Detection of outbound message signals in a power line two-way communications system

US8542720B2 · kind B2 · utility

Assignee

• Aclara Power-Line Systems Inc. · US

Inventors

• Quentin Spencer · Chesterfield, US
• John B. Hessling, Jr. · Hazelwood, US
• Benjamin A. Hammond · Creve Coeur, US
• Dennis L. Kelley · O'Fallon, US
• David W. Rieken · Saint Peters, US
• William J. Davis · Thousand Oaks, US
• Michael R. Walker · Warsaw, US

Key dates

• Filing date: Apr 18, 2008
• Grant date: Sep 24, 2013
• Expiry date: Jan 20, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B3/542
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

Improvements in the detection of TWACS outbound message signals. A first improvement involves matching some (or all) of the intermediate points in an outbound preamble occurring between bits of the preamble currently being detected. This reduces the possibility of a false synchronization and therefore decreases the probability of missing outbound message signals. A second improvement is to require some or all of the known preamble bits to exceed a predetermined threshold where both the thresh-old and which bits are adjustable. An additional approach is using 4-8 additional buffers in a transponder to detect preamble patterns in the outbound message. Each half cycle of the outbound message waveform requires entering a bit only into the buffers active for the particular frame of reference in which the message is being transmitted, since only buffers for that frame of reference are employed. The process continues until all bits specified to be sent, based on the length of the outbound message, are extracted. A CRC is then performed for the message. Using this method eliminates the problem of inbound messages being detected as outbound messages, and the resulting “blindness” of the tra…