Diversity for direct-sequence spread spectrum systems

摘要

Diversity for direct sequence spread spectrum wireless communication systems is provided by a transmitting technique for communicating a first signal comprising one or more segments to a receiver via a plurality of M antennas (T₁, T₁). The first signal includes one or more signal segments. The technique cmprises forming M copies of the first signal; for a segment of a signal copy, weighting (by 15) each of two or more sub-segments of the segment with a distinct signal (from 17), wherein a sequence of the distinct weighting signals for the segment is distinct from sequences of signals weighting the same segment of one or more other signal copies; and for each of M weighted signal copies U₁(n)..Um(n), transmitting a signal to the receiver using a distinct antenna (T₁, T₁), the transmitted signal being based on the weighted signal copy. Illustratively, the first signal is a spread spectrum signal (by 10,12). Moreover, the process of weighting comprises applying a phase shift to a sub-segment. The invention further provides a receiving technique which comprises, for a copy of a received signal, despreading a segment of the received signal, demodulating a plurality of sub-segments of the despread signal segment, wherein each sub-segment is demodulated with use of one or more estimated communication channel characteristics corresponding to the sub-segment, and forming a summation signal reflecting a summation of a plurality of demodulated sub-segments. The receiving technique further comprises forming a signal reflecting a signal segment value, the formed signal based on one or more summation signals. The step of demodulating may precede the step of despreading in some embodiments.