2.1 Introduction to Wireless Channel Modeling
A reliable wireless system design and system performance evaluation requires a realistic channel model, which closely resembles real propagation environments. Accurate propagation channel modeling is the first major step to be carried out before any system design, as evident as part of the many new technologies and wireless standards development such as IEEE 802.1 1n , IEEE 802.15.3c , IEEE 802. 11ad  and ITU-R IMT Advanced .
A good radio channel model can provide detailed insight into the complex radio wave propagation mechanisms as well as allowing study of the achievable performance from both theoretical and simulation standpoints. When implemented as channel simulators, the performance of different transmission technologies and signal processing algorithms can be compared without the need to perform expensive field trials or tests for every scenario under investigation. Unfortunately, the mechanisms that govern radio propagation in a wireless communication channel are very complex and diverse, which makes channel modeling interesting as a research subject. While it is important to keep the channel models as accurate as possible in order to sufficiently capture the key channel effects, the models developed must also be simple enough to be implemented. This is particularly important in system simulation that involves multiple-antenna systems such as ...