Joint Scheduling and Power Control for Efficient Consensus Transmission in Wireless Blockchain Systems

This paper proposes to implement the wireless blockchain in a cellular system and focuses on the communication demanding consensus processes. The consensus processes within the cellular network based on three typical consensus protocols, i.e., PoW, Raft and PBFT, are first analyzed. The delay optimal transmission problems subject to consensus traffic demands and power constraints are formulated for uplinks and downlinks respectively. The goal is to minimize the transmission airtime by joint user scheduling and power control of the multi-cell network. We adopt the column generation (CG) and fractional programming (FP) methods to improve transmission efficiency in consensus process. The original problem is first decomposed by the CG method into a restricted master problem and a pricing problem. Then, the FP method is adaptively adapted to optimize the pricing problem for potential improvement of the current solution. The two sub-problems are iteratively processed until the optimal solution is obtained. Numerical results demonstrate that the proposed CGFP algorithm efficiently mitigates the inter-user interference, attributing to the joint spatial-temporal optimization, and notably improves the transmission delay performance.