Title
The MIMO wireless switch: relaying can increase the multiplexing gain
Abstract
This paper considers an interference network composed of K half-duplex single-antenna pairs of users who wish to establish bi-directional communication with the aid of a multi-input-multi-output (MIMO) half-duplex relay node. This channel is referred to as the "MIMO Wireless Switch" since, for the sake of simplicity, our model assumes no direct link between the two end nodes of each pair implying that all communication must go through the relay node (i.e., the MIMO switch). Assuming a delay-limited scenario, the fundamental limits in the high signal-to-noise ratio (SNR) regime is analyzed using the diversity-multiplexing tradeoff (DMT) framework. Our results sheds light on the structure of optimal transmission schemes and the gain offered by the relay node in two distinct cases, namely reciprocal and non-reciprocal channels (between the relay and end-users). In particular, the existence of a relay node, equipped with a sufficient number of antennas, is shown to increase the multiplexing gain; as compared with the traditional fully connected K-pair interference channel. To the best of our knowledge, this is the first known exam pIe where adding a relay node results in enlarging the pre-log factor of the sum rate. Moreover, for the case of reciprocal channels, it is shown that, when the relay has a number of antennas at least equal to the sum of antennas of all the users, static time allocation of decode and forward (DF) type schemes is optimal. On the other hand, in the non-reciprocal scenario, we establish the optimality of dynamic decode and forward in certain relevant scenarios.
Year
DOI
Venue
2009
10.1109/ISIT.2009.5205876
international symposium on information theory
Keywords
Field
DocType
signal to noise ratio,information theory,time allocation
Relay channel,Wireless,Computer science,Signal-to-noise ratio,MIMO,Computer network,Communication channel,Interference (wave propagation),Multiplexing,Relay
Journal
Volume
Citations 
PageRank 
abs/0901.2588
19
1.02
References 
Authors
10
4
Name
Order
Citations
PageRank
Hassan Ghozlan1212.77
Yahya Mohasseb2639.48
Hesham El Gamal324029.84
Gerhard Kramer444534.21