# CoNTe: A Core Network Temporal Blockchain for 5G
## 1 Introduction  
Unlike alternative distributed ledger structures, such as Block Lattice [1], Directed Acyclic Graph [2], and Distributed Hash Tables [3], which gain flexibility through modification or fragmentation of the underlying hashed-linked storage; blockchain allows little manipulation of its base structure outside of consensus model and block size. This rigid chain structure guarantees auditability, making it especially well-suited to policy-based operations demanding transparency and coordination among unmanaged network peers. For example, in events of natural disaster, or widespread infrastructure failure, having access to a trusted, secure, and decentralized data store, can be extended to allow infrastructure coordination, such as network slice allocation and other decentralised cyber-physical control, delivering neutral carrier emergency services to endpoints who would not otherwise be known subscribers. Understanding that blockchain has the structural capability to allow for coordination among infrastructure peers, recent research has moved to focus on how to fit such coordination within existing and popular blockchain mechanics and, as a result, places incentive mechanics as core and requisite to operation. These range from shared infrastructure deployment of a virtual LoRaWAN network [4], resource management in neutral carrier [5], and 5G small cell deployment [6], as well as macro-level spectrum trading and management [7]. Beyond these, bespoke wireless network-specific forks of Ethereum have also been deployed to handle coordination of mesh infrastructure and last mile connectivity [8; 9]. Underneath each of these is a limitation that is imposed by using a linear forward-hashed blockchain system that includes currency operations; they cannot be easily fragmented, since, by nature, currency transactions rely on the preceding balance recorded in perpetuity. An inability to split up or retire ledger history has a secondary effect of reducing compatibility with the latest 5G and beyond network designs, which rely on virtual network functions with temporal/limited lifecycles and the ability to not only scale up, but also scale down. As network infrastructure is increasingly abstracted and replaced with software-defined platforms for 5G and beyond generations of deployment, use of blockchain allows for sharing and coordination in ways both known and unknown, and this shows further need for blockchain that is generalized and made widely compatible with cellular design. One way of doing this is returning blockchain to the function of 'dumb' storage and, in doing so, allow all cellular operations that store data, to make use of its decentralizing and immutable nature. On the path to generalizability in cellular deployment, it is important to recognize limitation in blockchain as a data structure, in that it is linear storage and, as such, does not scale in applications, where transactions have potential to be highly bursty, or expand exponentially, such as at the network edge. Recognizing this, and further time-bounds of edge operation, we target application of blockchain at the cellular core. Permissionless Blockchains Lack Lifecycle ControlIn order to address concern of its monolithic structure and unbounded resource use, Ethereum has progressed through investigating a number of methods to scale down and make modular its monolithic blockchain, including horizontal data sharding [10], and state channels [11], as well as a full migration away from its original proof-of-work consensus, to a less compute intense implementation of proof-of-stake, named Capser, allowing for linear compute complexity (O\({}^{2}\)) [12]. In each case, although more efficient, total storage remains unbounded, and without lifecycle, so the original difficulty to wholly package the system for temporal network function use remains. Further blockchain systems have focused on efforts to scale, but make no allowance for temporal use.