TITLE:
Incremental Diversity: A Framework for Rate-Adaptation/Energy-Conservation Enhancement in MIMO Systems
AUTHORS:
Tallal Elshabrawy, Sally Nafie
KEYWORDS:
MIMO Diversity-Multiplexing Tradeoff, Hybrid Spatial Multiplexing-Space Time Block Coding, Incremental Redundancy, Energy-Conservative MIMO, Rate-Adaptive MIMO
JOURNAL NAME:
International Journal of Communications, Network and System Sciences,
Vol.7 No.9,
September
10,
2014
ABSTRACT: In recent years, MIMO technology has
emerged as one of the technical breakthroughs in the field of wireless
communications. Two famous MIMO techniques have become investigated thoroughly
throughout the literature; Spatial Multiplexing, and Space Time Block Coding.
On one hand, Spatial Multiplexing offers high data rates. On the other hand, Space
Time Block Coding presents transmission fidelity. This imposes a fundamental
tradeoff between capacity and reliability. Adaptive MIMO Switching schemes have
been proposed to select the MIMO scheme that best fits the channel conditions.
However, the switching schemes presented in the literature directly switch
between the MIMO endpoints. In this paper, an adaptive MIMO system that
incrementally switches from multiplexing towards diversity is proposed. The
proposed scheme is referred to as incremental diversity and can be set to
operate in two different modes; Rate-Adaptive, and Energy-Conservative
Incremental Diversity. Results indicate that the proposed incremental diversity
framework achieves transmission reliability offered by MIMO diversity, while
maintaining a gradual increase in spectral efficiency (in the Rate-Adaptive
mode) or a reduction in required number of received symbols (in the
Energy-Conservative mode) with increase in the SNR.