Q. What are TV White Spaces? TV White Spaces are frequencies in the VHF and UHF broadcast bands that are either unassigned or unused by existing broadcast or other licensees. All TV broadcasts occupy designated channels (bands), which vary in assignment by location. But not all of these channels are in use, giving rise to unused “White Spaces” which may be available for other purposes.

Q. What is the Microsoft White Spaces Database? The MSFT White Spaces Database system maintains records of all authorized services in the TV frequency bands for a specific geographic location. It enables White Spaces devices by determining availability and providing lists of channels to certified and registered White Spaces Devices (WSDs).

Q. What is frequency sharing? Sharing bandwidth (frequencies) is designed to allow bandwidth to be used by another entity when it is not be utilized or is not required by the incumbent user. An example of this might be a government agency that does not require broadband transmission at specific times. In that case, those broadband frequencies can be utilized for commercial purposes during those specific periods of time.

This form of dynamic sharing of broadband use with White Spaces offers multiple users (including federal and commercial entities) the ability to share available radio bands and increase the potential of radio frequencies by using a White Spaces Regional Database.

Q. What is Broadband Spectrum? This term refers to a range of electromagnetic frequencies – in our case VHF and UHF – that are used for electronic devices, wireless communication, and broadcast media (such as Television, Radio and cell phones). This broadband spectrum has been organized into frequency “bands” (think of the channels on TV) to eliminate “bleeding” of transmissions from one channel onto another (like the electronic “snow” you sometimes see during a TV program).

Q. What is the Value of Bandwidth? As consumers, we use the WiFi spectrum every day – when you open the door to your car with a remote key or listen to your wireless headphones at the gym. All of this uses a portion of the wireless spectrum, and is dependent upon available bandwidth. And everyone uses it – TV and Radio stations, cell phone callers, police and fire departments, and government and military.

Q. Does TV White Spaces effect licensed operations? In a word – no. Trials and commercial pilots have already been conducted in Singapore, the U.S. the U.K. and elsewhere. Numerous tests have proved that TV band White Space Devices (WSDs) operate with no interference to existing licensees entitled to interference protection.

Q. Why don’t White Spaces Devices (WSDs) interfere with regular TV broadcasting? WSDs only use managed access to unused TV channels. Using their exact location in an authorized White Space database, channel lists are utilized (with other operating parameters, such as power, duration, and geographic boundaries). White Space devices only use those authorized channels. If no channels are returned, the WSD will not transmit on TV band spectrum.


Q. How do consumers benefit from White Spaces technology? Higher bandwidth and/or more widely available network access, for starters. That will enable everyone to enjoy the growing number of online services in the ever-expanding technological future enabled by emerging technologies.

Q. Do White Spaces transmissions travel farther? What about indoors? Traditional Wi-Fi signals fade after about 100 meters from a base station, while those of TV White Spaces can have outdoor ranges measured in kilometers. Indoors, White Spaces WiFi achieved approximately four times the range of a 2.4 GHz standard Wi-Fi channel with the same transmission power and receiver sensitivity (think home network here), with less noise and better propagation through walls and obstructions.

Q. What is the range of White Space transmission? How is White Space better for rural areas? Transmission range is dependent upon a number of potential factors, which is true of any transmission network. However, the maximum range of White Spaces transmission could be up to several miles, as UHF frequencies can boost the effective outdoor range as high as 5 to 10 times more than that for 2.4 GHz.


Q. What agency regulates bandwidth in the United States? Each country has their own communications regulator that manages bandwidth use. In the United States, the Federal Communications Commission (FCC), administers broadband use designated for civilian and commercial users, while the National Telecommunications and Information Administration (NTIA), administers broadband usage of federal organizations in America.

Q. What is the difference between Licensed and Unlicensed Users? Licensed bands are given out by the regulatory authority (in the United States, this is the FCC). A license is given to an entity for their exclusive use of a channel in a specific area or location. An example of this might be the radio station 107.7, which is exclusively licensed to public radio in the Seattle area.

