초록 ▼

An apparatus and method for communicating data between at least two data devices, suitable for use as a wireless local-area network, that provides robust data communication via a radio communications channel corrupted by multipath interference, particularly at high data rates. A preferred embodiment

An apparatus and method for communicating data between at least two data devices, suitable for use as a wireless local-area network, that provides robust data communication via a radio communications channel corrupted by multipath interference, particularly at high data rates. A preferred embodiment of the invention represents data as a sequence of Walsh-function waveforms encoded by pseudo-noise direct-sequence spread-spectrum modulation. Walsh-function-encoding of the data provides a long symbol duration, thereby allowing the spread-spectrum modulation to provide processing gain sufficient to substantially overcome multipath interference, while providing a high data rate. In another preferred embodiment, Walsh-function modulation is supplemented with various forms of phase modulation, such as coherent PSK for bi-orthogonal signalling, and DPSK between orthogonal symbols for noncoherent bi-orthogonal signalling, thereby further increasing data rate without reducing processing gain. In another preferred embodiment, Walsh-function modulation is supplemented with spectral shaping to allow increased bandwidth occupancy, thereby further increasing the processing gain without sacrificing data rate.

대표청구항 ▼

[ What is claimed is:] [1.] A method of creating a digital signal representative of data, comprising:(A) generating the data as a sequence of digital waveform symbols, wherein each digital waveform symbol (i) is selected from a set of 2.sup.N possible digital waveform symbols and (ii) represents N d

[ What is claimed is:] [1.] A method of creating a digital signal representative of data, comprising:(A) generating the data as a sequence of digital waveform symbols, wherein each digital waveform symbol (i) is selected from a set of 2.sup.N possible digital waveform symbols and (ii) represents N data bits, with each possible digital waveform symbol being unique from the others, and the symbol uniqueness being determined by a unique baud structure, and the baud rate defining a symbol modulation rate;(B) generating a direct-sequence spread spectrum encoding signal at a chip rate; and(C) combining the direct-sequence spread spectrum encoding signal with the sequence of digital waveform symbols so as to provide said digital signal;wherein the chip rate is equal to the symbol modulation rate.