As I was completing my research for an upcoming blog on LTE Carrier Aggregation, I found that my previous LTE Band Class reference sheet was missing some of the more recent Band Class updates, so I decided to share my new reference document with a few comments.FDD Band Classes:
The first notable band class addition in Band 30. This band class creates a definition for FDD operation in the WCS (2.3GHz) band which was previously defined only for TDD operation.
From the Spectrum Grid view of the Spectrum Ownership and Analysis Tool, you can see that Band 30 does not include the 5MHz channels that AT&T purchased to essentially become guard bands for the Satellite Audio guys. This will provide AT&T with a 10x10 LTE channel on a market by market basis, as they resolve the remaining ownership issues in the WCS band.
The next two band classes are not new, but I previously skipped over these band classes because I didn't fully understand their frequency breaks.Band 26
Previously I thought this was a specific band for Sprint IDEN operation that is adjacent to the cellular band. This is the band where Sprint is placing their 2nd LTE channel (5 MHz) and a CDMA channel (1.23 MHz). Looking at the frequencies in detail, the band class covers the IDEN spectrum and the adjacent cellular spectrum.
This is similar to Sprint's Band 25 which includes all of the PCS band plus their G block spectrum (but not the H block).
So you would think that all of the North American carriers could standardize to Band 25 for PCS operation and Band 26 for Cellular. Using the latest iPhone 5s LTE band support,
you can see the Verizon, T-Mobile, and AT&T iPhone's support Band 2 and 25 for PCS, but only the cellular band (Band 5). Sprint iPhone 5s includes,
both Band 2 and 25 for PCS and Band 5 and 26 for cellular.
This is referenced as the AWS extended band and you can note from above that it is not currently applied to smartphones like the iPhone 5s. This band class seems to be a preparation for the future use of the AWS-2 and AWS-3 spectrum and the government shared use band that are both adjacent to the existing AWS spectrum band. Here is how the downlink looks in the Spectrum Ownership Analysis Tool:
Note that Band 10 does not cover the entire band contemplated for AWS-3, nor does it include Dish's Band 23. For the uplink:
This again depicts that Band 10 is not currently set to include the entire shared government opportunity.
TDD Band Classes:
Here is the reference sheet the TDD band classes.
On this reference sheet I hadn't looked closely at band classes 35, 36, and 37. I had always focused on the 2.3GHz and 2.5GHz as the only bands that were designated for TDD support in North America. These three band classes create 140MHz block of spectrum that could be for TDD deployment. Here is how these bands appear in the Spectrum Ownership Analysis Tool:
I'm not sure what the history is on these band classes, but they would support TDD operation in both the PCS uplink and downlink bands as well as in the 20 MHz between the bands. Since the PCS frequencies are highly deployed, I would consider it very unlikely to see TDD systems in this band in the near future, and I doubt that the PCS band is authorized for TDD operation. It will be interesting to see whether any of the wireless carriers begin to look this direction. With Sprint stepping out of the H block auction, they seem to be signalling that TDD operation is more important to them and the Band 37 block (including Sprint's G block) could be the reason why Dish is pushing forward in the H block auction. Please comment if you are aware why the 3GPP has included these 3 TDD band classes.
With AT&T's announcement that they are meeting some challenges related to testing operation between LTE Band Class 29 and Band Classes 2 and 4, I figured that many readers would appreciate a reference map for how these band classes relate to the US mobile radio and satellite spectrum bands.
All of these screenshots are from the AllNet Labs Spectrum Ownership Analysis Tool, where we display and provide analysis tools related to spectrum ownership for all of the US mobile radio and satellite spectrum bands for all 50 states and US territories. AllNet Labs Spectrum Ownership Analysis Tool
In the images below, the band classes are color coded Gray for Uplink Spectrum, Yellow for Downlink Spectrum, and Blue for Spectrum supporting Time Division Duplex.
AWS/PCS Spectrum - Uplink
PCS/AWS Spectrum - Downlink
Last week the FCC released its Notice of Proposed Rulemaking for the Service Rules for the Advanced Wireless Services H Block. So despite the fact that the H channel in discussion here are virtually adjacent to the PCS block of spectrum, they are referred to as AWS H. I'll continue to call them PCS H because that have no relationship with the spectrum commonly referred to as AWS (1.7 and 2.1GHz). My primary question as I reviewed this rulemaking, was how the auction would be structured so there would be interest for this spectrum block, beside Sprint.
Clearly, this spectrum block is more valuable to Sprint, since it can be combined with its nationwide PCS G block to enable Sprint to migrate to a 10x10 LTE channel from its current 5x5 LTE channel. Doubling their channel size will get this LTE deployment on par with Verizon, AT&T, and T-Mobile's initial deployments.
Interestingly, the FCC doesn't comment to the use of the channel for LTE, they consider a deployment with CDMA more likely. This is probably the only way to think that there will be bidders beside Sprint. A T-Mobile or AT&T could purchase this spectrum for additional WCDMA capacity since a WCDMA channel would fit perfectly in this block, but I believe that a deployment of WCDMA in this block would be delayed by the 3GPP standards board in the same way that Sprint's LTE deployment would be waiting for standards body support for a new band plan.
Two other interesting notes from this rulemaking. The FCC is proposing to issue the spectrum with Economic Area (EA) Geographical Licensing. Above is a FCC map depicting the recognized Economic Area boundaries. Evidently EA licensing was chosen to encourage build outs in rural areas. Given that the build out requirements are easily met by building only the large cities first, I don't agree with this logic. More likely, the EA licensing allows the FCC to receive a higher price for rural areas since their POPS roll up within a more valuable metropolitan area.
