BAR: A Balance-Aware Routing Protocol in Payment Channel Networks

Payment channel networks (PCNs) have been proposed to tackle the scalability issues in blockchains by enabling off-chain transaction settlement. However, the balance depletion problem caused by unidirectional transactions may jeopardize the payments in PCNs. Existing works address this problem by sending artificial payments to rebalance the payment channels. In this paper, we take advantage of a unique property in PCNs, where the payments of opposite directions between two users can cancel each other out, to mitigate this channel depletion problem. Specifically, we design BAR, a distributed balance-aware payment routing protocol, subject to fee-based conservation, timeliness, and feasibility constraints. Moreover, to ensure payment security, we modify the original Hashed Time-Lock Contract (HTLC) protocol to adapt it to BAR, such that BAR achieves efficiency and atomicity. Extensive simulations demonstrate that BAR outperforms the state-of-the-art algorithms Spider [1] and LND [2] in terms of success ratio and success volume.