Unlicensed bands of spectrum are used by anyone who has a compliant device that follows basic guidelines set by the regulator (FCC again for the Unites States). For example, anyone can use a Wi-Fi router and transmit without a license, using the 2.4 GHz and 5 GHz bands. There is a standard that has been created that defines how mobile devices communicate with a Wi-Fi routers eliminating interference with other WiFi devices. This unlicensed activity permits a number of broadcasters to inhabit (broadcast) the same frequency simultaneously.

Q. What is an available channel? An available channel is a six-megahertz television channel which is not being used by an authorized service at or near the same geographic location as the TVBD, and is acceptable for use by an unlicensed device.

Q. What is the difference between fixed and portable devices? Fixed white space devices operated from a specified fixed, or non-moving locations. As such, they have more application for things like commercial Wi-Fi hotspots (think your local coffee shop), rural broadband distribution, or cellular-style installations. They typically operate at relatively higher power and use antennas mounted on higher buildings or a mast. This type of installation will have a stronger signal and reach greater broadcast distances than the signals sent by personal devices, so the regulations are stricter for them on location and hours of operation.

Comparatively, portable white space devices operate over shorter distances and utilize lower power levels (think laptops and smartphones). Since these devices generate a relatively small bandwidth or "footprint", they are permitted to have greater operating freedom in different locations and can use a larger number of frequencies.

Q. What are permissible channels of operation? Permissible channels of operation are available channels of operation for users that do not interfere with the operation of other protected TV broadband operators, as determined by a White Spaces TV bands database in accordance with interference avoidance mechanisms.

Q. What are the power limits? For fixed based TVBDs, the maximum power delivered to the transmitting antenna shall not exceed one watt per 6 megahertz of bandwidth on which the device operates. The power delivered to the transmitting antenna is the maximum conducted output power reduced by the signal loss experienced in the cable used to connect the transmitter to the transmit antenna. If transmitting antennas of directional gain greater than 6 dBi are used, the maximum conducted output power shall be reduced by the amount in dB that the directional gain of the antenna exceeds 6 dBi.

Q. What are the TVBD antenna requirements? All transmit and receive antennas of personal or portable devices shall be permanently attached to the device. The transmit antenna used with fixed devices may not be more than 30 meters above the ground. Also, fixed devices may not be located at sites where the antenna height above average terrain (HAAT) is more than 250 meters, which should be calculated by the TV bands database that the device contacts for available channels using computational software employing the methodology in §73.684(d). Refer to the FCC Electronic Code of Federal Regulations.

Q. What is the difference between Mode 1 and Mode 2 devices? Mode I TVBD portable devices do not have an internal geolocation capability, nor do they have database access. They must get a listing of available channels from a Mode II or Fixed device.

Mode II TVBD devices have internal geo-location capabilities, and database access to the channels in use.

Q. What kind of data is collected by the Regional Database? Microsoft is certified by the U.S. Federal Communications Commission (the FCC) to operate a database for the television bands (White Spaces) in the United States of America. Per FCC regulations, Microsoft collects the following information from protected entities and fixed base station operators.

Protected Entity Registration

Wireless microphones and multichannel video programming distributor receiver sites are excellent examples of a protected registered entities. Under FCC rules, they can register with the database to be protected from interference from other TV White Spaces Devices (WSDs). To do so, they must provide the following information:

  • Call signs and operating channels
  • ULS file number
  • Operator contact information
  • Geographic Location of the Transmitter
  • Geographic Location of the Receiver
  • Area of Protection
  • Schedule of operations

Fixed Base Station Registration

Fixed WSD base station operators register by location. As such, they must provide the following information:

  • Geolocation
  • FCC ID and Serial Number of Manufacturer
  • Height of Antenna
  • Owner information (Org. name, address etc.)

The Microsoft TVWS database must coordinate with other database administrators as designated by the FCC to provide the TVWS services. The complied information may be shared with other certified TVWS database operators, the FCC, and the general public.

In addition, the FCC also requires Microsoft to collect the following information from all TVWS devices that request spectrum access via the database:

  • Geographical location of the device
  • The device type (specified by the FCC’s - Fixed, Portable Mode I, or Portable Mode II)
  • The device identifier, including FCC ID and manufacturer serial number

Currently, FCC’s regulations require that all requester data and the database's response to the request be recorded and kept for 30 days for auditing purposes. This information is not shared with other database providers or the public.


