Implementation of Link Quality Evaluation Unit for HF Modems


Abstract:Link quality evaluation unit is very essential in recent digital data receiverespecially in time vary channel such as HF and mobile radio. It provides the adaptivedetector with the required information or parameters optimize its performance from thepower and rate points of views. These information parameters include the signal-tonoiseratio, Doppler spread, channel severity and the estimate of the sampled impulseresponse of the channel.Efficient schemes for the estimation of HF channel were presented. The chosenparameters are the Doppler spread, channel severity and the signal-to-noise ratio whichare the dominant ionosheric propagation parameters.Computer simulation tests have been carried out to evaluate these estimators over HFchannel that has been simulated based on Waterson model. Results of computersimulation tests have shown the ability of these estimators to track the variation of theHF channel accurately and efficiently.