Unified multi-carrier framework for multiple-access technologies

• US 20030147655A1
• Filed: 02/07/2003
• Published: 08/07/2003
• Est. Priority Date: 11/02/1999
• Status: Active Grant

• Current Assignee: Arnold Alagar, Department 13, Inc. (Department 13 International Ltd.), Steve Shattil
• Original Assignee: Lot 41 Acquisition Foundation LLC (Intellectual Ventures LLC)
• Inventors: Shattil, Steve J.
• Granted Patent: US 7,406,261 B2
• Time in Patent Office: Days
• US Class Current: 398/182
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

A wireless communication system transmits data on multiple carriers simultaneously to provide frequency diversity. Orthogonality is provided by carrier interference, which causes a narrow pulse in the time domain corresponding to each transmitted data symbol. Selection of the frequency separation and phases of the carriers controls the timing of the pulses. Equivalently, pulse waveforms may be generated from an appropriate selection of polyphase sub-carrier codes. Time division of the pulses and frequency division of the carriers may be employed for multiple access. Received signals are processed by combining frequency-domain components corresponding to a desired user'"'"'s allocated carriers. Individual data symbols are processed by providing polyphase decoding, matched filtering, or time-domain shifting the received carriers. Carrier Interferometry components may be used to build various signals corresponding to other transmission protocols.

Claims

1. A transmission system adapted to generate at least one multi-carrier signal, the transmission system including a carrier generator adapted to generate a plurality of orthogonal carrier frequencies allocated to at least one user, a data source adapted to impress at least one data symbol onto the carriers, and a combiner adapted to combine the carriers to generate a time-domain waveform, the transmission system characterized by;

a phase-shift module adapted to provide at least one predetermined set of poly-phase offsets to the carriers for generating at least one Carrier Interferometry (CI) signal, the phase offsets adapted to map each data symbol to a pulse waveform generated from a superposition of the carriers and centered at a predetermined instant in time.

2. A receiver system adapted to process at least one multi-carrier signal, the receiver including a filter bank adapted to separate at least one time-domain signal into a plurality of frequency-domain components, the receiver characterized by;

a phase-shift circuit adapted to provide the frequency-domain components with at least one set of phase offsets wherein each set of phase offsets corresponds to an orthogonal pulse centered at a predetermined instant in time, and

a combiner adapted to combine the phase offset frequency-domain components to produce at least one time-domain sequence of symbols.

3. A multi-carrier signal comprising at least one set of complex sub-carrier weights embodied in a plurality of subcarriers, the weights adapted to map a plurality of data symbols to a plurality of pulses, each pulse centered at a predetermined time instant, for producing a modulated pulse train from a superposition of the subcarriers.

4. A computer program embodied on a computer-readable medium for controlling a multi-carrier generator comprising:

a subcarrier allocation source code segment adapted to provide at least one set of subcarriers allocated to at least one user in a network, and

a subcarrier weighting source code segment adapted to provide at least one set of complex weights to the at least one set of subcarriers for mapping each of at least one data symbol to at least one carrier-superposition pulse centered at a predetermined instant in time.

5. A signal transmitter configured to form a signal comprising:

a plurality of subcarriers allocated to at least one user in a communications network, and

a plurality of complex sub-carrier weights (applied to the subcarriers for generating a plurality of weighted subcarriers, the weights) adapted to map each of a plurality of data symbols to at least one of a plurality of pulses generated by a superposition of the weighted subcarriers, each pulse centered at a predetermined instant in time.

6. A signal transmitter configured to form a signal comprising:

a plurality of subcarriers allocated to at least one user in a communications network, and

at least one pulsed waveform comprising the plurality of allocated subcarriers, the at least one pulsed waveform being impressed with at least one data symbol.

7. A transmission method configured to form a signal comprising:

a plurality of subcarriers allocated to at least one user in a communications network, and

a plurality of complex sub-carrier weights (applied to the subcarriers for generating a plurality of weighted subcarriers, the weights) adapted to map each of a plurality of data symbols to at least one of a plurality of pulses generated by a superposition of the weighted subcarriers, each pulse being centered at a predetermined instant in time.

8. A transmission method configured to form a signal comprising:

a plurality of subcarriers allocated to at least one user in a communications network, and

at least one pulsed waveform comprising the plurality of allocated subcarriers, the at least one pulsed waveform being impressed with at least one data symbol.

9. A computer program embodied on a computer-readable medium for controlling a multi-carrier receiver comprising:

a subcarrier weighting source code segment adapted to receive at least one channel estimate and generate therefrom at least one set of complex weights for at least one set of subcarrier components generated from a received signal,

a CI combining source code segment adapted to receive the at least one set of sub-carrier components and the at least one set of complex weights, the CI combining source code segment adapted to weight and combine the sub-carrier components to produce a sequence of symbols that conveys at least one transmitted signal value.