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On optimum asymptotic multiuser efficiency of randomly spread CDMA

Sedaghat, M. A ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1109/TIT.2015.2482483
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2015
  4. Abstract:
  5. We extend the result by Tse and Verdú on the optimum asymptotic multiuser efficiency of randomly spread code division multiple access (CDMA) with binary phase shift keying input. Random Gaussian and random binary antipodal spreading are considered. We obtain the optimum asymptotic multiuser efficiency of a K-user system with spreading gain N when K and N → ∞ and the loading factor, (K/N) , grows logarithmically with K under some conditions. It is shown that the optimum detector in a Gaussian randomly spread CDMA system has a performance close to the single user system at high signal-to-noise ratio when K and N → ∞ and the loading factor, (K/N), is kept less than (log3 K/2). Random binary antipodal matrices are also studied and a lower bound for the optimum asymptotic multiuser efficiency is obtained. Furthermore, we investigate the connection between detecting matrices in the coin weighing problem and optimum asymptotic multiuser efficiency. We obtain a condition such that for any binary input, an N x K random matrix, whose entries are chosen randomly from a finite set, is a detecting matrix as K and N → ∞
  6. Keywords:
  7. Code division multiple access (CDMA) ; compressive sensing ; detecting matrices ; multiuser detection ; optimum asymptotic multiuser efficiency ; random spreading ; Binary phase shift keying ; Bins ; Communication channels (information theory) ; Compressed sensing ; Efficiency ; Multiuser detection ; Phase shift ; Phase shift keying ; Phase shifters ; Signal to noise ratio ; Coin weighing problem ; Compressive sensing ; High signal-to-noise ratio ; Loading factors ; Multiuser efficiency ; Optimum detectors ; Random spreading ; Single-user system ; Code division multiple access
  8. Source: IEEE Transactions on Information Theory ; Volume 61, Issue 12 , 2015 , Pages 6635-6642 ; 00189448 (ISSN)
  9. URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7277041