Steven J. Crowley, P.E.
Archive for the ‘IMT-Advanced’ Category
This 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.
In a recent blog post, CTIA compares some measures of the U.S. wireless industry to those in nine other countries. The purpose is two-fold; to show the U.S. is a leader in number of subscribers, lowest cost per voice minute, and spectrum efficiency, and to argue the need for getting more mobile broadband spectrum in the “pipeline.” These goals are somewhat at odds, and the spectrum-efficiency argument I don’t get, as I’ll explain, but within the constraints of a blog post I think CTIA makes the case that the U.S. is a clear leader in some areas, and that the prospects for more mobile spectrum in the U.S. are fuzzier than they should be today.
The following is my response to a query on LTE versus wired, and the user experience. It capsulizes my current thinking, which evolves.
To your point, I don’t see LTE being competitive with wired in terms of speed or reliability today or in the future. You take the hit there for the convenience of mobile or portable operation. There’s a notion that if we just add enough base stations and repurpose enough spectrum to LTE, we can replicate the home wired experience in the mobile environment, but I don’t think that’s practical. The throughput from an LTE sector is divided among all users in the sector. If everyone wants to watch the Super Bowl at once on LTE, forget it (unless the LTE broadcasting standard is implemented, which let’s everyone watch the same channel like today’s TV (cough)). On FIOS or cable, the Super Bowl is no problem.
A couple of days ago the Mobile Future coalition posted a short video on YouTube advocating the allocation of more spectrum for mobile broadband. As evidence of the need, it says that, compared to feature phones, smartphones use 24 times the spectrum and tablets 120 times the spectrum.
The FCC relies on Cisco’s forecast of mobile-broadband data demand as a basis for spectrum policy. Called the Visual Networking Index, it comes up many times in the National Broadband Plan, in other documents, and in speeches.
The debate won’t end but the volume is dropping on the what-is-4G controversy. Previously, I’ve written about the ITU’s characterization of 4G as only applying to the two radio technologies it has designated as IMT-Advanced: LTE-Advanced and WirelessMAN-Advanced (the latest version of WiMAX).
On November 30, the FCC adopted a Notice of Proposed Rulemaking (NPRM) as a preliminary step toward making the current TV broadcast spectrum available for use by fixed and mobile wireless broadband services. The proposed rules would do three things: 1) make fixed and mobile wireless services co-primary with broadcasting in the FCC’s Table of Frequency Allocations, 2) create a regulatory structure giving two or more TV stations the option to share one 6 MHz channel, and 3) improve VHF TV reception through power increases and adoption of receiver antenna standards. No service rules are being proposed; they’re to come later. Congress has yet to approve incentive auction authority.
The IEEE 802 Executive Committee today approved correspondence asking ITU for clarification on its use of the term “4G” in an October 21 press release on IMT-Advanced. The main concern is ITU’s characterization of IMT-Advanced as “true 4G.” IEEE 802 observes that some in industry and government use 4G to mean mobile broadband technologies other than IMT-Advanced. Consequently, IEEE 802 says, ITU’s announcement has caused such users to be on the receiving end of “public response” (i.e., negative publicity), and could cause “significant disruption” to existing technical activities and documentation. It also observes that such use of 4G seems inconsistent with ITU-R Working Party 5D’s prior consideration of the term.
The FCC’s National Broadband Plan (NBP) recommends that the Commission make available 500 MHz of new spectrum for wireless broadband, including 300 MHz for mobile use. In support of that recommendation, on October 21, the FCC released an FCC Omnibus Broadband Initiative technical paper: Mobile Broadband: The Benefits of Additional Spectrum. The paper concludes that mobile data demand is likely to exceed capacity in the near term and, in particular, that the spectrum deficit is likely to approach 300 MHz by 2014.
On October 21 the ITU announced it had deemed two mobile broadband technologies as IMT-Advanced. They’re LTE-Advanced and WirelessMAN-Advanced (WiMAX Release 2 based on IEEE 802.16m). At the same time the ITU called these “true 4G technologies,” leading some in the trade press to say that marketing of some existing services as 4G is misleading.
No entity is the arbiter of the designations 2G, 3G, or 4G. Even the ITU generally uses these terms parenthetically. It recognizes the lack of consensus on their meaning, and does not say others are wrong. The ITU calls the IMT-Advanced technologies “true 4G,” and they are insofar as ITU has a view of 4G and the two technologies are truly consistent with that view.
In some of these articles, Sprint and Clearwire, to name two examples, catch flack for calling their current WiMAX offering 4G. I’d call it 3.5G, but I can’t say they’re wrong. An ABI Research analyst agrees with Sprint and Clearwire; his view is that everything TDMA is 2G, everything CDMA is 3G, and everything OFDMA is 4G, regardless of data rate. It’s a reasonable argument based on backward compatibility, but I’m not ready to agree. If that or something else ends up being the industry consensus, I won’t object.
Below is a comparison found on the ITU website. It’s generally consistent with my view.
Don’t like these classifications? Make your own. Within reason.
ABI analyst link updated with more current post.