Reliable and power efficient protocols for space communication and wireless ad -hoc networks

The central theme of this thesis is the design and analysis of reliable and power efficient networking protocols under various application scenarios. The work consists of two major parts. The first part focuses on networking issues for reliable data transfer in the context of space communication. The second part investigates power efficient topology control for wireless ad-hoc networks.;In the first part of research, we consider reliable space communication. In many cases, space networking faces extremely long propagation delays, intermittent link connectivity, limited bandwidth, and limited power budgets. Our main contribution is mathematical modelling and analysis of two ARQ schemes of CFDP, the Deferred NAK mode and the Immediate NAK mode, in the single-hop file transfer operation. We propose an ARQ timer-setting rule that minimizes the expected file delivery time under the constraint that the throughput efficiency is maximized. Then, we derive a closed-form expression for the expected file delivery time of the Deferred NAK mode of CFDP as well as upper and lower bounds expression for the expected file delivery time of the Immediate NAK mode of CFDP, respectively.;In the second part of research, we study power-efficient communication in wireless ad-hoc networks to provide end-to-end connectivity. Although power-efficient topology control can reduce the total power consumption of a network as a whole, a power-aware solution that allows power consumption to be evenly distributed among network nodes so as to prolong the network lifetime is highly desirable. Our main contribution is the development of a power-aware topology control algorithm and its associated CSMA/CA based MAC protocol. The proposed power-aware topology control algorithm at a given node only demands the residual energy levels and the location information of its reachable neighboring nodes. Besides, an algorithm to set up the RTS-CTS range in CSMA/CA-based MAC protocol is proposed to alleviate the hidden node problem, to avoid throughput degradation and to resolve the fairness problem. Finally, an analytical model that provides useful information to upper layer protocols to achieve better performance of the network is presented.