Adaptive Cooperative Transmission and Node Selection in Aircraft Approach

This paper presents a study of the non-regenerative amplify-and-forward(AF) aircraft cooperative relay transmission network.The model of a single relay cooperative transmission system is given,and the expression of the output signal-to-noise ratio(SNR) is derived and analyzed.After that,the cooperative transmission condition of the relay node is acquired.Then an efficient adaptive cooperative transmission scheme is proposed.First,the destination node determines whether or not relaying should be adopted and it sends the result to the relay node.The relay node adjusts its transmission mode according to the information it receives from the destination.In view of the fact that multi-node orthogonal cooperative transmission may greatly reduce the capacity performance of the system,a novel relay selection method is proposed based on maximizing the bounds of the output signal-to-noise ratio,and a preferable node is selected for cooperative transmission.In order to improve system performance further,the optimal power allocation between the cooperative nodes is analyzed and the optimal solution of the power allocation factor is acquired,based on which a new relay selection scheme is proposed.After the relay node is selected,the destination broadcasts this result to the relays through the control channel and the selected node participates in the next cooperative transmission,while other nodes enter an idle state.Simulation results show that by using the methods proposed above,the performance of the system can be improved significantly.