טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAran Bergman
SubjectEnergy Efficiency of Collision Resolution Protocols
DepartmentDepartment of Electrical Engineering
Supervisor Full Professor Sidi Moshe


Abstract

In today's wireless networks, when battery-operated devices are becoming ubiquitous, one of the key performance metrics is the energy consumption induced by the medium access control (MAC) algorithm employed. We concentrate on random access MAC algorithms called collision resolution protocols (CRPs) as they display the best stable properties and have better delay characteristics than scheduled MAC algorithms for a large population of “bursty” users. Many CRPs have been suggested and analyzed in the literature, but the main concern of the papers that deal with CRPs has so far been the stability conditions, the throughput-delay tradeoffs and how the algorithms can be optimized for these properties. The contribution of our work is a novel method of evaluating and optimizing the performance of CRPs. We suggest a utility function that reflects the tradeoff between the energy consumption induced by a CRP and its throughput, thus representing the energy efficiency of the algorithm. We exemplify the use of this utility function by analyzing and optimizing five known CRPs - three full sensing algorithms and two limited sensing algorithm. This analysis leads, in turn, to a suggested modification of the “0.487” algorithm, that improves its energy efficiency. For the limited sensing algorithms we suggest how the appropriate algorithm should be chosen and how its parameters should be optimized in order to achieve the best performance as measured by our suggested metric. We also found that for most scenarios, only the R = 1 and R = 2 instances of the last-come-first-served algorithm should be considered when optimizing its energy efficiency as measured by our utility function.