Resource Allocation in OFDM Based Wireless Relay Networks ...

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4.2 System Model of sub-carriers. In this work, we consider an OFDM based single user multi-relay network with dual hop AF transmission. We first design a resource allocation scheme in a non-orthogonal transmission such that the sub-carrier pairing at the relay nodes, the power loading over different sub-carriers at the source node, and the beamforming at the relay nodes are optimized jointly to maximize the end-to-end system throughput. Later, we consider the TDMA transmission and develop a resource allocation strategy to maximize the throughput over two hops. The rest of this chapter is organized as follows. In Section 4.2, we present the system model of multi-user two-way relay transmission and formulate the joint resource allocation problem. In Section 4.3, we develop the joint solution as well as the suboptimal method. The resource allocation algorithm under orthogonal transmission is studied in Section 4.4. Simulation results are presented in Section 4.5 and the chapter summary is reported in Section 4.6. 4.2 System Model Consider a cooperative relay system where a source node (SN) communicates with the destination node (DN) through N parallel RSs as shown in Fig.4.1. We adopt a dual hop transmission such that SN transmits in the first hop and the RSs transmit in the second hop. one antenna. Further, we assume that each node is equipped with only OFDM is applied and the available bandwidth is divided into K sub-carriers. Moreover, we assume that SN and DN are located far from each other such that there is no direct communication link [17]. In the first time slot, SN transmits symbol s k over sub-carrier k with power p k . The signal received at the n-th RS is y RS n,k = √ p k h n,k s k + z n,k , (4.1) where h n,k denotes corresponding channel coefficient and z n,k is the additive white Gaussian noise with variance σn,k 2 . We apply sub-carrier pairing over two hops such 63
4.3 Cooperative Non-Orthogonal Transmission Figure 4.1: System model for dual hop parallel relay network. that the signal received over the k-th sub-carrier will be forwarded to DN over the j-th sub-carrier. 4.3 Cooperative Non-Orthogonal Transmission In this section, we assume that in the first time slot all the relay nodes receive data from the SN over all the sub-carriers such that each relay occupy the same copy of source data. In the second time slot, all the relays simultaneously transmit the information to the destination node. Denote the channel coefficient between the n-th RS and DN on the j-th sub-carrier as g n,j . Denote w n,j as the complex beamforming weight applied at the n-th RS over the j-th sub-carrier which is to be designed later. The signal 64
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Resource Allocation in OFDM Based W
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Dedications: To my family
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Acknowledgment I am greatly thankfu
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Contents 2.3.3 Proposed Low-Complex
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Abstract The combination of relay t
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List of Tables 3.1 Complexity compa
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List of Figures 4.1 System model fo
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List of Acronyms IEEE MU RS AWGN OW
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1.1 Overview of Relay Networks wire
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1.2 Overview of OFDM Figure 1.2: Th
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1.3 Basics of the Optimization Theo
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1.3 Basics of the Optimization Theo
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1.4 Resource Allocation Problem is
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Page 31 and 32: 2.1 Introduction allocated to a nod
Page 33 and 34: 2.1 Introduction The main contribut
Page 35 and 36: 2.2 System Model where h m,k denote
Page 37 and 38: 2.3 Resource Allocation Schemes opt
Page 39 and 40: 2.3 Resource Allocation Schemes ( )
Page 41 and 42: 2.3 Resource Allocation Schemes and
Page 43 and 44: 2.3 Resource Allocation Schemes tha
Page 45 and 46: 2.3 Resource Allocation Schemes 2.3
Page 47 and 48: 2.4 Generalization to Multiple Rela
Page 49 and 50: 2.4 Generalization to Multiple Rela
Page 51 and 52: 2.5 Simulation Results • OptSol/J
Page 53 and 54: 2.5 Simulation Results 0.9 0.85 0.8
Page 55 and 56: 2.6 Summary 2.6 2.4 2.2 2 Rate (bit
Page 57 and 58: 2.6 Summary 2.4 2.2 2 1.8 N=4 N=3 N
Page 59 and 60: 3.1 Introduction A new technology c
Page 61 and 62: 3.1 Introduction • Broadcast Phas
Page 63 and 64: 3.2 System Model MU MU 3 8 A 1 2 7
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Page 69 and 70: 3.5 Step-Wise Low-Complexity Resour
Page 71 and 72: 3.6 Simulation Results and SNR B m,
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Page 75 and 76: 3.7 Summary 1.8 1.6 1.4 JntOpt SubO
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Page 87 and 88: 4.4 Optimization under Orthogonal T
Page 89 and 90: 4.4 Optimization under Orthogonal T
Page 91 and 92: 4.5 Simulations Then, the over all
Page 93 and 94: 4.5 Simulations 40 30 20 Sum−ρ S
Page 95 and 96: 4.6 Summary 0.9 0.8 0.7 JPSC Pow EP
Page 97 and 98: Chapter 5 Lifetime Maximization in
Page 99 and 100: 5.1 Introduction Figure 5.2: Linear
Page 101 and 102: 5.2 System Model antenna that canno
Page 103 and 104: 5.4 Lifetime Maximization Scheme 5.
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Page 107 and 108: 5.5 Simulation Results 150 OPT−SO
Page 109 and 110: 5.6 Summary Lifetime (S) 150 100 50
Page 111 and 112: Chapter 6 Resource Allocation in Co
Page 113 and 114: 7. Conclusions were considered for
Page 115 and 116: Bibliography [12] A. Peled, and A.
Page 117 and 118: Bibliography [36] Z. Luo and S. Zha
Page 119 and 120: Bibliography [61] D. H. N. Nguyen,
Page 121 and 122: Bibliography [84] A. Goldsmith, S.
Page 123 and 124: Bibliography [105] Y. Li, W. Wang,
Page 125 and 126: Appendix A Derivations of Closed-Fo
Page 127: B. Derivations of the Optimal Power
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