| CPC H04L 25/0254 (2013.01) | 8 Claims | 

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               1. An active terminal detection and channel estimation method of a base station in a wireless communication system based on grant-free uplink transmission, the method comprising: 
            receiving superimposed signals ( 
                 ) from k active terminals;calculating, using a first artificial neural network and using the received signals ( 
                 ) as input, an estimated probability (Ω) that each of all terminals in a cell of the base station is an active terminal; andestimating channels of the active terminals using a second artificial neural network with the received signals ( 
                 ) and an active terminal detection result value as input,wherein the first artificial neural network and the second artificial neural network are each an artificial neural network based on long short-term memory (LSTM) networks, and 
                wherein the first artificial neural network is established by learning a direct mapping according to Equation 5, and the second artificial neural network is established by learning a direct mapping according to Equation 8: 
                Ω=gand( 
                 :θA)  [Equation 5]wherein θA is a parameter of the first artificial neural network used for the active user detection, 
                ĥΩ=gce( 
                 ,Ω;θC)  [Equation 8]wherein θC is a parameter of the second artificial neural network used for the channel estimations. 
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