Multiple access method and system

A carrier-interference multiple-access (CIMA) communication system comprising:

• an electromagnetic-wave transmitter comprising a multicarrier generator (14n) capable of generating a plurality of electromagnetic carrier signals having a plurality of frequencies, and a carrier modulator (12) capable of modulating the carrier signals with at least one information signal, the improvement comprising:
• a phase-space controller (16n) adapted to provide the carriers with at least one predetermined phase space, each phase space mapping a data symbol to one of a plurality of pulse waveforms generated from a superposition of the carriers and centered at a predetermined instant in time, the pulse waveforms being positioned substantially orthogonally in time,
• an output coupler (24) capable of combining the modulated, phased carriers in at least one communication channel to produce at least one CIMA signal having a plurality of carrier-signal components, and
• an electromagnetic-wave receiver having a receiving element (52) capable of receiving transmitted signals from a communication channel for providing at least one set of received multi-frequency carrier-signal components, the improvement comprising:
• a combiner (62mn) capable of combining the plurality of received multi-frequency carrier-signal components in phase to produce at least one constructive interference signal indicative of at least one information signal.

A method of processing a received multi-carrier signal representing a plurality of symbols and including a plurality of carriers, a subset of said plurality of carriers being allocated to at least one user, the method including:

• providing for performing a time domain to frequency domain transform operation on the plurality of carriers to generate a frequency-domain signal therefrom;
• providing for filtering the frequency-domain signal to remove at least one carrier in said plurality of carriers that are not included in said subset of carriers;
• performing a frequency domain to time domain transform operation on the filtered frequency-domain signal to generate a filtered time-domain signal;
• and
• recovering symbols transmitted to the at least one user from the filtered time-domain signal.

A method of receiving at least one data symbol spread by at least one carrier interferometry (CI) code across a plurality of multi-frequency carriers, the at least one CI code configured to map the at least one data symbol to at least one pulse waveform produced by a superposition of the plurality of multi-frequency carriers and centered at a predetermined instant in time, the method including:

• providing for selecting a plurality of received multi-frequency carriers within a predetermined bandwidth;
• providing for generating at least one received pulse waveform from a superposition of selected multi-frequency carriers;
• and
• providing for estimating the at least one data symbol impressed on the at least one received pulse waveforms.

A receiver adapted to receive at least one data symbol spread by at least one carrier interferometry (CI) code across a plurality of multi-frequency carriers the at least one CI code configured to map the at least one data symbol to at least one pulse waveform produced by a superposition of the plurality of multi-frequency carriers and centered at a predetermined instant in time, the receiver including:

• a filter adapted to select a predetermined set of received multi-frequency carriers;
• a combiner coupled to the filter, the combiner adapted to combine the received multi-frequency carriers to produce at least one modulated pulse waveform;
• and
• a decision device coupled to the combiner, the decision device adapted to generate at least one estimate of the at least one data symbol from the at least one modulated pulse waveform.

A receiver adapted to receive at least one data symbol spread by at least one carrier interferometry (CI) code across a plurality of multi-frequency carriers, the at least one CI code configured to map the at least one data symbol to at least one pulse waveform produced by a superposition of the plurality of multi-frequency carriers and centered at a predetermined instant in time, the receiver including:

• a filter adapted to select a predetermined set of received multi-frequency carriers;
• a combiner coupled to the filter, the combiner adapted to optimally combine the set of received multi-frequency carriers in the presence of at least one of interference and multipath to generate at least one signal indicative of a modulated pulse waveform;
• and
• a decision device coupled to the combiner, the decision device adapted to generate at least one estimate of the at least one data symbol from the at least one signal indicative of the modulated pulse waveform.

An apparatus for receiving a frequency division multiplexed signal representing a plurality of symbols and including a plurality of carriers, a subset of said plurality of carriers being allocated to at least one user, the apparatus including:

• a time to frequency domain transform module adapted to generate a frequency-domain signal from the frequency division multiplexed signal;
• a filter adapted to filter at least one carrier from the frequency domain signal other than those included in the subset to thereby generate a filtered frequency-domain signal;
• a frequency to time domain transform module adapted to perform a frequency domain to time domain transform operation on the filtered frequency-domain signal to thereby generate a time-domain signal;
• and
• a decision module coupled to the frequency to time domain transform module for mapping received signal values at points in time to estimated symbol values.

A method of generating a multicarrier communication signal transmitted by a communication device, the method including:

• providing a symbol duration having equally spaced time instants;
• allocating a predetermined set of carrier frequencies to the communication device;
• receiving as input data, data symbols to be transmitted by the multicarrier communication signal;
• mapping the data symbols to the equally spaced time instants in the symbol duration to generate a discrete signal of mapped symbols;
• and
• spreading the data symbols over the predetermined set of carrier frequencies by applying a pulse function to the discrete signal, the pulse function comprising a superposition of the predetermined set of carrier frequencies.

A method for generating a multicarrier communication signal having carrier frequencies distributed over a predetermined bandwidth, the method including:

• providing for defining a symbol duration for the multicarrier communication signal;
• providing for defining a plurality of time instants in the symbol duration;
• providing for allocating a set of carrier frequencies from the carrier frequencies distributed over the predetermined bandwidth to a particular communication device;
• providing for receiving as input, data symbols from a data source;
• providing for mapping the data symbols to the time instants to generate a discrete signal in the time domain;
• and
• providing for spreading the data symbols over the set of carrier frequencies by applying pulse functions to the discrete signal, the pulse functions comprising a superposition of the set of carrier frequencies.

A method of generating at least one Carrier Interferometry signal comprising data spread over a plurality of multi-frequency carriers, the method including:

• providing for selecting a plurality of multi-frequency carriers within a predetermined bandwidth;
• providing for generating at least one pulse waveform, each of the at least one pulse waveform comprising a superposition of the selected multi-frequency carriers;
• providing for accepting at least one information symbol;
• and
• providing for spreading the at least one information symbol over the selected multi-frequency carriers by modulating the at least one information symbol onto the at least one pulse waveform.

A transmitter adapted to generate at least one Carrier Interferometry signal, including:

• a carrier generator adapted to generate a plurality of multi-frequency carriers within a predetermined bandwidth;
• a pulse generator coupled to the carrier generator, the pulse generator adapted to produce at least one pulse waveform comprising a superposition of selected multi-frequency carriers;
• and
• a modulator coupled to the pulse generator, the modulator adapted to spread an information symbol across the selected multi-frequency carriers to produce at least one information-modulated pulse waveform.

A communication system adapted to generate a multicarrier signal having carrier frequencies distributed over a predetermined bandwidth, the communication system including:

• a carrier generator adapted to generate an allocated carrier set selected from carrier frequencies distributed over the predetermined bandwidth;
• an interval delay circuit adapted to provide a plurality of information symbols to prescribed time instants in a symbol duration to generate a discrete signal of symbols;
• and
• a pulse-generation circuit adapted to spread each of the plurality of information symbols across the allocated carrier set to generate a pulse sequence by applying predetermined pulse functions to the discrete signal, the pulse functions characterized by a superposition of carrier frequencies in the allocated carrier set, the pulse functions configured for operating on the discrete signal such that values of the pulse sequence at the prescribed time instants are equal to the information symbols, and a frequency response of the pulse sequence includes sinusoids having non-zero values at frequencies within the allocated carrier set and zero values at the remaining frequencies.