The licensees will receive 10-year licenses with the requirement that 40% of the POPS are covered within 4 years and that 70% are covered before the license is renewed after year 10. Neither of these requirements will drive investment into rural areas.
This spectrum will be challenging to utilized near the borders: San Diego, Detroit, Buffalo, and McAllen/Brownsville since Canada and Mexico are running 3-4 years behind the US in spectrum policy. The use of this spectrum in border markets has to be done without interference with the Canadian and Mexican systems currently using this spectrum.
Lastly, this spectrum comes with a requirement to share the microwave relocation costs that Sprint and UTAM incurred to make the PCS G block usable.
When Clearwire first offered wholesale access to its spectrum, it was using the WiMax technology. It had built this technology in the 2.5GHz band and it was covering up to 80 markets by the end of 2010. At this time Clearwire provided meaningful WiMax coverage in each of their markets for Sprint, Comcast, Time Warner, and Best Buy to provide their customers 4G Only WiMax devices. Essentially, Clearwire's WiMax network had broad enough coverage that these operators could selectively offer their customers service in the markets that Clearwire offered WiMax service.
As Clearwire has embarked on the TDD-LTE strategy, their wholesale model has gotten a bit more complex. First, they continue to sign up relatively small partners for their WiMax wholesale offering: Simplexity, Freedom Pop, Best Buy, CBeyond, Mitel, NetZero, Locus, and Kajeet. They have Sprint already signed for Wholesale Access to the forthcoming TDD-LTE network and added Leap to the WiMax partner list early in 2012.
Leap demonstrates the change of direction for wholesale agreements for the TDD-LTE network. For their TDD-LTE roaming strategy, a roaming partner would need a "thin" LTE network providing coverage in their markets. They would then roam over to the Clearwire TDD-LTE "hot spots" only for capacity. Sprint's 5x5MHz FDD-LTE deployment would qualify as a "thin" LTE deployment. This implicit requirement for a "thin" coverage network, eliminates non-carriers from the TDD-LTE wholesale process since it would be difficult to sell "spots" of coverage across Los Angeles if you didn't have service already over the area.
In addition, the quantity of sites in the Clearwire LTE plan started at 8,000 of their 16,000 sites, was reduced to 5,000 sites and recently has arrived at 2,000 sites. This has increased the challenge of finding wholesale partners with this very limited coverage.
On the surface, a deal to host Dish's spectrum on Sprint's Network Vision platform would make alot of sense. The chart below highlights that part of Dish's (DI) spectrum is adjacent to the AWS-2 spectrum that recently has been referred to as the PCS H spectrum. Sprint is interested in acquiring this spectrum to increase their LTE channel size from 5x5 FDD-LTE to 10x10 FDD-LTE. Unfortunately, the Dish spectrum is configured where the uplink (from the handset to the cell site) would be adjacent to Sprint's LTE downlink (cell site to handset). This will be problematic for Dish. Cell sites transmit at much higher power than handset signals are received. Expensive filters on the separate Dish antennas may not be enough to allow the Dish antennas to be installed in the same plane (level) as the Sprint antennas.
You can look at this as being similar to the Lightsquared deal, except Lightsquared was planned into the deployment through the zoning and permitting process. With the standards body processes that are in front of Dish, it would still be years before equipment is installed and a network operating on Sprint's towers. A Dish MVNO to operate on Sprint's 3G Voice and LTE network would allow Dish to get a wireless product to market quickly.
Clearly the wireless industry has locked in spectrum pricing with the MHz-POP pricing model, but is this the right way to look at it as we move into a 4G World where data throughput and capacity are key? For those that aren't familiar, the typical value of spectrum is determined by the $/MHzPOP which is the dollars spent for the spectrum divided by the total amount of spectrum times population that spectrum covers. This model falls short now as carriers are interested in acquiring larger contiguous blocks of spectrum enabling higher users speeds and more capacity.
To use a real estate analogue, a large plot of land is much for flexible for multiple uses, than two plots, even if they are in the same neighborhood. In real estate, the developer that is able to consolidate several tracks of land into a larger development is rewarded as he sells the larger development.
In the wireless industry, we continue to price based upon the $/MHz POP basis, even as carriers such as T-Mobile and Clearwire have combined adjacent channels to create larger bands of spectrum to utilize in larger LTE channels. T-Mobile has worked this year with Verizon, SpectrumCo, and MetroPCS which will allow it to assimilate a 2X20MHz LTE channel on a national basis. Clearwire has leased and purchased operators in the BRS and EBS spectrum bands providing it with an average of 160MHz of spectrum in the top markets. Since Clearwire's spectrum has many geographical boundaries, it is difficult to say how many 20MHz channels they could support across each of their markets, but they have been successful consolidating small bands of spectrum into larger more flexible spectrum bands.
How does a larger band of spectrum affect the wireless carriers? In the US, carriers have deployed FDD-LTE in 1.25MHz channels, 5MHz channels, and 10MHz channels. As you increase the channel size throughput performance improves because a lower percentage of the data packets are dedicated to overhead activities Qualcomm has provided achievable LTE Peak Data Rates for different channel bandwidths based upon whether the antennas are 2x2 or 4x4 MIMO.Link to Qualcomm Document
As you can see in the 4x4 MIMO downlink case, the throughput is 12Mbps greater in the 20MHz channel than the composite of 4-5MHz channels.
So if a 20MHz channel is 4% more efficient than 4 - 5MHz channels should the MHz POPs pricing adjust accordingly?
By the way.. I am going to look for more source data on the capacity improvements for wider channels, a 4% improvement would seem to be relatively negligible. I recall hearing 30% improvements in capacity when a channel size is doubled, but I haven't been able to re-source that data for this blog. More to come.