Research On Single-Carrier Cooperative Diversity Technology

A fundamental challenge in transmitting high speed data over radio channels is ISI (Inter Symbol Interference) caused by multi-path propagation. In order to overcome ISI and decrease Bit Error Rate(BER), equalization technology is widely used in high speed wireless communication system. Single Carrier/Frequency Domain Equalization(SC/FDE) allows an advantageous of high-speed data transmission in frequency-selective fading channel. It avoids the complexity of Single Carrier/Time Domain Euqalization(SC/TDE), and the high RAPR of OFDM as Well. It becomes one of the most important components of thewideband wrieless access technique. In recent years, there is more and more discussion about SC/FDE, including been brought into the IEEE802.16a Protocol.On the other hand, the current study of diversity technique is focused on space diversity technique. SC/FDE combine with MIMO has been proposed as one of effective anti-multipath techniques in the physical layer of IEEE802.16a standards, in order to absorbs their own relative merits, and achieves diversity gain with a low algorithmic complexity. However, installing two or more aerials in the mobile terminal is very difficult, which leads to MIMO technology is unachievable in the Ad-hoc networks and the cellular networks. The advent of cooperative diversity sets up a new approach for the realization of MIMO technology. Cooperative diversity is a very promising space diversity technique.This thesis focuses on the implementation Scheme of SC/FDE technology combine with cooperative diversity technology. Firstly, the fundamental principles, frequency domain equalizer and channel estimation methods of SC/FDE system is explained. Secondly, the general outline of Cooperation model and Cooperation protocols is discussed, especially the scheme of space-time cooperation system, which brought space time coding to the cooperative diversity technology is emphasized. Lately, a simulative results of the error bit rate performance is given. Since the design of space-time cooperation system is basic on flat rayleigh fading channel, to make this system is still applicable to Frequency-Selective Fading Channels, this thesis came up with the scheme which adopted SC/FDE technology as the transmmission scheme of this system. This article demonstrated the the construction of transmission time slot and the treatment scheme along with channel estimation scheme in receiving terminal accordingly, called single carrier space-time cooperation system. On the basis of that, a new improved scheme in which the Cooperation protocols evolution and introducing diversity reception into single carrier space-time cooperation system is proposed. Simulation results show that the improved scheme is feasible and effective.