Adaptive equalizer for multiray model in high-speed digital land mobile radio communications

An effective method of signal processing related to adaptive equalization and frame synchronization is proposed, which provides good characteristics for frequency-selective fading due to multipath propagation represented by the multiray model in high-speed digital land mobile communications. This can be realized by adding two types of signal processing to the decision feedback adaptive equalizer based on dual-mode equalization combined with frame synchronization that establishes frame timing from the arriving wave with the strongest correlation with the equalization training sequence. The principle of the proposed signal processing is based on the formation of a data sequence synchronized hypothetically with the preceding and final delayed waves by means of the time shift and on the selection of the best adaptive equalization result. The bit error rate characteristics obtained by the proposed signal processing method are presented under the condition that 16 QAM is used as the modulation scheme and frequency-selective fading is characterized by the 3- through 6-ray models delayed at a symbol period interval with D/U = 0 dB, and they are quantitatively evaluated in terms of the frame timing, Eb/N0, and the amount of shift.