US 6,650,658 B1 · Controlled aliasing to simplify service selection

Abstract

A system and method for a handshake protocol for digital subscriber line (DSL) and similar telecommunication systems that makes beneficial use of aliasing to select and decode signaling tones. In particular, the invention carefully selects signaling tones at frequencies such that higher frequency tones would alias down and coincide with specific base tones after sub-sampling. Thus, rather than filtering out higher frequencies to avoid aliasing, aliasing is exploited to use these higher frequencies. This technique would allow a receiver to detect and decode the higher frequency tones at lower frequency tone locations or bands. A related innovation is a band set, which includes one or more tones within a particular frequency band, where typically each tone in a band set corresponds to a different tone set. Exploiting the effects of aliasing eliminates the need to search for compatible spectrum, simplifies receiver design, provides flexibility, scalability and future-proofing, and allows handshaking sessions to be established across mutually exclusive spectrums. The invention is particularly useful for DSL systems, and in particular is well suited for the proposed G.hs standard.

Claims12

Dependent claims

A system for communicating capabilities between a first telecommunication unit and a second telecommunication unit, the system comprising:

a transmitter in the first telecommunication unit that generates a first tone set for signaling the second telecommunication unit, the first tone set including a set of tones that alias onto a first base tone when sub-sampled;
the first tone set defined as:
Cds=(32×m)±n, for m=1,3,5, . . . , (N/32)and 0<n<12
where N=the number of downstream carrier tones supported at the first telecommunication unit, and N is an integer power of 2 greater than 32;
and
a receiver in the second telecommunication unit that samples the first tone set transmitted by the first telecommunication unit, the receiver sampling the first tone set at a rate below the Nyquist sampling frequency of the lowest frequency tone in the first tone set that is above the frequency of the first base tone;
wherein sampling the first tone set causes tones in the first tone set that are above the first base tone to alias onto the base tone.

4 more elements

A protocol for communicating capabilities between a first telecommunication unit and a second telecommunication unit, each unit having a receiver, the protocol including a first tone set including at least one tone for signaling from the first telecommunication unit to the second telecommunication unit, the first tone set including a base tone such that all other tones within such first tone set alias onto the base tone of the first tone set when sub-sampled by the receiver within the second telecommunication unit wherein the first tone set is defined as:

Cds=(32×m)±n, for m=1,3,5, . . . , (N/32) and 0<n≦2
where N=the number of downstream carrier tones supported at the first telecommunication unit, and N is an integer power of 2 greater than 32.

A method for communicating capabilities between a first telecommunication unit and a second telecommunication unit, each unit having a receiver, the method including:

(a) defining a first tone set for signaling from the first telecommunication unit to the second telecommunication unit, the first tone set including a first base tone such that all other tones within the first tone set alias onto the first base tone when sub-sampled by the receiver within the second telecommunication unit, wherein the first tone set, Cds, is defined as:
Cds=(32×m)±n+fds, for m=1,3,5, . . . and n=10and 14
where fus and fds is a constant frequency offset:
(b) transmitting at least one tone of the first tone set from the first telecommunication unit to the second telecommunication unit, the at least one tone of the first tone set being a tone other than the first base tone;
(c) generating an alias frequency having the same frequency of the fist base tone, the alias frequency being generated by sampling, at the receiver of the second telecommunication unit, the at least one tone of the first tone set at a sampling rate below the Nyquist sampling frequency of the at least one tone of the first tone set;
(d) defining a second tone set for signaling from the second telecommunication unit to the first telecommunication unit, the second tone set including a second base tone such that all other tones in the second tone set alias onto the second base tone when sub-sampled by the receive within the first telecommunication it wherein the second tone set, Cus, defined as:
Cus=(32×m)±n+fus, for m=1,3,5, . . . and n=2 and 6
where fus is a constant frequency offset;
(e) transmitting at least one tone of the second tone set from the second telecommunication unit to the first telecommunication unit the at least one tone of the second tone set being a tone other than the second base tone;
and
(f) generating an alias frequency having the same frequency of the second base tone, the alias frequency being generated by sampling, at the receiver of the first telecommunication unit, the at least one tone of the second tone set at a sampling rate below the Nyquist sampling frequency of the at least one tone of the second tone set.

8 more elements

A method for communicating capabilities between a first telecommunication unit and a second telecommunication unit, each unit having a receiver, the method including:

(a) defining a first tone set for signaling from the first telecommunication unit to the second telecommunication unit, the first tone set including a first base tone such that all other tones within the first tone set alias onto the first base tone when sub-sampled by the receiver within the second telecommunication unit;
(b) transmitting at least one tone of the first tone set from the first telecommunication unit to the second telecommunication unit, the at least one tone of the first tone set being a tone other than the first base tone;
and
(c) generating an alias frequency having the same frequency of the first base tone, the alias frequency being generated by sampling at the receiver of the second telecommunication unit, the at least one tone of the first tone set at a sampling rate below the Nyquist sampling frequency of the at least one tone of the first tone set;
(d) defining a second tone set for signaling from the second telecommunication unit to the first telecommunication unit, the second tone set including a second base tone such that all other tones in the second tone set alias onto the second base tone when sub-sampled by the receiver within the first telecommunication unit, wherein the second tone set is defined as:
C(K,n,f)=(K×m)±n+f, for m=1,3,5, . . . 0<n<K,
where K=a Nyquist tone associated with the lowest sub-sampling rate to be supported, and f is a constant frequency offset;
(e) transmitting at least one tone of the second tone set from the second telecommunication unit to the first telecommunication units the at least one tone of the second tone set being a tone other than the second base tone;
and
(f) generating an alias frequency having the same frequency of the second base tone the alias frequency being generated by sampling, at the receiver of the first telecommunication unit, the at least one tone of the second tone set at a sampling rate below the Nyquist sampling frequency of the at least one tone of the second tone set.

7 more elements

Dependencies are inferred from the claim text.

Controlled aliasing to simplify service selection

Life of this patent

Controlled aliasing to simplify service selection

Life of this patent

Abstract

Claims12