Capacity Region of the Two-Way Multi-antenna Relay Channel with Analog Tx-Rx Beamforming
In this paper we study the multiple-input multiple-output two-way relay channel (MIMO-TWRC) when the nodes use analog beamforming. Following the amplify-and-forward (AF) strategy, the problem consists of finding the transmit and receive beamformers of the nodes and the relay, and the power allocated to each one, that achieve the boundary of the capacity region. We express the optimal node beamformers in terms of the relay beamformers, and show that the capacity region can be efficiently characterized using convex optimization techniques. Numerical examples are provided to illustrate the results of this paper, and to compare the capacity region achieved by analog beamforming against the conventional MIMO schemes that operate at the baseband.
Keywordstwo-way relay channel analog beamforming convex optimization capacity region
Unable to display preview. Download preview PDF.
- 2.Vía, J., Elvira, V., Santamaría, I., Eickhoff, R.: Analog antenna combining for maximum capacity under OFDM transmissions. In: Proceedings of the 2009 IEEE International Conference on Communications, Dresden, Germany, pp. 3129–3133 (2009)Google Scholar
- 4.Vía, J., Elvira, V., Santamaría, I., Eickhoff, R.: Minimum BER beamforming in the RF domain for OFDM transmissions and linear receivers. In: IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP 2009), Taipei, Taiwan (March 2009)Google Scholar
- 5.Santamaría, I., Vía, J., Nazábal, A., Lameiro, C.: Capacity region of the multiantenna gaussian broadcast channel with analog Tx-Rx beamforming. In: 5th International ICST Conference on Communications and Networking in China (CHINACOM), Beijing, China (August 2010)Google Scholar
- 7.Wang, X., Zhang, X.-D.: Optimal beamforming in MIMO two-way relay channels. In: IEEE Global Communications Conference (GLOBECOM 2010), Miami, FL, USA (December 2010)Google Scholar
- 8.Wyrembelski, R.F., Oechtering, T.J., Boche, H.: MIMO bidirectional broadcast channels with common message. In: IEEE Global Communications Conference (GLOBECOM 2010), Miami, FL, USA (December 2010)Google Scholar
- 10.Tse, D., Viswanath, P.: Fundamentals of Wireless Communications. Cambridge University Press (2004)Google Scholar
- 11.Boyd, S., Vandenberghe, L.: Convex Optimization. Cambridge University Press (2004)Google Scholar
- 14.Palomar, D., Eldar, Y.: Convex Optimization in Signal Processing and Communications. Cambridge University Press (2010)Google Scholar