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UBC Theses and Dissertations

In-band full-duplex power line communications Prasad, Gautham


Power line communication (PLC) exploits the existing power-grid infrastructure for signal transmission at various avenues from large-scale transmission and distribution networks to smaller-scale in-home and in-vehicle electrical wiring frameworks. PLC provides gigabit-range throughput, which also makes it a viable solution for multimedia communication in indoor local area networks. However, the low-pass nature of power line channels and the strict electromagnetic compatibility regulations governing PLC hinder adequate data rate gains that can be further achieved by traditional means of increasing transmit power and/or bandwidth. One solution to improve data rate under such restrictions is to use in-band full-duplexing (IBFD), which doubles the spectral efficiency for a given channel quality by enabling simultaneous bidirectional data communication in the same frequency band. With the backdrop of existing IBFD implementation in various communication systems from analog telephones to more recent proposals for wireless communications, we investigate the requirements for an IBFD PLC system and propose solutions that counter the unique challenges encountered in the harsh power line environment. Simulation results show that our low-cost and low-complexity design achieves over 80% increase in median bidirectional data rates under typical in-home power line networking conditions without any additional power or bandwidth requirement. Aside from improving spectral efficiency, IBFD allows us to solve several electromagnetic compatibility issues observed at PLC deployments. By using IBFD, PLC transceivers can simultaneously transmit data packets while also sensing the operating spectrum. We use this spectrum aware transmission ability of IBFD-enabled PLC modems to propose cognitive coexistence techniques to eliminate or reduce the impact of the electromagnetic interference caused by unintentional PLC radiation on broadcast radio services, digital subscriber line communications, and neighboring PLC systems in a heterogeneous PLC environment. Along with obtaining physical layer advancements, we further apply IBFD to achieve medium access control (MAC) layer enhancements to improve its efficiency, which is known to deteriorate under heavily loaded network conditions. We propose an IBFD priority resolution procedure and a combined frequency domain contention resolution and preamble collision detection technique that improve the MAC efficiency by reducing the time spent in resolving priorities and contentions by up to 85%.

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Attribution-NonCommercial-NoDerivatives 4.0 International