Albreem, Mahmoud A. M.
(2013)
Lattice Sphere Detection Techniques
In Block Data Transmission And
Multiuser Wireless Systems.
PhD thesis, Universiti Sains Malaysia.
Abstract
Recent years have witnessed an increase in demand for higher transmission data rates for
wireless multimedia communications applications. Block Data Transmission Systems (BDTS)
and Code Division Multiple Access (CDMA) are considered as efficient techniques for high
data rate transmission and found in the coming generation of mobile and wireless technologies
such as Long Term Evolution (LTE) systems. The Exhaustive Search (ES) detector is the
optimum. Owing to its high computational load, lattice sphere detection (LSD) technique and
its variants had been proposed. For the system designer, the main objective is to achieve an
attractive performance-complexity tradeoff. In this research, LSD based detectors are designed
for BDTS and Multi-User Detection (MUD) system. LSD searches lattice points in a sphere
within a predetermined radius. In LSD, when the initial radius increases, the performance
and complexity increased. This research produces exact expression for the sphere radius used
in LSD technique which depends on the lattice dimension and average received power. It is
well known fact that a small condition number results in a better detection performance. This
research aims to reduce the condition number value to its smallest possible using the regularization
methods (L1-regularization and L2-regularization), and utilizing special matrices (i.e.,
Hankel and Toeplitz). Sequentially, this research proposed a new detection technique which
called as a near-An-LSD technique. Exact relationships between the LSD performance and condition
number, and the relationship between the radius and condition number had been derived.
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