Gerald A Duggan Deceased974 Cloverleaf Ave SE, Melbourne, FL 32909

4896369, Jan 23, 1990

Dec 28, 1984

6/687269

William C. Adams - Indialantic FL
Charles R. Patisaul - Melbourne FL
Gerald S. Duggan - Indialantic FL

Harris Corporation - Melbourne FL

H04B 7185
H04B 160

455 12

The possibility of overload (saturation-lockup) condition of an ALPC satellite communication network is avoided by a scheme that grants network entry (allocates TWT power) to each link one at a time. As each link is granted entry into the network, the corresponding TWT probability density function is computed and then integrated to obtain a TWT cumulative distribution function. The required rain margin M. sub. r for a specified availability is determined from the cumulative margin. The computed margin M. sub. r is set equal to the initial satellite TWT operating point change (multiplicative factor) MR. sub. 1 due to rain fade, MF. sub. 1 =M. sub. r to ensure that network stability considerations and rain fades equally constrain network performance. This result is then used to compute the value of the corresponding multiplicative factor MF. sub. 2. These two factors, when expressed in decibels, may be added to the nominal (no rain) TWT operating point (also expressed in decibel notation) to predict the maximum TWT operating point value in response to rain stress at the specified system availability.

4776035, Oct 4, 1988

Nov 8, 1985

6/798246

Gerald S. Duggan - Indialantic FL

Harris Corp. - Melbourne FL

H04B 100

455 69

A mechanism for avoiding satellite transponder TWT saturation in an ALPC communication network detects the onset of a lockup condition through an avalanche detector. In response to avalanche detection, those links which have been identified as participating in a downlink fade have their ALPC attenuator settings placed at a minimum level, so that the operating point of the transponder TWT may be reduced below the avalanche threshold. Thereafter, as the fade recedes, those units whose ALPC attenuators have minimum power settings may be restored to normal operation. Because the orderwire which couples link quality data from a received terminal monitor unit to transmitter attenuator control units through the avalanche detection and recovery scheme may itself be impacted by a downlink fade, the foregoing scheme is augmented by a lockup detection and avoidance mechanism through which recovery from an actual lockup may take place. Transmit and receive terminal data is monitored and prescribed signal quality and ALPC attenuator setting data are correlated with one another. When a lockup condition has been detected, all of the links are effectively turned off to permit the TWT to recover from its saturation condition.