Larry L Palmer

US Patent:

56256400, Apr 29, 1997

Filed:

Sep 16, 1994

Appl. No.:

8/308003

Inventors:

Larry C. Palmer - Potomac MD
Leonard S. Golding - Potomac MD

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

H04B 1713
H04B 719

US Classification:

375202

Abstract:

An apparatus and method for return-link transmission in direct broadcast satellite networks having a hub earth station transmitting forward-link signals, and a plurality of remote terminal stations receiving the forward-link signals and transmitting return-link spread-spectrum signals in the same transponder as the forward-link signal so that both are received at the hub station. The apparatus located at the hub station is comprised of a demodulator and a remodulator of the forward-link signals, delay as necessary for composite signals comprising the forward-link signals interfered with the return-link signals and received from a satellite, and a canceler subtracting the remodulated signals from the composite signals. The method includes a sequence of steps for synchronizing the return-link signals with the forward-link signals at the remote terminal stations, synchronizing the return-link signals with the forward-link signals at the satellite, receiving at the hub station from the satellite the composite signal having the forward-link signals interfered with the return-link signals, and canceling at the hub station the forward-link signals in the composite signals prior to spread-spectrum demodulation of the return-link signals.