%0 PDF %T Cellular Networks Performance Under User-Assisted Relaying %A Elkotby, Hussain. %D 2018-03-16T09:33:52.457-04:00 %8 2018-03-16 %R http://localhost/files/t148fv35x %X Abstract: User-assisted relaying is a promising technology to help cellular user equipments (UEs) achieve the envisioned seamless experience especially needed near the cell edge. In user-assisted relaying, the base station (BS) serves a UE using an adaptive direct and relaying transmission scheme according to a cooperation strategy. In case of relaying transmission, the active (served) UE selects an idle UE based on the cooperation strategy to act as a relay. In this thesis, we evaluate the performance of user-assisted relaying in single and multiple antenna networks with a focus on cell edge UEs. Using stochastic geometry and Poisson point processes as tools to model locations of network nodes, UEs and BSs, we first propose practical cooperation strategies, which determine how to select the relaying UE and when to perform relaying transmission, and derive their probabilities. These in turn are used in the development of a statistical inter-cell interference power model to facilitate network performance evaluation. For single antenna networks, {\color{blue}the} Gamma distribution provides a good model for the interference power by analytically matching the first two moments. For multiple-input multiple-output (MIMO) cellular networks, a mixture of inverse Gaussian and inverse Weibull distributions models the interference power using a combination of moment matching and maximum likelihood estimation (MLE). Using the proposed cooperation strategies and interference models, we evaluate the performance of user-assisted relaying in single antenna and MIMO networks using as metrics the average transmission rate and outage probabilities. For single antenna networks, results show that user-assisted relaying can significantly improve per-user transmission rate and outage probability despite the increased inter-cell interference. The transmission rate gain is significant for active users near the cell edge and further increases with higher idle users' density, supporting user-assisted relaying as a viable solution to crowded population areas. For MIMO networks, we implemented a simple transmit beamforming scheme and two optimized receive combining schemes depending on interference awareness. Provided sufficient density of potential relay UEs, results illustrate user-assisted relaying most beneficial for improving the reliability for cell edge UEs when these UEs are equipped with multiple antenna elements and their signals propagate in relatively high shadowing environments.; Thesis (Ph.D.)--Tufts University, 2018.; Submitted to the Dept. of Electrical Engineering.; Advisor: Mai Vu.; Committee: Eric Miller, Misha Kilmer, and Alexander Wyglinski.; Keyword: Electrical engineering. %[ 2022-10-11 %9 Text %~ Tufts Digital Library %W Institution