On Channel Estimation and Capacity for Amplify and Forward Relay Networks

Behbahani, Alireza S.; Eltawil, Ahmed M.

doi:10.1109/glocom.2008.ecp.708

Cited by 28 publications

(22 citation statements)

References 6 publications

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“…In support of this assumption, we note that estimates of the product channel gains (γα) k1 * and (γβ) k1 * j 's can be obtained using the techniques proposed in [14], [15]. The imperfections in the knowledge of these channel vectors are modeled as (γα) k1 * = ( γα) k1 * +e * (γα) k 1 * and (γβ) …”

Section: B Imperfect Csi Modelmentioning

confidence: 85%

Amplify-and-forward relay beamforming for secrecy with cooperative jamming and imperfect CSI

Vishwakarma

Chockalingam

2013

2013 IEEE International Conference on Communications (ICC)

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Abstract-In this paper, we compute worst case secrecy rates in amplify-and-forward (AF) relay beamforming with cooperative jamming (CJ) in the presence of imperfect channel state information (CSI). A source-destination pair aided by M relays is considered. Number of eavesdroppers J can be more than the number of relays. Out of the M relays, k1 relays (1 ≤ k1 ≤ M ) act as data relays and the remaining k2 = M − k1 relays act as jamming relays. Data relays aid the communication by relaying data in AF mode, and jamming relays cooperate by transmitting jamming signals (artificial noise). The jamming signals are created such that they degrade the eavesdroppers' channels but do not significantly affect the intended receiver's channel, thereby improving secrecy rate. Imperfection in the CSI is modeled using a norm-bounded error model. We solve for the optimum (k1, k2) and the weights of data relays and jamming relays that maximize the secrecy rate subject to a total relay power constraint. We relax the rank-one constraint on the complex semi-definite data relays and jamming relays weight matrices and reformulate the optimization problem into a form that can be solved using convex semi-definite programming. Numerical results on the secrecy rate that illustrate the effect of cooperative jamming, imperfect CSI, and number of eavesdroppers are presented.keywords: Cooperative relay beamforming, physical layer security, secrecy rate, amplify-and-forward, cooperative jamming, imperfect CSI, multiple eavesdroppers, semi-definite programming.

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Section: B Imperfect Csi Modelmentioning

confidence: 85%

Amplify-and-forward relay beamforming for secrecy with cooperative jamming and imperfect CSI

Vishwakarma

Chockalingam

2013

2013 IEEE International Conference on Communications (ICC)

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“…(The optimal MMSE estimator is too complex because of the non-Gaussian nature of the cascaded channel gain and noise.) In [7], the authors extended the LMMSE channel estimator for relay networks with time division multiplexing (TDM). In [8], the authors proposed a low rank MMSE (LrMMSE) estimator based on the singular value decomposition (SVD) in order to avoid the inverse operation of channel correlation matrix in LMMSE estimator.…”

Section: Introductionmentioning

confidence: 99%

An EM Algorithm-Based Channel Estimation for OFDM Amplify-And-Forward Relaying Systems

Sheu

Sheen

2010

2010 IEEE International Conference on Communications

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The issue of channel estimation is investigated for the orthogonal frequency-division multiplexing (OFDM) relaying system with amplify-and-forward (AF) operation mode. Channel estimation in the AF mode is unique in that both the source-torelay and relay-to-destination channels are needed at the destination in order to perform optimum combining of the received signals from the direct (source-to-destination) and relay paths if a cooperative diversity transmission is employed. Until now, however, there have been only literatures to study the estimation of the composite channel of the relay path. In this work, an iterative expectation-maximization (EM) algorithmbased channel estimation is proposed for respective estimations of the source-to-relay and relay-to-destination links at the destination. Computer simulations show that the iterative channel estimator performs satisfactorily and converges rapidly.

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“…Channel estimation for AF relay channels has been introduced in [3], [4], where it is shown that the estimation scheme in AF relay channels is quite different from the traditional one, and the overall channels from source to destination via relaying, should be estimated all at once. It is a natural extension to the state of the art by coupling relay channels with MIMO techniques due to the fact that MIMO relay could further improve spectral efficiency and link reliability.…”

Section: Introductionmentioning

confidence: 99%

Channel Estimation and Optimal Training Design for Amplify and Forward MIMO Relay Channel under Spatial Fading Correlation

Pang¹,

Shen²,

Wang³

et al. 2010

2010 IEEE 72nd Vehicular Technology Conference - Fall

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In this paper, we study the channel estimation problem for time division multiplex amplify-and-forward (AF) relay channels. Both the source and the destination and also the in-between relay node comprise multiple antennas, and there are spatial fading correlations in each hop. We first derive a linear minimum mean square error (LMMSE) channel estimator from a simple scenario where there are no correlations among the relay antennas to a more general scenario where the multiple relay antennas are also spatially correlated. And then we design the optimal training sequences by minimizing the mean square error (MSE). Also the impacts of spatial correlations, relay power gain and the number of relay antennas on the MSE are studied to some extent. It is proved that the channel estimation and optimal training sequences have nothing to do with the spatial correlation at the destination and the derived estimator and designed sequences can be directly extended to multi-hop relay channels. Simulations are conducted to corroborate the proposed studies.

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On Channel Estimation and Capacity for Amplify and Forward Relay Networks

Cited by 28 publications

References 6 publications

Amplify-and-forward relay beamforming for secrecy with cooperative jamming and imperfect CSI

Amplify-and-forward relay beamforming for secrecy with cooperative jamming and imperfect CSI

An EM Algorithm-Based Channel Estimation for OFDM Amplify-And-Forward Relaying Systems

Channel Estimation and Optimal Training Design for Amplify and Forward MIMO Relay Channel under Spatial Fading Correlation

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