تخمين كانال و آشكار سازي در سيستم هاي رله دو راهه

چكيده انگليسي :

Channel Estimation and Symbol Detection in Two Way Relay Systems Maryam Masjedi m masjedi@ec iut ac ir Date of submission 19 12 2016 Department of Electrical and Computer Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Supervisor Dr A Doost Hosseini alimdh@cc iut ac ir1st Advisor Dr S Gazor 2st Advisor Dr M M Naghsh Department Graduate Program Coordinator Dr M R Taban Department of Electrical and Computer Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Department of Electrical and Computer Engineering Queen s University Kingston ON K7L 3N6 Canada AbstractThis dissertation focuses on channel estimation and symbol detection in two way relay systems First we assumethat channels exhibits block flat fading and derive generalized likelihood ratio test GLRT detector along with aconvergent iterative blind joint estimation and detection JED method to resolve its computational complexity We also propose simple least squares LS and weighted LS WLS estimators for low SNRs Then we proceedto temporally correlated channels and orthogonal signaling to propose a channel estimation technique withoutpilot assistance In this method users apply known periodic phase shifts to their transmit symbols and adoptmaximum likelihood ML or linear minimum mean square error LMMSE criteria to estimate the channels Optimal and suboptimal phase shifts are designed to minimize MSE Third we assume the channels are fastRayleigh fading and derive the optimal detector and two closed form suboptimal structures to circumvent itshindering numerical integration We investigate non coherent detection in a denoise and forward DNF relayscheme and design the optimal and suboptimal detectors for fast fading channels With additional practicalorientation we derive optimal detector for amplitude block fading channels and propose efficient estimators forthe amplitudes Key WordsAmplify and Forward Channel Estimation Denoise and Forward Detection Two WayRelaying Introduction Research on cooperative communications and relay networks has increased dramaticallyover recent years Relay systems act as distributed multiple input and multiple output MIMO systems and provide spatial diversity which enhances transmission rate and extendcoverage Relay networks are classified as one way OWRN and two way TWRN TWRNshave received further attention due to their superior spectral efficiency In amplify and forward AF or analog network coding ANC strategy users transmit their data to the relayin the first phase simultaneously The relay amplifies the superposed signal and sends it backto the users In link layer network coding LNC users transmit their data to the relay in thefirst two phases sequentially The relay detects decodes the received bits in these phasesand modulates encodes their XOR and sends it back to the users in the third phase Indigital network coding DNC users transmit their data to the relay in the first phasesimultaneously The relay detects decodes the XOR of the users bits modulates encodes and sends it back to the users in the second phase If the relay decodes and re encodes theXOR of users transmitted bits the strategy is called decode and forward DF but if it onlydetects and re modulates the XOR of users transmitted bits the strategy is calleddemodulate and forward detect and forward or denoise and forward DNF

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تخمين كانال و آشكار سازي در سيستم هاي رله دو راهه

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