4G Spectrum Investigation

Overview:

Attached is a spectrum report for Seattle, Washington, focusing on the spectrum band currently utilized for mobile voice,  3G data, and 4G data.  We are using this market to develop an understanding of the way spectrum ownership affects the ability for a carrier to deploy 4G technologies. The spectrum bands covered include: 700MHz, Cellular, 1.4-1.6GHz satellite,  Personal Communcations Services (PCS), Advance Wireless Services (AWS), Wireless Communications Services (WCS), Broadband Radio Service (BRS), and Educational Broadcast Service (EBS).  The outcome of the analysis in this report details the amount of spectrum that each of the current carriers have available for 4G broadband services.  This report focuses on each carrier’s spectrum ownership, not whether the spectrum is currently loaded with either voice or data services.

Band Construction:

To build this report, information on each of the band configurations was gathered from the FCC website.  Using this information it is easy to see what channel blocks are contiguous, and how the existing spectrum ownership can be converted over time to 4G spectrum operation.  For the purpose of this report, we have only considered the adoption of 10MHz carriers for 4G.  The frequency division duplex (FDD) version of LTE can be operated in paired channel bandwidths of 1.25MHz, 5MHz, 10MHz, 15MHz, and 20MHz.  Currently, LTE only has commercial implementations in 5MHz (MetroPCS) and 10MHz (Verizon Wireless).    Users are reporting 3G type speeds on the MetroPCS network (700kbps download), so we consider 10MHz a minimum channel bandwidth for 4G services.

4G Spectrum Bands

Frequency Band	Starting Frequency	Ending Frequency
700MHz	698MHz	806MHz
Cellular	824MHz	894MHz
1.4GHz	1390MHz	1425MHz
1.5/1.6GHz	1525MHz	1660.5MHz
1.670GHz	1670MHz	1675MHz
Advance Wireless Services	1710MHz	2155MHz
Personal Communications Services	1850MHz	1995MHz
Wireless Communications Services	2305MHz	2360MHz
Broadband Radio and Educational Broadcast Service	2496MHz	2690MHz

Spectrum Ownership:

Spectrum ownership was determined for each channel block using the FCC’s Universal Licensing System (ULS) market based license search, with the geographic boundaries of King County.  Each active licensee in one of these spectrum blocks was translated to the appropriate major carrier name and the licensed spectrum information was logged on Appendix A.   If a lease was indicated within the FCC ULS records, the corresponding spectrum was allocated to the controlling carrier.  This predominantly affects the EBS spectrum used by Clearwire.   The PCS spectrum blocks have been broken down, consistently, into 5MHz blocks to account for the reauctions and spectrum trades that have broken the original auction spectrum blocks into smaller pieces.  It is important to note that virtually the entire spectrum covered in this report has been configured as paired spectrum, which would typically be put to use in a Frequency Division Duplex (FDD) system like LTE(FDD).  There is 42MHz of unpaired spectrum in the EBS/BRS band which is not paired, leaving a Time Division Duplex (TDD) system as the only current 4G option.

Analysis:

The analysis is fairly straight forward.  The columns on Appendix A are essentially roads of exclusive spectrum ownership or control.  For each 10MHz of contiguous spectrum, a carrier was allotted one - 4G carrier.  In the current LTE implementations, the same 4G carrier is assigned to each of the three sectors on a typical cell site, thus a carrier with only one 4G carrier available could complete a market-wide deployment using that carrier, but they wouldn’t have any spectrum to deal with data capacity issues across their network.  Any high usage areas would require the permitting and construction of a new site to offload the existing network capacity. 

Lightsquared has a shared licensing interest for the 1.5/1.6GHz frequency band.  We have indicated a maximum number of 4G carriers that could be defined within this mobile satellite band.  This spectrum is frequency-coordinated between international operators and operators in Mexico and Canada and will require satellite receivers to be modified before wideband spectrum will be available.  In addition, the FCC is likely to require that a portion of this band be dedicated to satellite operation, making it unavailable for the contemplated Lightsquared terrestrial deployment.  Each of these factors makes it difficult to determine the final number 4G carriers Lightsquared will have available.  Since this is a spectrum exercise, Lightsquared’s dispute with the GPS community and the filed GPS interference issue is a noteable risk to the use of this spectrum, but doesn’t affect ownership.

