Improvement on Virtual Subcarrier Assignment (VISA) for Spatial Filtering of OFDM Signals: Multiple Subcarrier Puncturing

We have proposed a novel spatial filtering technique named Virtual Subcarrier Assignment (VISA) for orthogonal frequency division multiplexing (OFDM) signals, which enables the transceiver equipped with an adaptive array antenna (AAA) to selectively receive or reject OFDM signals through coloring them with different virtual subcarrier positions in their frequency spectra. In this paper, we develop the VISA to use multiple virtual subcarrier assignment, which assigns a different combination of multiple virtual subcarrier positions in the frequency spectrum to each OFDM signal. Furthermore, we present two kinds of recursive least square (RLS)-based array weight control methods to support the VISA with multiple subcarrier puncturing in an IEEE802.1 la-based system and evaluate the link-level performance in typical indoor wireless environments by computer simulations.