Demonstration and evaluation of co-channel DBPSK source separation

Abstract

This thesis presents a Differential Binary Phase Shift Key (DBPSK) source separation system implemented with the GNU Software Defined Radio (SDR) platform and interfaced with the existing MIT community Radio Frequency Identification (RFID) system. Source separation, well studied in the theoretical signal processing setting, presents an opportunity to achieve higher throughput in a practical SDR deployment. While much research has centered around the design of complex multi-input-multi-output (MIMO) and code division multiple access (CDMA) systems, single antenna source separation presents a simple alternative that is suitable in settings such as RFID where sources are naturally synchronized. Motivated by the analysis of physical channel properties with GNU SDR, this thesis documents the complete design process from the physical layer to the application layer and presents a realization of a co-channel DBPSK source separating technique. The result is an intelligent RFID source-separating reader that is capable of decoding multiple "dumb" cards.