Biblio

As the ocean covers 70% of the Earth's surface, it becomes inevitable to develop or extend underwater applications. Compared to Visible Light medium, Acoustic medium has been widely used to transmit the data from source to destination in underwater communication. Data transmission, however, has the limitation such as propagation delay, reliability, power constraints, etc. Although underwater MAC protocols have been developed to overcome these challenges, there are still some drawbacks due to the harsh underwater environment. Therefore, the selection mechanism for underwater multi-media communication is proposed inside Medium Access Control (MAC) layer. In this paper, the main focus is to select the appropriate medium based on the distance between nodes and transmission power. The result of performance evaluation shows that this multimedia approach can complement the existing underwater single medium communication. As a result, underwater multimedia mechanism increases the reliability and energy efficiency in data transmission.

The number of sensors and embedded devices in an urban area can be on the order of thousands. New low-power wide area (LPWA) wireless network technologies have been proposed to support this large number of asynchronous, low-bandwidth devices. Among them, the Cooperative UltraNarrowband (C-UNB) is a clean-slate cellular network technology to connect these devices to a remote site or data collection server. C-UNB employs small bandwidth channels, and a lightweight random access protocol. In this paper, a new application is investigated - the use of C-UNB wireless networks to support the Advanced Metering Infrastructure (AMI), in order to facilitate the communication between smart meters and utilities. To this end, we adapted a mathematical model for C-UNB, and implemented a network simulation module in NS-3 to represent C-UNB's physical and medium access control layer. For the application layer, we implemented the DLMS-COSEM protocol, or Device Language Message Specification - Companion Specification for Energy Metering. Details of the simulation module are presented and we conclude that it supports the results of the mathematical model.