Design, analysis and implementation of a versatile software defined radio platform

Today public safety community seeks technology to offer agility, adaptability, and interoperability to efficiently carry out co-operative communication. A Software Defined Radio can address these issues by optimally changing the operational parameters of the radio (frequency bands, throughput, etc.) to best match the communication scenario requirements. Also multi-antenna techniques can make spectrally efficient, broadband and adaptive communications possible. This thesis presents an FPGA-based real time SDR platform, designed to achieve the stringent requirement of public safety communication networks. Furthermore a flexible, multi-user, multi-antenna based OFDMA system is implemented using this platform and real time wireless video streaming application has been demonstrated as a proof of concept.;To make the SDR platform reconfigurable and flexible, a software-hardware coimplementation approach is adopted where hardware modules can be run time configured by software drivers. Such feature can be used to maintain quality of service by constantly monitoring channel conditions and changing the operating parameters of the OFDMA PHY to compensate for any channel degradation. A central part of the system architecture is a PowerPC processor. Software code consisting of CSMA MAC runs on this processor while time critical digital signal processing algorithms are executed by RTL hardware. Furthermore a non real time prototyping system is developed to facilitate evaluation of algorithms before actual hardware implementation. It provides means of transporting raw samples over the air and access to these sample values from MATLAB to execute algorithms in non real time.;The Wireless Open-Access Research Platform (WARP) developed at Rice University is utilized to develop the proposed SDR system. It is a highly versatile and extensible platform consisting of Virtex2pro FPGA for baseband processing and four daughter-card slots. These slots could be utilized to house radio boards and/or other peripherals. Present OFDMA RTL system requires more resources than available on Virtex2 FPGA offered by WARP. To provide this additional fabric, Virtex5 based baseband processing daughter-card is designed.;Finally, integration of Multifunctional Reconfigurable Antennas (MRAs) with the proposed current SDR system has been proposed to offer high directivity with beam tilting capabilities. These reconfigurable antennas are made up of metal strips interconnected by MEMS actuators, and these actuators work as switches that close/open upon application of high voltage. Depending on the combination of these open/close actuators, the antenna exhibits different radiation patterns. An interfacing card is designed to provide a link between actuators and FPGA. It translates output logic level of FPGA pins into high potential difference that causes MEMS actuator to flip state from open/close. Different radiation patterns can be generated by means of changing digital bits coming from the FPGA RTL core.