December 9, 2016
In-building wireless (IBW) networks play a vital role in the safety of public safety officials and their ability to rescue and/or treat civilians. Recognizing the need to ensure communications with police officers, firefighters, EMTs and disaster relief personnel when they go into any structure, government agencies, vendors, and industry organizations have been diligently working on developing systems, processes and technologies to ensure everyone’s safety. In today’s post, we will discuss some of the efforts and how they are improving in-building communications for the benefit of all.
FirstNet - Most IBW systems utilize DAS, which can increase potential interference due to the frequency assignments for the public safety sector getting closer to commercial spectrums within a building. FirstNet is proposing a convergence of cellular and LMR systems when operating indoors to lessen interference. In the interim, potential problems can be reduced by:
- Using a separate DAS for each sector – Effective in significantly reducing interference, it typically gets expensive and poses certain reliability issues.
- Using a hybrid DAS System – Both sectors share cabling but the signal is separated at the antenna.
- Combining everything into a single DAS – This requires extensive filtering, which would add more cost and complexity.
Enhanced 911 - The call-locating process associated with traditional landline 911 calls that relied on a public-safety answering point (PSAP) falls short in today’s mobile device world. For this reason, the FCC created Enhanced 911 (E-911) to locate the exact position of a wireless emergency call. E-911 is being rolled out in three phases:
- Phase 0 – All 911 calls must be relayed to a call center, regardless of whether the mobile phone user is a customer of the network being used
- Phase 1 – Wireless network operators must identify the phone number and cell tower used by callers within six minutes of a request by a PSAP
- Phase 2 – Wireless network operators must provide the latitude and longitude of callers within 300 meters within six minutes of a request by a PSAP
In February 2015, the FCC voted unanimously to improve the indoor location tracking of wireless 911 calls. All Commercial Mobile Radio Service (CMRS) providers must provide dispatchable location or x/y location within 50 meters for the following percentages of all emergency calls made with a mobile device within the following timeframes:
- 2 years: 40%
- 3 years: 50%
- 5 years: 70%
- 6 years: 80%
All CMRS providers must also provide vertical location information within the following timeframes:
- 3 years: All CMRS providers must make uncompensated barometric sensor data available to PSAPs from any applicable handset. Plus, nationwide CMRS providers must use an independently administered and transparent test bed process to develop a proposed z-axis accuracy metric and must submit it to the FCC for approval.
- 6 years: Nationwide CMRS providers must deploy technology that achieves the Commission-approved z-axis metric, in each of the top 25 Cellular Market Areas (CMAs).
- Within 8 years: Nationwide CMRS providers must deploy dispatchable location or z-axis technology in accordance with the above benchmarks in each of the top 50 CMAs.
- Non-nationwide carriers that serve any of the top 25 or 50 CMAs will have an additional year to meet these benchmarks, respectively.
Fire and Building Codes - In 2009, the International Code Council (ICC) introduced in-building public safety communications into the IFC code that specified general building coverage must be 95% for wireless networks. The U.S. follows guidelines based on the National Fire Protection Agency (NFPA) requirements that mandate 90% general coverage but 99% coverage for critical areas such as control rooms. Both codes require two specific measurements be made to determine coverage – RF signal strength and Delivered Audio Quality (DAQ). These codes are enforced through required certifications each year and consist of mapping signal coverage across the entire building.
With updated codes mandating strong and reliable in-building communications systems, the methods of developing and testing these systems must keep pace. One of the most practical methods in which inspectors are now mapping coverage involves using devices with multiple sensors, including a compass, gyroscope, accelerometer, altimeter and barometer. These sensors measure direction, turns, speed and height above sea level to create a three-dimensional view of a location.
One example of these new solutions that address government and industry requirements is the MA8100A TRX NEON Signal Mapper, which is used with Anritsu handheld instruments like the LMR Master™ S412E (figure 1). Developed by Anritsu and TRX Systems, the solution uses a tracking unit worn on the user’s belt and connected to an Android device to provide location information without the use of GPS data, which is not available indoors. Using this tracking unit with Anritsu analyzers and included cloud service allows users to generate 3D geo-referenced signal coverage maps and allows for real-time monitoring of the mapping process (figure 2).
The Anritsu Signal Mapper eliminates the inconveniences and inconsistencies associated with traditional methods of signal mapping. Along with making the process go more smoothly, the measurements are more precise than those made using other methods, which is exceptionally valuable for establishing communications systems that can literally mean life and death.
To learn more about the standards and technologies influencing in-building wireless systems for public safety communications, watch this new webinar.