Deficiencies of T-Mobile’s 2.5GHz Spectrum October 26, 2021 16:38
Recent discussions around the wireless industry have included opining on why T-Mobile acquired 40MHz of C-band spectrum when they control so much 2.5GHz spectrum. Although the 2.5GHz spectrum is a valuable spectrum asset, there are two challenges to this spectrum that are not well understood by the industry and we believe that T-Mobile’s C-band purchases were a strategic purchase to provide a path to overcome these two spectrum licensing limitations.
License Areas Controlled by the FCC:
The first limitation is unlicensed or whitespace areas in core urban markets. To highlight these areas, we are going to start with some whitespace analysis that we have developed as part of our EBS Auction Tool. In this analysis, the percentage of the population that is available in the whitespace area is indicated for each EBS channel in a county. We have also calculated the percentage of the population that is contained with T-Mobile license area and the percentage of the population that is contained within the license area of any other carrier. In the image below we are showing the percentage of the population under T-Mobile’s control and under the FCC control (whitespace) for the entire 2.5GHz frequency band including both the EBS and BRS channels. The color ranges start at 0% with red, 50% with yellow, and 100% with green. In our initial analysis we will be focusing on the first auction channel (black box) in the six counties that make up the Chicago CMA market. We prefer to use the CMA market structure to evaluate urban areas because they include only the most populated counties in each urban area.
2.5GHz Full-band Population Percentage View (Chicago):
2.5GHz – 1st EBS Auction Channel Population Percentage View (Chicago):
In the top section of the chart above, it is apparent that T-Mobile controls all of the 1st EBS Auction channel in Cook, DuPage, and Will counties but they only control all of the A1-A2-A3 channels in Kane County. Fortunately, the parts of 1st EBS Auction channel that they don’t own will be available in the Auction 108. The available whitespace is indicated in the lower half of the chart. Looking at McHenry County, 100% of the C1-C2 channels will be available in the EBS Auction (108).
These charts highlights the percentage of the population available either for T-Mobile’s licenses or for the FCC’s whitespace. Next we will look at the geographic constraints of T-Mobile’s licenses and the shape of each county’s whitespace area. In the map below we are able to show the license areas for the A1-A2-A3 channels because the license areas of interest are identical. It is apparent that T-Mobile has the rights to operate the A1-A2-A3 channels completely across the counties in the Chicago CMA except Lake and McHenry.
Licensing Map – A1-A2-A3 (Chicago):
Looking at the B1-B2-B3 & C3 channels, a whitespace area exists covering almost all of Kane County along with similar whitespace areas in McHenry and Lake counties.
Licensing Map – B1-B2-B3 & C3 (Chicago):
Our final map delineates the largest limitations to the areas that T-Mobile can deploy the C1-C2 channels in the Chicago CMA market. Their base stations located in the gray areas of Kane, Lake, and McHenry counties cannot use the C1-C2 channels.
Licensing Map – C1-C2 (Chicago):
Looking again at the T-Mobile’s control of the 1st EBS auction channel we can highlight the deployment limitations that the whitespace area presents. Since the 1st Auction channel is 49.5MHz, this chart indicates that T-Mobile can deploy roughly a 50MHz channel on any sites in Cook, DuPage, and Will counties. In Kane County they are limited to a 15MHz channel in the available 16.5MHz of spectrum. To have a consistent deployment of a 50MHz channel across Chicago, they would need to purchase the whitespaces areas for each of these channels in each of the Chicago counties.
Looking again at the T-Mobile’s control of the 1st EBS auction channel we can highlight the deployment limitations that the whitespace area presents. Since the 1st Auction channel is 49.5MHz, this chart indicates that T-Mobile can deploy roughly a 50MHz channel on any sites in Cook, DuPage, and Will counties. In Kane County they are limited to a 15MHz channel in the available 16.5MHz of spectrum. To have a consistent deployment of a 50MHz channel across Chicago, they would need to purchase the whitespaces areas for each of these channels in each of the Chicago counties.
The last perspective that we want to share on the Chicago market is the actual population in each of the whitespace areas for each county. Although we thought that 100% of the population was available for each channel in Cook County, the whitespace population table indicates that there is a very small population and small geographic area that is a whitespace within Cook County for the B1-B2-B3-C1-C2-C3 channels.
2.5GHz – 1st EBS Auction Channel Population View - Whitespace (Chicago):
License Areas Controlled by Other Carriers:
The second limitation is spectrum blocks that are controlled by other carriers in core urban markets. To highlight these areas we are going to look at the four counties in the Los Angeles CMA market. For the Population Percentage Chart below, we are including the population percentage for other carriers rather than the whitespace percentages.
2.5GHz Full-band Population Percentage View (Los Angeles):
2.5GHz – 3rd EBS Auction Channel Population Percentage View (Los Angeles):
In the Top View it is apparent that T-Mobile already controls the spectrum across all of the BRS channels (gray) in Los Angeles County but they are missing roughly 10% of the population for the G1-G2-G3 channels. In between the two BRS blocks of spectrum are the K guard band channels. The ownership of these guard band channels mirrors the ownership of the primary channel e.g. G1=KG1. The BRS channels and the EBS G1-G2-G3 channels total to 87MHz of spectrum, providing T-Mobile the ability to deploy an 80MHz NR channel throughout most of Los Angeles County. Unfortunately in Orange County, another carrier owns 98% of the G1-G2-G3 channels limiting T-Mobile to a 10MHz channel in the first BRS block (F4-E4) and a 50MHz channel in the second BRS block (BRS2-E123-F123-H123).
Los Angeles CMA Counties:
In looking at the G1-G2-G3 licensing map, you can see that there are actually three licenses that T-Mobile does not control in the Los Angeles CMA Market.
Licensing Map – G1-G2-G3:
2.5GHz – 3rd Auction Channel Population View – Other Carriers (Los Angeles):
The Other Carriers Population percentage view indicates the large licensed population that is controlled by other carriers and would need to be purchased by T-Mobile.
Conclusion:
With these two examples we have shown that missing 2.5GHz spectrum either due to it being unlicensed or being controlled by another carrier present challenges that likely limit T-Mobile’s largest 5G channel size to a subset of each urban market. We believe that T-Mobile’s participation in the C-band and the current 3.45GHz auction was to “future” proof their ability to offer large channel sizes in the upper mid-band spectrum. With either the C-band spectrum or the 3.45GHz spectrum, T-Mobile could use carrier aggregation to achieve 100MHz effective channel sizes even in areas where their 2.5GHz spectrum is more limited.
