By enabling Broadband access for ~99% of rural American households over existing phone lines, Xtendwave's Adaptive Filter Bank Modulation (AFBM) technology can meet the USDA's SBIR objectives of development of a new technology that addresses important economic and social development issues and problems in rural America (Rural Development, topic 8.6). This Phase I funding proposal, targeted specifically at the long line lengths found in rural America, proposes a) modeling of performance impairments (bridged taps, impedance discontinuities, and other) specific to very long rural loops (over 18k feet), b) development of solutions to combat the impairments, c) initial field trial testing of Xtendwave's alpha-prototype modem boards in an actual rural telco environment on telecom lines, and d) validating (or modifying) solutions to address any issues found, related to specific impairments modeled and tested. In the physical-layer communication system being developed, conventional Fourier Transform (FT) based Discrete-Multi-Tone (DMT) techniques are replaced with the more spectrally efficient Wavelet based Adaptive Filter Bank Modulation (AFBM) technology patented by Xtendwave. Xtendwave's key innovation is in the adaptive nature of its modulation method, optimizing the use of available channel capacity and allowing it to more effectively work around impaired or attenuated portions of the channel's spectrum, particularly on long-reach rural lines. Based on preliminary analysis and experimentation, it is anticipated that this project will result in at least doubling of area coverage, for very long loops or more than doubling of throughput at fixed distances, compared to existing DSL technologies. Providing improved broadband access addresses the USDA's Long Term Goals: Helping to create sustainable rural economies, enhancing economic vitality of rural areas, and promoting job creation and income growth in rural areas. With Xtendwave's technology, the 20 million unserved farms, households, businesses, and public service entities in rural locations can gain affordable broadband access to the internet. For many rural areas, it will offer the only low-cost broadband access alternative to costly, inefficient satellite coverage. By working with service providers and equipment providers, Xtendwave's technology will be very cost-effectively deployed, compared to traditional trenching and fiber. Xtendwave's business model is to be an integrated circuit (IC) supplier to multiple telecom equipment manufacturers. Multiple telecom service providers have conveyed their pressing need for the throughput and range performance enhancements offered by Xtendwave's technology. Xtendwave has four issued patents and additional US and international patents pending. Xtendwave's research collaboration with neighboring Southern Methodist University will serve to steer academic research in this field towards the actual needs and interests expressed by service providers. OBJECTIVES: The goals and objectives of this project relate to the need to provide broadband service to residents in rural America, and in particular, those residents with telephone line lengths in excess of 18,000 feet from a central office, and outside the reach of other broadband access technologies such as fiber, cable, and wireless. The proposed technology is intended to provide DSL broadband access at distances of up to 25,000 feet from a central office, and is targeted specifically at the long line lengths typical of those found in rural America. The project proposes a) modeling of performance impairments (bridged taps, impedance discontinuities, and other) specific to very long rural loops (over 18k feet), b) development of solutions to combat the impairments, c) initial field trial testing of Xtendwave's alpha-prototype modem boards in an actual rural telco environment on telecom lines, and d) validating (or modifying) solutions to address any issues found, related to specific impairments modeled and tested. to Technical objectives for this Phase 1 project are as follows: 1. Characterization of the very long loops (VLLs) and problematic channels of interest through literature surveys and measurements (frequency response, interference characteristics, etc.). 2. Statistical data collection for the prevalence of the various types of channels. 3. Development of modeling capabilities that would allow the performance evaluation of the AFBM based solutions that are to be developed for the VLL and problematic channels. 4. Initial development of AFBM (Adaptive Filter Bank Modulation) solutions to combat the impairments defined in objective 1 above. 5. Formalization of a set of solutions to provide all or most standardized loops with broadband rates (i.e., bitrates in excess of 768 kbps downstream). 6. Validation and proof of concept through field trials under conditions typical of rural applications in collaboration with service providers
