Equalizer for a mobile communication device and process to compensate for modification of channel conditions caused by movement of a mobile communication device

摘要

"EQUALIZER FOR A MOBILE COMMUNICATION DEVICE AND PROCESS TO OFFSET CHANGE OF CHANNEL CONDITIONS CAUSED BY MOVEMENT OF A MOBILE COMMUNICATION DEVICE". An equalizer (74) is provided for use in a mobile radio communication system to compensate for changing channel conditions caused by movement of a device at varying speeds. The equalizer includes an estimator (84) that receives a digital signal (72) transmitted through a communication channel, the digital signal being adversely modified by the fading during transmission caused by the movement of the mobile communication device at variable speeds, and a signal of channel estimation (94), the estimator responsively producing a decision signal (96) that represents an approximation of the transmitted digital signal with eliminated fading. First and second channel trackers (86, 88) are provided, each tuned to a different speed from the mobile communication device and each receiving the decision signal. The decision circuit receives the decision signal and responsively selects one of the first and second channel trackers to produce the channel estimate signal.