Modern cellular systems feature increasingly dense base station deployments,
augmented by multiple tiers of access points, in an effort to provide higher network
capacity as user traffic, especially data traffic, increases. The primary limitation of
these dense networks is co-channel interference. The primary source of interference
is inter-cell and cross-tier interference, which is especially limiting for users near the
boundary of the cells. Inter-cell interference coordination (ICIC) is a broad umbrella
term for strategies to improve the performance of the network by having each
cell allocate its resources such that the interference experienced in the network is
minimized, while maximizing spatial reuse. Fractional frequency reuse (FFR) has
been proposed as an ICIC technique in modern wireless networks. The basic idea of
FFR is to partition the cell’s bandwidth so that (i) cell-edge users of adjacent cells
do not interfere with each other and (ii) interference received by (and created by)
cell-interior users is reduced, while (iii) improving spectral reuse compared to conventional
frequency reuse. It is attractive for its intuitive implementation and relatively
low network coordination requirements compared to other ICIC strategies including
interference cancellation, network MIMO, and opportunistic scheduling. There are two common FFR deployment modes: Strict FFR and Soft Frequency Reuse (SFR).
This dissertation identifies and addresses key technical challenges associated with
fractional frequency reuse in modern cellular networks by utilizing an accurate yet
tractable model of both the downlink (base station to mobile) and uplink (mobile to
base station) based on the Poisson point process for modeling base station locations.
The resulting expressions allow for the development of system design guidelines as a
function of FFR parameters and show their impact on important metrics of coverage,
rate, power control, and spectral efficiency. This new complete analytical framework
addresses system design and performance differences in the uplink and downlink.
Also, this model can be applied to cellular networks with multiple tiers of access
points, often called heterogeneous cellular networks. The model allows for analysis
as a function of system design parameters for users under Strict FFR and SFR with
closed and open access between tiers. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/ETD-UT-2012-05-5184 |
| Date | 12 July 2012 |
| Creators | Novlan, Thomas David |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | thesis |
| Format | application/pdf |
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