Adaptive rate QS-CDMA UWB systems using ternary OVSF codes with a zero-correlation zone

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations

Abstract

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.

Original languageEnglish (US)
Title of host publication2006 IEEE Wireless Communications and Networking Conference, WCNC 2006
Pages1068-1073
Number of pages6
StatePublished - 2006
Event2006 IEEE Wireless Communications and Networking Conference, WCNC 2006 - Las Vegas, NV, United States
Duration: Apr 3 2006Apr 6 2006

Publication series

NameIEEE Wireless Communications and Networking Conference, WCNC
Volume2
ISSN (Print)1525-3511

Other

Other2006 IEEE Wireless Communications and Networking Conference, WCNC 2006
Country/TerritoryUnited States
CityLas Vegas, NV
Period4/3/064/6/06

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Keywords

  • Orthogonal variable-spreading-factor (OVSF)
  • Quasi-synchronous (QS)
  • Ultra-wide band (UWB)
  • Zerocorrelation zone (ZCZ)

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