Cloud radio access network (C-RAN) supports the explosion of Internet of Things (IoT) applications and the demand for massive access in 5G networks. However, centralized access of trustless operators causes severe malicious insider threats, such as maliciously tamper and accidentally delete data. Blockchain, a traceable and non-tamper distributed ledger maintained by all nodes, has been considered as a feasible method to overcome these threats, while the size of the blockchain network is limited by practical byzantine fault tolerance (PBFT) consensus algorithm where the participants, the nodes who participate in consensus algorithm, bring heavy communication traffic. In this paper, we first propose a C-RAN enabled by blockchain (BC-RAN) for 5G with PeerTrust-based PBFT (Trust-PBFT) consensus algorithm to prevent the malicious insider threats and scale up the size of the blockchain network. We also propose a tri-chain structure of blockchain to divide transactions into three categories for storage to facilitate traceability. The algorithm calculates the trust value of each node, and those with high trust values will be elected to be the participants of PBFT. Simultaneously, due to the introduction of PeerTrust, another benefit is to improve the fault tolerance performance efficiently. Besides, an adjustment mechanism is designed-newly and implemented in the algorithm to impede effects produced by the malicious nodes in the blockchain network. Finally, several simulation experiments are designed to evaluate and compare the fault-tolerance performance and scalability of Trust-PBFT.

云无线电接入网络（C-RAN）支持物联网（IoT）应用程序的爆炸式增长以及5G网络中大规模访问的需求。但是，对不信任操作员的集中访问会导致严重的内部恶意威胁，例如恶意篡改和意外删除数据。区块链是由所有节点维护的可追溯且非篡改的分布式分类帐，被认为是克服这些威胁的可行方法，而区块链网络的规模受到实用的拜占庭式容错（PBFT）共识算法的限制，参与者参与共识算法的节点带来了大量的通信流量。在本文中，我们首先提出一种基于区块链的C-RAN（BC-RAN），用于基于5G的PeerTrust PBFT（Trust-PBFT）共识算法，以防止恶意的内部威胁并扩大区块链网络的规模。我们还提出了区块链的三链结构，将交易分为三类进行存储以促进可追溯性。该算法将计算每个节点的信任值，并且将选择具有高信任值的那些节点作为PBFT的参与者。同时，由于引入了PeerTrust，另一个好处是有效地提高了容错性能。此外，重新设计并在算法中实现了一种调整机制，以阻止区块链网络中恶意节点产生的影响。最后，