NSF Award
9961230
This Small Business Technology Transfer Phase I project from Efficient Channel Coding (ECC) will investigate a combination of techniques to enable the transmission of CD-quality digital audio using subcarriers in the commercial FM band. Unlike other proposed services, this approach promises to allow the present analog FM channels to co-exist with new digital services with minimal interference and without requiring vacant FM channels. Specifically, in Phase I, Efficient Channel Coding will determine the feasibility of the reliable transmission of Motion Pictures Experts Group Advanced Audio Coding (MPEG-AAC) digital audio data at the maximum rate of 96 kbps through the existing subcarrier allocation 54-98 kHz above and below the host analog FM-channel. This effort will lead to a prototype implementation and on-air characterization under Phase II. The techniques to be employed included a powerful error correction technique called Turbo Product Codes (TPCs), Orthogonal Frequency Division Multiplexing (OFDM), and a variety of interference rejection techniques. Within the feasibility study, only algorithms that have a clear path to implementation will be considered. Turbo Product Codes-Application Specific Integrated Circuit (TPC-ASIC) and software devices already developed by ECC will greatly accelerate the practical implementation of the system.<br/><br/>The ability to successfully deploy CD-quality digital audio in the U.S. is of obvious merit. The ability to achieve this result without a new frequency band and without impacting the current FM infrastructure is the key to making this happen. The difficulties being encountered with the current IBOC/IBAC systems provide the opportunity for new technology to make an impact. The result of technology and work performed in this project will be a design specification that can be taken forward to the broadcast community (primarily the National Association of Broadcasters) for comment and review.
