Communication Management in Multiclient System Using SMS Gateway

This chapter is part of a wide work developed in the context of smart cities and Internet of Things (IoT). We proposed a new approach in communication with IoT devices via SMS messages. This can be beneficial during changing configuration of IoT devices or during sending data from IoT devices. Of course, using SMS has several disadvantages: security and effective payload. As the security is an ongoing topic in this field, with our solution we manage to speed up key exchange process up to 62% compared to other solutions. We add the possibility of quick exchange of API key. API key is a key part in the process of creating key for symmetric encryption in communication between IoT device and central server. With limitations of SMS length, we design the use of compression methods which can send 304 bytes in 140 bytes of SMS body. Depending on the final usage of IoT device there is a possibility to turn on/off the option for security and/or compression. These new functions for communication have only 4.3% time overhead in the process of sending data and that is negligible in devices which have to communicate usually in the case of special events or only a few times a day.