Google's Experimental Network - Mountain View, CA

There is a little buzz this morning about an application from Google to construct a experimental network on 2.5GHz frequencies on the Mountain View, CA campus.  Here is a link to the application.  The application states that they will be using spectrum between 2.524 and 2.546GHz and between 2.567 and 2.625GHz.  The top issues with this application is that Clearwire operates their WiMax network within this market and has states on their earnings calls that they typically deploy using between 30MHz and 60MHz of spectrum.  Google would need to guarantee that there would be no harmful effect to this commercial network.  Now lets look at the specific spectrum allocations.

In the above image from my Spectrum Ownership Landscape Report, you can see that the lower band matches correctly to the B2, B3, C1, and C2 channels.  The upper band matches the LTE Band 38 so there would appear to be a desire to test TDD-LTE equipment in that portion of the band.

Can Google do this without Clearwire's agreement and assistance?  I don't think so.  The B2,B3 channels are owned by The Santa Clara Board of Education (Call Sign WHG338) and don't appear to be leased to Clearwire so they are ok.  C1,C2 (Call Sign WHR466) are owned by The Assocation for Continuing Education and they appear to be leased to Clearwire.  The spectrum in Band 38 is particularly interesting.  First of all, it is the portion of the spectrum that is currently dedicated to video operation, so Google would need to work with each of the broadcasters and convince them that their operation in Mountain View would not interfer with the ability of the broadcaster's clients to receive their desire video broadcast.  In addition, the presence of this high powered video interference would make Google's tests much more challenging, especially outdoors. On the far right of the spectrum allocation Google has requested is the BRS2 channel that is clearly owned by Clearwire.

For the video spectrum, Clearwire still holds the leases for the A4, C4, D4, E4, and F4 channels.  I anticipate that Clearwire is not supportive of this testing without their involvement and they will protest the experimental authorization.  In my history with with wireless carriers, it was not unusual to see a experimental application for my carrier's spectrum without being contacted directly for the use of my carrier's spectrum.

LTE Broadcast - What is the problem with video?

Verizon's announced last week that they were looking into broadcasting multicast video utilizing the LTE Broadcast feature, known in the standard as EMBMS - Evolved Multimedia Broadcast / Multicast Service.  After watching a video interview by Dan Meyer with RCR Wireless with Lynette Luna from Current Analysis I thought a short description of the challenge of multicast video would be in order.

The goal transmitting multicast video is to limit the number of unique video sessions that are coming into your network, loading your switches, routers, cell site backhaul, and finally cell site RF capacity.  In the diagram above I have shown Netflix/You Tube video traffic in red.  From Dan and Lynette's conversation, this would be considered Over the Top (OTT) video, essentially video not provided or managed by the network carrier.  With 3 handsets all receiving a unique You Tube video or Netflix movie, there are 3 streams of video capacity (red circles) used at the market switch (2 are shown).  The South Market Switch still is burdened with 3 video streams.  The backhaul to the 1st cell site on the South market switch is still carrying all three video streams, but since no users are on the 1st cell site, no RF coverage is consumed.  The link between the 1st and 2nd site still carries 3 video streams while the link between the 2nd and 3rd site only carries 2 video streams. 

Looking at the North Market Switch we can see what is desired with multicasting video.  The key is to realize that this video is synchronized for all users like a live sports game or a broadcast television program that starts at the same time for all users.  The network will have the intelligence to recognize that multiple users are requesting the same video stream and it will only set it up once on each switch, cell site backhaul, and cell site that has a user requesting the service.  You can see that there is one site off the North Market Switch that does not have a Live Broadcast User, thus neither the site or the site backhaul would be carrying that video stream, eliminating that required capacity.

I see this as a limited offloading opportunity.  US Consumers have been trained with DVRs to timeshift TV viewing and to utilize Quickskipping to eliminate commercials.  For consumers, applications like Dish Anywhere which allows me to record my programs, including Live Sports, and send them to my handset when I want to start them, will continue to be very popular.  This would be an OTT video example that I gave above.  Wireless carrier's could enable DVR functionality in the handset, allowing the customer to pause the live broadcast at their handset and continue playback at their convenience, but that is an expensive handset that doesn't exist today. 

Globalstar - Terrestrial Low-Power Service (TLPS)

Globalstar's Proposed Terrestrial Low-Power Service (TLPS) has some well thought-out approaches.  Globalstar has petitioned the FCC to allow them to utilize their 2484-2500 MHz "Big Leo" satellite spectrum to provide terrestrial coverage.

Globalstar's spectrum lies directly above the 2.4GHz ISM band which hosts a vast majority of the WiFi in use today, as well as bluetooth and microwave ovens.  Directly above the Globalstar spectrum is the EBS/BRS spectrum controlled primarily by Clearwire.

Globalstar has proposed terrestrial operation on a the newly named AWS5 band.  It would essentially be a 4th non-overlapping WiFi channel (Channels 1,6,and 11 are the primary non-overlapping WiFi channels).  It would still be a 22MHz wide channel, using the ISM band above Channel 11 (which is lightly used) and about 10MHz of their AWS5 channel.  Globalstar believes that most existing WiFi devices could support this spectrum with a over-the-air software updates so a massive number of devices could be overloaded to this network once it is constructed.

