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On Full Duplex Wireless Networks: PHY, MAC and Network Layers Perspective

Student thesis: Doctoral ThesisDoctor of Philosophy

In conventional half-duplex (HD) wireless communications systems, bidirectional communications between a pair of nodes is achieved with either
frequency division duplexing (FDD) or time division duplexing (TDD).
The former technique employs different frequency bands for the uplink
(UL) and downlink (DL), whereas, in the latter technique, a single channel is shared in the time domain for both UL and DL. Such techniques
however may not be suitable to fulfil the envisioned requirements of next
generation wireless systems. Historically, simultaneous transmission and
reception in wireless communications was deemed infeasible in practice
due to the so called self-interference (SI), which is the interference generated by the transmitter of a radio on its own receiver. Recent developments in SI cancellation techniques have led to the practical realization
of FD radios. FD technology has a number of attractive features, for
example, it can potentially double (theoretically) the ergodic capacity,
reduce the feedback delay, decrease the end-to-end delay, improve the
network secrecy and increase the efficiency of network protocols.
Motivated by these developments,first in this study, a two-tier heterogeneous cellular networks (HCNs) wherein the first tier comprises half-duplex (HD) macro base stations (BSs) and the second tier consists of FD small cells. Advocating for the use of small cells as a strong candidate to deploy FD technology, for its
low-powered nature and ease of deployment. The study is conducted through a stochastic geometry approach, we characterize and derive the closed-form expressions for the outage probability and the rate coverage.
Furthermore, we move up the layers of the protocol stack and present
an energy-effcient medium access control (MAC) protocol for distributed
full-duplex (FD) wireless network, termed as Energy-FDM. The key aspects of the Energy-FDM include energy-effciency, co-existence of distinct types of FD links, throughput improvement, and backward comparability with conventional half-duplex (HD) nodes.
Finally, we present a cross-layer aided routing protocol, termed as
X-FDR, for multi-hop FD wireless networks. X-FDR exploits a Physical
(PHY) layer model capturing imperfection of SI cancellation. At the
medium access control (MAC) layer, X-FDR adopts an optimized MAC
protocol which implements a power control mechanism without creating
the hidden terminal problem. X-FDR exploits the unique characteristics
of FD technology at the network layer to construct energy-efficient and
low latency routes in the network.
Original languageEnglish
Awarding Institution
Supervisors/Advisors
Award date2017

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