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Blockchain technology is one among the recent innovations in the computing industry. Blockchains have gathered a widespread interest in the industry mainly due to their security promise. Despite the anticipated benefits of Blockchains, there are several limitations which make the technology less suitable in large scale applications such as banking, one being low throughput. Several initiatives to improve the throughput of Blockchains are being tried out both in the academia and the business worlds but no systematic classification of the initiatives and the strategies used has been done. This study explores Blockchain performance improvement initiatives and classify the initiatives by the improvement strategy used. This study has found that, out of 365 articles on the area of Blockchain performance, 300 were solution proposals aimed at improving the performance of Blockchains. The most used strategies in these proposals were alternative to PoW, sharding and multi-chain architecture.

A resource sharing in power line communications (PLC) for the home network is restricted by the channel assignment techniques which decide who has the right to gain access to send data. The channel assignment techniques include contention-free and contention-based. The former requires high synchronization due to the deterministic round-trip time. Besides, contention-based utilizes CSMA/CA techniques that allow stations in a network to compete for channel access and are suitable for decentralized network topology. However, a trade-off exists between the number of stations required to gain access versus system efficiency. Whilst some research has been carried out on CSMA/CA resource sharing techniques that allow only one user to transmit, there is very little work done on multiuser access to optimize system efficiency and reduce collisions in a network. The purpose of the current study was to review the CSMA/CA techniques for resource sharing to improve system efficiency in power line communications. In carrying out this study, a systematic literature review methodology to evaluate different related works and determine the most suitable approach to allow multiuser channel access was used. The study further demonstrated the impact multichannel access has on system efficiency. In addition, the study provides recommendations for future research. Keywords: CSMA/CA; Medium access control; OFDMA; power line; resource sharing;