Technology Guidance for In-Building Cellular Coverage

When poor cellular reception exists in campus buildings, the Wireless Governance Committee (WGC) recommends Wi-Fi Calling be utilized rather than the historical approach of deploying a Distributed Antenna System (DAS). DAS’s have been previously implemented primarily in campus Residential Halls and a few recent capital projects like the Champions Center.  

Using Wi-Fi Calling leverages the ubiquitous campus Wi-Fi network and thus will be much less expensive and complicated than a DAS implementation.  There may be circumstances where a DAS provides a better technology solution, but a review with the WGC is recommended before proceeding with design and/or any related contracting.  

Background Information

New building construction may create challenges for cellular service as building materials, especially those used in compliance with LEED certifications, can impede cellular signals. Additionally, the cellular reception strength is not as strong as desired in many of the non-LEED buildings across campus.   In the past, a Distributed Antenna System (DAS) could be included in the construction cost and cellular carriers would be solicited to connect to the system. CU has had various levels of success with this model especially with the long-term funding of maintenance and on-going operational expenses. 

Recently cellular carriers have begun to view wireless as the 4th utility, with the responsibility of funding and ensuring in-building cellular coverage falling onto the building owner. With no guarantee a cellular provider will invest in the equipment required for the source signal, the expense of installing a DAS along with the uncertainty of extracting value from it requires CU to revisit its strategy for ensuring in-building coverage for cellular service.

Recommendation

The WGC recommends users leverage Wi-Fi calling when cellular coverage is inadequate. To allow for this, the WGC recommends all new construction include adequate Wi-Fi coverage, designed and built to OIT specifications, to allow for Wi-Fi calling in all areas of the building.

Implications of Recommendation

  • Expectation that cellular users inside campus buildings have a phone with Wi-Fi capabilities and are connected to University Wi-Fi inside the building. Ninety percent of smartphones offered by cellular service providers have the capability to use Wi-Fi for voice and data traffic when there is little or no cellular coverage.
  • It is acknowledged that Wi-Fi calling is not available on 100% of phones. Data shows many customers of campus Wi-Fi are already using Wi-Fi Calling in buildings.
  • OIT design of Wi-Fi infrastructure must include the capability to handle Wi-Fi calling. All budgeting and estimating tools for Wi-Fi will include a Wi-Fi calling requirement in the design.

Known Risks of Recommendation

  • Wi-Fi calling mechanisms are controlled by the service provider and/or the phone manufacturer.  Therefore, problems could exist with call completion even in areas with a good Wi-Fi signal.  
  • E911: Wi-Fi calling has limitations in automating caller location to 911 dispatch. The industry along with the FCC are building a standard to resolve this, which may be available in 2022.
  • Some buildings have older Wi-Fi infrastructure and may not support Wi-Fi calling until they are upgraded. [OIT can provide status of Wi-Fi per building.]
  • Bathrooms, stairwells and some other locations historically have not been designed for Wi-Fi coverage. Work needs to be done in coordination with OIT and Facilities Management to include these areas based on this recommendation, specifically in construction standards.
  • Wi-Fi operates on unlicensed RF spectrum and is susceptible to interference. ​

Exception(s)

Exceptions may exist, such as specific public safety situations including operations for CUPD or City Fire, where a DAS installation or Bi-Directional Amplifier (BDA) would be the preferred technological solution. In such cases, it is recommended the usage needs be reviewed with WGC prior to proceeding with design and/or any related contracting.  

Additional Notes

This market space continues to evolve and this recommendation is based on current industry standards and known factors that make Wi-Fi calling the most economical and viable solution for in-building voice calling via cell phone today. OIT continues to monitor the market as new technologies in the future may result in modifications of this recommendation.

Last Updated: November 2019