Higher rate extrapolations based on in-flight testing of an advanced OFDM system

This paper presents an implementation of novel signal processing techniques for an OFDM system designed to restore losses caused by extremely high dynamic mobile conditions and frequency selective fading while maintaining compatibility with the packet format defined by the IEEE 802.11a standard. The prototype is an implementation of innovative techniques such as multi-pass carrier and symbol/sample timing acquisition; joint pilot- and data-aided channel estimation, tracking, and equalization; and diversity combining. The FPGA OFDM system implementation is designed for at least an order of magnitude improvement in link reliability when combating Doppler and multipath fading for high-speed platforms. Flight results are presented and extensions to higher order modulations and cyclic delay diversity schemes are investigated based on available link margin in these corridors.