Non-Orthogonal Hash Access for Grant-Free IoT Blockchain Radio Access Networks

Abstract

We consider a blockchain radio access network where the devices share the wireless channel using the hash access (HA) protocol. In HA, devices obtain access to the channel with low collision probability and little control overhead upon reaching a valid hash value, below an advertised target. We elaborate on the HA protocol by proposing the non-orthogonal hash access (NOHA) scheme, where successive interference cancellation (SIC) is used with non-orthogonal multiple access (NOMA), dealing with collisions not handled by the standard HA protocol, boosting the network performance. Moreover, we find the optimal hash difficulty to access the channel that maximizes the network throughput. Analytical and numerical results show that with a single additional SIC iteration we are capable of achieving more than double the throughput of the standard HA protocol.