US 5,282,222 A · Method and apparatus for multiple access between transceivers in wireless communications using OFDM spread spectrum

Abstract

A method for allowing a number of wireless transceivers to exchange information (data, voice or video) with each other. A first frame of information is multiplexed over a number of wideband frequency bands at a first transceiver, and the information transmitted to a second transceiver. The information is received and processed at the second transceiver. The information is differentially encoded using phase shift keying. In addition, after a pre-selected time interval, the first transceiver may transmit again. During the preselected time interval, the second transceiver may exchange information with another transceiver in a time duplex fashion. The processing of the signal at the second transceiver may include estimating the phase differential of the transmitted signal and pre-distorting the transmitted signal. A transceiver includes an encoder for encoding information, a wideband frequency division multiplexer for multiplexing the information onto wideband frequency voice channels, and a local oscillator for upconverting the multiplexed information. The apparatus may include a processor for applying a Fourier transform to the multiplexed information to bring the information into the time domain for transmission.

Claims12

Dependent claims

A transceiver including a transmitter for transmitting electromagnetic signals and a receiver for receiving electromagnetic signals having amplitude and phase differential characteristics, the transmitter comprising:

an encoder for encoding information;
a wideband frequency division multiplexer or multiplexing the information onto wideband frequency channels;
a low pass filter;
a local oscillator for upconverting the multiplexed information for transmission;
a processor for applying a fourier transform to the multiplexed information to bring the information into the time domain for transmission;
further including, in the receiver of the transceiver;
a bandpass filter for filtering the received electromagnetic signals;
a local oscillator for downconverting the received electromagnetic signals to produce output;
a sampler for sampling the output of the local oscillator to produce sampled signals to the channel estimator;
a channel estimator for estimating one or both of the amplitude and the phase differential of the received signals to produce as output one or both of an estimated amplitude and an estimated phase differential respectively;
and
a decoder for producing signals from the sampled signals and the output from the channel estimator.

9 more elements

Dependencies are inferred from the claim text.

Method and apparatus for multiple access between transceivers in wireless communications using OFDM spread spectrum

Life of this patent

Method and apparatus for multiple access between transceivers in wireless communications using OFDM spread spectrum

Life of this patent

Abstract

Claims12