US 6,839,429 B1 · Spectral optimization for communication under a peak frequency-domain power constraint

Abstract

System and methods for determining an optimized transmit spectra (spectral distributions of transmission power) for a set of communications channels that experience cross-talk among themselves and for transmitting data on the channels. The transmit spectra are preferably constructed so that largely contiguous frequency bands are allocated to each signaling direction (upstream/downstream) on each communications channel and/or to each channel in the set of channels. In one embodiment, each communications channel is restricted to a maximum time-averaged power. The method preferably includes steps of determining the channel transfer functions of the communications channel, determining interference characteristics of the channels, calculating substantially optimal transmit spectra for the communications channels, and redistributing the frequency bins so that they are contiguously grouped in each transmit spectra. The contiguous groupings allow wider frequency bands for signaling in the channel. In one embodiment, the channel is limited by a “peak-power constraint.”

Claims84

Dependent claims

A method for communicating data on a set of communications channels limited by predetermined peak power constraints in frequency, and wherein each communications channel in the set of communications channels is subject to interference, the method comprising:

determining channel transfer functions of the set of communications channels;
determining interference characteristics of the set of communications channels;
determining transmit spectra for the set of communications channels in response to the channel transfer functions, the interference characteristics, and the predetermined peak power constraints in frequency, wherein said determining the transmit spectra comprises using a peak-constrained water-filling technique to determine power spectral density functions for the set of communications channels;
and
transmitting data on the set of communications channels with spectral power distributions given by the transmit spectra.

2 more elements

determining channel transfer functions of the set of communications channels;
determining interference characteristics of the set of communications channels;
determining transmit spectra for the set of communications channels in response to the channel transfer functions, the interference characteristics, and the predetermined peak power constraints in frequency;
and
transmitting data on the set of communications channels with spectral power distributions given by the transmit spectra,
wherein said determining the transmit spectra comprises determining two transmit spectra for each one communications channel in the set of communications channels, wherein for each communications channel the two transmit spectra are used for signaling in opposite directions along the communications channel, and wherein said determining two transmit spectra for one communications channel comprises:
determining a substantially optimized transmit spectrum Su(f) for signaling in a first direction in response to the channel transfer function of the one communications channel and in response to the interference characteristics;
determining a first transmit spectrum Soptu(f) in the two transmit spectra from the substantially optimized transmit spectrum Su(f) and from the predetermined peak power constraint in frequency Q(f), wherein Soptu(f)=Su(f) in spectral regions where Su(f)<=Q(f) and wherein Soptu(f)=Q(f) in spectral regions where Su(f)>Q(f), and wherein the first transmit spectrum Soptu(f) is useable for transmitting data on the one communications channel in the first direction;
and
determining a second transmit spectrum Soptd(f) in the two transmit spectra from the first transmit spectrum Soptu(f), wherein the second transmit spectrum Soptu(f) is complementary to the first transmit spectrum Soptu(f), and wherein the second transmit spectrum Soptd(f) is useable for transmitting data on the one communications channel in a second direction.

7 more elements

determining channel transfer functions of the set of communications channels;
determining interference characteristics of the set of communications channels;
determining transmit spectra for the set of communications channels in response to the channel transfer functions, the interference characteristics, and the predetermined peak power constraints in frequency;
and
transmitting data on the set of communications channels with spectral power distributions given by the transmit spectra,
wherein the predetermined peak power constraint in frequency includes a first peak power constraint in frequency Qu(f) for signaling in a first direction and a second peak power constraint in frequency Qd(f) for signaling in a second direction, and wherein the communications channels are further limited by a predetermined total power constraint,
wherein said determining the transmit spectra comprises determining two transmit spectra for each one communications channel in the set of communications channels, wherein for each communications channel the two transmit spectra are used for signaling in opposite directions along the communications channel, and wherein said determining the two transmit spectra for one communications channel comprises:
determining a substantially optimized transmit spectrum Su(f) for signaling in a first direction in response to a channel transfer function of the one communications channel and in response to the interference characteristics;
determining a first constrained transmit spectrum Soptu(f) in response to the substantially optimized transmit spectrum Su(f) and in response to a combined peak power constraint Q(f)=max(Qu(f), Qd(f)), wherein Soptu(f)=Su(f) in spectral regions where Su(f)<=Q(f) and wherein Soptu(f)=Q(f) in spectral regions where Su(f)>Q(f);
determining a second constrained transmit spectrum Soptd(f) in response to the first constrained transmit spectrum Soptu(f), wherein the second constrained transmit spectrum Soptd(f) is complementary to the first constrained transmit spectrum Soptu(f);
merging the first and second constrained transmit spectra to form a combined constrained transmit spectrum Sopt(f);
determining a first transmit spectrum S1u(f) in the two transmit spectra from the combined constrained transmit spectrum Sopt(f) in response to Qu(f) and Qd(f);
determining a second transmit spectrum S1d(f) in the two transmit spectra from the combined constrained transmit spectrum Sopt(f) in response to Q(f) and Qd(f);
if a total power of the first transmit spectrum violates the predetermined total power constraint, modifying the first transmit spectrum S1u(f) to reduce the total power of the first transmit spectrum;
and
if a total power of the second transmit spectrum violates the predetermined total power constraint, modifying the second transmit spectrum S1d(f) to reduce the total power of the second transmit spectrum.

13 more elements

A method for communicating data on a communications channel, wherein the communications channel is limited by a predetermined peak power constraint in frequency, and wherein the communications channel is subject to interference, the method comprising:

determining a channel transfer function of the communications channel;
determining interference characteristics of the communications channel;
determining a transmit spectrum in response to the channel transfer function, the interference characteristics, and the predetermined peak power constraint in frequency;
and
transmitting data on the communications channel with a spectral power distribution given by the transmit spectrum,
wherein the communications channel is further limited to a predetermined average power, and wherein said determining the transmit spectrum comprises:
(a) determining a first transmit spectrum S1(f) in response to the channel transfer function and the interference characteristics;
(b) comparing the first transmit spectrum S1(f) to the predetermined peak power constraint Q(f);
(c) determining a second transmit spectrum S2(f), wherein S2(f)=S1(f) in spectral regions where S1(f)<=Q(f) and wherein S2(f)=Q(f) in spectral regions where S1(f)>Q(f);
(d) determining an average power of the second transmit spectrum S2(f);
and
(e) if the average power of the second transmit spectrum S2(f) is not substantially equal to the predetermined average power, modifying the first transmit spectrum S1(f) and repeating said steps (b)-(e).

9 more elements

Dependencies are inferred from the claim text.

Spectral optimization for communication under a peak frequency-domain power constraint

Life of this patent

Spectral optimization for communication under a peak frequency-domain power constraint

Life of this patent

Abstract

Claims84