Summary:

Spectrum Available for a 10MHz 4G Configuration – Seattle (King County)

Company	MHz that could be combined for 4G (FDD)	Number of 10MHz (FDD) Carriers (Paired)	MHz that could be combined for 4G (TDD)
Clearwire	140	7	40
AT&T	80	4	0
T-Mobile	40	2	0
Verizon	40	2	0
Sprint	40	2	0
Lightsquared	40	2	0
Cricket	20	1	0
MetroPCS	0	0	0
USCellular	0	0	0
Other	20	1	0

As this data describes, there is very little spectrum available for 4G deployments.  Much of the spectrum that the carriers own is already deployed with the carrier’s existing voice and data technologies.  Verizon Wireless carries virtually all of its CDMA voice and data traffic in the cellular band with a small holding (5MHz) in the PCS band.  Verizon’s LTE deployment uses the 10MHz paired block that it has at 700MHz.  For Verizon to grow its LTE network to a second carrier of capacity, they would need to clear virtually all of the voice and 3G data traffic from the cellular band and then overbuild their entire network with cellular frequency radios, since today they only have the 700MHz frequency equipment in place.  In addition, all of Verizon’s LTE devices only work on the 700MHz band C block channels, thus, they would need to be swapped to operate on the additional bands, once constructed.  If spectrum acquisition is an option, only 20MHz of spectrum (AWS) is not in the control of a regional or national wireless player. 

Another example to understand is the effect of the  AT&T and T-Mobile merger.  The alignment of the spectrum in the Seattle market doesn’t create any additional 4G spectrum opportunities for AT&T than the companies had separately.  These opportunities would come from 5MHz spectrum pieces that align with the other carrier’s stranded spectrum.  While the merger will allow the combined company to have AT&T’s four  – 4G carriers plus T-Mobile’s two - 4G carriers for a combined six - 4G carriers.  They will be spread through five different frequency bands (four if you consider PCS and AWS to be similar in frequency to share cell site radios and antennas).

Frequency	AT&T 4G Carriers	T-Mobile 4G Carriers	Total Carriers
700MHz	1	0	1
Cellular	1	0	1
PCS/AWS	2	2	4
WCS	0	0	0

Operationally, both T-Mobile and Verizon are going to have a more complex radio environment to optimize because of their use of multiple frequency bands, thus multiple radios, at their cell sites for their 4G networks.  It is likely that the higher frequency sectors will need to hand their data calls to a lower frequency sectors before the data call is handed to an adjacent site.  Each of these handovers has to be optimized for vehicle and walking traffic or the customer will experience dropped packets or a data call failure.

The final area we analyzed is the ability of the carriers to grow to higher speed solutions.  To increase the speed from the existing 10x10 LTE(FDD) deployments will require stepping to a 15MHz or 20MHz channel solution, like 20x20 LTE (FDD).   In the Seattle market, AT&T and Sprint (owners of the MTA blocks of PCS spectrum) would be able to deploy a single 15MHz 4G carrier throughout the market.  Neither the 700MHz or Cellular bands have the spectrum bandwidth to deploy this broadband carrier.  In comparison, Clearwire’s spectrum position provides three -20 x20 carriers, operating in a paired configuration, between the EBS/BRS lower band and upper band. 

LTE Speed Comparisons by RF Channel Configuration

	Frequency Band	Configuration	Downlink	Uplink
Verizon Wireless Commercial Offer	700MHz	FDD 10x10 (MHz)	5-12Mbps	2-5Mbps
Clearwire LTE Trial	BRS/EBS	FDD 10x10 (MHz)	50Mbps	15Mbps
Clearwire LTE Trial	BRS/EBS	FDD 20x20 (MHz)	90Mbps	30Mbps
LTE Theoretical Peak Rate (4x4 MIMO)		FDD 20x20 (MHz)	300Mbps	150Mbps

Appendix A – Seattle (King County) Spectrum Band Maps