Cognitive Radio (CR)-based solutions have been suitable for efficient spectrum sharing among the unlicensed and licensed Internet of Things (IoT). Consequently, keeping a careful balance among several priority class users ensures that network congestion is avoided. In order to regulate data transmission and interconnectivity among various IoT devices, this paper proposes an event-triggered sliding mode controller for congestion maintenance, abbreviated as ETSMCC. The suggested controller improves the disturbance rejection capabilities and robustness in an IoT protocol stack for cognitive networks. Using this method, unscrupulous spectrum sharing and efficient congestion control is achieved. Our approach reduces energy expenditures and computational difficulties in the IoT protocol stack. ETSMCC with IoT protocol stack achieves an average distortion rate of 0.009%, throughput of 256 Kbps, 23% packet loss, delay with 0.32 ms and packet delivery ratio of 7.21%. ETSMCC performs better than state-of-the-art schemes, such as context-aware congestion control (CACC) and dynamic, driven congestion control (DDCC).

It is projected that communication among cognitive machine-to-machine (M2M) in smart grid networks is necessary and vital in forthcoming years. The objective of this paper is to bring out the significance of cognitive medium access control (MAC) protocol focusing on the distinctive characteristics of the devices in M2M and requirements of the smart grid communication. Therefore, developing a cognitive radio system which supports dynamic access to the spectrum available that is recently considered as a novel solution for extending wireless systems. In this paper, MAC layer sensing approaches in cognitive radio networks are investigated by considering both proactive and reactive sensing. To evaluate the performance, analytical modeling and simulation studies are carried out by comparing with state of art methods. As a result, the proposed HCM2M-MACachieves 687.3 kbps of blocking probability, 368.6kbps of dropping probability, 96.4% bandwidth utilization, 67.3% end to end delay and 89.3% of throughput.

The concept of deep-space optical communications was formulated shortly after the invention of lasers. The promise of laser communications, high data rate delivery with significantly reduced aperture size for the flight terminal, led to the pursuit of several successful experiments from Earth orbit and provided the incentive for further demonstrations to extend the range to deep space. This paper is aimed at presenting an overview of the current status of optical communications with an emphasis on deep space. Future perspectives and applications of optical communications related to near-Earth and interplanetary communications are also addressed.

Significant technological advances were made toward utilizing the Hale telescope for receiving the faint laser communication signals transmitted from an optical transceiver on a spacecraft orbiting Mars. The so-called Palomar receive terminal design, which would have supported nominal downlink data rates of 1-30 Mbps, is described. Testing to validate technologies for near-Sun (3deg from edge of solar disc) daytime operations is also discussed. Finally, a laboratory end-to-end link utilizing a 64-ary pulse-position modulated photon-counting receiver and decoder that achieved predicted near-capacity (within 1.4 dB) performance is described.

NASA's Mars laser communications demonstration (MLCD) project (since discontinued) was designed to achieve data rates greater than 1 Mb/s from the farthest Mars range and greater than 30 Mb/s from the nearest Mars range. We present here pathways whereby ongoing optical technology advances should allow 30 dB of increased data rates relative to MLCD by 2020. In other words, technical advances should soon allow the return of deep-space data at rates of 1 Gb/s from the maximum Mars range, 100 Mb/s from Jupiter distances, and 10 Mb/s from Uranus, all many orders of magnitude greater than present radio-frequency capabilities. The potential for realizing the stated capability with less than a three times increase in dc power required from the spacecraft and no increase in payload mass is discussed.