  It is widely expected that future networks of 6G and beyond will deliver on
the unachieved goals set by 5G. Technologies such as Internet of Skills and
Industry 4.0 will become stable and viable, as a direct consequence of networks
that offer sustained and reliable mobile performance levels.
  The primary challenges for future technologies are not just low-latency and
high-bandwidth. The more critical problem Mobile Service Providers (MSPs) will
face will be in balancing the inflated demands of network connections and
customers' trust in the network service, that is, being able to interconnect
billions of unique devices while adhering to the agreed terms of Service Level
Agreements (SLAs). To meet these targets, it is self-evident that MSPs cannot
operate in a solitary environment. They must enable cooperation among
themselves in a manner that ensures trust, both between themselves as well as
with customers.
  In this study, we present the BEAT (Blockchain-Enabled Accountable and
Transparent) Infrastructure Sharing architecture. BEAT exploits the inherent
properties of permissioned type of distributed ledger technology (i.e.,
permissioned distributed ledgers) to deliver on accountability and transparency
metrics whenever infrastructure needs to be shared between providers. We also
propose a lightweight method that enables device-level accountability. BEAT has
been designed to be deployable directly as only minor software upgrades to
network devices such as routers. Our simulations on a resource-limited device
show that BEAT adds only a few seconds of overhead processing time -- with the
latest state-of-the-art network devices, we can reasonably anticipate much
lower overheads.
