Patent ID: 6078576
Filing Date: 2000-06-20
Classification: H04B

Abstract:
A spread-spectrum time-division-multiple-access (SS-TDMA) system for communicating data, comprising:a remote unit having a SS-TDMA transmitter, said SS-TDMA transmitter including,a transmitter-first-in-first-out (transmitter-FIFO) memory, coupled to a data input, for storing data;a transmitter TDMA subsystem, coupled to said transmitter-FIFO memory, for sending the data in a time slot from said transmitter-FIFO memory as TDMA data;a demultiplexer, coupled to said transmitter TDMA subsystem and having a plurality of outputs, for demultiplexing the TDMA data into a plurality of sub-data-sequence signals, with a respective sub-data-sequence signal at a respective output of said demultiplexer;chip-sequence means for outputting a plurality of chip-sequence signals, with each chip-sequence signal orthogonal to the other chip-sequence signals in said plurality of chip-sequence signals;a plurality of product devices, coupled to the plurality of outputs of said demultiplexer, respectively, and to said chip-sequence means, for multiplying each of the sub-data-sequence signals by a respective chip-sequence signal, thereby generating a plurality of spread-spectrum channels;a combiner, coupled to the plurality of product devices, for algebraically combining the plurality of spread-spectrum channels as a multichannel-spread-spectrum signal;a header device, coupled to said combiner, for concatenating a header for chip-sequence synchronization, to the multichannel-spread-spectrum signal, thereby generating a spread-spectrum time division multiple access (SS-TDMA) signal; anda transmitter-carrier subsystem, coupled to said header device, for transmitting on a carrier frequency the SS-TDMA signal using radio waves over a communications channel; anda base terminal having a SS-TDMA receiver, said SS-TDMA receiver including,a translating device, coupled to the communications channel, for translating the SS-TDMA signal from the carrier frequency to a processing frequency;a header-matched filter, coupled to said translating device and having an impulse response matched to the header, for detecting, at the processing frequency, the header in the SS-TDMA signal, and for outputting, responsive to detecting the header, a header-detection signal;a receiver processor, coupled to said header-matched filter, responsive to the header-detection signal, for generating control and timing signals;a plurality of data-matched filters, coupled to said translating device, with each data-matched filter having an impulse response matched to a chip-sequence signal of the plurality of chip-sequence signals, respectively, for despreading the multichannel-spread-spectrum signal embedded in the SS-TDMA signal as a plurality of received spread-spectrum channels, respectively;a multiplexer, coupled to said plurality of data-matched filters, for multiplexing the plurality of received spread-spectrum channels as received-TDMA data;a receiver-TDMA subsystem, coupled to said receiver processor and responsive to the control and timing signals, for selecting the received TDMA data from a particular time slot as received data; anda receiver-FIFO memory, coupled to said receiver TDMA subsystem, for storing the received data, and for outputting the received data to a data output.