Here it is: At 600 MHz, interference travels farther than it does at higher frequencies, all else equal.
Archive for the ‘White Space’ Category
A crucial engineering fact I’m not hearing from municipal TV white space proponents
Monday, February 11th, 2013Experimental radio applications at the FCC
Sunday, September 9th, 2012This summarizes a selection of applications for the Experimental Radio Service received by the FCC during July and August, 2012. These are related to medium-frequency communications, meteor radar, space-to-space communications, UAV communications, synthetic aperture radar, TV white space, 600 MHz LTE, disaster communications, cellular content caching, GSM, passive intermodulation distortion, ultra-wideband, TDD, ground-mapping radar, Doppler radar, and ground surveillance radar. The descriptions are sorted by the lowest frequency in the application.
Experimental Radio Applications at the FCC
Sunday, February 5th, 2012This summarizes a selection from 215 applications for the Experimental Radio Service received by the FCC during October, November, and December 2011. These are related to AM broadcasting, FM broadcasting, spread spectrum on HF and VHF, unmanned aerial vehicle control, electronic warfare support, small satellites, white space technology, video production, managed access, TV interference, RFID, and radar. The descriptions are listed in order of the lowest frequency found in the application.
Experimental Radio Applications at the FCC
Sunday, November 6th, 2011This summarizes a selection from 173 applications for the Experimental Radio Service received by the FCC during August and September 2011. These are related to long-range low-frequency radar, amateur radio, shortwave data, wireless microphones, single-sideband, mine detection, millimeter-wave communications, signal intelligence, automotive radar, satellite feeder links, meteor-burst communications, aircraft telemetry, white space systems, border security radar, 3G and 4G applications, RFID, wind turbine testing, unmanned aerial vehicles, spacecraft telemetry and control, aircraft passenger broadband, and autonomous aircraft landing systems. The descriptions are sorted by the lowest frequency found in the application.
Experimental Radio Applications at the FCC
Monday, June 13th, 2011This summarizes a selection of applications for the Experimental Radio Service received by the FCC during April and May 2011. These are related to TV white space, electromagnetic compatibility testing, train control, point-to-multipoint communications, satellite communications, radar, unmanned aerial vehicles, GPS, ultra-wideband, mobile satellite service, UMTS, mobile broadband picocells, wireless backhaul, and IEEE 802.11p. The descriptions are sorted by frequency.
Experimental Radio Applications at the FCC
Tuesday, March 15th, 2011This summarizes a selection of applications for the Experimental Radio Service received by the FCC during February 2011. These are related to cognitive radio, land mobile, TV white space, unmanned aircraft systems, satellite terminals, ultra-wideband, wildlife tracking, interference detection, and radar. The descriptions are sorted by frequency.
Experimental Radio Applications at the FCC
Wednesday, November 3rd, 2010This summarizes a selection of applications for the Experimental Radio Service received by the FCC during October 2010. These are related to ultra-wideband, machine-to-machine, satellite, GSM, white space, and radar.
What do I mean by “selection?” I look at all applications for new experimental license or special temporary authority (ignoring renewals, modifications of existing licenses, and transfers of control). From those, I pick the ones I find most interesting, which is most except for the following:
- GPS repeaters, such as those put in a factory to replicate a GPS environment for testing. (Note, however, that companies regularly get tripped up by not demonstrating compliance with separate NTIA requirements.)
- Short-term authority for video program production. Someone needs a video link to cover a golf tournament or football game, perhaps by using flight-test telemetry bands (with that coordinator’s permission) for a day.
- Demonstrations for customers. Demonstrations at trade shows.
- An application very similar to one covered recently.
- Applications too vague or lacking enough detail to write much about. If applications are very lacking, FCC staff will sometimes ask for more information.
- Electromagnetic compatibility (EMC) compliance testing including RF immunity testing for compliance with European regulations.
- RF integration testing. (A radar from company A is paired with telemetry from company B and installed on a ship from company C.)
- Applications for general-purpose antenna test ranges.
- Applications for which confidentiality treatment has been sought. Companies can do this under the FCC’s rules, but I suspect it’s overdone at times. The request for confidentiality is made public, and may have some details. (A couple of times I have seen companies put what I think is the confidential information in the confidentiality request.) That, and a bit of independent research, can give me an idea what they’re up to. If I can make an educated guess, I will, saying so.
On to October’s applications:
- Zimmerman Associates filed an application (with supporting exhibits) for special temporary authority to test the capability of using a full polarimetric UWB radar system for identifying roadside bombs and improvised explosive devices (IEDs). Testing is to be on 3100-5600 MHz at Fort A.P. Hill, Virginia. The prototype equipment uses time-modulated ultra-wideband (UWB) technology developed by Time Domain Corporation. It generates a signal that is position modulated; the position of the modulated pulse varies randomly in time so as to produce a spectrum that approximates Gaussian noise.
FCC Finalizes White-Space Rules
Thursday, September 23rd, 2010The FCC finalized its white-space rules today, acting on petitions for reconsideration of its earlier decisions. It issued an 88-page Second Memorandum Opinion and Order that explains its decisions and includes the final white-space rules. A much-shorter press release was also issued.
At least one FCC observer has noted an uncharacteristic level of hype in today’s announcements. The FCC calls it “super Wi-Fi,” and adds the “potential uses of this spectrum are limited only by the imagination.”
Over two years ago, Google called it “Wi-Fi on Steroids.” It was later picked up by the popular press. Not all agree; it’s “Wi-Fi on Crutches” according to one who dares to consider the realities of physics and economics.
I’ll call it “Wi-Fi on Caffeine,” at least with respect to better range and coverage — if not data rates — compared with current Wi-Fi equipment. This is partly due to operation in the UHF-TV band instead of the 2.4 GHz band. In major markets and their suburbs, there will be few or no channels available for white space use. In rural areas and other less dense areas, the technology will be a good fit with Wireless Internet Service Providers (WISPs) and other longer-distance applications.
Cellular operators would like some of the white space on a licensed basis for backhaul in rural areas. They didn’t get it today, but the FCC is actively considering it and we may hear more on that by the end of the year. No way are all these vacant channels going to be occupied by internet services in the most rural areas, so the proposal of the operators makes sense.
In IEEE 802, Working Groups 802.22 and 802.11 are working on standards that can be used by equipment in these applications; 802.22 may be the one with longer range. Working Group 802.19 is trying to facilitate coexistence between the two. Now, there are asymetric interference effects, which is causing friction between the two groups beyond the normal competition. (802.22 takes the harder interference hit.)
There will be other standards and equipment as well. The white space concept is international, but unique to each area of the world.
Equipment is not easy; it’s challenging to develop sufficiently-broadband power amplifiers and antennas, and to meet the emission mask in a cost-effective manner.
Another challenge is developing a business plan when 120 MHz of TV spectrum could be taken away under the National Broadband Plan.