Cellular Networks Performance Under User-Assisted Relaying
Elkotby, Hussain.
2018
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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 ... read moreselects 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.read less - ID:
- t148fv35x
- Component ID:
- tufts:24312
- To Cite:
- TARC Citation Guide EndNote
