Parameter optimization for amplify-and-forward relaying systems with pilot symbol assisted modulation scheme
Original version
Wu, Y., & Pätzold, M. (2009). Parameter optimization for amplify-and-forward relaying systems with pilot symbol assisted modulation scheme Wireless Sensor Network 1(1), 7-14. doi: 10.4236/wsn.2009.11003Abstract
Cooperative diversity is a promising technology for future wireless networks. In this paper, we consider a
cooperative communication system operating in an amplify-and-forward (AF) mode with a pilot symbol assisted
modulation (PSAM) scheme. It is assumed that a linear minimum mean square estimator (LMMSE) is
used for the channel estimation at the receiver. A simple and easy-to-evaluate asymptotical upper bound
(AUB) of the symbol-error-rate (SER) is derived for uncoded AF cooperative communication systems with
quadrature amplitude modulation (QAM) constellations. Based on the AUB, we propose a criterion for the
parameter optimization in the PSAM scheme. We discuss how the pilot spacing and the length of the Wiener
filter should be chosen under the constraint of a tradeoff between pilot overhead, estimation accuracy, and
receiver complexity. We also formulate an power allocation problem for the considered system. It is shown
that the power allocation problem can optimally be solved by means of a gradient search method. Numerical
simulations are presented to verify the correctness of the theoretical results and to demonstrate the benefits of
the parameter optimization.
Description
Article published in the journal:Wireless Sensor Network
Also available from publisher:
http://dx.doi.org/10.4236/wsn.2009.11003