Power Allocation and Subcarrier Pairing in OFDM-Based Relaying Networks

Li, Yong; Wang, Wenbo; Kong, Jizhou; Wang, Hong; Zhang, Xing; Peng, Mugen

doi:10.1109/icc.2008.493

Cited by 101 publications

(99 citation statements)

References 10 publications

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“…These two ways of pairing lead to the following two sets of disjoint paths from the source to the destination: {P (1) i } = { (1, 1, c(3, 1)), (2, 2, c(3, 2))} and {P (2) i } = { (1, 2, c(3, 1)), (2, 1, c(3, 2))}, where the superscript j in {P (j) i } indicates a different set of path selection. By considering the equivalent channels from the source to the second relay, using the existing optimality result for dual-hop relaying [8], it is easy to see that c(3, 1) = 1 and c(3, 2) = 2 are optimal for {P (1) i }. Furthermore, we only need to show log 2 1 + γ SD (P (1) 1 ) + log 2 1 + γ SD P (1) 2 ≥ log 2 1 + γ SD P (2)…”

Section: Discussionmentioning

confidence: 99%

“…In the absence of the direct source-destination link, for the practical case of noisy-relay, by using the property of L-superadditivity of the rate function, the authors of [7] proved that the sorted-SNR CP still remains optimal for sum-rate maximization in dual-hop AF relaying OFDM system. Subsequently, it was further proved in [8], through a different approach, that the sorted-SNR CP scheme is optimal for both AF and DF relaying in the same setup. When the direct sourcedestination link is available, [9] presented two suboptimal CP schemes.…”

Section: B Related Workmentioning

confidence: 99%

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Optimal Channel Pairing and Power Allocation for Multi-channel Multi-hop Relay Networks

Hajiaghayi

Dong

Liang

2012

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering

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We study the problem of channel pairing and power allocation in a multi-channel multi-hop relay network to enhance the end-to-end data rate. Both amplify-and-forward (AF) and decode-and-forward (DF) relaying strategies are considered. Given fixed power allocation to the channels, we show that channel pairing over multiple hops can be decomposed into independent pairing problems at each relay, and a sorted-SNR channel pairing strategy is sum-rate optimal, where each relay pairs its incoming and outgoing channels by their SNR order. For the joint optimization of channel pairing and power allocation under both total and individual power constraints, we show that the problem can be decoupled into two subproblems solved separately. This separation principle is established by observing the equivalence between sorting SNRs and sorting channel gains in the jointly optimal solution. It significantly reduces the computational complexity in finding the jointly optimal solution. It follows that the channel pairing problem in joint optimization can be again decomposed into independent pairing problems at each relay based on sorted channel gains. The solution for optimizing power allocation for DF relaying is also provided, as well as an asymptotically optimal solution for AF relaying. Numerical results are provided to demonstrate substantial performance gain of the jointly optimal solution over some suboptimal alternatives. It is also observed that more gain is obtained from optimal channel pairing than optimal power allocation through judiciously exploiting the variation among multiple channels.Impact of the variation of channel gain, the number of channels, and the number of hops on the performance gain is also studied through numerical examples.

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Section: Discussionmentioning

confidence: 99%

Section: B Related Workmentioning

confidence: 99%

Optimal Channel Pairing and Power Allocation for Multi-channel Multi-hop Relay Networks

Hajiaghayi

Dong

Liang

2012

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering

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“…Contrary to the above gradient, the updates according to (26) will not be undone if the objective becomes worse after an update. Thus, the implemented algorithm has to keep track of the best achieved sum rate and corresponding resource allocations:…”

Section: Subgradient Methodsmentioning

confidence: 99%

“…initialise allocation elements according to (30), (31), (32) repeat for all resource allocation vectors x do calculate partial derivatives according to (27) repeat apply feasibility updates (28) and (29) until update direction is feasible update allocation elements according to (26) …”

Section: Algorithm 1 Gradient Descent Algorithmmentioning

confidence: 99%

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Resource allocation for the multiple-access relay channels and OFDMA

Schedler

Kühn

2013

EURASIP J. Adv. Signal Process.

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Within this article, the resource allocation problem for the multiple-access relay channel with orthogonal channel access is analysed. We propose a centralised optimisation framework that maximises the achievable sum rate of the network and that can be applied to a wide range of scenarios. We analyse different approaches to tackle the problem with individual transmit power constraints such as relaxing of constraints and splitting of the joint problem into a carrier allocation and individual power allocations. The carrier allocation deals with the exclusive assignment of subcarriers to different users, and the power allocation addresses the distribution of available power over assigned subcarriers. Several approaches are proposed for amplify and forward, decode and forward, and compress and forward strategies, and the performance as well as computational effort is evaluated by simulations. The obtained results suggest that the proposed algorithms can perform close to optimal.

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QoS‐driven jointly optimal subcarrier pairing and power allocation for OFDM amplify‐and‐forward relay systems

Huang

Luo

et al. 2013

Int J Communication

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SUMMARYIn this paper, we investigate the quality-of-service (QoS) driven subcarrier pairing and power allocation for two-hop amplify-and-forward OFDM relay systems. By integrating the concept of effective capacity, our goal is to maximize the system throughput subject to a given delay QoS constraint. We propose a jointly optimal subcarrier pairing and power allocation scheme, which can be implemented with two separate steps. First, pair the subcarriers over the source-relay channel and relay-destination channel by the descending order of the subcarriers' channel gains. Second, by making use of the derived equivalent end-to-end channel gains of the subcarrier pairs, optimally allocate power over the subcarrier pairs, and then optimally partition the power of the subcarrier pairs between the source and the relay. The simulation results show that our proposed scheme can efficiently provide different levels of delay QoS guarantees, even if under stringent delay QoS constraints. The simulation results also verify that our proposed scheme shows significant superiorities over the other existing schemes.

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Power Allocation and Subcarrier Pairing in OFDM-Based Relaying Networks

Cited by 101 publications

References 10 publications

Optimal Channel Pairing and Power Allocation for Multi-channel Multi-hop Relay Networks

Optimal Channel Pairing and Power Allocation for Multi-channel Multi-hop Relay Networks

Resource allocation for the multiple-access relay channels and OFDMA

QoS‐driven jointly optimal subcarrier pairing and power allocation for OFDM amplify‐and‐forward relay systems

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