Power Allocation and Subcarrier Pairing Algorithm for Regenerative OFDM Relay System

Wang, Ying; Qu, Xinchun; Wu, Tong; Liu, Baoling

doi:10.1109/vetecs.2007.560

Cited by 82 publications

(63 citation statements)

References 9 publications

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“…In order to solve problem (11), an iterative coordinate ascent approach is adopted. Each iteration is carried out in two stages: the MSSA stage and the PA stage.…”

Section: The Overall Ra Algorithmmentioning

confidence: 99%

“…During the second TS, except for the relay, the source might also transmit symbols on subcarriers unused by the relay. Adopting the DF relaying, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] have investigated intensively the RA problems for downlink OFDMA.…”

Section: Introductionmentioning

confidence: 99%

“…Considering the case when the S-D link is available, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] have studied RA in systems with opportunistic relaying (sometimes termed as selection relaying). To start with, [8][9][10][11][12][13] have studied a low spectrum efficiency (LSE) protocol, when only the relay transmits symbols during the second TS. Specifically, each subcarrier can choose either the relayaided mode or the direct mode for data transmission.…”

Section: Introductionmentioning

confidence: 99%

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Distributed algorithms for sum rate maximization in multi-cell downlink OFDMA with opportunistic DF relaying

Jin

Wang

Wei

et al. 2014

J Wireless Com Network

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This paper considers a multi-cell orthogonal frequency division multiple access (OFDMA) downlink system with several decode-and-forward (DF) relay stations (RSs) aiding the base station (BS) transmissions. The problem considered is the maximization of the system sum rate with a total power constraint in each cell. An iterative semi-distributed resource allocation (RA) algorithm is first proposed to optimize mode selection (decision whether relaying should be used or not and which relay), subcarrier assignment (MSSA), and power allocation (PA), alternatively. During the MSSA stage, the problem is decoupled into subproblems which can be solved distributively in linear time. During the PA stage, an algorithm based on single condensation and Lagrange duality (SCLD) is designed to optimize PA with the tentative MSSA results. The convergence of the SCLD-based RA algorithm is theoretically guaranteed and an local optimum is reached after convergence. To solve the formulated problem autonomously, a modified iterative water-filling (IWF) algorithm is further proposed. Specifically, each cell autonomously optimizes its own sum rate with the estimated power values of the received interferences from the other cells. An optimum algorithm is proposed to solve the local RA problem in each cell. Through numerical experiments, the convergence of the two proposed algorithms as well as their benefits compared with a centralized algorithm (CA) are illustrated.

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“…In order to solve problem (11), an iterative coordinate ascent approach is adopted. Each iteration is carried out in two stages: the MSSA stage and the PA stage.…”

Section: The Overall Ra Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distributed algorithms for sum rate maximization in multi-cell downlink OFDMA with opportunistic DF relaying

Jin

Wang

Wei

et al. 2014

J Wireless Com Network

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show abstract

“…Using the same approach in [14], we solve the problem in the dual domain and obtain the optimum value of , k m which satisfies (11). This solution will be an upper bound for problem (17).…”

Section: Solution To Optimization Problem [P1]mentioning

confidence: 99%

Weighted Sum Rate Maximization in OFDM Based Cooperative Cognitive Radios: A Joint Optimization Approach

Johari

Vakili

2012

IJCNS

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Improving utilization of the radio spectrum is the main goal of Cognitive Radio Networks (CRN). Recent studies made use of cooperative relay technology in cognitive networks, to increase transmission diversity gain. In this paper we consider an OFDM based cooperative cognitive network with a pair of Source-Destination nodes as the primary user (PU), and a pair of Source-Destination nodes-which is assisted with a relay-as the secondary (cognitive) user (SU). Both primary and secondary users share a same spectrum. In a two hop transmission, the source transmits in the first hop, and the half-duplex relay decodes the message, re-encodes and forwards it to the destination in the second hop on a different subcarrier. The cognitive network obeys an underlay paradigm where the SU is allowed to transmit simultaneously with PU, while its power is limited such that the interference caused for PU does not exceed a defined temperature. Under this constraint, a joint subcarrier pairing and power allocation is proposed for SU to maximize its weighted sum rate. The problem is transformed to a convex optimization problem and solved in the dual domain. Then an algorithm to achieve feasible solutions is used based on the optimization results. Through extensive simulations, we compare the spectrum utilization of the proposed approach with the existing ones, and show that interestingly the proposed method improves the weighted sum rate of SU.

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“…During the second TS, except from the relay, the source might also broadcast symbols on subcarriers not used by the relay, as will be elaborated later. Adopting DF relaying, the authors in [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] have studied the RA problems for downlink OFDMA intensively.…”

Section: Introductionmentioning

confidence: 99%

Weighted sum of per cell min-rate maximization for multi-cell downlink OFDMA with opportunistic DF relaying

Jin

Wang

Wei

et al. 2014

J Wireless Com Network

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This paper considers a multi-cell relay-aided orthogonal frequency division multiple access (OFDMA) downlink system, in which all stations are coordinated by a central controller for resource allocation (RA). The decode-and-forward (DF) protocol with opportunistic relaying (OR) and high spectrum efficiency (HSE) is applied. The problem of maximizing the weighted sum of per cell min-rate (WSMR) with per-cell total power constraints is formulated, and its per-cell maximum fairness property is proven. An iterative RA algorithm is proposed to optimize mode selection (decision whether the relay should help or not), subcarrier assignment (MSSA) and power allocation (PA) alternatively. Each iteration is composed of the MSSA stage and the PA stage. During the MSSA stage, the original problem is decoupled into mixed integer linear programs (MILPs) with the tentative PA results, which can be solved by typical MILP solvers. To solve the MILPs more efficiently in polynomial time, a randomized rounding-based MSSA (RR-MSSA) algorithm and a direct rounding-based MSSA (DR-MSSA) algorithm are further proposed. During the PA stage, an algorithm based on single condensation and geometric programming (SCGP) PA is designed to optimize PA with the tentative MSSA results. The convergence and the per-cell user fairness of the proposed RA algorithm are proven. Finally, the performance of the RA algorithm and the benefits of using OR and the HSE protocol are illustrated through numerical experiments.

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Power Allocation and Subcarrier Pairing Algorithm for Regenerative OFDM Relay System

Cited by 82 publications

References 9 publications

Distributed algorithms for sum rate maximization in multi-cell downlink OFDMA with opportunistic DF relaying

Distributed algorithms for sum rate maximization in multi-cell downlink OFDMA with opportunistic DF relaying

Weighted Sum Rate Maximization in OFDM Based Cooperative Cognitive Radios: A Joint Optimization Approach

Weighted sum of per cell min-rate maximization for multi-cell downlink OFDMA with opportunistic DF relaying

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