Abstract: Techniques for modulation and demodulation using near-Nyquist sampling operate using substantially band-limited signal. In modulating, the substantially band-limited signal is formed by filtering modulated symbol date to produce a complex sample stream having a bandwidth of less than the twice the associated symbol transmission rate and with a sample rate of less than twice the symbol rate. In demodulating, a substantially band-limited signal having a bandwidth of less than twice the associated symbol transmission rate is sampled at a sample rate of less than twice the symbol rate of the modulation.

Abstract: Techniques for efficient upconversion can process complex input data, such as for example data in an inphase and quadrature form. Half sample interpolation filtering and delay can be performed, and the results can be combined in a quarter-rate upconverter. The quarter rate upconversion can allow one of the half-sample interpolating filtering and the delay to be performed on one of either the inphase and quadrature samples.

Abstract: A mobile distributed antenna array can include a plurality of mobile platforms, each platform having at least one antenna element and radio equipment coupled to the at least one antenna element. The radio equipment can be capable of transmission, reception, or both of propagated radio signals. A control platform can be capable of communication with the mobile platforms to control movement of the mobile platforms to position the mobile platforms relative to each other to provide a desired array pattern.