Optimal Transaction Queue Waiting in Blockchain Mining

Blockchain systems are being used in a wide range of application domains. They can support trusted transactions in time critical applications. In this paper, we study how miners should pick up transactions from a transaction pool so as to minimize the average waiting time per transaction. We derive an expression for the average transaction waiting time of the proposed mining scheme and determine the optimum decision rule. Numerical results show that the average waiting time per transaction can be reduced by about 10% compared to the traditional no-wait scheme in which miners immediately start the next mining round using all transactions waiting in the pool.