(12) United States Patent ao) Patent No.: us 6,201,830 Bi
Chellali et al. (45) Date of Patent: Mar. 13,2001
(54) LOW COMPUTATION IDLE TRANSMISSION METHOD FOR DSL MODEMS
(75) Inventors: Adam M. Chellali, Dallas; Michael O.
Polley; Alan Gatherer, both of
Richardson, all of TX (US)
(73) Assignee: Texas Instruments Incorporated,
Dallas, TX (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/096,061
(22) Filed: Jun. 11, 1998
Related U.S. Application Data
(60) Provisional application No. 60/052,855, filed on Jun. 11, 1997.
(51) Int. CI.7 H04B 1/38; H04L 5/16
(52) U.S. CI 375/222; 370/287
(58) Field of Search 375/222, 219,
375/220, 224, 228, 130, 133, 134, 137, 259, 340; 370/287-282, 311; 379/407;
(56) References Cited
U.S. PATENT DOCUMENTS
4,468,785 * 8/1984 Harris 375/214
4,507,792 * 3/1985 Yamakido et al 375/249
4,569,062 * 2/1986 Dellande et al 375/370
A method is described for reducing computational requirements during idle transmission in remote access systems incorporating digital subscriber line (DSL) modems, including asymmetrical DSL (ADSL) systems. Processing power is saved during idle transmission by generating an idle signal using low-complexity techniques. The generated idle signal is made spectrally compatible with xDSL systems, and a non-disruptive signaling scheme is used to indicate to the far-end receiver the transition between idle to active or active to idle status. A technique is presented that modulates the phase of the pilot tone to signal status transitions to the remote receiver. The computational complexity at the receiver is reduced because fill demodulation and decoding is not required to determine that an idle signal is being transmitted.
20 Claims, 3 Drawing Sheets