  Exploiting cognition to the cache-enabled device-to-device (D2D)
communication underlaying the multi-channel cellular network is the main focus
of this paper. D2D pairs perform direct communications via sensing the
available cellular channels, bypassing the base station (BS). Dynamic service
is considered and the network performance is evaluated with the stochastic
geometry. Node locations are first modeled as mutually independent Poisson
Point Processes, and the service queueing process is formulated. Then the
corresponding tier association and cognitive access protocol are developed. The
delay and the length for the queue at the BS and D2D transmitter are further
elaborated, with modeling the traffic dynamics of request arrivals and
departures as the discrete-time multiserver queue with priorities. Moreover,
impacts of the physical layer and content-centric features on the system
performance are jointly investigated to provide a valuable insight.
