The demand for mobile communication systems with high data rates and improved link quality for a variety of applications has dramatically increased in current years. New concepts and techniques are necessary in order to cover this huge demand, which take advantage of the impairments of the mobile communication channel and optimally exploit the limited resources such as power and bandwidth. Multiple antenna systems are an efficient means for increasing the performance and reliability. In order to utilize the huge potential of multiple antenna techniques, it is necessary to resort to new transmit strategies, known as Space-Time Codes. The performance of such Space-Time Codes is analyzed in this book with and without conventional channel coding strategies.