This paper assesses the feasibility of a novel dynamic spectrum sharing approach for a cellular downlink based on cognitive overlay to allow non-orthogonal cellular transmissions from a primary and a secondary radio access technology concurrently on the same radio resources. The 2-user Gaussian cognitive interference channel is used to model a downlink scenario in which the primary and secondary base stations are co-located. A system architecture is defined that addresses practical challenges associated with cognitive overlay, in particular the noncausal knowledge of the primary user message at the cognitive transmitter. A cognitive overlay scheme is applied that combines superposition coding with dirty paper coding, and a primary user protection criterion is derived that is specific to a scenario in which the primary system is 4G while the secondary system is 5G. Simulation is used to evaluate the achievable signal-to-interference-plus-noise ratio (SINR) at the 4G and 5G receivers, as well as the cognitive power allocation parameter as a function of distance. Results suggest that the cognitive overlay scheme is feasible when the distance to the 5G receiver is relatively small, even when a large majority of the secondary user transmit power is allocated to protecting the primary user transmission. Achievable linkmore »
Modeling Aggregate Interference with Heterogeneous Secondary Users and Passive Primary Users for Dynamic Admission and Power Control in TV Spectrum
Interference management in current TV white space and Citizens Broadband Radio Service networks is mainly based on geographical separation of primary and secondary users. This approach overprotects primary users at the cost of available spectrum for secondary users. Potential solutions include acquiring more primary user information, such as a measurement-enhanced geographical database, and cooperative primary user, such as the TV set feedback in the next generation TV systems. However, one challenge of these solutions is to effectively manage the aggregate interference at TV receivers from interweaving secondary users. In this paper, a stochastic geometry-based aggregate interference model is developed for unlicensed spectrum shared by heterogeneous secondary users that have various transmit powers and multi-antenna capabilities. Moreover, an efficient computation approach is presented to capture network dynamics in real-time via a down-sampling that preserves high-quantile precision of the model. The stochastic geometry-based model is verified experimentally in ISM band. It is shown that the model enables separate control of admission and transmit power of multiple co-located secondary networks to protect primary users and maximize spectrum utilization.
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- International Balkan Conference on Communications and Networking
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- National Science Foundation
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