Design of Co-phasing Allpass Filters for Full-Duplex OFDM Relays

T. RIIHONEN; S. WERNER; J. E. COUSSEAU; R.WICHMAN

Pacific Grove, CA, USA

Conferencia; Asilomar Conf. on Signals, Systems and Computers; 2008

This paper studies amplify-and-forward relaying ofOFDM signals. In the considered cellular hotspot scenario, adestination node receives superposition of single-hop transmissionfrom a source node and two-hop transmissions via full-duplexrelays. We propose a novel co-phasing scheme that results insignificant coherent combining gain in the destination due tosubcarrier phase rotation in the relays. In full-duplex relays, thephase rotation is achievable by time-domain baseband filtering.Taking into account the properties of this particular application,we propose to use a complex FIR eigenfilter method for designingapproximately allpass filters with desired phase response.