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Satellite Digital Audio Radio Service (SDARS) (Sirius & XM)
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Sirius and XM, which are now one company, use this band to transmit digital radio from their satellites and also from ground-based transmitters (terrstrial repeaters) that fill in coverage gaps due to building and terrain blockage of the satellite signals.
According to the FCC (FCC 10-82), "The Commission's rules define SDARS - commonly known as "satellite radio" – as "[a] radiocommunication service in which audio programming is digitally transmitted by one or more space stations directly to fixed, mobile, and/or portable stations, and which may involve complementary repeating terrestrial transmitters, telemetry, tracking and control facilities." Thus, SDARS is primarily a satellite-delivered service in which programming is sent directly from satellites to subscriber receivers either at a fixed location or in motion. Because a direct line of sight is generally required in order to receive an acceptable satellite signal, ground-based terrestrial repeaters are used in many areas to re-transmit the same signals provided by satellites directly to subscribers in order to maintain adequate signal power. These areas include "urban canyons" between tall buildings, heavily foliaged areas, tunnels, and other places where obstructions could limit satellite visibility or cause multipath interference from reflected signals.
"Licenses to provide SDARS within the United States were awarded by auction in early April, 1997. The two winners of the auction – XM and Sirius – were each assigned 12.5 megahertz of spectrum for their exclusive use on a primary basis. XM and Sirius launched their satellites and began commercial operations in 2001 and 2002, respectively. As of March 31, 2010, Sirius XM reported it had 18,944,199 subscribers in the conterminous United States.
"On August 5, 2008, the Commission approved the merger of XM and Sirius, which have subsequently combined to form a merged entity called "Sirius XM." In the merger proceeding, the Commission found that significant engineering differences in the XM and Sirius infrastructures make integration of the two systems difficult in the short term. In addition, the Commission noted that XM and Sirius had each invested significantly in their existing infrastructure, with the expectation of operating this infrastructure for years to come. Thus, despite the merger of the two companies, the XM and Sirius satellite and repeater infrastructures will operate as separate, legacy systems, at least in the near term.
"Sirius XM offers hundreds of channels of music, entertainment, news, and sports programming on the Sirius and XM satellite radio networks, as well as weather and data information services for maritime, aeronautical, and other purposes. SDARS radio receivers are used in cars, trucks, boats, aircraft, and homes – and are available for portable use..."
Acccording to SiriusXM, their satellite signals cover the 48 contiguous states, and 200 miles "off shore."
Historical Information on SDARS
The following is historical information on SDARS from Benn Kobb's 2001 book Wireless Spectrum Finder. That book is now (c) SpectrumWiki.com:
*****
The principal worldwide band for audio broadcasting direct to the public from satellites (Broadcasting-Satellite Service (Sound) or BSS) is the so-called L-band, 1452—1492 MHz.
That band falls within aeronautical test telemetry spectrum in the U.S. (see 1435—1525 MHz).
As an alternative, the International Telecommunication Union (ITU) allocated the S-band, 2310—2360 MHz, for domestic satellite audio broadcasting in the U.S. Other nations, especially Canada, criticized this action as detrimental to the realization of a uniform worldwide service in the L-band.
The ITU also allocated 2520—2670 MHz for BSS national and regional systems for community reception. (India and Mexico also are authorized to use the S-band for BSS.)
Against ferocious opposition from conventional broadcasters, the FCC eventually allocated 2320—2345 MHz to satellite Digital Audio Radio Services (SDARS or DARS). “Satellite DARS will provide continuous radio service of compact disc quality for all listeners and will offer an increased choice of over-the-air audio programming,” the FCC said.
No other significant terrestrial U.S. users are in the S-band, but adjacent countries operate terrestrial fixed point-to-point, fixed point-to-multipoint, and aeronautical mobile telemetry systems in the band. Satellite DARS operators must take precautions to avoid interference with the systems of other nations.
Sirius and XM
There are two SDARS licensees : Sirius Satellite Radio (2320—2332.5 MHz), formerly Satellite CD Radio and XM Satellite Radio (2332.5—2345 MHz), formerly American Mobile Radio.
