As stated earlier, communication access technologies are a vital aspects of SG network ranging from wired to wireless technologies. It is essential to study the performance of various access technologies in order to establish the appropriate ones for a reliable SG net- work. This then necessitates investigative study on performance measurements of access technologies for SG network. However, most of the works are tilted toward Communication network architecture in SG in order to achieve a reliable SG communication network. Hence, communication network architecture in smart grid have been addressed in one way or the other. A study in [194] proposed three layers-architecture for communication network architecture in the Smart Grid. The first layer represents the wireless local area network (WLAN) by using Wi-Fi to provide communication inside the data centres and link to metering devices and to the next layer. The second layer is the wireless metro network (WMAN) by using WiMAX to provide communication between data centres and transmission substations to the utility. The third layer is the wide area network (WAN) using fibre optic between the data centre and control to the utility. However, it does not consider performance measurements of the access devices used. Also, CRSN and interoper- ability issues are not considered in its architecture.
Another work suggests a hybrid network architecture by incorporating a wired infrastruc- ture, WSN, and a PLC for the Smart Grid [195]. Their proposed architecture has three subsystems comprising the data acquisition subsystem, communication subsystem, and supervisory control subsystem. However, the work has the following drawbacks such as not adopting the NIST framework model in its architecture and no technology for mitigating interference was also adopted.
The study in [200] proposed communication network architecture alongside software architecture in terms of energy efficiency in the neighborhood area network (NAN) of the smart grid. The drawback of this work is that its architecture is only for NAN and not for the entire SG. Also, the communication network architectures that support most of the smart grid applications, ranging from power generation to distribution as well as automatic metering infrastructures (AMI), are discussed in various research works such as in [201]–[203]. But these studies do not consider implementation models that involve heterogeneity and multihoming in the communication network including performance measurements of the access devices for SG. This is because various SG applications re-
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quires different transmission bandwidths and latency.
Obviously, many researchers employed the use of wireless sensors for monitoring in various SG applications. For example, using wireless sensors for smart grid multimedia applications are investigated in [204]. Mirza et al. [205] proposed the use of CR based Wi-Fi for field area network (FAN) in SG. The difference between their work and ours is that their focus is on FAN, and they did not incorporate low power wide area network (LPWAN) technologies and multihoming. Whereas our work considered in detail the entire SG communication network domain.
Another area of work which is of concern to the research community is the issue of blocking probability in CRSN for a SG. For instance, the authors in [150] proposed a non-cooperative channel packing scheme (CPS) to reduce the blocking probability in a heterogeneous CRSN for an SG. Numerical results show that the CPS scheme significantly reduces the blocking probability, and increases the spectrum utilization. However, this work did not consider bit error rate (BER) nor channel fragmentation with a diversity scheme in their investigation. Ref. [206] proposed a new binary exponential backoff (NBEB) algorithm that significantly reduces the blocking/dropping probability, and improves the performance of the commu- nication in CR for SG. Ref. [207] proposed the use of buffer occupancy as an indicator of the sensor node priority to access spectrum in order to mitigate congestion and packet blocking probability in a CRSN for a SG. Ref. [145] investigated blocking probability based on prioritizing traffic in a CR network-based SG. The blocking probability in the SUs of the prioritized system increases very little. Whereas, the blocking probability of SUs in the non-prioritized system increases greatly. In [140], a hybrid dynamic Spectrum Access together with joint WAN/NAN Spectrum Management has been proposed. The scheme actually outperforms the traditional system by significantly decreasing the dropping and blocking probability.
Another study [72] proposed communication network architecture that support high data rate applications with low data transfer latency by using wireless multi-homing of two heterogeneous wireless networks in a SG. The difference between their work and ours is that their work is not on CRSN based SG, there is also no consideration of LPWAN technologies for energy efficiency. The study here involves consideration of performance measurements of access technologies including consideration of improved CR model for SG communication. This is achieved through the use of multihoming in heterogeneous wireless networks utilizing LPWAN technology, such as LTE cat1/LTE-M1, and the use of CR technology in the form of TV band devices (TVBDs), also called super Wi-Fi, for cognitive capability. Hence, the focus here is on performance measurements of access tech- nologies jointly with improved CR model for SG communication that utilizes the technology discussed above with the following considerations:
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Standards is addressed.
2) Support for various SG application including high data rate is included. 3) The energy efficiency of the technology used is considered.
4) An Improved CR model is also considered.
Based on the studies reported in the available literature related to this work, to the au- thors’ best knowledge, it can be observed that no other research has holistically considered the technologies discussed above, and consideration of performance measurements jointly with improved CR model in a CRSN based SG.