Optimal Bit and Power Loading for Amplify-and-Forward Cooperative OFDM Systems

Amin, Osama; Uysal, Murat

doi:10.1109/twc.2011.011111.091233

Cited by 21 publications

(9 citation statements)

References 35 publications

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“…A number of related techniques have been investigated in , to address the frequency‐selective fading in relay communications. Cooperative filter‐and‐forward beamforming techniques were proposed and optimized to maximize the signal‐to‐noise ratio (SNR) under power constraint or to minimize the transmitted power subject to the SNR constraint.…”

Section: Introductionmentioning

confidence: 99%

A two-hop equalize-and-forward relay scheme in OFDM-based wireless networks over multipath channels

Gao

Wang

Leung

2015

Wirel. Commun. Mob. Comput.

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Relay communications have attracted increasing research attentions as a cost-effective technique to improve spatial diversity, service coverage, and energy efficiency in wireless networks. However, existing relay schemes (e.g., amplifyand-forward and decode-and-forward (DF) schemes) still face several major challenges, particularly the accumulation of multipath channels effect in AF and long processing latency in DF. To address these issues, we propose a novel equalizeand-forward (EF) relay scheme to enhance the retransmission reliability while maintaining low processing delay at the relay node. In particular, the proposed EF relay estimates and equalizes the channel between source and relay to eliminate the channel accumulation effect without signal regeneration. To further reduce the relay processing time, the channel estimation and equalization in the proposed EF design are performed in parallel. The proposed equalization is realized by presetting the equalizer coefficients with the current channel response that is predicted in parallel using multiple past channel responses. Numerical results show that the proposed EF relay scheme can achieve comparable symbol error rate performance as the DF relay with much less relay latency. In addition, the EF relay exhibits low outage probability at the same data rate as compared with traditional amplify-and-forward and DF schemes.

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Section: Introductionmentioning

confidence: 99%

A two-hop equalize-and-forward relay scheme in OFDM-based wireless networks over multipath channels

Gao

Wang

Leung

2015

Wirel. Commun. Mob. Comput.

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“…The data rate and Bit Error Rate (BER) performance of the two-way relay system can be improved with the use of AOFDM [9]. Adaptive modulation based two-way relay system was first introduced in [10]. But this work assumed that CSI is perfectly known.…”

Section: Introductionmentioning

confidence: 99%

Performance study of BFAM 2D-RLS channel estimator for AOFDM based two-way relay

Joy¹,

Chakka

2014

2014 6th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)

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In this paper we introduce an adaptive channel estimation scheme for two-way relay with node capability. The adaptive filter used is called Block Fast Array Multichannel 2D-Recursive Least Square (BFAM 2D-RLS). The modulation used is Orthogonal Frequency Division Multiplexing (OFDM) and channel estimation is done in the frequency domain. The proposed channel estimator considers correlation of channel frequency response in both time and frequency domain. The computational complexity is calculated and convergence performance of the adaptive channel estimator is studied. This paper also introduces an AOFDM scheme for two-way relay systems. The effect of channel estimation error on performance of Adaptive OFDM (AOFDM) is analyzed for pedestrian A (pedA) channel. All computer simulations are performed using MATLAB R .

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“…Multiple RSs are considered in [13], in which allocation of power, subchannel, and time duration for multiple UE is studied. Resource allocation strategies for cooperative OFDM systems with 0018-9545 © 2013 IEEE multiple amplify-and-forward (AF) RSs are studied in [14] and [15]. In [14], power allocation with an individual power constraint is investigated without considering subcarrier pairing.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the objective functions are designed either to maximize the throughput or to minimize the total transmission power. An exception is [15], which aims at optimizing the BER under the constraints of total power and target data rates.…”

Section: Introductionmentioning

confidence: 99%

Green Resource Allocation Schemes for Relay-Enhanced MIMO-OFDM Networks

Chang

Feng

Lin

et al. 2013

IEEE Trans. Veh. Technol.

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This paper studies the problem of joint allocation of subchannel, transmission power, and phase duration in relayenhanced bidirectional multiple-input-multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) networks. The goal of resource allocation is to minimize transmission energy consumption in networks with multiple decode-and-forward relay stations (RSs) under the data rate constraints of user equipment (UE). The challenges of this resource allocation problem arise from the complication of multiple-phase assignments within a subchannel since the RS can provide an additional transmission path from the base station to the UE. Existing research does not fully take into account all of the influential factors to achieve feasible resource allocation for relay-enhanced MIMO-OFDM networks. Green resource allocation (GRA) schemes with reduced computational complexity are proposed in this paper to develop joint allocation of subchannel, power, and phase duration for the UE with the consideration of direct and two-hop communications. Both the separate-downlink (DL)-and-uplink (UL) and mixed-DL-and-UL relaying assignments and the linear block diagonalization (LBD)technique are adopted to obtain the solutions for the proposed GRA schemes. Simulation results show that the proposed GRA schemes can provide comparably better energy conservation with the consideration of quality-of-service (QoS) support.Index Terms-Energy conservation, linear block diagonalization (LBD), multiple-input multiple-output orthogonal frequencydivision multiplexing (MIMO-OFDM), relay station (RS), resource allocation.

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Optimal Bit and Power Loading for Amplify-and-Forward Cooperative OFDM Systems

Cited by 21 publications

References 35 publications

A two-hop equalize-and-forward relay scheme in OFDM-based wireless networks over multipath channels

A two-hop equalize-and-forward relay scheme in OFDM-based wireless networks over multipath channels

Performance study of BFAM 2D-RLS channel estimator for AOFDM based two-way relay

Green Resource Allocation Schemes for Relay-Enhanced MIMO-OFDM Networks

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