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New Achievable Rates In Frequency Hopped Spread Spectrum Systems

Aref, Vahid | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39209 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Marvasti, Farrokh
  7. Abstract:
  8. In  this  dissertation,  we  investigate  the  frequency  hopped  spread  spectrum  systems  which are extensively used in many communication systems. We derive the capacity region  of  Synchronous  Frequency  Hopped  Multiple  Access  (FHMA)  channels  (for  any  kind of noisy or nonselective fading environment) by using the side information which exists in the multi‐user detection. We assume that random hopping patterns are used by all the transmitters, and the common receiver knows the hopping patterns. We also compute  the  capacities  of  FHMA  with  and  without  power  control  for  AWGN  and  noiseless MFSK (in particular BFSK) modulated systems and compare the results with the  previous  works.  Also  the  capacity  region  for  non‐selective  fading  channel  is  evaluated. We also define a criterion as the hopping pattern security which shows how difficult the hopping pattern could be found by interceptors. We also show that the entropy of the hop set has some proper characteristics to represent this criterion. Then, in frequency selective  channel  we  optimize  the  user  rate  as  a  function  of  hopping  pattern  security  and power allocation between frequency hops
  9. Keywords:
  10. Side Information ; Partial Channel State Information ; Frequency Hopping Code Division Multiple Access (FH-CDMA) ; Spread Spectrum Code Division Multiple Access (SS-CDMA) ; Capacity Region

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