Reliable Uncoordinated Medium Access for Critical Low-Latency Communication

Research Project, 2017 – 2020

Communication that requires the information to be delivered with very high probability within a certain deadline is referred to as critical communication. A system where nodes move in and out of the communication range unpredictably is called a highly dynamic network. The main objective of this project is to analyze a promising class of medium access protocol, namely frame-asynchronous coded slotted ALOHA (FA-CSA). It is believed that the extension to all-to-all broadcast FA-CSA (BFA-CSA) can provide reliable low-latency communication for many uncoordinated users. Here BFA-CSA is applied to cooperative vehicular communications, since that is one of the most challenging problems in communication engineering today. The reliability for such an application needs to be very high and it is also necessary that the latency is low to assure traffic safety. Our suggested approach to predict the performance and to optimize the system is based on union bounds on stopping sets, density evolution, and finite-length scaling, borrowed from the framework for low-density parity-check codes. The outcomes of the project are a fundamental knowledge about BFA-CSA that can also be used in other communication systems that require reliable low-latency uncoordinated communication in highly dynamic networks.