Canceled Tutorial

Tutorial Overview

Topics we will cover include:

• A look back on regulatory approach and spectrum allocation
• White spaces - what are they and their applications?
• The Sept. 23rd FCC ruling: Rules and regulations
• Challenges and complexity of building white space networks
• World-wide harmonization efforts and status
• Standardization efforts (IEEE, ECMA, White Space Alliance …)
• Available hardware and databases
• Case studies
• Research: Unsolved hard problems (sensing, heterogeneity, power, coexistence, …)

Background

Global mobile data volumes have more than doubled every year for the past four years and it is projected that in 2016 there will be more than 10 billion mobile devices moving approximately 10 exabytes of data per month, an 18- fold increase from where we are today.

Unfortunately, only a small portion of the spectrum is currently allocated for data communications. To obtain additional spectrum, regulators around the world are considering various proposals for assigning more spectrum for exclusive use licensing However, nearly all the RF spectrum is allocated for specific applications, making reallocation extremely challenging.

The reality is, large portions of the allocated spectrum are not actively used in space and time. To alleviate this disparity in spectrum use, researchers and policy makers have proposed the concept of Dynamic Spectrum Access (DSA) that is, allowing devices to use unoccupied portions of spectrum without interfering with the licensee’s transmissions.

In November 2008, the first serious DSA technology was approved by the FCC for data communication in the unused TV channels (also referred to as the TV White Spaces (TVWS)). The rules were further relaxed in September 2010. Subsequently, the OFCOM (UK), IC (Canada), IDA (Singapore) and several other regulatory agencies announced plans for similar rules in the coming years.

The standard bodies and industry have moved speedily to develop techniques to use the TVWS spectrum. For example, IEEE 802.11 working group is considering adapting Wi-Fi to work in this spectrum through a new standard called 802.11af. The IEEE 802.22 standard is ratified to operate in long range Wireless Regional Area Networks (WRANs). Neul and other companies have recently developed a new standard for M2M scenarios over the TVWS, called WeightLess. Additionally, there is also a lot of startup activity around new radios that operate in this low-frequency band. In fact, the first ASIC to operate in the TVWS was announced just last week.

White Space (WS) networking is also an active area of research, primarily because it requires a fundamental change to the way wireless devices form a network. In contrast to existing networks where devices can start using any portion of the spectrum, WS devices need to first determine if the channel is available. They need to move out of the spectrum when the primary user of the spectrum shows up. This problem is more challenging when the primary user is not a TV broadcasting station, for example a RADAR, Satellite, or a wireless Microphone. Devices also need to coordinate with other devices operating in the same spectrum, which is more important and challenging in the lower frequencies. All these necessitate the design of new PHY/MAC/Coexistence protocols for devices to operate harmoniously.

We note that the TVWS is just the first instantiation of DSA. Moving forward, concepts being tested under the guise of TVWS will likely be applied in other parts of the spectrum, as was mentioned in the recent President’s Council of Advisors on Science and Technology (PCAST) report.

Why attend the SIGCOMM tutorial?

World-wide interest in spectrum access has intensified and we face significant challenges in providing un-compromised connectivity and performance as we work towards making technology accessible to everyone. DSA and in particular, WS networking is timely and important topic. All around us there are lots of recent startups, regulatory and standards activities and trial deployments. Innovations in WS technology have the potential profoundly changing the wireless landscape.

The TVWS regulations have recently been formed in the US, the first commercial radios are showing up, the standards are getting ratified, and several pilot deployments have been rolled out in several parts of the world. The nascent shape of this field will benefit through active participation of the SIGCOMM community. Even simple and fundamental principles have a high likelihood of making real impact.

There are several hard problems of interest to the SIGCOMM community that need to be solved for the DSA concept to be become the norm. More than ten regulatory agencies worldwide are looking for ways to enable data networking over TVWS. The FCC has recently issued a Notice of Proposal for Rule Making (NPRM) to try and use DSA technologies in the 3.5 GHz of the spectrum, where RADARs and Satellites operate. Some of the fundamental problems around detecting primary users, and forming a network, need innovation in the Physical and MAC layers of the network stack.

Furthermore, very recently, hardware and software are becoming available for researchers and practitioners to begin experimenting with. There is a web service that can tell if a TV channel is available at a location 1, and another service that can measure spectrum utilization at various locations from 30 MHz to 6 GHz2. An additional ORBIT testbed for DSA research has been setup by WinLAB at Rutgers University. This is being used for a DARPA Spectrum Challenge.

Intended audience

This is a fast paced tutorial geared towards graduate students, practicing engineers, spectrum regulators, and industry executives who have a stake in the future of wireless communications. The level of this tutorial is between intermediate and advanced.

Requirements for the attendees

Students should have:

• Basic understanding of computer networking
• Working knowledge of IEEE 802.11{a,b,g,…} (Wi-Fi) standards
• Some basic knowledge of wireless broadband technologies and related issues
• A strong inclination towards designing practical systems
• Some hands on implementation experience

Materials to be distributed

Participants will be given a copy of the

• Lecture notes
• Pointers to reference papers.

Technical Program

• 9:00-9:20 Need for Dynamic Spectrum Access

• 9:20-9:40 White Spaces and its applications

• 9:40-10:00 Regulations worldwide (FCC, OFCOM, Canada,…)

• 10:00-10:30 Challenges in building white space networks and proposed solutions

• 10:30-11:00 Coffee Break

• 11:00-11:20 Currently available databases and radios

• 11:20-11:40 White space trials and pilots

• 11:40-12:00 Unsolved hard research problems

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About the Presenter