Resource Allocation in OFDM Based Wireless Relay Networks ...

More documents

Recommendations

Info

3.2 System Model relay node distributes its power to all available OFDM sub-carriers in BCP. – Sub-carrier assignment among different users such that the same sub-carrier should be assigned to the two terminals in a user-pair for a particular transmission phase. – The tone matching at the relay node, where the signal received in MAP over one sub-carrier is re-transmitted on a different (or same) sub-carrier in BCP. • To reduce the complexity, we further propose a suboptimal method that sacrifices very little on the performance as demonstrated by the numerical examples. • A complexity comparison of the joint and the suboptimal methods is provided and the numerical examples show a better performance over the existing trivial methods. The rest of this chapter is organized as follows. In Section 3.2, we present the system model. The joint resource allocation problem is formulated in Section 3.3. In Section 3.4, we develop the dual decomposition method. The low complexity suboptimal algorithm is presented in Section 3.5. Simulation results are presented in Section 3.6 and conclusions are given in Section 3.7. 3.2 System Model We consider a two-way multi-user relay network that consists of M pre-assigned pairs of MUs and one fixed RS, all equipped with only one antenna that cannot transmit and receive simultaneously, as shown in Fig. 3.3. Further, we assume that a direct communication link is missing between two users and all the communication is carried out through RS which operates in AF mode. In MAP, all MUs transmit information to RS simultaneously via non-overlapping carriers. In BCP, the RS 47
3.2 System Model MU MU 3 8 A 1 2 7 3 8 2 7 A 3 1 4 5 1 4 5 B 1 A 2 1 2 5 1 2 5 RS 3 6 8 3 6 8 B 2 4 6 7 4 6 7 B 3 Figure 3.3: System model for an OFMDA aided multi-user TWRN. broadcasts the received signal after certain processing, for example power amplifying and carrier permutation. The two users of the m-th user pair, denoted as A m and B m , transmit simultaneously on the same carriers, for example the kth carrier in MAP, 1 while the received signal will be sent back over the j-th sub-carrier in BCP. Assigning which carrier to which user-pair, as well as the matching strategy (k, j) will be optimized in this work. Denote the channel coefficient from A m to RS as h m,k , the one from B m to RS as g m,k , the one from RS to A m as ˜h m,j , and the one from RS to B m as ˜g m,j . 2 Then the received signal at RS is √ √ yk RS = p A m,k h m,kx A m,k + p B m,k g m,kx B m,k + wk RS , (3.1) where x A m,k and xB m,k are the information symbols to be exchanged, pA m,k and pB m,k are the corresponding powers over the k-th carrier, and w RS k Gaussian noise with variance σ 2 . is the additive white If the power allocated at RS over sub-carrier j is represented as p R j , then the 1 That is to say, A m1 and B m2 will not transmit on the same carrier during MAP. 2 By letting ˜h m,j = h m,j and ˜g m,j = g m,j , the scenario here reduces to the reciprocal channels. 48
Page 1 and 2:
Resource Allocation in OFDM Based W
Page 3 and 4:
Dedications: To my family
Page 5 and 6:
Acknowledgment I am greatly thankfu
Page 7 and 8:
Contents 2.3.3 Proposed Low-Complex
Page 9 and 10:
Abstract The combination of relay t
Page 11 and 12: List of Tables 3.1 Complexity compa
Page 13 and 14: List of Figures 4.1 System model fo
Page 15 and 16: List of Acronyms IEEE MU RS AWGN OW
Page 17 and 18: 1.1 Overview of Relay Networks wire
Page 19 and 20: 1.2 Overview of OFDM Figure 1.2: Th
Page 21 and 22: 1.3 Basics of the Optimization Theo
Page 23 and 24: 1.3 Basics of the Optimization Theo
Page 25 and 26: 1.4 Resource Allocation Problem is
Page 27 and 28: 1.5 Contribution and Organization o
Page 29 and 30: 1.5 Contribution and Organization o
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: 3.1 Introduction • Broadcast Phas
Page 65 and 66: 3.4 Joint Resource Allocation Schem
Page 67 and 68: 3.4 Joint Resource Allocation Schem
Page 69 and 70: 3.5 Step-Wise Low-Complexity Resour
Page 71 and 72: 3.6 Simulation Results and SNR B m,
Page 73 and 74: 3.6 Simulation Results 3 2.5 2 Uppe
Page 75 and 76: 3.7 Summary 1.8 1.6 1.4 JntOpt SubO
Page 77 and 78: 4.1 Introduction • Non-orthogonal
Page 79 and 80: 4.3 Cooperative Non-Orthogonal Tran
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.
Page 105 and 106: 5.4 Lifetime Maximization Scheme wh
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
show all

Resource Allocation in OFDM Based Wireless Relay Networks ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?