Impact of Cooperative Relays on Low-Rank MIMO Channels
Multiple-input multiple-output (MIMO) communication systems are able to substantially increase the data rate (bit/sec) or to improve the transmission quality (bit error rate) in a wireless link . However, a necessary condition to achieve potentially higher data rates is a channel matrix with high rank which is provided by rich-scattering radio channels. In line-of-sight propagation environments (for example in a future wireless LAN which operates at 17GHz) the scattering will be low and the resulting channel matrix rank deficient. In a recent work  we have shown that wireless relay networks  can help to solve this problem: Instead of transmitting the data packets directly to the destination, the packets are sent first to some amplify-and-forward relays (could be idle mobiles) which then forward the packets to the destination. Relaying the packets introduces an artificial scattering environment which leads to a high-rank channel matrix.
In this project you will study different channel models (log-normal shadowing, ray-tracing, spatial scatterer models) and investigate their impact on the outage and average channel capacity of the relay assisted MIMO link. A further goal is to find appropriate gain allocation schemes for the amplify-and-forward relays.
 D. Gesbert and J. Akhtar, "Breaking the barriers of Shannon's capacity: An overview of MIMO wireless systems", Telektronikk Telenor Journal, Jan. 2002.  A. Wittneben and B. Rankov, "Impact of Cooperative Relays on the Capacity of Rank-Deficient MIMO Channels", IST Mobile & Wireless Communications Summit 2003  M. Gastpar and M. Vetterli, "On the Capacity of Wireless Networks: The Relay Case", IEEE Infocom 2002.
|Subject area||Capacity of wireless relay networks, MIMO communication systems|
|Type of work||50% Theory, 50% Software (Matlab)|
|Student||Phillip Schaller, Konstantin Zurbriggen|
|Supervisor||Dr. Boris Rankov, Dr. Ingmar Hammerström|
|Professor||Prof. Dr. Armin Wittneben|