What Should We Learn from... Software-Defined Networking

Software defined radio (SDR) is an architecture for designing more flexibility and generalized hardware for communication systems, radar, sonar or remote sensing systems making more intelligent and multi-function radio systems possible. In the January 2015 issue of the Proceedings of the IEEE, two articles present surveys in the fields of software defined networking (SDN) and the spectrum management for radar systems which is one of the key techniques for radar and wireless communication.

Traditional IP networks have certain limitations in spite of their widespread acceptance. In addition to being quite complex, they can be difficult to configure and reconfigure. Additionally, current networks are also vertically integrated, which means that the control and data planes are bundled together. In an effort to overcome these limitations, an emerging paradigm, namely, software defined networking, breaks vertical integration by separating the network’s control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. This allows for increased flexibility. In the article “Software-Defined Networking: A Comprehensive Survey” by Diego Kreutz et al, the authors use a layered approach to methodically dissect the state of the art in terms of concepts, ideas, and components of SDN, covering a broad range of existing solutions, as well as future directions. More specifically, an analysis of SDN infrastructure building blocks is presented and, using a bottom-up approach, an in-depth overview of eight fundamental facets of the SDN problem is provided.

Spectrum management is one of the key problems in both software defined radio and cognitive radar/communication systems. The radio-frequency (RF) spectrum refers to that part of the electromagnetic spectrum which extends from 1 MHz to about 100 GHz. In most countries, the generation of radio waves is strictly controlled by the government. The RF spectrum is widely used for a number of applications such as communications, radio and television broadcasting, radio navigation, and sensing. Within the RF spectrum, the radar bandwidth represents a fundamentally important part. Radars can determine an object’s position, velocity, and/or other characteristics by means of the propagation properties of radio waves. They can be used in applications such as air traffic control, geophysical monitoring of Earth resources from space, automotive safety, severe weather tracking, and surveillance for defense and security. There is a constant need for greater bandwidth for nearly all the services within the RF spectrum. This means that there will be increasing competition for this finite resource.What is then the radar spectrum management? Why should it be important to the concerned citizens in a manner similar to that which invokes their passion for the Net neutrality? The paper “Radar Spectrum Engineering and Management: Technical and Regulatory Issues” by Griffiths et al. more than adequately describes the present situation and cautions against the consequences if we do not pay enough attention to it. Both technical and regulatory points of view are covered. These include improved transmitter spectral purity, passive radar, and intelligent, cognitive approaches that dynamically optimize spectrum use.
References:
[1] Diego Kreutz, Fernando M. V. Ramos, Paulo Siamak Azodolmolky, and Steve Uhlig. Software-Defined Networking: A Comprehensive Survey. Proceedings of the IEEE. 2015, 103(1)
[2] Amitava Dutta-Roy. An Introduction to the paper by Griffiths, Cohen, Watts, Mokole, Baker, Wicks, and Blunt. Radar Spectrum Engineering and Management: Technical and Regulatory Issues. Proceedings of the IEEE. 2015, 103(1)
[3] Hugh Griffiths, Lawrence Cohen, Simon Watts, Eric Mokole, Chris Baker, Mike Wicks, Shannon Blunt. Radar Spectrum Engineering and Management: Technical and Regulatory Issues. Proceedings of the IEEE. 2015, 103(1)