Also intriguing is the improved performance characteristics of this spectrum.  First, since it is licensed to Globalstar, they can control the use of the spectrum.  They envision a carrier grade network using this spectrum that would manage Hotspot power levels and interference.  Since this spectrum has much less interference, it is capable of covering larger areas with higher speeds than typical WiFi.

If Globalstar can figure out the backhaul aspect to providing this service, I think they will have a leg up on other white-glove WiFi service providers since they are better able to manage the RF environment for their frequencies. It is conceivable that Globalstar would host WiFi overloading for all of the 4 national carriers.  I still see the biggest challenge to be in a residential environment where they envision a hotspot in my house being under their control, but likely on my cable internet service.  I'm pretty sure Comcast won't react well to my residential internet service supporting a commercial operation.

Is this a service that could be considered or expanded into the EBS/BRS channels that are adjacent to Globalstar's spectrum?  The answer is yes.  Clearwire has stated that they have excess spectrum.  I would anticipate that this would look like a private LTE network on Clearwire's spectrum versus WiFi on Globalstar's, but it would not be as feasible as Globalstar's proposal due to the current lack of devices that support LTE on the EBS/BRS frequencies.

DISH Counter-Offer for Clearwire

Dish's counter-offer for Clearwire is intriguing.  I recently completed a presentation detailing the challenges of a spectrum sale in the EBS/BRS spectrum.  Clearwire's press release states that this offer was on the table when Sprint's offer was received but Sprint's offer was deemed better.  Tim Farrar's Blog indicates that the spectrum sale would likely be for Clearwire's BRS spectrum.  This is a realistic assumption.  In my presentation (linked in a previous blog) I highlighted that one of the primary problems with the leased spectrum is that it has limited geographic coverage, covering many of the dense metro areas but not contiguous all the way to a county or BTA border.  There are still a few elements of a BRS spectrum sale that should be understood.

From the image above, the BRS spectrum sale would include the Orange (BRS1/BRS2) channels, the Pink (E channels), Light Blue (F channels) and Brown (H channels). This would equate to one contiguous block of 55.5MHz of spectrum, a 12MHz block of spectrum (E4,F4), and the isolated BRS1 channel.  The 12MHz block could only be used if mid-band video operations have ceased in a market.  Currently, I don't believe that any of the Top 10 markets have completed ceased video operations.  The 55MHz of spectrum can support 2 - 20MHz TDD-LTE channels.  This would virtually eliminate the ability to utilize the EBS/BRS spectrum for any FDD-LTE operations.  It may be possible with a guardband in the H channels to operate the D channels and G channels in a FDD-LTE configuration.

In looking at the LTE Bandplans, the potential Dish spectrum allocation would miss the international TDD-LTE Band 38 which Softbank, China Mobile, and the UK auctions are using.  We will have to watch carefully to see if international devices will include functionality of Band 41.

My last area of concern is whether that will leave enough spectrum for Clearwire to continue to operate their WiMax network as they bring their TDD-LTE network online.  Additionally, with the geographic limitations of the leased channels, there may be a limited number of sites operating on Clearwire's network today, that won't have available spectrum without the owned channel spectrum.

Webcast: Clearwire's Spectrum Explained

Below is a link to an Investor's Presentation provided by AllNet Labs detailing the licensing, geographic, and leased versus owned challenges of Clearwire's Spectrum.

Audio and Slide Presentation

Presentation Outline

Agenda

• History of the EBS/BRS Spectrum
• Owned versus Leased Spectrum
• LTE Band Configuration
• Recent Auctions
• Substantial Service
• Issues before the FCC
• Spectrum Sale Challenges

Small Cells Rulemaking: 3550-3650MHz - Citizens Broadband Service (CBS)

Interesting facts from the Small Cell Rulemaking.  A signal at 3.5GHz would have 29% reduced range compared to BRS/EBS (2.5GHz), 45% compared to PCS (1.9GHz) and 75% compared to the Cellular (850MHz) bands.

Half of this band is currently used for receive frequencies for earth/satellite stations in 37 cites and adjacent radar systems exist from 3650-3700MHz.

There will be large exclusion zones due to incumbent use of the spectrum.  West Coast, East Coast, Gulf Coast, Hawaii, and Guam. Approximately 190 million people or 60% of the US population would not have access to small cell technology in the 3.5GHz band.  From the map below, the only Top 10 markets that could use this frequency band would be Chicago and Detroit with Detroit being a question mark due to issues with Canada.

FCC 12-148A1 - Figure 2

FCC Small Cell Definition

Small cells are low-powered wireless base stations intended to cover small indoor or outdoor areas ranging in size from homes and offices to stadiums, shopping malls, and metropolitan outdoor spaces. Small cells are typically used to extend wireless coverage to areas where macro cell signals are weak or to provide additional data capacity in areas where existing macro cells are overloaded. Small cells are also characterized by their inclusion of novel sensing technologies such as environmental recognition and auto-configuration. (Paragraph 30, FCC 12-148A1)

The FCC has proposed a multi-tier licensing framework:

• Incumbent Access - federal and grandfathered Fixed Satellite Service (FSS) providers
• Priority Access - critical services including hospitals, utilities, state, and local governments
• General Authorized Access (GAA) - commercial, opportunistic users as well as business and homeowners.  GAA users would be required to register in the SAS.

A Spectrum Access System (SAS) similar to the Television Whitespace Database used to coordinate unlicensed usage of the UHF broadcast TV whitespace. SAS would manage CBS access and ensure that lower tiered users will not harm federal and FSS users.