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Study On Two-way Relaying System With Network Coding

Posted on:2014-01-29Degree:DoctorType:Dissertation
Country:ChinaCandidate:H ZhiFull Text:PDF
GTID:1268330425971451Subject:Communication and Information System
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Fading is the main negative factor that degrades the quality of radio communication, whereas diversity is an effective method to combat the fading in wireless communication. Relay-aided cooperative communication can combat the fading effectively through spatial diversity, so it has been paid more attention and recognition by previous investigations in recent years. Most investigations about relay-aided cooperative communications follow the half-duplex constraint because of the complex realization of full-duplex mode, however the half-duplex mode will cause low spectral efficiency of the system. Two-way relaying with network coding can significantly improve system spectral efficiency. The researches about two-way relaying system with network coding have many problems to solve or improve at present, thus this dissertation gives a deep study of the two-way relaying system with network coding. The main contributions are summarized as follows.1) The system performance of Decode-and-Forward Two-Way Opportunistic Relaying (DF-TWOR) system is investigated. First, an analytical method for system outage probability and ergodic capacity of DF-TWOR system is formulated, and the exact expressions (or bounds) of outage probability, ergodic capacity and Average Bidirectional Ergodic Capacity (ABEC) for max-min relay selection, random relay selection and direct transmission scheme are derived. Then, based on the above performance analyses, a novel relay selection scheme, named Maximum Average Bidirectional Mutual Information (MABMI), is proposed and the closed-form solutions to the system outage probability and ABEC of the proposed scheme are obtained. The theoretical analyses and simulations demonstrate that the proposed MABMI scheme can always achieve larger ABEC than other schemes while keeping low outage probability.2) The average Symbol Error Rate (SER) and the Optimal Power Allocation (OPA) scheme for Amplify-and-Forward Two-Way Opportunistic Relaying (AF-TWOR) system are investigated. First, based on mathematical model of the AF-TWOR system, the closed-form solutions to the Probability Density Function (PDF), Cumulative Distribution Function (CDF), and Moment Generating Function (MGF) of the equivalent received Signal-to-Noise Ratio (SNR) is derived. Then, according to these derived statistical results, an analytical method of the total average SER for AF-TWOR system is formulated, and the expression of total average SER for the Non-OPA AF-TWOR system is obtained through appropriate approximation. Finally, by aiming at minimizing the total average SER, the OPA scheme subject to a total transmission power constraint is provided. The simulation results show that the system average SER performance can be improved under the proposed OPA scheme.3) The jointed adaptive modulation relay selection scheme for AF-TWOR system is investigated. First, two novel best-relay selection schemes, the jointed Adaptive Modulation Max-Min (AM-MM) scheme and the jointed Adaptive Modulation Maximum Harmonic Mean (AM-MHM) scheme, are proposed for AF-TWOR system by integrating the adaptive modulation with the conventional Max-Min (MM) and Maximum Harmonic Mean (MHM) relay selection schemes respectively. Then, the analytical expressions to the approximate upper bound of system average SER for AM-MM and AM-MHM schemes are obtained through theoretic analysis. The numerical results demonstrate that the average SER of AF-TWOR system can be improved greatly when the proposed jointed adaptive modulation relay selection schemes are performed.4) The jointed precoding and decoding scheme for multiple-antenna multiple-relay amplify-and-forward two-way relaying system is investigated. A jointed precoding and decoding scheme is proposed, the goal is to jointly optimize the source precoding, the relay precoding and the destination decoding based on Minimum Mean Square Error (MMSE) criteria under transmit power constraints. First, a nonlinear constrained optimization problem is formulated with respect to precoding and decoding matrices according to the optimization goal. Then we decompose the primal optimization problem into four sub-problems and solve the primal optimization problem by using a convergent iterative algorithm which includes these four sub-problems. Furthermore, during the solving process, a simplified approach is proposed to reduce the computational complexity. Simulation results show that the proposed scheme can achieve lower Bit Error Rate (BER) and larger sum rate than other schemes.
Keywords/Search Tags:Two-way relaying, Network coding, Outage probability, Ergodic capacity, Symbolerror rate, Relay selection scheme, Precoding, Decoding
PDF Full Text Request
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