugate of the first signal are transmitted from the first antenna and the second antenna, respectively. In a specific embodiment of the invention, reduced complexity in the implementation is realized by a reverse order complex conjugate and a reverse order, reverse sign (−) complex conjugate and judicious selection of the processed data signals in order to transmit the appropriate ones of the signals during the first and second OFDM intervals. Again, if the channel remains constant over the two OFDM intervals, diversity combination is realized for each frequency subchannel. In another embodiment of the invention, antenna-group hopping is employed in conjunction with pairing in time of the OFDM frequency subchannel signals to realize increased transmit diversity without rate loss.
REFERENCES:
patent: 5914933 (1999-06-01), Cimini et al.
patent: 6317411 (2001-11-01), Whinnett et al.
patent: 6377631 (2002-04-01), Raleigh
patent: 6542556 (2003-04-01), Kuchi et al.
patent: 6628638 (2003-09-01), Sato et al.
patent: 6728302 (2004-04-01), Dabak et al.
patent: 6775260 (2004-08-01), Dabak et al.
patent: WO 99/14871 (1999-03-01), None
S.M. Alamouti, “A Simple Transmit Diversity Technique for Wireless Communications”,IEEE Journal on Select Areas in Communications, vol. 16, No. 8, pp. 1451-1458, Oct. 1998.
V. Tarokh et al., “Space-Time Block Codes from Orthogonal Designs”.IEEE Transactions on Information Theory, vol. 45, No. 5, pp 1456-1467, Jul. 1999.
Li Xiaodong
Papadias Constantinos Basil
Viswanathan Harish
Duong Frank
Jagannathan Melanie
Lucent Technologies - Inc.
Thomas Stafford
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