TV white spaces and cognitive radio took some big steps towards commercialization in 2011. On the regulation side, FCC in the US put out the final rulings to allow TV white spaces and Ofcom in the UK has intended to allow it. FCC also designated 10 database administrators. On the TV white spaces standardization side, the standards IEEE 802.22 for rural broadband was finalized and the IEEE 802.11af for Super WiFi progressed. The former also won the IEEE standards association emerging technology award. The Protocol to Access White Space Datababase (PAWS) by the IETF was also established.
Recently, near the end of 2011, the FCC chairman Genachowski announced two big steps for TV White Spaces. First, Spectrum Bridge‘s TV White Space database system was approved for operation from 26.January 2012, after successfully having conducted a 45 day trial of the system. Second, the first device for operation in TV White Spaces by Koos Technical Services was approved.
Another step is the establishment of the Whitespace Regional Area Network Alliance that promotes the development, deployment and use of standards based products and services as a means of providing broadband services using TV band frequencies. This might especially be considered an important step for IEEE 802.22. It still remains to be seen what happens with IEEE 802.11af in the Wi-Fi Alliance, but it is official that the Wi-Fi Alliance applauds the FCC ruling on TV white spaces.
With these notable steps near the end of 2011, it will be exiting to see what 2012 will bring. We will probably see some commercial IEEE 802.22 networks and maybe some trials with draft-IEEE 802.11af equipment.
The International Dynamic Spectrum Access Networks (DySPAN) symposium has emerged as the preeminent event to gather international economists, engineers, network architects, researchers and academic scholars together to share cutting edge research on and demonstrations of emerging wireless technology. DySPAN has since 2005 had a major influence on policy and technology research and development in the United States, Europe and Asia. The following bullets summarizes my key takeaways from DySPAN 2011:
- Much focus was on TV White Spaces (TVWS). Studies on available TVWS channels in different regions was presented, and there seems to be a lot. The correctness of TVWS database estimations with different path loss models was presented by Ranveer Chandra from Microsoft by comparing with sensing results. None of the path models tested gave false positives, thought the accurateness of the path loss model is crucial for maximizing spectrum utilization. Furthermore, Victor Bahl from Microsoft also presented their TVWS network trials. Bahl stated that Microsoft and Google are enemies when it comes to search, but they are in bed together when it comes to TVWS because both want to provide connectivity to everyone to best extent possible. Overall, TVWS seems to be accepted by the DySPAN community.
- Douglas Sicker from FCC presented the Spectrum Dashboard which also can be considered a tool to find available spectrum bands in the US. He also emphasized the importance of internationalization and encouraged a global market for dynamic spectrum access. He sends the message to DySPAN to work on this issue.
- David Cleevely presented analysis of the value per MHz versus technology and concluded that unlicensed spectrum generates more value than licensed spectrum! Furthermore, he concludes that femtocells will revolutionize the mobile industry.
- Krishan Sabnani from Bell Labs talked about spectrum virtualization and that a spectrum server is the final thing. He wants to use practices from virtualization in data computing. Base stations can be virtualized and run in the cloud.
- Pierre De Vries presented a paper where he propose that operating rights should be articulated using transmission permissions and reception protections, defined probabilistically (the Three Ps). Such a policy would remove the zero tolerance of interference limit violation and ease the introduction of dynamic spectrum access.
- Martin Weiss presented a paper where he focuses on the importance for the emergent regulatory policies to explicitly consider the requirements of secondary users, which not has been done yet because the secondary users not exists in meaningful number nor does they have any clear application. Furthermore he proposes to address this by explicitly consider the impact of the spatiotemporal properties of spectrum holes on the use decision by potential secondary users.
- Mitola is worried about commercializing the white space databases since he doubts that we can trust the commercial sector?
