Dual‐mode equalization for digital mobile radio

Abstract The performance of digital mobile radio systems when transmitting at over several tens of kbit/s severely degrades with the onset of fast fading multipath propagation. This paper proposes a dual‐mode equalization (DME) method to overcome the degradation and experimentally verifies the effectiveness of the method. The new method uses decision feedback equalizers (DFEs) in two modes simultaneously, a normal mode, and a time‐reversal mode, and selects the best equalization result. The time‐reversal equalization mode improves the characteristics of equalization and adaptation in the non‐minimum phase condition. It converts the nonminimum phase to the minimum phase condition by the time‐reversal operation. Principles of dual‐mode equalization, an algorithm for mode output selection, and timing problems are discussed in detail. Experiments demonstrate average BER performance in two‐path and typical multipath environments. The proposed dual‐mode equalization technique improves average BER performance by 2 dB E b /N 0 .