Linear Precoding Design for Cache-aided Full-duplex Networks

Abstract

Edge caching has received much attention as a promising technique to overcome the stringent latency and data hungry challenges in the future generation wireless networks. Meanwhile, full-duplex (FD) transmission can potentially double the spectral efficiency by allowing a node to receive and transmit simultaneously. In this paper, we study a cache-aided FD system via delivery time analysis and optimization. In the considered system, an edge node (EN) operates in FD mode and serves users via wireless channels. Two optimization problems are formulated to minimize the largest delivery time based on the two popular linear beamforming zero-forcing and minimum mean square error designs. Since the formulated problems are non-convex due to the self-interference at the EN, we propose two iterative optimization algorithms based on the inner approximation method. The convergence of the proposed iterative algorithms is analytically guaranteed. Finally, the impacts of caching and the advantages of the FD system over the half-duplex (HD) counterpart are demonstrated via numerical results. Index terms-Edge caching, delivery time, full-duplex, optimization.

Probabilistic Analysis of Operating Modes in Cache-Enabled Full-Duplex D2D Networks

“…• Further, using the closed-form expressions of the probabilities for all operating modes, we aim to derive the Probability Mass Functions (PMFs) of the number of nodes that randomly operate in different modes. Different from [30]- [32], in which the density of transmitters, receivers, and relay nodes are determined by the cache placement probabilities thanks to Thinning Theory, here we obtain PMFs not only for HD transmitters/receivers and FD transceivers, but also PMFs of the outage users that fail to retrieve contents from their nearby nodes. Moreover, different from [33], in which the PMF is obtained only for the transmitters that actively transmit at any given time by considering intuitive deterministic caching policy, here we precisely obtain PMFs for all modes by considering stochastic caching policy and compare the PMFs of both caching policies in terms of system key parameters.…”

“…FD-enabled transmitters in [28], [29] operate as relays to relay contents from the central base station (BS), when the desired content of the receiver of interest is not stored in the nearby transmitter. In the other approach [30]- [32], it is assumed that the portion of transmitters operate in FD mode, while the rest of users and backhaul wireless access point operate in HD mode. Therefore, the existing works focus on a very specific cases out of all possible scenarios that could occur in a cache-enabled D2D networks in which the nodes are endowed with FD capability.…”