In this paper, the performance of Network Coded (NC) based cooperative network for various relay location over Rayleigh fading channels is studied. Comparisons of Amplify and Forward (AAF), Detect and Forward (DTF) and Decode and forward (DCF) protocols for the proposed system are shown. The performance of relays in AAF, DTF and DCF is analyzed in terms of bit error rate (BER) vs signal to noise ratio (SNR). Matlab is used to build Monte-Carlo link level simulation. The effect of relays at different position is studied.
Recently, multi-carrier transmission schemes have been introduced into Code Division Multiple Access (CDMA) systems to gain advantages for high data rate transmission as well as security. Due to pseudorandom code there is no chance to Inter Symbol Interference (ISI). There are different techniques to mitigate multipath fading. One of the method is to transmit identical narrowband direct-sequence (DS) waveforms in parallel over a number of sub-channels using frequency diversity. Implementation this multi-carrier modulation technique in CDMA system is known as multi-carrier CDMA (MC-CDMA). In Rayleigh fading channel, due to multi-carrier modulation, when one subcarrier goes deep fade another subcarrier may remain safe. Therefore it combats multi-path fading and signal can be received in low bit error rate.
This paper presents the performance of double threshold energy detection in cooperative cognitive networks over Nakagami-m fading channel. Square Law Combining (SLC) diversity technique helps in detection at cognitive center for different values of shape factor M and this algorithm is examined by placing multiple relays between Primary user (PU) and Secondary user (SU). Performance of the network has been analyzed for amplify and forward relaying scheme as irrespective of their location and distance from the primary users and cognitive center. The simulated results are shown for detection probability (P d ), collision probability (P c ) and unavailable probability (P n ) .
Keywords-primaryusers; secondary user;cognitive center;square law combing ; double threshold energy detection; amplify and forward.I.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.