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The Internet of Things movement opens new possibilities for services and business along with new technological challenges, such as power efficiency, operation in constrained environments, security, and privacy. With the expectation of a high amount of devices connected in this Future Internet, scalability is also assumed to be a challenge. To address these limitations, several protocols are being proposed. In this paper, two of them, MQTT and COAP, are presented and qualitatively compared, summarizing their main features and limitations, highlighting the best scenarios where each approach is more suitable.

This article presents the development of an electrically controlled reconfigurable antenna array and its implementation in a low‐cost embedded wireless cognitive network with a real‐time multi‐sector spectrum sensing. The proposed approach has been implemented in the unlicensed 2.4GHz ISM band with the purpose of independently performing spatial and spectrum sensing over different sectors of the wireless coverage area in real time. This novel network functionality is ensured by the use of an antenna array that is able to provide a reconfigurable radiation pattern. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1929–1934, 2016