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Spectrum Analysis...Does Sprint have more options for additional LTE carriers?

Posted by S4GRU, in Author: Andrew J. Shepherd 08 February 2012 · 13,477 views

Sprint Network Vision LTE Spectrum PCS 1900 800MHz
Spectrum Analysis...Does Sprint have more options for additional LTE carriers? by Andrew J. Shepherd
Sprint 4G Rollout Updates
Wednesday, February 8, 2012 - 10:01 AM MST


Within the wireless industry and among wireless enthusiasts, it is fairly common knowledge that Verizon Wireless (VZW) and AT&T Mobility (AT&T) have landed Boardwalk and Park Place, respectively, in terms of wireless spectrum for LTE deployment.  (Pardon the Monopoly…er, duopoly pun.)  VZW has huge Upper 700 MHz C block 22 MHz licenses that it holds nationwide.  And AT&T has a not quite as consistently strong but still substantial collection of Lower 700 MHz B block 12 MHz and C block 12 MHz licenses that it can span together in many markets for a similarly large bandwidth LTE network.

In order to compete with VZW’s and AT&T’s LTE deployments, Sprint has put together a multi-pronged course of action.
  • Sprint is rolling out its Network Vision platform this year, utilizing its “green field” PCS G block 10 MHz nationwide licenses to deploy an initial 5 MHz x 5 MHz LTE channel.
  • Sprint has inked a deal to host LightSquared’s L-band Ancillary Terrestrial Component LTE bandwidth on the Network Vision platform.
  • Sprint plans to “refarm” its rebanded SMR 800 MHz spectrum for LTE as the former Nextel iDEN network is shut down over the next two years.
  • Sprint expects to gain TD-LTE capacity in major markets once Clearwire starts to shift its focus from WiMAX to LTE.

However, the LightSquared agreement appears to be living on borrowed time, since LightSquared has failed to solve the ATC interference issues required to satisfy its FCC waiver.  And neither SMR 800 MHz spectrum nor Clearwire TD-LTE is likely to be widely available until 2013 or 2014.


Sprint LTE Deployment to Earn an A, B, or C?

So, Sprint could stand pat with its planned 5 MHz x 5 MHz LTE roll out (while VZW launches 10 MHz x 10 MHz in all of its LTE markets, AT&T in most of its LTE markets).  Or, better yet, Sprint could add a fifth prong to its plan of attack:  Sprint leverages its existing PCS A-F block spectrum assets for an additional LTE channel in many top markets.

At the first FCC PCS 1900 MHz auction that ended almost 17 years ago in early spring 1995, Sprint and its partners came away the big winners, acquiring PCS A block 30 MHz or B block 30 MHz licenses across an overwhelming majority of the 49 MTAs that make up the 50 states.  Today, Sprint retains its full 30 MHz allotment in greater than 24 major markets, including seven of the top 10 markets.  Furthermore, Sprint has acquired additional spectrum in six other major markets to increase its licensed PCS A-F bandwidth in those as well to 30 MHz.  And, finally, Sprint has three other major markets in which it retains or has acquired just under 30 MHz of PCS spectrum.  I call these three groups, respectively, “original,” “accumulated,” and “borderline” 30 MHz PCS A-F bandwidth markets.

For a rundown of these Sprint markets and their PCS spectrum holdings, view the linked spreadsheet.  Or click here to download Excel version.


What is the magic amount of spectrum needed?

So, you might ask, “Why is 30 MHz the magic number?”  Well, actually, 20 MHz is the greater figure of merit, while 30 MHz represents a latently important 10 MHz above and beyond that core 20 MHz bandwidth.

If you examine Sprint’s PCS A-F spectrum holdings nationwide, you find that the minimum bandwidth that Sprint holds in almost any major market is 20 MHz, which is sufficient spectrum for six (or, in some cases, seven) CDMA2000 carrier channels plus guard bands.  Such 20 MHz bandwidth markets include Chicago, San Francisco, Houston, Atlanta, etc.  With Sprint’s cell site density achieved over the last 15 years, 20 MHz seems to represent a sufficient bandwidth “floor.”

