MURI BAA for “Space Time Processing for Tactical Mobile Ad-Hoc Networks” • Objective: • “ Develop cross-layer, energy-efficient MIMO signal processing • algorithms for mobile, multi-user ad-hoc networks employing • directional antenna arrays and STC for tactical applications ” • Physical Layer: • Medium Access Control (MAC) Layer: • Networking Layer: • Signaling issues • BF vs. STC tradeoff • CSI estimation in interference-limited environment • MIMO CSI in MAC protocols • Transmission-rate adaptability, beamforming, location info • Transmission scheduling in context of STC • Energy efficiency • MAC scheduling, generated traffic, STC/BF to reduce signaling overhead, improve robustness and probability of intercept
Research Status • Obtained capacity results for networks with MIMO nodes (submitted to Infocom 06) • Developed the first analytical models for ad hoc networks that (a) can take into account realistic antenna gain patterns, and considers STC technology. • Network topologies & protocols to integrate CSI parameters into the MAC and higher layers in progress • Beamforming vs STC comparisons in progress • MAC/Routing protocols using spatial re-use that incorporate antenna arrays, STC & MUD in progress • Channel access protocols for collaborative MIMO nodes • Data forwarding policies using wireless relays to reduce power consumption, transmission delay and packet loss rate in progress
Research Status (cont.) • Quantified effects of imperfect CSI on waveform design and routing protocols for mobile multiuser systems • Tradeoffs in spatial and temporal diversity evaluated for coherent and incoherent MIMO modulations for time varying channels • Interference suppression through channel equalization (precoding) at the transmittter • Effects of quantization of the CSI information and the training and pilot signal parameters being evaluated • Channel prediction distance of a 3x3 MIMO system shown to be significantly greater than a SISO system • Experimental channel characterization of time variations • Assessment of time-variation and superdirectivity in MIMO antennas • Canadian contribution to expand current wideband MIMO channel measurement capabilities are planned
Project Summary • Publications in first year • 36 conference papers • 8 journal paper submissions, 1 accepted • Management Plan • Many of the PIs co-authored papers and co-advised PhD dissertations prior to the beginning of the MURI • Frequent interaction through seminars • Educational Outreach • 17 FTE graduate students • Significant interest from industry • Deliverables-papers, protocols, code, algorithms, training • Workshops/ Short Courses?