National Spectrum Managers AssociationUnlicensed DevicesMay 16, 2006Mitchell Lazarus | 703-812-0440 | firstname.lastname@example.org
Topics • TV “white space” legislation • Proposed service changes in the 902-928 MHz band • 5 GHz U-NII band expansion.
Background • Many TV channels in every market are vacant: • co-channel, adjacent channel separations • “UHF taboos” (needed for early receivers) • broadcasting on one UHF channel limits 16 others • Proposal: unlicensed operation on unused TV channels • Need mechanism to protect TV receivers: • unlicensed device can move from place to place • TV channel assignments change over time • TV channels also used for land mobile, wireless microphones, medical telemetry, radio astronomy.
FCC Proceeding • May 2004: NPRM on unlicensed use of vacant channels • fixed: 4 watts EIRP • portable: 0.4 watts EIRP • To protect TV operations, unlicensed device – • looks for “control signal” identifying locally vacant channels, or • uses “detect-and-avoid” (DAA) technology, or • has built-in GPS and channel database • Strong and specific opposition; lukewarm support • Mid-2005: FCC seemed ready to abandon the proposal.
Problems (2): DAA in Shadow TV Tower Figure 2: Unlicensed DAA device in shadow can cause interference Unlicensed Device in Shadow TV Receiver Building / Terrain
Problems (3): DAA at Distance Figure 3: Unlicensed transmitter can fail to detect distant signal TV Tower Outdoor TV Antenna Unlicensed Device Misses Weak Signal Great Distance
Problems (4): GPS with Database • GPS works poorly indoors • Problem of keeping millions of databases current as TV channels move and change • Problem of occasional malfunctioning unlicensed device.
Senate Action • February 2006: Senate introduced legislation requiring FCC to allow unlicensed operation in TV bands • Current version of bill* instructs FCC to: • have rules take effect within 270 days of passage • protect licensees from harmful interference • require devices to have FCC certification • require a mechanism for disabling devices remotely • address interference complaints “immediately.” * “Communications, Consumer’s Choice, and Broadband Deployment Act of 2006,” S. 2686, Sec. 602 (May 1, 2006).
Opposition • Broadcast industry vigorously opposes Senate bill • concerned about interference to TV reception • seeks delay at least until end of digital TV transition • Other parties concerned about precedent • Congress created the FCC to make technical decisions • Congress is not well equipped to decide on feasibility of new wireless services • first time in recent memory that Congress would have dictated a specific outcome on a technical issue • message to public: if the FCC does not accept your technical arguments, try Congress instead.
IEEE 802.22 Proposal • Fixed devices only • base station must be professionally installed • programmed for available TV channels • remote can be installed by consumer • but needs enabling signal from base to operate • remote frequencies under control of base station • All devices on network monitor for TV signals • remotes report unexpected TV signal to base station • base station takes remotes off that frequency.
Present Uses of 902-928 MHz • ISM devices (industrial, scientific, and medical) – unlimited power • Location and Monitoring Service (LMS) – 49 watts • Federal radar – unknown power • Federal fixed and mobile – unknown power (secondary) • Amateur radio – 1,500 watts (secondary) • Unlicensed devices – 0.001-4 watts. • RFID, home security, industrial remote controls, medical devices, home audio and video, more. (Power ratings are not directly comparable.)
Multilateration LMS (M-LMS) • Triangulates from differences in arrival times • Authorized at 904-909.75, 919.75-928 MHz • rules restrict type of service, telephone interconnection • effectively limits numbers of units in use • 1999, 2001: M-LMS licenses auctioned for $4.4 million • 2000: U.S. Gov’t turned off “dither” in GPS • greatly improved accuracy; and prices dropped sharply • M-LMS never constructed • 2002: Progeny asked for “flexibility to offer whatever services the market can support and demand.”
FCC NPRM -- 1 • Drop restriction on type of service • no limitation; allow telephone interconnection, or • add flexibility to location services • Technical proposals: • reduce power to 10 watts EIRP • adopt Part-15-type digital modulation rules • limit number of units operating simultaneously • limit duty cycle
FCC NPRM -- 2 • Eliminate spectrum aggregation limits • Retain current Part 15 protections: • M-LMS licensees must prove lack of interference to Part 15 by field testing. 47 C.F.R. § 90.353(d) • Part 15 devices that meet “safe harbor” conditions are deemed not to cause harmful interference to M-LMS. 47 C.F.R. § 90.361.
Possible Opposition • Part 15 interests • likely concerns: power, density, duty cycle • likely to favor retaining existing protections • Wireless companies may allege unfair competition • LMS auctions: $311 thousand/MHz • PCS auction 58: $17 million/MHz (for partial licenses) • Amateur radio • Federal users (but may have approved NPRM).
Other Proceedings at 902-928 MHz • Amateur spread spectrum, RM-11325 • present rules: • spread spectrum to 100 watts • over 1 watt requires automatic power control • request: drop requirement for automatic power control • Cellnet proposal, ex parte in ET Docket No. 03-201 • full power only for 10% duty cycle or less • power limit drops as duty cycle exceeds 10%.
FCC Rulemaking • November 2003: FCC Report and Order (R&O) added 255 MHz to the 5.8 GHz U-NII band • expanded band covers 5.470–5.825 GHz • New requirements across entire band (to protect radars): • dynamic frequency selection (DFS) • transmit power control (TPC) • But compliance test procedure was difficult to specify • implementation dates repeatedly postponed.
2006 Action • March 30: NTIA filed 47-page compliance test procedure • agreed to by FCC, NTIA, industry panel • April 26: FCC seeks to refresh the record on three requests to clarify original R&O • Comments May 15, replies May 18 • Under current schedule, DFS and TPC rules take effect for: • certification applications filed on or after July 20, 2006 • devices imported or marketed on or after July 20, 2007.
Thank you! Mitchell Lazarus | 703-812-0440 | email@example.com