A Blockchain-Assisted Federated Learning Method for Recommendation Systems

Due to the privacy advantages of federated learning (FL), federated recommendation systems (FedRSs) are gaining popularity for improving recommendation performance through training on local data. However, FedRSs frequently face the significant challenge of high communication costs between the server and clients. Most FedRSs utilize a client-server communication architecture, leading to heavy communication loads and single points of failure due to dependence on a central server. Clients may also encounter problems due to limited communication resources. In view of this challenge, in this paper, we propose a blockchain-assisted federated learning method at edge for communication-efficient recommendation systems, named BFedRec. Specifically, BFedRec reduces reliance on the central server by utilizing blockchain systems on edge servers to aggregate and distribute the recommendation model. To mitigate the high communication costs between clients and blockchain in each iteration, a communication-efficient training algorithm is used that trains the recommendation model directly on low-rank compressed parameters. Finally, we conduct extensive experiments on real-world datasets to verify the communication efficiency of BFedRec compared to existing methods. The experimental results show that BFedRec effectively improves communication efficiency without compromising recommendation performance.