Constant modulus equalizer with asymmetric taps for unmanned vehicle data link

Wireless wideband data link is one of the key enabling techniques for various unmanned terrestrial and aerial vehicles in future battlefield. To combat multipath frequency selectivity, adaptive equalizers are often invoked at the receiver to eliminate the Inter-Symbol Interferences (ISI). Unlike most existing works where the equalizers have the same amount of taps at each sides of their primary tap which is initialized to 1, in this paper we consider asymmetric equalizers which include more taps at the leading side of the primary tap than at the lagging side. We will show the proposed asymmetric equalizer, in the context of Constant Modulus (CM) adaptive scheme, performs almost as well as its symmetric counterpart in terms of convergence and converged performance, yet exhibits at least 1/3 complexity cut-off, as it may better fit in with the nature of the multipath fading channel. Computer simulations are corroborated with in-field test results.