- In a panel about business perspectives on dynamic spectrum access, the urge of testbeds on white spaces was stressed by many. From an operators perspective Berna Sayrac from France Telecom mention that cognitive radio is much more than dynamic and opportunistic spectrum access, but that it can be used to manage our spectrum more efficiently. From a vendor perspective Lasse Wieweg from Ericsson mention that the most important for them is economy of scale, hence spectrum should be harmonized and he would like to see regulators worldwide to agree with each other and coordinate. He also states: do not be afraid of the higher bands such as 3.5 and 4.2 GHz.
The Internet Engineering Task Force (IETF) has recently initiated a standardization effort to standardize a Protocol to Access White Space databases (PAWS). The TV white space band is maybe the only relevant white space band at the moment, but it should be noted that this protocol addresses white spaces in general and can therefore be used for any band. This is an interesting standardization effort for future secondary spectrum access in various bands and also for the commercial progress of cognitive radio.
In more detail, the protocol will explore the various aspects of specifying a messaging interface between white space devices and the white space database. The protocol will also consider that multiple databases exist which contains information available channels at different locations.
Some days ago, FCC designated nine TV White Space database managers. These are:
- Frequency Finder
- KB Enterprises and LS Telcom
- Key Bridge Global LLC
- Spectrum Bridge
- Telcordia Technologies
- WSdb LLC
All companies have submitted proposal to be selected as a database administrator and all are selected for a period of 5 years if they succeed in implementing and testing the database. A trial of 45 days should also be successful prior to commercial launch of the database. Progressively, workshops that address the operation of the databases to ensure consistency and compliance with the rules and the database trials, are planned as soon as March 10, 2011.
Interestingly, FCC also explicitly states in the report that “… the Commission is also considering employing similar database approaches in other spectrum bands.”
Recently, FCC officially opened for TV white space spectrum, now without the strict requirement of sensing in the terminals. Interestingly, Ofcom in the UK also seem to take a similar approach. There is much discussion about which applications that will be used in the TV White Spaces (TVWS) and trials have been launched among others by Google. Obviously we have rural broadband and super-WiFi, but there are many others. In fact, most generally used applications for wireless communications could potentially be used in TVWS, but the big pros with the TVWS are the great propagation characteristics which provide for great coverage and also the relatively great bandwidths. However, some applications are more attractive than others when considering commercial and technical aspects. Therefore I provide a ranked list of 5 promising applications in the TV White Spaces:
- Wide area coverage in rural areas (e.g. IEEE 802.22): This has great potential since there especially exist much white spaces in the rural areas. Also, TVWS has perfect characteristics for this applications where propagation effects give high ranges and there are relatively wide bandwiths of 6, 7 or 8 MHz in US, Asia and Europe respectively. Broadband to rural areas might therefore be provided very cheap.
- Hotspot/low-power broadband (e.g. IEEE 802.11af): Since the much used 2.4 GHz band for WiFi is quite congested in urban areas, IEEE 802.11af also called super-WiFi will probably be used in the unlicensed TVWS. In some urban areas there does not exist much white spaces for high power systems such as (1) above, but there could be potential for low power broadband systems such as for WiFi hotspots that exploit smaller portions of TV white space. Femto-, pico and micro-cells for wireless broadband in TVWS are other examples, but these are not naturally unlicensed such as WiFi.
- Backhaul for WiFi in hotels, campuses, businesses (WiFi could be IEEE 802.11af or IEEE 802.11a/b/g/n): When WiFi is installed in hotels, campuses or business the greatest challenge is often the cabling to provide internet connectivity to the WiFi access points. By using TVWS as backhaul for WiFi access points in such installations we could avoid the costly, time consuming and challenging cabling issues. This is due to the propagation effects in the TVWS where radio signals better penetrates building walls and floors.
- Connectivity for security cameras (example):With TVWS it will be easier to install security cameras anywhere with lack of connectivity.
- Remote monitoring (power plants, patients, metering, …): Due to the propagation effects of TVWS it will be easy to provide access to power plants far away, and to patients far away and moving around potentially in the basement where signal loss is severe, but connectivity achievable with TVWS.
Other domains of interest for TVWS applications that could be mentioned are ad-hoc networks (e.g. internal sensor network or mesh network communication), healthcare applications, vehicular communications and cellular networks offloading.