Reducing the propagation delay of compact block in Bitcoin network

Bitcoin is a Blockchain-based network in which thousands of nodes are directly connected and communicate via a gossip-based flooding protocol. Mined blocks are propagated to all participating nodes in the network through a CBR (compact block relay) protocol developed to reduce the block propagation delay. However, propagation delay persists. The relay time between nodes must be measured and analyzed to determine the cause of the delay and provide solutions for reducing block propagation time. Previously, we measured the relay time and investigated the cause of the delay. According to the findings of the previous study, the delay of the relay time occurs when assembling compact blocks, depending on whether transactions are requested. In this paper, we find the reasons for requesting transactions. The reasons are due to the transaction propagation method and the characteristics of the transaction itself. We propose a solution based on this. It is a method of reducing probability of requesting transactions by using the compact block's “PREFILLEDTXN” to send the transactions expected to be requested with the block. The probability of requesting is reduced by up to 67% when transactions that have just entered the memory pool are propagated by PREFILLEDTXN. The block relay time is reduced by up to 44% as a result. Finally, this research reduces block relay time between nodes.