Improved Root-Mean-Square-Gain-Combining for SIMO Channels

The major problem that wireless communication systems undergo is multipath fading caused by scattering of the transmitted signal. However, we can treat multipath propagation as multiple channels between the transmitter and receiver to improve the signal-to-scattering-noise ratio. While using Single Input Multiple Output (SIMO) systems, the diversity receivers extract multiple signal branches or copies of the same signal received from different channels and apply gain combining schemes such as Root Mean Square Gain Combining (RMSGC). RMSGC asymptotically yields an identical performance to that of the theoretically optimal Maximum Ratio Combining (MRC) for values of mean Signal-to- Noise-Ratio (SNR) above a certain threshold value without the need for SNR estimation. This paper introduces an improvement of RMSGC using two different issues. We found that post-detection and de-noising the received signals improve the performance of RMSGC and lower the threshold SNR.

Authors:

• Rania Minkara
• Jean-Pierre Dubois

Keywords:

• Bit error rate
• de-noising
• pre-detection
• root-meansquare gain combining
• single-input multiple-output channels.

References:

[1] N. Blaunstein, J. Andersen, Multipath phenomena in cellular networks,
Artech House, MA, 2003.
[2] T. Rappaport, Wireless communications: principles and practice,
Prentice Hall Inc., NJ, 2nd edition, 2002.
[3] O. Abdul-Latif and J. Dubois, "LS-SVM detector for RMSGC diversity
in SIMO channels," IEEE International Conference on Information
Sciences, Signal Processing and its Applications, Dubai, Feb. 2007.
[4] R. Ayoubi, J. Dubois and O. Abdul-latif, "FPGA implementation of a
novel receiver diversity combining technique," IEEE International
Conference on Signal Processing and Communications, Dubai, Nov.
2007.
[5] J. Anderson, "Antenna arrays in mobile communications," IEEE Ant. &
Prop., vol. 42, 2000, pp.12-16.
[6] M. Simon, M. Alouini, Digital communication over fading channels,
Wiley Interscience, 2000.
[7] J. P. Dubois, "Recent Advances in Wireless MIMO Sytems with
Improved Receiver Diversity Combiners," in Annual Review of
Communications: Volume 60, A. Sulluchuco, Editor, International
Engineering Consortium (IEC), Chicago, USA, ISBN: 978-1-931695-
59-6, pp. 513 - 527, 2007.
[8] J. Dubois and O. Abdul-Latif, "Novel Diversity Combining in OFDMBased
MIMO Systems," American Conference on Applied Mathematics,
Harvard, Cambridge, MA, USA, 2008.