Maximizing the System Energy Efficiency in the Blockchain Based Internet of Things

In this paper, we focus on the energy efficiency aware architecture of caching the necessary production messages and the transaction process to support a readable and tamper proof internet of things (IoT). To achieve this, blockchain can provide a reliable distributed storage of the messages, because any changes of the cached messages will break the structure of the blockchain. Specifically, we assume that the access points belonging to different telecom operators collect the messages in the IoT network, wherein multiple servers used for either caching or computing are placed at each access point. We define that the caching servers can be divided into the data loading caches for caching the received wireless IoT data and the data transmission caches for transmitting the IoT data into the blockchain based cloud caching servers. The blocks generated in the data loading caches at each access point will be written into the blockchain based on both the proof-of-work and the capacity of the data loading caches at each access point. Then, we formulate the optimization problem maximizing the system energy efficiency by optimizing the allocation of cache, computation and communication resources by a geometric programming model. By the CVX tool in matlab software, the geometric programming model can be solved effectively. We study the impact of different parameters involved in the blockchain on the system performance, and verify the effectiveness of our proposed energy efficiency aware optimization mechanism in the blockchain based IoT.