Diversity Techniques in Wireless Communication Systems: A Review

Fading can be considered as the major impairment of wireless communication channels. To overcome this problem, diversity techniques have been proposed. Diversity is a powerful communication technique that can be applied in time, frequency, and spatial domains in order to enhance communication system performance. The doctrine of diversity is based on the idea of deploying multiple antennas to transmit/receive multiple copies from the desired signals over independent paths to avoid simultaneous fading. In this paper a review of diversity techniques is done. An overview of differently proposed diversity techniques is made to highlight the problem statement in each of it and how the solutions are suggested and applied to conclude the best proposed ones to mitigate the problem of fading in wireless communication channels. The use of multiple antennas at both ends of the system and the principles of MIMO systems is also discussed in this article. Finally, the application of MIMO systems into 5G communication systems is reviewed.&nbsp

Plataforma hardware para el desarrollo de sistemas MIMO

In this work we present a low-cost and flexible 2×2 MIMO testbed operating on the ISM band of 2.4 GHz with a total bandwith of 20 MHz. The transmitter and receiver baseband modules are PCs equipped with ADCs, DACs, memories, DSPs and FPGAs modules that allow a data transfer rate up to 200 MB/s per channel. Signals are generated at an IF of 15 MHz, upconverted to RF by two signal generators and downconverted to 15 MHz by means of two circuits specifically designed for this platform