AbstractThis thesis presents the development of an efficient and adaptable simulation model for characterization and estimation of MIMO-HF channel subjected to impairments, such as multipath fading, system non-linearity and non-Gaussian noise. Under channel characterization and modelling, this thesis proposes the extension of conventional Watterson model for SISO to MIMO-HF channel incorporating the associated spatial correlation and the non-linearity of the system. The novelty of the developed model lies in the capability of its impulse response to emulate nearly the practical HF channel by incorporating the cited adverse channel impairments. This thesis proposes the modelling of MIMO-HF channel through the computationally efficient IIR /AR filter approach instead of conventional FIR filter. The generic and the versatile features of IIR filterbased approach for modelling the HF channel impairments have been demonstrated by its application to both SISO and MIMO-HF systems.
Within the purview of channel estimation for improved reliability and enhanced data rate of the MIMO-HF communication link, this thesis proposes a novel PF based channel estimation technique for HF communication links subjected to multipath fading and system non-linearity. The PF based channel estimation algorithm proposed in thesis for MIMO-HF is shown to closely approximate the impulse response of the channel induced by the channel impairments. The improved channel estimation facilitates the effective utilization of system resources to ensure enhanced capacity and reliability of HF links. Although one can conceive an idea of invoking the PF concept devoid of EKF, this thesis attempts to adopt a unified approach wherein PF and EKF schemes are combined to realize better posterior density functions, thereby improving the accuracy in channel estimation. The advantageous and desirable features derived by invoking the proposed PF formulation over the conventional RLS have also been addressed. This thesis also addresses the effects of spatial correlation, system non-linearity and the non-Gaussian noise on the proposed PF based channel estimation algorithm. The expected improvement in the receiver performance in lieu of improved channel estimation algorithms, as well as replacement of conventional SISO with MIMO, is validated through the performance parameters such as capacity and reliability.
|Date of Award||2013|
|Supervisor||Govind Kadambi (Supervisor) & James Brusey (Supervisor)|