Spread-time code division multiple access technique with arbitrary spectral shaping
First Claim
1. Circuitry in a receiver for spectrally decoding a spectrally encoded transmitted time signal conveying data symbols at a symbol rate as communicated by a corresponding transmitter and detected on a channel having a channel characteristic and noise interference, the transmitted time signal being derived from a transmitter pulse having a unique pseudo-noise code assigned to the phase characteristic of the transmitter pulse, the circuitry comprisingmeans for synchronizing the receiver to the corresponding transmitter at the symbol rate,means, responsive to said means for synchronizing, for truncating the transmitted time signal over predetermined time intervals to produce a windowed time signal,means, coupled to said means for truncating and said means for synchronizing, for separating said windowed time signal into time segments,means, responsive to said means for synchronizing, for Fourier transforming each of said segments to produce transformed spectra,means for generating a modulation spectrum in correspondence to the pseudo-noise code and the channel characteristic,means, responsive to said transformed spectra and said modulation spectrum, for modulating each of said transformed spectra to produce a modulator output spectrum, andmeans, coupled to said means for modulating and said means for synchronizing, for estimating each of the data symbols from the transmitted time signal.
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Abstract
A spread-time code division multiple access (ST-CDMA) technique is disclosed for bandlimited access to a channel. With ST-CDMA, pseudo-random (PN) sequences are assigned to each transmitter in the multi-transmitter system, and the Fourier transform of the transmitter pulse for a given transmitter is determined by modulating the phase of the desired transmitter spectrum by the PN sequence assigned to the transmitter. The data symbols produced by the transmitter are conveyed by delayed versions of the transmitter pulse. The transmitted data for a particular transmitter is recovered at a receiver synchronized to the transmitter by sampling the output of a filter matched to the corresponding transmitter pulse.
30 Citations
2 Claims
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1. Circuitry in a receiver for spectrally decoding a spectrally encoded transmitted time signal conveying data symbols at a symbol rate as communicated by a corresponding transmitter and detected on a channel having a channel characteristic and noise interference, the transmitted time signal being derived from a transmitter pulse having a unique pseudo-noise code assigned to the phase characteristic of the transmitter pulse, the circuitry comprising
means for synchronizing the receiver to the corresponding transmitter at the symbol rate, means, responsive to said means for synchronizing, for truncating the transmitted time signal over predetermined time intervals to produce a windowed time signal, means, coupled to said means for truncating and said means for synchronizing, for separating said windowed time signal into time segments, means, responsive to said means for synchronizing, for Fourier transforming each of said segments to produce transformed spectra, means for generating a modulation spectrum in correspondence to the pseudo-noise code and the channel characteristic, means, responsive to said transformed spectra and said modulation spectrum, for modulating each of said transformed spectra to produce a modulator output spectrum, and means, coupled to said means for modulating and said means for synchronizing, for estimating each of the data symbols from the transmitted time signal.
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2. A method in a receiver for spectrally decoding a spectrally encoded transmitted time signal conveying data symbols at a symbol rate as communicated by a corresponding transmitter and detected on a channel having a channel characteristic and noise interference, the transmitted time signal being derived from a transmitter pulse having a unique pseudo-noise code assigned to the phase characteristic of the transmitter pulse, the method comprising the steps of
synchronizing the receiver to the corresponding transmitter at the symbol rate, truncating the transmitted time signal over predetermined time intervals to produce a windowed time signal, separating said windowed time signal into time segments, Fourier transforming each of said segments to produce transformed spectra, generating a modulation spectrum in correspondence to the pseudo-noise code and the channel characteristic, modulating each of said transformed spectra to produce a modular to output spectrum, and estimating each of the data symbols from the transmitted time signal.
Specification
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- Resources
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Current AssigneeTelcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
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Original AssigneeBell Communications Research, Inc. (Telefonaktiebolaget LM Ericsson)
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InventorsHonig, Michael L., Salehi, Jawad A., Crespo, Pedro M.
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Primary Examiner(s)Barron, Jr., Gilberto
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Application NumberUS07/901,833Time in Patent Office183 DaysField of Search375/1, 375/96, 370/18, 370/19, 370/21, 370/23US Class Current375/343CPC Class CodesH04J 13/0003 Code application, i.e. aspe...H04J 13/16 Code allocationH04L 5/02 Channels characterised by t...
