Retracted: Study on ALOHA Anti-Collision Algorithm Based on LoRa for Internet of Things

For collision avoidance of data, related existing technologies and algorithms are studied and compared in advantages and disadvantages. In addition, in order to solve the problem of excessive collision probability in data collision avoidance algorithm (ALOHA) in LoRaWAN, the CDMA idea is introduced, and an improved data collision avoidance algorithm (CD-ALOHA) is introduced. This algorithm utilizes the multiple accessibility of orthogonal spreading codes and also preserves the competitive backoff strategy in the ALOHA algorithm. Compared with other algorithms, it further increases the network channel throughput and reduces the average time delay of data transmission. The effectiveness of the CD-ALOHA algorithm is verified by theoretical derivation and simulation experiments.