Performance of time-frequency coded spread spectrum systems operating over noisy fading channels

1988 ◽  
Vol 135 (6) ◽  
pp. 513 ◽  
Author(s):  
P. Belezinis ◽  
L.F. Turner
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Time Frequency ◽  
Spread Spectrum Systems

scholarly journals Code-Time Diversity for Direct Sequence Spread Spectrum Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
A. Y. Hassan
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Mimo Systems ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Probability Of Error ◽  
Spreading Codes ◽  
Time Diversity ◽  
Spread Spectrum Systems ◽  
Diversity Scheme

Time diversity is achieved in direct sequence spread spectrum by receiving different faded delayed copies of the transmitted symbols from different uncorrelated channel paths when the transmission signal bandwidth is greater than the coherence bandwidth of the channel. In this paper, a new time diversity scheme is proposed for spread spectrum systems. It is called code-time diversity. In this new scheme,Nspreading codes are used to transmit one data symbol overNsuccessive symbols interval. The diversity order in the proposed scheme equals to the number of the used spreading codesNmultiplied by the number of the uncorrelated paths of the channelL. The paper represents the transmitted signal model. Two demodulators structures will be proposed based on the received signal models from Rayleigh flat and frequency selective fading channels. Probability of error in the proposed diversity scheme is also calculated for the same two fading channels. Finally, simulation results are represented and compared with that of maximal ration combiner (MRC) and multiple-input and multiple-output (MIMO) systems.

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