What was the FCC’s role in the United States?The Federal Communications Commission (FCC) regulates interstate and international communications by radio, television, wire, satellite and cable. It had been reviewing Microsoft research papers on the subject of White Spaces from the very beginning and throughout the project - literally as research and findings were being released by company IT professionals. By the time of the initial demonstration in July of 2009, the entire process of acceptance was much easier, as credibility had already been established for the entire project through peer reviews and collaboration with the academic community at large.

The FCC issued an experimental license in July 2009 for White Spaces technology to operate inside Microsoft’s Redmond campus (roughly 1 square mile). In October 2009, MSFT IT deployed the world’s first operational white-spaces network. In 2010, the FCC ruled that devices could use a database to determine available white spaces. From there, a host of pilot projects ensued across the globe…

Q: What is the 4Afrika Initiative? Microsoft’s 4Afrika Initiative, launched in February 2013, actively promotes African economic development using relevant, affordable and accessible technology. The direct impact of TVWS is already visible with increased access for both communities and businesses that is the potential of unlimited broadband. TVWS is already beginning to enable communities with the establishment of e-commerce services in the small and medium commercial environment, as well as in the facilitation of government services - such as education and health care.

In collaboration with local public and private sector partners, Microsoft 4Afrika is currently piloting TVWS projects in Kenya, Tanzania, South Africa and Ghana. In addition, Microsoft is acting as a technology advocate for laws and regulations that promote more efficient and effective utilization of this technology as a member of the Dynamic Spectrum Alliance

Q: What is the KNOWS project? The KNOWS project stands for Networking over White Spaces. It is a group of dedicated Microsoft technical professionals involved in the process of analyzing wireless networking problems as we understand them today and designing new solutions that incorporate advances in software and hardware technologies for networking over the white spaces spectrum. Their work, in conjunction with other, forward-thinking technologists around the world, is helping to create the next generation of wireless networks.

Q: What is OFCOM? Ofcom is the communications regulator in the UK, and regulates the TV and radio sectors, fixed line telecoms, mobiles, postal services, plus the airwaves over which wireless devices operate. They ensure that Great Britain has a wide range of electronic communications services, including high-speed services such as broadband, television and radio programs are provided, and that the radio spectrum (the airwaves used by everyone from taxi firms and boat owners, to mobile-phone companies and broadcasters) is used in the most effective way.

Q: What is the Singapore Infocomm Development Authority (IDA) The mission of the Singapore Infocomm Development Authority, or IDA, is to develop information technology and telecommunications within Singapore. The IDA actively supports the growth of innovative technology in conjunction with industries and start-ups, and works with leading global IT companies (such as Microsoft) as well as developing cutting-edge IT and telecommunications infrastructure, policies and capabilities for Singapore.

Q: What is UN-RIO+20 Summit? Microsoft demonstrated the potential of TV White Spaces in providing high throughput Wi-Fi for rapid deployment scenarios, such as disaster relief, at the UN-RIO+20 Summit.

The demonstration illustrated how TV band White Spaces technology can significantly increase the rapid deployment of network coverage that provides an almost instant wide area communications network of critical communications with access for first responders. Featuring a satellite infrastructure and capacity, communication terminals, and rapid deployment logistics it received extremely positive feedback - not only from government representatives, but also the private organizations that typically deploy when disasters strike.

Q: What was the Cambridge White Spaces Trial? Launched in June 2011, the Cambridge White Spaces Trial evaluated both the technical capabilities of the technology as well as potential end-user applications and scenarios. The consortium explored and measured a range of applications, including rural wireless broadband, urban pop-up coverage and the emerging “machine-to-machine” communication, and found TV White Spaces can be successfully utilized to help satisfy the rapidly accelerating demand for wireless connectivity.

The trial completed in 2012 after over 10 months of comprehensive testing in urban and rural areas in and around Cambridge. Based on the results, the consortium recommended that Ofcom complete the development of its regulatory framework to enable the commercialization of the technology.