Input: Parameters of ACFEC scheme
Output: Relay nodes
(1) Acquire the SNR value of MIMO channel with real-time detection.
(2) Gain the SNR threshold SNRTE based on the QoS analytical model.
(3) If the SNR of one sensor node is less than or equal to SNRTE
(4)   select the node as relay node
(5) end if
(6) While (the data packet is received successfully or discarded actively)
(7)   If channel state information is known
(8)       Implement the relay selection mechanism when.
(9)   end if
(10) end While
Algorithm 2: Relay selection algorithm of ACFEC at relay node.