Asymmetric and self-matching modulations for estimation-assisted detection in fading channels.
Published: 2005
Language: eng
Number of pages: 199
Description: In multiplicative fading channels, the commonly used symmetric signal constellations and space-time block codes cause ambiguities since joint channel estimation and data detection (CE/DD) schemes cannot differentiate certain sequences of symbols in single-input single-output (SISO) systems and certain sequences of space-time block codewords in multiple-input multiple-output (MIMO) systems. This phenomenon; known as isometry; leads to irreducible estimation and detection error floors. Since the channel state has to be estimated in most practical communications systems, isometry degrades the performances of such systems. This thesis introduces a unifying framework that effectively eliminates isometry by using asymmetric modulation schemes: one algorithm is proposed to construct asymmetric signal constellations to solve isometry in SISO systems, two algorithms are proposed to construct asymmetric space-time block codes (STBCs) to mitigate isometry. To further improve the estimation and detection performances of CE/DD schemes, a self-matching STBC is proposed in this thesis. The self-matching STBC improves detection performance by adapting its code properties according to the estimation error calculated by the Kalman recursion; by improving estimation performance using embedded training, and by breaking isometry with asymmetry. These asymmetric modulation schemes are shown in this thesis, both analytically and via simulations, to be novel, simple, effective and robust solutions to isometry.
Notes: Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.

Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 3317.