TY - GEN
T1 - Adaptive rate QS-CDMA UWB systems using ternary OVSF codes with a zero-correlation zone
AU - Wu, Di
AU - Spasojević, Predrag
PY - 2006
Y1 - 2006
N2 - For a quasi-synchronous code-division multiple access (QS-CDMA) system, the relative time delays between the signals of different users can be maintained with a given time certainty. In this paper, the time delay is modelled as a uniformly distributed random variable on (-τ,τ). It is known that the multiple access interference (MAI) of the QS-CDMA system can be significantly reduced by employing spreading sequences with a zero-correlation zone (ZCZ). Hence, we propose a construction method for the design of ternary orthogonal variable-spreadingfactor (OVSF) codes with a ZCZ of arbitrary lengths. Based on the knowledge of τ, we demonstrate how to select the OVSF code tree with different ZCZ to increase the aggregate throughput of DS-UWB systems with a loose synchronization. Once the OVSF code tree is selected, an adaptive date rate transmission scheme is proposed which can further increase the aggregate throughput by allocating OVSF codes to the active users.
AB - For a quasi-synchronous code-division multiple access (QS-CDMA) system, the relative time delays between the signals of different users can be maintained with a given time certainty. In this paper, the time delay is modelled as a uniformly distributed random variable on (-τ,τ). It is known that the multiple access interference (MAI) of the QS-CDMA system can be significantly reduced by employing spreading sequences with a zero-correlation zone (ZCZ). Hence, we propose a construction method for the design of ternary orthogonal variable-spreadingfactor (OVSF) codes with a ZCZ of arbitrary lengths. Based on the knowledge of τ, we demonstrate how to select the OVSF code tree with different ZCZ to increase the aggregate throughput of DS-UWB systems with a loose synchronization. Once the OVSF code tree is selected, an adaptive date rate transmission scheme is proposed which can further increase the aggregate throughput by allocating OVSF codes to the active users.
KW - Orthogonal variable-spreading-factor (OVSF)
KW - Quasi-synchronous (QS)
KW - Ultra-wide band (UWB)
KW - Zerocorrelation zone (ZCZ)
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M3 - Conference contribution
AN - SCOPUS:34250369678
SN - 1424402700
SN - 9781424402700
T3 - IEEE Wireless Communications and Networking Conference, WCNC
SP - 1068
EP - 1073
BT - 2006 IEEE Wireless Communications and Networking Conference, WCNC 2006
T2 - 2006 IEEE Wireless Communications and Networking Conference, WCNC 2006
Y2 - 3 April 2006 through 6 April 2006
ER -