US 7,149,238 B2Granted

Highly bandwidth-efficient communications

AssigneeCingular Wireless II, LLC

InventorsBrian G. Agee, Matthew Bromberg, Derek Gerlach, David Gibbons, James Timothy Golden, Minnic Ho, Elliott Hoole, Mary Jesse, Robert Lee Maxwell, Robert G. Mechaley, Jr., Robert Ray Naish, David J. Nix, David James Ryan, David Stephenson

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Abstract

A discrete multitone stacked-carrier spread spectrum communication method is based on frequency domain spreading including multiplication of a baseband signal by a set of superimposed, or stacked, complex sinusoid carrier waves. In a preferred embodiment, the spreading involves energizing the bins of a large Fast Fourier transform (FFT). This provides a considerable savings in computational complexity for moderate output FFT sizes. Point-to-multipoint and multipoint-to-multipoint (nodeless) network topologies are possible. A code-nulling method is included for interference cancellation and enhanced signal separation by exploiting the spectral diversity of the various sources. The basic method may be extended to include multielement antenna array nulling methods for interference cancellation and enhanced signal separation using spatial separation. Such methods permit directive and retrodirective transmission systems that adapt or can be adapted to the radio environment. Such systems are compatible with bandwidth-on-demand and higher-order modulation formats and use advanced adaptation algorithms. In a specific embodiment the spectral and spatial components of the adaptive weights are calculated in a unified operation based on the mathematical analogy between the spectral and spatial descriptions of the airlink.

Claims20

Dependent claims

A highly bandwidth-efficient communications method to optimize a multiple cell network for inter-cell interference, comprising:

receiving at a first base station located in a first cell, a first spread signal comprising a first data signal spread over a plurality of discrete tones received over a first path from a first remote station located in said first cell, said first signal further comprising an interfering signal spread over said plurality of discrete tones received over an interference path from a second remote station located in a second cell;
adaptively despreading the signal received at the first base station by using first despreading codes that are based on the characteristics of the received spread signal over said first path and over said interference path;
spreading a second data signal at the first base station with first spreading codes derived from said despreading codes based on a retrodirectivity of said first path and of said interference path, the first spreading codes distributing the second data signal over a plurality of discrete tones, forming a second spread signal that is selectively diminished in said interfering path to said second remote station;
transmitting said second spread signal from the first base station over said first path to said first remote station and transmitting the second signal selectively diminished over said interference path to said second remote station;
receiving at said second remote station said selectively diminished second spread signal;
adaptively despreading the selectively diminished second signal received at the second remote station by using second despreading codes that are based on the characteristics of the received second signal over said interference path;
spreading a third data signal at the second remote station with second spreading codes derived from said second despreading codes based on a retrodirectivity of said interference path, the second spreading codes distributing the third data signal over a plurality of discrete tones, forming a third spread signal that is selectively diminished in said interfering path to said first base station;
and
transmitting said selectively diminished third spread signal from the second remote station over said interference path to said first base station.

6 more elements

A highly bandwidth-efficient communications system to optimize a multiple cell network for inter-cell interference, comprising:

means for receiving at a first base station located in a first cell, a first spread signal comprising a first data signal spread over a plurality of discrete tones received over a first path from a first remote station located in said first cell, said first signal further comprising an interfering signal spread over said plurality of discrete tones received over an interference path from a second
remote station located in a second cell;
means for adaptively despreading the signal received at the first base station by using first despreading codes that are based on the characteristics of the received spread signal over said first path and over said interference path;
means for spreading a second data signal at the first base station with first spreading codes derived from said despreading codes based on a retrodirectivity of said first path and of said interference path, the first spreading codes distributing the second data signal over a plurality of discrete tones, forming a second spread signal that is selectively diminished in said interfering path to said second remote station;
means for transmitting said second spread signal from the first base station over said first path to said first remote station and transmitting the second signal selectively diminished over said interference path to said second remote station;
means for receiving at said second remote station said selectively diminished second spread signal;
means for adaptively despreading the selectively diminished second signal received at the second remote station by using second despreading codes that are based on the characteristics of the received second signal over said interference path;
means for spreading a third data signal at the second remote station with second spreading codes derived from said second despreading codes based on a retrodirectivity of said interference path, the second spreading codes distributing the third data signal over a plurality of discrete tones, forming a third spread signal that is selectively diminished in said interfering path to said first base station;
and
means for transmitting said selectively diminished third spread signal from the second remote station over said interference path to said first base station.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/409,437Filed 21 Apr 2006 · continuation
Priority: 24 Feb 1997
Published: US 2006/0193373 A131 Aug 2006
Granted: 12 Dec 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

H04B 1/69
Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised…
H04B 1/707
Spread spectrum techniques: using direct sequence modulation
H04B 1/7107
The interference being multiple access interference: subtractive interference cancellation
H04L 5/0021
Time-frequency-code: in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA

Family

Application08/804,619Parent of this continuation · filed 24 Feb 1997
Application08/993,721Parent of this continuation · filed 18 Dec 1997
Application09/920,903Parent of this continuation · filed 3 Aug 2001
US 6,359,923 B1Parent of this continuation · filed 19 Mar 2002
US 2006/0193373 A1Pre-grant publication · published 31 Aug 2006
US 2002/0122465 A1Published application
US 7,106,781 B2Related patent
US 7,149,238 B2This patent

From the US filing history. Foreign family members aren’t listed.