Lockup detection and avoidance scheme for satellite communication network
First Claim
1. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified and relayed by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a method of preventing said satellite amplifier device from being driven to a signal amplification degradation state by adaptive link power control, in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, comprising the steps of:
- (a) monitoring a signal representative of the signal amplification state of said satellite amplifier device; and
(b) in response to the signal monitored in step (a) having a characteristic indicative of the onset of aaid signal amplification degradation state, selectively adjusting a prescribed characteristic of signals conveyed from said transmitting links to said satellite amplifier device.
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Accused Products
Abstract
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. Thereafter, those links which have not been identified as being in the path of a downlink fade are restored to normal service. When the fade recedes, those links which have had their power settings minimized for the presence of the fade are restored.
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Citations
69 Claims
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1. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified and relayed by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a method of preventing said satellite amplifier device from being driven to a signal amplification degradation state by adaptive link power control, in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, comprising the steps of:
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(a) monitoring a signal representative of the signal amplification state of said satellite amplifier device; and (b) in response to the signal monitored in step (a) having a characteristic indicative of the onset of aaid signal amplification degradation state, selectively adjusting a prescribed characteristic of signals conveyed from said transmitting links to said satellite amplifier device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a method of detecting the occurrence of said satellite amplifier device being driven into a signal amplification degradation state by adaptive link power control in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, and causing said satellite amplifier device to recover from said signal amplification degradation state comprising the steps of:
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(a) monitoring the quality of signals received at said receiving terminals; (b) monitoring signals representative of the effective irradiated power contained in signals transmitted by said transmitting terminals; and (c) adjusting the effective irradiated power contained in signals transmitted by selected ones of transmitting terminals associated with links for which the quality of signals monitored in step (a) is less than a prescribed quality and for which the effective irradiated power contained in signals monitored in step (b) is above a prescribed level. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a method controlling the amplification of signals relayed by said satellite amplifier device in the presence of signal amplification degradation causing conditions in links of said channel comprising the steps of:
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(a) monitoring a signal representative of the signal amplification state of said satellite amplifier device; (b) in response to the signal monitored in step (a) having a characteristic indicative of the onset of a signal amplification degradation state of said satellite amplifier device, selectively adjusting a prescribed characteristic of signals conveyed from said transmitting links to said satellite amplifier device; (c) monitoring the quality of signals received at said receiving terminals; and (d) in response to the quality of signals monitored in step (c) being less than a prescribed quality and in response to the signal monitored in step (a) being representative that the level of the signal amplification state of said satellite amplifier device is above a prescribed level, adjusting the effective irradiated power contained in signals transmitted by selected ones of said transmitting terminals. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified and relayed by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a system for preventing said satellite amplifier device from being driven to a signal amplification degradation state by adaptive link power control in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, comprising:
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first means for monitoring a signal representative of the signal amplification state of said satellite amplifier device; and second means, coupled to said first means and responsive to the signal monitored by said first means having a characteristic indicative of the onset of said signal amplification degradation state, for selectively adjusting a prescribed characteristic of signals conveyed from said transmitting links to said satellite amplifier device. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a system for detecting the occurrence of said satellite amplifier device being driven into a signal amplification degradation state by adaptive link power control in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, and causing said satellite amplifier device to recover from said signal amplification degradatin state comprising:
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first means for monitoring the quality of signals received at said receiving terminals; second means for monitoring signals representative of the effective irradiated power contained in signals transmitted by said transmitting terminals; and third means, coupled to said first and second means, for adjusting the effective irradiated power contained in signals transmitted by selected ones of transmitting terminals associated with links for which the quality of signals monitored by said first means is less than a prescribed quality and for which the effective irradiated power contained in signals monitored by said second means is above a prescribed level. - View Dependent Claims (52, 53, 54, 55, 56, 57)
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58. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a system for controlling the amplification of signals relayed by said satellite amplifier device in the presence of signal amplification degradation causing conditions in links of said channel comprising:
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first means for monitoring a signal representative of the signal amplification state of said satellite amplifier device; second means, responsive to the signal monitored by said first means having a characteristic indicative of the onset of a signal amplification degradation state of said satellite amplifier device, for selectively adjusting a prescribed characteristic of signals conveyed from said transmitting links to said satellite amplifier device; third means for monitoring the quality of signals received at said receiving terminals; and fourth means, coupled to said first and third means, and responsive to the quality of signals monitored by said third means being less than a prescribed quality and in response to the signal monitored by said first means being representative that the level of the signal amplification state of said satellite amplifier device is above a prescribed level, for adjusting the effective irradiated power contained in signals transmitted by selected ones of said transmitting terminals. - View Dependent Claims (59, 60, 61, 62, 63, 64, 65, 66, 67, 68)
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69. For use in an adaptive link power control (ALPC) satellite communications network wherein signals conveyed over a communications channel between transmitting and receiving terminals are amplified and relayed by a satellite amplifier device the power availability of which is controlled to meet the demands of the links of the channel, a method of preventing said satellite amplifier device from being driven to a signal amplification degradation state by adaptive link power control, in response to the attenuation of a signal relayed by said satellite amplifier device between said transmitting and receiving terminals, comprising the steps of:
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(a) monitoring the quality of signals conveyed over said communications channel by way of said satellite amplifier device; (b) in response to a prescribed condition of said communications channel, causing an increase in the power of signals conveyed over communications channel by way of said satellite amplifier device; and (c) in response to step (a) detecting a decrease in quality of signals with an increase in signal power in step (b), controllably preventing a further increase in signal power by step (b).
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Specification