3 research outputs found
Geometry-based stochastic physical channel modeling for cellular environments
Telecommunication has experienced significant changes over the past few years and its
paradigm has moved from wired to wireless communications. The wireless channel
constitutes the basic physical link between the transmitter and the receiver antennas.
Therefore, complete knowledge of the wireless channel and radio propagation
environment is necessary in order to design efficient wireless communication systems.
This PhD thesis is devoted to studying the spatial and temporal statistics of the wireless
channel in cellular environments based on a geometry-based stochastic physical channel
modeling approach. Contributions in this thesis report include the following:
• A new physical channel model called the eccentro-scattering model is proposed
to study the spatial and temporal statistics of the multipath signals in cellular
environments.
• Generic closed-form formulas for the probability density function (pdf) of angle
of arrival (AoA) and time of arrival (ToA) of the multipath signals in each cellular
environment are derived. These formulas can be helpful for the design and
evaluation of modern communication systems.
• A new Gaussian scattering model is proposed, which consists of two Gaussian
functions for the distribution of scatterers around base station (BS) and mobile
station (MS) and confines these scatterers within a scattering disc.
• The effect of mobile motion on the spatial and temporal statistics of the
multipath signals in cellular environments is discussed. Three motion scenarios are
considered for the possible trajectory of the mobile unit. Furthermore, two different
cases are identified when the terrain and clutter of mobile surrounding have
additional effect on the temporal spread of the multipath signals during motion.
• The physical channel model is employed to assess the performance of a RAKE
receiver in cellular environments.
• Comparisons between uniform scattering and Gaussian scattering, which are the
two assumptions for the distribution of scatterers usually used in the derivation of
the pdf of AoA, are also presented.
• An overview of earlier physical channel models and comparisons between these
models and with the proposed model are presented
Mobility Characteristics for Multimedia Service Adaptation
In personal communications systems, it is an emerging necessity to adapt services prior to delivery according to up-to-date customer profiles and mobility behaviors. Therefore, it is important to determine distinct mobility descriptors that would successfully model the entire sample space of different mobility characteristics. The aim of this paper is to define unique descriptors that are to be extracted from mobility patterns of a single mobile user and to investigate the level of distinctness of each defined descriptor. We finally show how the studied descriptors can be used in service adaptation