Systems, methods, and instrumentalities are described herein related to cooperative user detection in non-terrestrial networks. For example, a wireless transmit/receive unit (WTRU) may be provided for cooperative user detection. A configuration may be received. The configuration may comprise configuration information associated with cooperative user detection in a non-terrestrial network. The configuration information may indicate a detection duration value and a reference signal. A notification may be received. The notification may indicate that the WTRU is to monitor the reference signal. A duration timer may be started. The duration of the duration timer may be set to the detection duration value. A measurement of the reference signal may be determined before the expiration of the duration timer. It may be determined that the WTRU is a cooperative user on a condition that the measurement exceeds a threshold.

The present disclosure addresses unresolved problems of task scheduling by adding redundancy in a collection task schedule generated by a ground control station. Embodiments of the present disclosure provide a randomization based redundant collection task scheduling for mitigating occlusions in sensing by small satellite constellations. The randomization based redundant collection task scheduling algorithm receives as input a set of region of observations tessellated into sub-regions, and then collection opportunities for each sub-region is computed based on satellite tracks data. Further, a sub-set of collection opportunities is determined from all the possible collection tasks for each sub-region to further generate the collection task schedule for each of the region of observation. Number of collections opportunities is controlled by a decay function which holds number of redundant collections to a bound, thereby increasing chance of good collection without investing too much resource in redundancy to mitigate occlusions.