Amazon Technologies, Inc.

Vikram Chandrasekhar

Arunabha Ghosh

Tanim Mohammed Abu Taher

Mustafa Cenk Erturk

A radio network with many endpoints, such as many user terminals (UTs) accessing a constellation of many satellites, may experience self-interference due to reduced apparent angular separation between endpoints. For example, many UTs that are covered by a satellite's antenna gain pattern of an uplink may interfere with one another if those UTs use the same frequencies at the same time. The UTs may be geographically separated, but due to relative position between them and the satellite, they appear within the same gain pattern. Resource mapping is performed to allocate link resources to mitigate self-interference. A conflict graph is determined and used to allocate link resources, such as particular combinations of timeslot and frequency, to reduce or eliminate self-interference. The conflict graph may be determined using one or more analytical or heuristic techniques. Resource allocation may be performed for links such as satellite uplinks, satellite downlinks, or both.

System for interference mitigation in a satellite communication system

Satellites communicate with user terminals (UTs) based on accurate timing. A UT clock provides a pulse per second (PPS) signal to coordinate operation of the UT, such as transmitting data on an uplink at specified times. The clock may be disciplined by an external source that provides accurate and precise true time, such as a global navigation satellite system. The external source may sometimes be unavailable. The UT uses information about its location, satellite location, the ephemeris of the satellite, and timing data transmitted by the satellite, to calculate an estimated delay due to propagation, scintillation, and so forth. The timing data and estimated delay are used to determine a time correction. The time correction is applied to the timing data and used to determine estimated true time, that is then used to generate an alternate PPS signal. The estimated true time is used until the external source is available.

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San Jose, CA, United States of America

Vikram Chandrasekhar