This Small Business Innovation Research (SBIR) Phase I project carried out by Xtendwave targeted significantly improved performance for broadband access over the nation’s telecommunications infrastructure, in both urban and suburban/rural environments.  For many underserved/rural areas, the improved use of copper-wire infrastructure will provide a broadband access alternative to costly, inefficient satellite coverage.  A key aspect of this Phase 1 project was the optimization of available capacity of existing phone lines, and bundles of copper wires, for DSL internet service, and cell phone “backhaul” service.  The advantage of this optimization approach is that it accelerates the availability of broadband internet service to residences, businesses, schools, and government entities, and avoids the large expenditures (both public and private) associated with installing new fiber optic cables to existing locations. The Phase 1 project comprised both in-depth theoretical analysis, as well as implementation work, and established proof-of-concept of Xtendwave’s innovations in this field. The R&D targeted improved spectrum utilization in the constrained copper-wire channels, with adaptive features enabling improved performance in a range of applications and situations.  Based on preliminary analysis and experimentation, it is anticipated that this project will result in a doubling of area coverage for broadband and backhaul service, based on distance from a telecom central office, or other distribution point.  Prototyping and commercialization of this work will be carried out in Phase 2 of the project.

The Phase 1 R&D, in which the majority of the technical team at Xtendwave was involved, was successful both in achieving the original technical objectives, while gaining considerable learning, as well as in defining the path for commercialization, as defined for the Phase 2 project, which has received funding.  The targeted objectives were achieved, including the refinement and optimization of the simulation models, as well as the investigation and exploration of various techniques to increase the system throughput, for both long-reach DSL, and other data transmission over copper wire infrastructure. Additional challenges and research objectives have been identified and explored, particularly in the context of interference, which will be targeted in the Phase 2 project, and in other work carried out separately by Xtendwave.

The objective of the Phase I R&D was to explore the potential performance improvements offered by novel modulation and encoding methods to be applied in DSL (Digital Subscriber Line) broadband access systems, for the purpose of achieving greater distances and data-rates than are achievable with the use of existing standards. The work was carried out in collaboration with Southern Methodist University (SMU), with the work at SMU under the direction of Prof. Dinesh Rajan. The work was successful in validating the potential for significantly improved performance. The R&D work investigated two particular applications that were identified:  extended-reach access, i.e., distances that are beyond those normally served by today’s widely deployed DSL solutions and short-range high-rate solutions, allowing services where fiber-to-the-node is available (distances of about 3,000 feet with aggregate data rates of about 75Mbps).  Plans for continuation in Phase 2 have been refined to focus commercial efforts on both DSL service and copper backhaul service to cell towers, campuses, and businesses.

The broader impact of this project will be to enable improved broadband internet service to the millions of households, businesses, and instit...

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