For example, on a recent trip to Chicago, I noted that Sprint is operating at or near the maximum carrier channel capacity of its 20 MHz of spectrum.  I encountered three CDMA1X and two EV-DO channel assignments out of a possible total of six channels.  Moreover, my own empirical observations in 30 MHz markets seem to corroborate the 20 MHz bandwidth “floor.”

Kansas City is one such market, a PCS A block 30 MHz “original” market.  Of course, it is Sprint’s home market, in which Sprint is a close number two in market share, thus should be a reasonably demanding market for Sprint.  Even though Sprint has 30 MHz (up to 11 carrier channels) to play with in Kansas City, I encounter most regularly three CDMA1X and three EV-DO channel assignments.  And those six carrier channels plus guard bands occupy 17.5 MHz out of Sprint's 30 MHz license.


Just because not all markets can do it, doesn't mean that it shouldn't be done

To summarize, Sprint has demonstrated that it can successfully operate many, if not all of its CDMA2000 markets in no greater than 20 MHz of deployed bandwidth.  In the 24 aforementioned “original” PCS A-F 30 MHz markets, as well as the six “accumulated” PCS A-F 30 MHz markets, Sprint thus has 10 MHz of spectrum that it could ostensibly put to use for a second 5 MHz x 5 MHz LTE channel.  Better yet, in four markets (including high tech hot beds Seattle and Austin), Sprint has “accumulated” the right combination of PCS C block and G block contiguous licenses that Sprint could actually deploy a 10 MHz x 10 MHz LTE channel to match VZW and AT&T.

Even in the three “borderline” markets where Sprint holds 25-27.5 MHz of PCS A-F spectrum, Sprint might still be able to operate CDMA1X and EV-DO within 15-17.5 MHz bandwidth, once more freeing up 10 MHz for a second LTE channel.  Not to mention, once Sprint launches one LTE channel, the demands on existing EV-DO channels start to ease, thereby reducing the load on the limited CDMA2000 bandwidth.

Of course, Sprint does not have enough PCS A-F block spectrum to carve out a second LTE channel in all of its markets.  But there is an elegant, collaborative solution to that problem.  So, stay tuned for the next article in this three part series to learn how and why a PCS LTE spectrum and network sharing agreement would fit both Sprint and its prospective network partner to a “T”…  

Click link for next article


Posted Image

Link to Excel Spreadsheet for download


Sources:  FCC, author’s notes




Can't wait for part 2 of this article...T-Mobile? Great analysis on the spectrum holdings on the major markets.

I still believe that Sprint needs to look for more spectrum some time in 2013 whether that is through a spectrum auction OR through a spectrum hosting deal where Sprint has the benefit to use some of that spectrum to bolster its LTE network.

One question about your CDMA1x/EVDO analysis about how three 1x carriers and three EVDO carriers take up 17.5 Mhz. How much spectrum do guard bands take? If I do the math (1.25 x 6 = 7.5 Mhz) that would mean that guard bands take up 10 Mhz and this was done on CDMA2000 1x? Also we have to keep in mind that 1x Advanced for voice will be more spectral efficient and support a larger capacity. This would definitely mean that the same number of 1xAdvanced carriers would take up less spectrum and support more customers. Once 1x Advanced can be put on 800 Mhz that would free up more 1900 Mhz spectrum since Sprint can put 2 1xAdvanced voice carriers on 800 Mhz.

EDIT: One last observation is that I noticed your spreadsheet has nothing filled out for the F block. Does this mean that Sprint doesn't have any F block spectrum in any markets or are the smaller markets using the F block?
solid article. Do you by chance have a map/spreadsheet showing all of sprints spectrum holdings exactly detailed out?
Been looking for one for awhile and always seem to get old info with them or just bits of it, not showing exactly all the details.

One question about your CDMA1x/EVDO analysis about how three 1x carriers and three EVDO carriers take up 17.5 Mhz. How much spectrum do guard bands take? If I do the math (1.25 x 6 = 7.5 Mhz) that would mean that guard bands take up 10 Mhz and this was done on CDMA2000 1x?


