ECE MS Thesis Defense: Ibrahim Farah

MS Thesis Defense: Multipath Beam Steering for OFDM Systems

Ibrahim Farah

Location: Zoom

Abstract: OFDM systems prove effective in combatting the frequency-selective fading, dispersive response of underwater acoustic channels. Coherent symbol detection requires estimation of this channel response at each receiving element, typically done through tap-based models (Least Squares) or path-based models (Path Identification). This talk presents a spatial processing design which uses a multi-channel receiver to isolate individual multi-path returns, both easing the channel estimation requirements and increasing the SNR for symbol detection. The beam steering algorithms are considered in both a coherent and differential OFDM system context and include narrowband and broadband beamforming to the principal, stable path, as well as narrowband and broadband null-steering. These spatial processing algorithms are then extended to an iterative implementation, which approaches the theoretical performance for a beamformer with full multipath channel knowledge. The performance of these algorithms is compared to their single-channel equivalents using both the LS and PI algorithms for coherent detection.