This thesis deals with dual-polarized multiple input multiple output (MIMO) channels,
an important issue for the practical deployment of multiple antenna systems. The MIMO
architecture has the potential to dramatically improve the performance of wireless systems.
Much of the focus of research has been on uni-polarized spatial MIMO configurations,
the performance of which, is a strong function of the inter-element spacing. Thus the
current trend of miniaturization, seems to be at odds with the implementation of spatial
configurations in portable handheld devices. In this regard, dual-polarized antennas present
an attractive alternative for realizing higher order MIMO architectures in compact devices.
Unlike spatial channels, in the presence of polarization diversity, the subchannels of
the MIMO channel matrix are not identically distributed. They differ in terms of average
received power, envelope distributions, and correlation properties. In this thesis, we report
on an indoor channel measurement campaign conducted at 2.4 GHz, to measure the copolarized
and cross-polarized subchannels, under line-of-sight (LOS) and non-line-of-sight
(NLOS) channel conditions. The measured data is then analyzed, to draw a fair comparison
between spatial and dual-polarized MIMO systems, in terms of channel characteristics and
achievable capacity.
The main drawback of the MIMO architecture is that the gain in capacity comes at a
cost of increased hardware complexity. Antenna selection is a technique using which we can
alleviate this cost. We emphasize that this strategy is all the more relevant for compact
devices, which are often constrained by complexity, power and cost. Using theoretical analysis and measurement results, this thesis investigates the performance of antenna selection
in dual-polarized MIMO channels. Our results indicate that, antenna selection when combined
with dual-polarized antennas, is an effective, low-complexity solution to the problem
of realizing higher order MIMO architectures in compact devices.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/14651 |
| Date | 12 April 2006 |
| Creators | Anreddy, Vikram R. |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Thesis |
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