Multi-domain joint active user identification method in satellite Internet of Things
In the uplink grant-free access scenario of the satellite Internet of Things(IoT),users directly send data to the satellite without the need for dynamic resource allocation,which makes it difficult for the receiving end to distinguish active users in advance.To recover the transmitted data,Active User Detection(AUD)is required.Currently,code domain methods are commonly used for active user identification,but the density of IoT devices far exceeds that of mobile communication users.Relying solely on code domain identification can lead to a dramatic increase in the dimension of address codes,reducing frame efficiency.Moreover,many collection and monitoring IoT terminals have weak capabilities and cannot report their own positions,resulting in the loss of this dimension of access auxiliary information,which is not conducive to improving the performance of active user detection.Aiming at the future development trend of satellite-borne phased array,this paper introduces the concept of spatial domain identification.By cascading identification in the spatial and code domains,a multi-domain joint method is used for active user detection.Simulation results show that the proposed method can enhance the identification capability when there is an address code conflict.
satellite Internet of Thingsgrant-free accessActive User Detectionspace-borne phased array
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