Variable bit rate video transmission for code-division multiple-access systems in wideband fading channels

Cyril-Daniel Iskander
Efficient real-time transmission of video data over bandwidth-constrained wireless channels is challenging in several ways: in particular, due to the underlying compression algorithms, the source rate can vary in bursts, which complicates the resource allocation problem, isolated channel errors can totally corrupt a video frame if sensitive information is affected, and errors in earlier frames can cause damage to later frames due to error propagation. This thesis will dear in particular with
more » ... effect of source rate variability on current and future cellular systems which employ code-division as the multiple-access strategy, such as IS-95B and IS-2000 systems. The problem will be approached from a physical-layer perspective: hence issues relating to the channel- and cellular-level performances will be addressed in detail, and then integrated into the system-level performance. This nonconventional cross-layer approach allows us to obtain additional insights over studies which tackle the issue mainly or exclusively at the higher system layers. In the first part of this thesis, several contributions are made to the theory of wideband fading channels, which will be considered as the physical channel model throughout the thesis. We derive the analytical level-crossing rates, average fade durations, envelope autocorrelations and baseband spectra of several channel models for some common diversity techniques. Based on some of the previously derived properties we design a fast wideband Nakagami channel simulator. We then derive the exact analytical error probabilities of several linear modulation schemes with diversity in correlated Nakagami channels, and validate them through simulation. In a second part, we derive accurate analytical or semi-analytical error probability expressions for the multicode and multirate configurations used in the physical layers of both the uplink and downlink of IS-95B and IS-2000 systems, in the presence of wideband fading. It is demonstrated that the effect of the multicode interference m [...]
doi:10.14288/1.0065376 fatcat:hnjfkvfhufgcrlnk5hlapluwja