These companies won their licenses by bidding $83 million and $89 million, respectively, at an April 1997 auction. The FCC concluded that only enough spectrum existed in the S-band for two SDARS licensees of 12.5 MHz each. The FCC requires that SDARS receivers be capable of picking up broadcasts from both of the licensees.
The licensees must deploy hundreds of terrestrial repeaters, ground transmitters that relay broadcasts from satellites. Most of the gap-fillers will be in urban areas where obstructions inhibit satellite reception.
Sirius will use three satellites in inclined elliptical orbits will offer a service directed mainly to vehicle radios. Sirius-1 and Sirius-2 had been launched at this writing. The major investors in Sirius include Ford and Loral.
XM will use two geostationary satellites (officially designated “Rock” and “Roll”) that are directed both to vehicle and portable radios. XM’s major investors include GM and its DirecTV business; Clear Channel Communications; and Liberty Media, in addition to its founder, Motient Corp., formerly American Mobile Satellite Corp.
Uplink stations in 7.025—7.075 GHz feed these satellites. They use frequencies in the S-band in 3.7—4.2 GHz, and 5.925—6.425 GHz for telemetry and control, operation during transfer to final orbit, and for contingency purposes.
Other SDARS-Related Issues
Sirius and XM might have faced competition from SDARS service in the Wireless Communications Service (WCS) band. A group of WCS licensees applied for permission to use their licenses to provide SDARS (see 2305—2310 MHz). They later abandoned the idea.
The FCC licensed, originally on an experimental basis only, the WorldSpace SDARS system to broadcast in the L-band (see 1435—1525 MHz). It later granted full authorization to the Washington, D.C.-based WorldSpace, but does not permit the company to serve U.S. audiences.
NASA’s Goldstone Solar System Radar operates at 2320 MHz and 8.56 GHz in the Mojave Desert northeast of Los Angeles. Scientists used it to observe Comet Hyakutake when it passed within 9.3 million miles of Earth in 1996.
SDARS interference is expected to make radar astronomy operations at 2320 MHz “nearly impossible,” according to NASA’s Jet Propulsion Laboratory.
The 2310—2390 MHz spectrum is one of many restricted bands in which the FCC Part 15 rules permit unlicensed devices to emit only very low level emissions.
***** (End of historical information from Wireless Spectrum Finder)
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NTIA Spectrum Use Summary
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The federal agencies use this band for fixed point-to-point microwave communication systems for national and military test range communications, and the remote transmission of radar video and other data for functions such as weather, vessel traffic control in harbor areas, and hydroelectric grid power management. This includes the Federal Aviation Administration use of this band for fixed point-to-point microwave communications networks to connect remote long-range aeronautical radionavigation radars to air traffic control centers.
The National Aeronautics and Space Administration and the National Oceanographic and Atmospheric Administration use the 6425-7250 MHz band for passive sensing of the Earth from space using microwave radiometers to obtain measurements of sea surface temperature which is a key component in weather forecasting and climatological studies. This band is used in conjunction with passive sensing bands around 10.6, 18.7, 23.8 and 36 GHz to obtain several important climatological parameters.
The NTIA does not issue information on the use of specific band segments in the 7/8 GHz band for fixed links, but the following information is available in a 2000 NTIA Report (NTIA Report 00-378) regarding government fixed service use in the 7125-8500 MHz range:
The FAA has 4,010 fixed assignments, including the radio communications link (RCL) system, a nationwide network used to connect air traffic controllers with communications and radar data from remote radar sites. The Air Force has 710 fixed assignments, used to support a large number of activities on numerous test and training ranges. The Navy has 800 fixed assignments, used mainly in voice and data links, ground forces communication, and land-line back up.
The Army has 450 fixed assignments, used for video scoring, closed circuit TV (security), point-to-point communications training, and for administrative traffic.
DOE has 1,200 fixed assignments used for system control and data acquisition (SCADA) for electric power distribution networks, perimeter security surveillance, laboratory telecommunication systems, and test site surveillance. Justice has 400 fixed assignments, used for fixed backbone nets used in law enforcement communications.
The Coast Guard has 160 fixed assignments, used to relay maritime radar and
communications needed for safety and navigation purposes in harbors and other critical locations. TVA has 140 fixed assignments, used for SCADA for electric power distribution systems.
