Back to results
US 6,725,462 B1Granted
Optimizing upstream transmission in a cable television distribution plant
AssigneeAT&T Corp.
InventorAlan Edward Kaplan
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeAT&T Corp.
InventorAlan Edward Kaplan
Estimating the term…
A method and apparatus for reducing delay distortion of upstream transmissions in a cable television (CATV) distribution plant. Upstream transmission in a CATV distribution plant, i.e., from the customer premises toward the head-end, is made difficult by delay distortion caused by diplexing filters used in bi-directional amplifiers and other components in the CATV distribution plant. A database storing information relating to each cable modem (CM) in the CATV distribution plant is maintained, and the delay distortion for each upstream transmission is calculated using information queried from the database. Delay distortion in the upper portion of the upstream bandwidth in a CATV distribution plant is preferably minimized by assigning CMs having a transmission path that causes relatively minimal delay distortion to the upper portion of the upstream bandwidth. Alternatively, the upper portion of the upstream bandwidth is preferably assigned to the largest number of CMs that have the same number of bi-directional amplifiers in their respective transmission paths. For either frequency assigning technique, a fixed equalizer may be used to further minimize delay distortion. Alternatively, delay distortion for upstream transmissions transmitted on any frequency in the upstream bandwidth may be minimized using a variable equalizer. The delay distortion for an upstream path is calculated using information queried from the database. The tap weights for the variable equalizer are adjusted depending on the calculated distortion for each upstream transmission.
A method of assigning upstream bandwidth to a downstream cable modem communicating with a cable modem termination system in a cable television distribution plant, the method comprising steps of:
A method of assigning upstream bandwidth in a cable television distribution plant, comprising steps of:
A method of assigning upstream bandwidth in a cable television distribution plant, comprising steps of:
A method of assigning upstream bandwidth in a cable television distribution plant, comprising steps of:
A hybrid-fiber coaxial distribution plant, comprising:
A hybrid-fiber coaxial distribution plant, comprising:
A hybrid-fiber coaxial distribution plant, comprising:
A hybrid-fiber coaxial distribution plant, comprising:
A cable television distribution plant comprising:
Dependencies are inferred from the claim text.