| dc.description.abstract | In this work, we consider a multi-user peer-to-peer relay network with multiple multiantenna
relays which employ amplify-and-forward relaying protocol. Assuming distributed
relay beamforming strategy, we investigate the design of each relay processing
matrix to minimize the per-antenna relay power usage for given users’ Signal-to-Noise
Ratio (SNR) targets. As the problem is NP-hard, we develop an approximate solution
through the Lagrange dual domain. Through a sequence of transformations, we
obtain a semi-closed form solution which can be determined by solving an efficient
semi-definite programming problem. We also consider the semi-definite relaxation
(SDR) approach. Compared with this SDR approach, the proposed solution has significantly
lower computational complexity. The benefit of such a solution is apparent
when the optimal solution can be obtained by both approaches. When the solution is
suboptimal, simulations show that the SDR approach has better performance. Thus,
we propose a combined method of the two approaches to trade-off performance and
complexity. Simulations showed the effectiveness of such a combined method. In the
next step, we change the previous objective and constraints to turn the optimization
problem into a total power minimization problem for the relay network. We
use an approximation by solving this problem in the Lagrange dual domain, and we
finally obtain a semi-closed form solution through the dual approach. The use of the
SDR approach to solve this problem is also discussed. After analysis, we find the
two methods have an advantage over different aspects, thus we propose a combined
method for this problem. We eventually compare the two combined methods to see
the performance difference in the per-antenna power case and the total relay power
case, and discuss reasons for this difference. | en |
