Fast Qr Decomposition Of Adaptive Equalization

Frequency-selective fading due to multipath propagation is a big obstacle in wireless Communication. In the condition, the Intersymbol Interference (ISI) comes into being and communication system appears error received symbol. The adaptive equalization is just the main method of eliminating ISI, and its theory is to equalize the characteristic of the communication channel or the whole communication system.The main works of the dissertation is to study a kind of adaptive equalization based on fast QR-decomposition. The study result will be applied to the 45M high-speed wireless communication system.In the dissertation, firstly, the traits of wireless communication channel are described, and the imitated model of multipath channel is founded.Secondly, an improved QR_RLS algorithm is introduced. The improved algorithm not only inherits the fast convergence trait from RLS and realizable Systolic Array from QR_RLS, but also eliminates square-root operation and gets directly equalizer output signals from Systolic Array. So this algorithm has more simple operation, faster executing speed, less hardware resource and lower hardware cost.Some different equalization algorithm are imitated on the QPSK communication system with multipath channel. A practicable equalizer is brought forward definitely which has DFE structure and mixed QR_RLS/LMS algorithm.Then, the equalization project applied to the 45M high-speed wireless communication system is put forward. According to the project, the equalizers with different steps are imitated in the condition of different channel parameters.At last, the hardware realization of the improved QR_RLS and LMS arithmetic are particularly described.The study conclusions of the dissertation indicated the mixed QR_RLS/LMS adaptive equalization with DFE structure can eliminate the ISI of communication system and reduce the bit error rate of the system .