Vehicular communication networks promise to reduce the number and severity of traffic accidents, as well as to provide the capabilities for high data rate information and entertainment systems in vehicular environments. Numerous research activities have been carried out in the past years to develop communication facilities needed for establishing Intelligent Transportation Systems (ITS). This thesis first of all provides an overview of vehicular communications protocol specifications developed by IEEE (Institute of Electrical and Electronics Engineers). Performance and reliability of these specifications were investigated through MATLAB-based simulations.
Past research activities have shown some deficiencies of the underlying communication standard IEEE 802.11p regarding transmission reliability.
Vehicular communications opportunities provide a broad spectrum of safety-related applications. Especially for these issues, a high transmission reliability or robustness is essential. The transmission quality suffers from absence of continuous LOS (Line of Sight) wireless links between transmitter and receiver and time-variant channel conditions. In order to increase the transmission quality, the use of multi-antenna systems is suggested. This thesis provides an analysis of how the transmission reliability and performance can be increased by implementing MIMO (Multiple-Input Multiple-Output) transmission schemes.
The utilization of multiple antennas at the transmitter requires the implementation of Space-Time Codes (STC). The investigated spatial coding schemes are Alamouti's space-time block code and the Golden Code.
In the fourth chapter, this thesis provides an evaluation of the above mentioned MIMO schemes in comparison with the pure IEEE 802.11p SISO (Single-Input Single-Output) communication standard. This comparison is performed with various wireless radio propagation channel models suitable for vehicular communications.