Analysis and Design of Pilot-aided Multicarrier Systems over Doubly Selective Channels with a Local Subcarrier Processing Constraint

In the near future, the need for portable multi-antenna wireless devices supporting high data-rates in a harsh mobile environment is anticipated. Typically, in this scenario, the underlying wireless channels are timeand frequency selective, hence doubly selective (DS). Multicarrier modulation (MCM) schemes, wherein data is split into sub-streams and transmitted on a set of subcarriers in parallel, is frequently used on wireless communication systems. DS channels generate both inter-symbol interference (ISI) as well as inter-carrier interference (ICI) for MCM transmissions, thereby making the design of MCM receivers a challenging task. The challenge is compounded by strict computational power constraints as a result of the demand for light, portable, low-power devices, and by the lack of channel state information (CSI) in practical wireless receivers. Local subcarrier processing (LSP) using CSI acquired via pilot-aided channel estimation is arguably the most popular MCM receiver design technique. The LSP constraint allows the use of only a small subset of local observations and dominant ICI coefficients to retrieve information transmitted on each subcarrier. The characterization of performance limits imposed by the LSP constraint on generic MCM schemes serves as the primary motivation for this dissertation. We characterize a lower-bound on the ergodic LSP-constrained achievable-rate of channel-estimation based generic multi-antenna MCM receivers operating over DS