Research On Single Carrier Time Domain Equalization Applied For Uplink Of Aero-video Communication System

As an important part in information system, aero-wireless communicationhas become a heated research topic in recent years. Aero-wirelesscommunication systems are dynamic and fast multi-path fading. Equalizer isused to cope with the channel fading, so it’s determinant for the performanceof aero-wireless communication system.In this dissertation, at first I introduce the wireless channel andaero-wireless communication channel and their impact on signal transmission.The four channel models of aero-wireless communication system forsimulation is also introduced.Then different types of single carrier adaptive equalization and arithmeticrules widely used on adaptive equalization are introduced.The receive system of uplink of aero-vedio communication system is onthe plane, so it’s limited on volume and power. The blind equalizer workedonly with differential coding can compensate the amplitude change and phase shift in transmission, so it doesn’t need synchronization module, whichmeans it will synplify communication system and lower the power. The blindequalizer doesn’t need training sequence, which help to improve theutilization of the channel. Although differential coding will cause pofermanceloss of SNR, we can improve the transmission power to compensate it inuplink. Since blind equalizer is suitable for uplink of aero-vediocommunication system, this dissertation introduced the working principle,characters and mathematical model of blind equalizer.This dissertation alsosimulinks and analysis some kinds of common equalization arithmetics.Since the MMMA arithmetic has two adjust process: it first drag thesignals to the unit circle, then adjust the phase of signals, so it has a slowconvergence speed.Aimed at the defect,this dissertation propose a blendedMMMA and DD-LMS arithmetic based on block. Simulations show that thenew arithmetic’s convergence speed is50%faster than the MMMAarithmetic, which improves the perfermance of the equalization underaero-vedio channels. Since the MMMA arithmetic worked with π/4-DQPSKhas a weak performance on the Doppler Frequency Shift in the channels, thisdissertation introduces the Multi-Lag High-order Instantaneous Moment,which can counterwork the Doppler Frequency Shift in the channels whenworked with blind equalizations. Formula derivation and computersimulation show that used with the blended MMMA and DD-LMS blind equalizer arithmetic, the Multi-Lag High-order Instantaneous Moment cancounterwork the phase offset and Doppler Frequency Shift in the signaltransmission, which shows the applicability of blind equalizer in uplink ofaero-vedio communication system.This dissertation introduces the Multi-Lag High-order InstantaneousMoment, which can counterwork the Doppler Frequency Shift in thechannels. Formula derivation and computer simulation show that used withblended MMMA and DD-LMS arithmetic based on block, the Multi-LagHigh-order Instantaneous Moment can counterwork the phase offset andDoppler Frequency Shift under the rough ground channel when the SNR ishigh, which shows the applicability of blind equalizer in uplink of aero-vediocommunication system.