With the advent of 128-bit Internet protocol, version 6 (IPv6) addresses, every “thing” can be identified through an IP address. These addressed “things” can communicate with each other and can be controlled remotely. This ability to identify things through their IPv6 addresses has given rise to technologies such as the Internet of Things (IoT) and machine-to-machine (M2M) communication.

While M2M communication opens numerous avenues for applications in the areas of healthcare, home and industrial automation, transportation, education, and surveillance to name a few, it increases the traffic in the network tremendously. Hence, more resources and bandwidth must be made available to make M2M communication a success. In wired networks, it is easy to increase bandwidth by investing in resources. In the case of wireless networks, it is not that easy because of the limitation of available spectrum. Therefore, the use of methods or techniques that allow efficient usage of the available spectrum are required. Cognitive radio is one such technology, which makes it possible to use the available wireless spectrum efficiently.

This paper presents different application possibilities where cognitive radio technology can be used to realize efficient M2M communication. The paper starts with highlighting the use of M2M communication in ad hoc and sensor networks, security systems, intelligent road-traffic management, telemetry, and building management systems. It then explains the need for cognitive radio technology in M2M communication and discusses various proposals for applications where cognitive radio technology can be used for spectrum-efficient M2M communication.

This paper gives insight into different domains of M2M communication where cognitive radio technology can be used to attain spectrum-efficient communication. Researchers who wish to work in this field can gain insight into applications of cognitive radio technology in M2M communication through the proposals presented. This paper delivers all that it promises in its title and abstract. However, in my opinion, the paper should have also discussed the challenges of applying cognitive radio technology in the presented application proposals. Doing this would have helped researchers to prepare for the challenges they may face when trying to bring the suggested application proposals to reality.