Just as LTE is 5 MHz x 5 MHz, 10 MHz x 10 MHz, etc., keep in mind that CDMA1X and EV-DO are 1.25 MHz x 1.25 MHz. In other words, do not forget to count both uplink and downlink. Thus, each carrier channel is 2.5 MHz bandwidth in total. Then, do the math (e.g. 2.5 MHz x 6 = 15 MHz). And a good rule of thumb is that a CDMA2000 deployment requires guard bands equivalent to the bandwidth of one carrier channel (i.e. 2.5 MHz, split 625 kHz at the top/bottom of the uplink and top/bottom of the downlink). Do the math again (e.g. 15 MHz + 2.5 MHz = 17.5 MHz), and there you have it.

Once 1x Advanced can be put on 800 Mhz that would free up more 1900 Mhz spectrum since Sprint can put 2 1xAdvanced voice carriers on 800 Mhz.


The uplink/downlink calculations above are equally relevant here. If Sprint's final rebanded SMR 800 MHz allocation is 14 MHz (i.e. 7 MHz x 7 MHz), and Sprint deploys one 5 MHz x 5 MHz LTE channel, then Sprint will be able to support concurrently just one 1.25 MHz x 1.25 MHz CDMA1X Advanced carrier.

AJ

solid article. Do you by chance have a map/spreadsheet showing all of sprints spectrum holdings exactly detailed out?Been looking for one for awhile and always seem to get old info with them or just bits of it, not showing exactly all the details.


Sgt., I did that legwork on Sprint's PCS 1900 MHz spectrum holdings about nine years ago. You may have already come across my old spectrum catalog and map at wirelesswavelength.com. Unfortunately, I do not have more recent info in finished form (only the raw data that I have compiled for this article and others). That said, my nine year old info is still ~90 percent accurate.

AJ
Readers...don't forget to rate the article with the stars at the top.

- Robert

solid article. Do you by chance have a map/spreadsheet showing all of sprints spectrum holdings exactly detailed out?Been looking for one for awhile and always seem to get old info with them or just bits of it, not showing exactly all the details.


Maybe if we can ask nicely, AJ can work in a revised map that we can host up on the S4GRU page. It would be a great resource. I know our readers would love a geeky detailed map.

I still resource AJ's old spectrum map from 2004. Would love to have something up to date! AJ, feel free to send me a Private Message about it if you are interested. I'd be happy to do the graphics.

- Robert
WiWavelength,

Yeah I came across it as it was one of few things that has some info in it.

This article just made me want to know more exactly as to what areas they own what exact spectrum and how much of it. Like me not seeing Raleigh(my home, lol) in the spreadsheet just makes me want to know more at the least about their holdings here and else where to try to get a grasp on their possibilities.

When i was doing the looking around the info was so sporadic and even conflicting at times it made it seem like getting the real info would take forever to piece together.

LTE wise though I just wanna see them pump Clearwire full of $$ and allow that spectrum to be used like it could if done right. too much bandwidth there to let sit around. There is a solution to be found to help the building penetration/coverage issues they have with current WiMax config. Solve that riddle and bandwidth issues are a thing of the past no?

WiWavelength,Yeah I came across it as it was one of few things that has some info in it. This article just made me want to know more exactly as to what areas they own what exact spectrum and how much of it. Like me not seeing Raleigh(my home, lol) in the spreadsheet just makes me want to know more at the least about their holdings here and else where to try to get a grasp on their possibilities.


At the very least, I can tell you that Sprint's PCS 1900 MHz licenses in Raleigh-Durham have not changed. That market I know off the top of my head. Sprint still holds its original PCS D block 10 MHz license won at FCC auction and a PCS A5 block 10 MHz partition/disaggregation acquired from the old AT&TWS. Since both the PCS A5 and D blocks are contiguous, Sprint in Raleigh-Durham controls a solid 20 MHz block of spectrum, in which it can deploy a max of seven CDMA2000 carriers.

AJ
Thank you for the information and I also cannot wait for part deux. I did not know sprint was using so many channels. I expect with them switching to 1xA that they will cut down on the amount of Voice channels they use in each market.

Also with Sprint already using multiple channels of EVDO in each market, I believe that Sprint should switch to EVDO rev. Multicarrier. They would get speeds of 9.3/5.4 max, and sprint would only need to do a software update at the towers. I know current phones will not see a huge improvement, but I believe the increase capacity alone would be worth it.
Next article in series is up. Click on this link.