Results 281 to 290 of about 375,907 (328)

An Amplify-and-Forward architecture for low spectral efficiencies

2009 IEEE International Symposium on Circuits and Systems, 2009
This paper proposes a simple architecture for half-duplex cooperative systems which use Amplify-and-Forward (AF) as a relay strategy and one-dimensional modulations for source messages. The proposed solution uses the two orthogonal channels of quadrature modulation in order to allow a node to behave simultaneously as a source and a relay. We prove that
Krikidis, Ioannis A., Krikidis, Ioannis A.   +1 more
openaire   +2 more sources

Design of limiting amplifier models for nonlinear amplify-and-forward distributed estimation

2013 18th International Conference on Digital Signal Processing (DSP), 2013
This paper describes the design of limiting amplifier models to be used in the implementation of non-linear amplify-and-forward distributed estimation systems. The use of nonlinear amplifiers in amplify-and-forward distributed estimation can yield significant gains in sensor power efficiency compared to the more conventional linear amplifiers.
Robert W. Santucci, Mahesh K. Banavar, Andreas Spanias, Cihan Tepedelenlioglu   +3 more
openaire   +1 more source

Linear detection for the nonorthogonal amplify and forward protocol

IEEE Transactions on Wireless Communications, 2009
In this paper, we present three new detection schemes for the nonorthogonal amplify and forward (NAF) protocol in a cooperative diversity system based on a multiuser detection approach, namely, a channel inversion type detector, a maximal-ratio combining (MRC) type detector, and a biased maximum likelihood (ML) detector. The decision variables in these
Aakanksha Chowdhery, Ranjan K. Mallik
openaire   +1 more source

Amplify-and-forward with full-duplex relay selection

2012 IEEE International Conference on Communications (ICC), 2012
This paper focuses on the relay selection problem in amplify-and-forward (AF) cooperative communication with full-duplex (FD) operation. Different relay selection schemes assuming the availability of different instantaneous information are studied. We consider an optimal relay selection that maximizes the instantaneous FD channel capacity and requires ...
Krikidis, Ioannis A., Suraweera, H. A., Yuen, C., Krikidis, Ioannis A., Suraweera, H. A., Yuen, C.   +5 more
openaire   +2 more sources

Beamforming in Nonorthogonal Amplify-and-Forward Relay Networks

IEEE Transactions on Vehicular Technology, 2011
This paper considers wireless amplify-and-forward (AF) relay networks in which the source communicates with the relays and destination in the first phase and the relays simultaneously forward signals to the destination in the second phase over uncorrelated Rayleigh fading channels.
Tung T. Pham, Ha H. Nguyen 0001, Hoang Duong Tuan   +2 more
openaire   +1 more source

On the Error Exponent of Amplify and Forward Relay Networks

IEEE Communications Letters, 2011
In this letter we derive the exact random coding error exponent of a dual hop amplify and forward (AF) relay network with channel state information (CSI) assisted ideal relay gain. Numerical results have been presented, which provide insight about the performance tradeoff between the error exponent and the data rate of the network.
Bappi Barua, Mehran Abolhasan, Farzad Safaei, Daniel Robert Franklin   +3 more
openaire   +2 more sources

Cooperative Amplify-and-Forward with Trellis Coded Modulation

2009 IEEE Wireless Communications and Networking Conference, 2009
In a cooperative communication network, individual users are encouraged not only to transmit their own data, but also relay other user's data. This relaying transmission creates spatial diversity to combat the effect of individual severe fading and path loss.
Li Chen 0013, Rolando A. Carrasco, Stéphane Y. Le Goff, Ian J. Wassell   +3 more
openaire   +1 more source

On the Power Allocation for Cooperative Amplify-and-Forward Transmission

2007 IEEE 66th Vehicular Technology Conference, 2007
In this paper, efficient power allocation strategy for user cooperative transmission using amplify-and-forward (AF) approach is investigated. Power allocation is solved by finding the desirable ratio of power used for cooperative- information transmission to total power in an attempt to minimize bit error rate (BER) with a constraint of fixed total ...
Lian Zhao, Zaiyi Liao
openaire   +1 more source

Cooperative Phase Sweep Amplify-and-Forward Transmission

2008 IEEE 68th Vehicular Technology Conference, 2008
This work presents a new amplify-and-forward (AF) cooperative multiple input multiple output (MIMO) transmission scheme based on phase sweep transmit diversity. In a single hop cooperative link, the relay node imposes a phase sweep on the signal it receives from the source node.
Geoffrey G. Messier, Sebastian Magierowski, Jean-Francois Bousquet   +2 more
openaire   +1 more source

Overview of Amplify-and-Forward Relaying

2010
Amplify-and-Forward (AF) is a simple cooperative strategy for ad-hoc networks with critical power constraints. It involves an amplification of the received signal in the analogue domain at the relays without further signal processing. This chapter gives an overview of the basic AF protocols in the literature and discuss recent research contributions in
Ioannis Krikidis, John S. Thompson
openaire   +1 more source