A method and apparatus are provided for implementing an impulse ultra-wideband communications system which combines the technique of transmitted reference (TR) with a code-sifted reference scheme that separates the reference and the data pulses with a sequence of codes such as a subset of Walsh codes. The combination of the two techniques in ultra-wideband (UWB) radio systems removes the wideband delay elements required by conventional TR UWB systems. The invention provides a system with no analog carriers and lower complexities than other UWB systems, and which has better performances, higher tolerance to nonlinearity, and larger capacities