# Next-Generation Payment System for Device-to-Device Content and Processing Sharing
## 2 Background
Furthermore, the confirmation of a transaction requires a relatively long latency (ranging from about 20 to 200 min on average, occasionally exceeding 17 h around February 2018) [23]. This duration is relatively small and is around 13.72 min on average as of February 2022 [24]. The limit on the size of the blocks is another issue that increases transaction fees and transaction processing time. It is estimated that a switch to proof-of-stake could save 99.95% of the energy currently required to run a proof-of-work based system [23] in addition to the reduction in processing time. In light of these observations, many alternative digital currencies, namely \"altcoins\", have been designed and have started circulation. Ethereum [25] is an open-source distributed platform based on blockchain and a virtual machine that runs on the distributed ledger. The advantages of Ethereum over the technology behind Bitcoin include improved block processing time (around 15 s, as opposed to Bitcoin's 10 min on the average [26]), unlimited block size, and the perpetual addition of \"Ether\" to the system in contrast to the ultimate limit on the total amount of Bitcoins mineable and the \"smart contracts\", which interact with the ledger using a domain-specific language. LiteCoin [27] is a form of BitCoin and claims that the transaction confirmation time is almost zero, making it a strong candidate for real-time payment applications [28]. Nano [29], another altcoin, differs from the others in that it uses Proof of Stake (PoS) instead of PoW in order to avoid power-consuming computations. Another cryptocurrency designed for facilitating financial operations without any banking system involved is TelCoin [30], which considers the subscribers of mobile operators as the potential users. A subscriber of a member mobile operator is able to transfer or receive TelCoin to or from other subscribers. TelCoins can be obtained by transferring from other members, or they can be bought directly from the mobile operator, unlike other cryptocurrencies where mining is normally the only method to produce currency. The security aspect of blockchain contracts in IoTs are currently in the focus of the researchers. In one of the recent papers [31], the authors focus on the security aspects of smart contracts in IoT use-case scenarios and found out that their model established a firm architecture to be used in real life. In this work, we concentrate on blockchain-based incentive mechanisms to be used in real-life scenarios, without disregarding the security, reliability, and usability properties of a typical blockchain. Scarcity of resources presented people with an opportunity to convert their idle resources into economic value. This idea led to house sharing, car sharing, bicycle sharing, and even wireless network sharing [32]. Mobile device bandwidths are limited resources, but at the same time, they may sit idle for a long time before being utilized. As mentioned earlier, in one of the early papers [32] on blockchain and cryptocurrencies, researchers investigated the possibility of resource sharing in a wireless mesh network. They stated that, \"The idea of the compensation system is to create a balance between total resource contribution and its consumption. The economic value of the contribution and consumption of network resources for each participant in a given locality are recorded\". Intheir reference architecture, bandwidth-sharing was performed manually, and they made it fully automatic, rule-based sharing using a controlled blockchain deployment. Use of blockchain in telecommunication networks is particularly attracting attention in recent years. We have compiled a list of articles and compared the related work in Table 1. These have been selected from the search results on Google Scholar from 2018 onward using the following search phrases: \"blockchain and telecommunications\", \"blockchain and incentive\", \"blockchain and iot\", and \"blockchain and device-to-device\".