Provided is a communication system for ultra wide band impulse communication, and more particularly, to a communication apparatus and method that can be used in a sensor network or a low-rate wireless personal area network. To be more specific, the present research suggests a transmitter employing multi-coded bi-orthogonal pulse position modulation/demodulation and a method thereof. The transmitter of the present research provides: a serial-to-parallel converter for convening L-bit serial data to be transmitted into parallel data by performing grouping on the L-bit serial data; a multi-coder for generating a multi-coded symbol by multiplying the parallel data by total L orthogonal codes of length Ns; a bi-orthogonal pulse position modulator for positioning the multi-coded symbol in a predetermined pulse period and performing biorthogonal pulse position modulation; and a pulse generator for multiplying an output signal of the bi-orthogonal pulse position modulator by a predetermined pulse and outputting an output signal.