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Frequency Bands |
| Band | Use | Service | Table |
| 7125 - 7145 MHz | NTIA Spectrum Use Summary | - | F |
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802.11/WLAN/Wi-Fi/WiGig
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Wireless LANS utilize various channels in the 2.4, 5, and 6 GHz bands (multiple countries), and (in theory) the 3.6 GHz band (U.S. only). For a list of which channels are available in which regions, refer to the Wikipedia article.
Wi-Fi is a trademark permitted for devices that are based upon a published standard of the IEEE 802.11 committee and that have been certified by the Wi-Fi Alliance. Wi-Fi is presently incorporated in about three billion devices. Wireless cash registers were one of the earliest applications of what is now Wi-Fi.
Wi-Fi devices operate on an unlicensed basis, generally meaning they cannot cause interference to licensed services, and must accept any interference caused to them. Wi-Fi shares bands with other unlicensed or ISM devices, such as cordless phones at 2.4 and 5.8 GHz and microwave ovens at 2.4 GHz.
Some of the key patents related to Wi-Fi are credited (in the courts at least) to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, which has collected over $400 million in royalties and legal settlements over patent rights.
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Frequency Bands |
| Band | Use | Service | Table |
| 2400 - 2495 MHz | Wireless LANs | - | - |
| 3655 - 3700 MHz | Wireless LANS (U.S. only; standardized but not used) | - | - |
| 4910 - 4990 MHz | Wireless LANs (Japan) (U.S. public safety 4940-4990) | - | - |
| 5030 - 5090 MHz | WLANs (Japan, 2002-2017) | - | - |
| 5150 - 5350 MHz | Wireless LANs (U-NII-1 and U-NII-2A) | - | - |
| 5470 - 5895 MHz | Wireless LANs (U-NII-2C, U-NII-3, U-NII-4) | - | - |
| 5925 - 7125 MHz | Wireless LANs (U-NII-5, U-NII-6, U-NII-7, U-NII-8) | - | - |
| 42.39 - 46.71 GHz | Wireless LANs (WiGig) | - | - |
| 57.24 - 74.52 GHz | Wireless LANs (WiGig) | - | - |
External Links:
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IEEE 802.15.4 HRP UWB
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High pulse repetition frequency ultra-wideband (HPR UWB) is one of the physical layers defined for low data rate personal area network (LR-WPAN) communications in the IEEE 802.15.4 standard.
According to the FiRa Consortium:
"In challenging environments, such as parking structures, hospitals, airports and high density venues, ultra-wideband (UWB) technology outperforms other technologies in terms of accuracy, power consumption, robustness in wireless connectivity, and security, by a wide margin.
"UWB securely determines the relative position of peer devices with a very high degree of accuracy and can operate with line of sight at up to 200 meters. In contrast to narrow band wireless technologies, the use of wide bandwidth means UWB provides very stable connectivity, with little to no interference and offers highly precise positioning, even in congested multi-path signal environments.
"By calculating precise location, fine ranging based on UWB is a more secure approach to closing and opening locks, whether those locks are installed on a car door, a warehouse entryway, a conference room, or your front door."
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Frequencies |
| Frequency | Bandwidth | Use | Service | Table |
| 499.2 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 0 | - | - |
| 3494.4 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 1 | - | - |
| 3993.6 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 2 | - | - |
| 3993.6 MHz | 1.3312 GHz | 802.15.4 HRP UWB Channel 4 | - | - |
| 4492.8 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 3 | - | - |
| 6489.6 MHz | 1.0816 GHz | 802.15.4 HRP UWB Channel 7 | - | - |
| 6489.6 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 5 | - | - |
| 6988.8 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 6 | - | - |
| 7488 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 8 | - | - |
| 7987.2 MHz | 1.3312 GHz | 802.15.4 HRP UWB Channel 11 | - | - |
| 7987.2 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 9 | - | - |
| 8486.4 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 10 | - | - |
| 8985.6 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 12 | - | - |
| 9484.8 MHz | 1.35497 GHz | 802.15.4 HRP UWB Channel 15 | - | - |
| 9484.8 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 13 | - | - |
| 9984 MHz | 499.2 MHz | 802.15.4 HRP UWB Channel 14 | - | - |
External Links:
Associated Files:
802.15.4 HRP UWB PHY band allocation
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