mmWave frequencies are poised to play a significant role in the future of 5G. The FCC, 3GPP, and other standards bodies for 5G mobile networks have already reserved them. Channel measurements capture how wireless signals are affected in a given environment. For example, channel measurements can show how signals bounce off (or are blocked by) objects such as trees, buildings, cars, and even people.
Characterizing wireless channels is crucial for researchers defining 5G technologies, as it will help lay the foundation for the architecture and design of these new wireless networks. We believe this work will play a role in AT&T's future 5G development by creating accurate models that will help determine where AT&T places its network equipment to deliver the best possible mobile experience for customers.
“Using mmWave spectrum for mobile 5G presents numerous challenges that we believe can be overcome,” said Marachel Knight, senior vice president of wireless network design and architecture at AT&T. “We knew early on that designing and real-time control of mmWave spectrum needs to be much more precise than current cellular systems. With the help of NI’s flexible hardware and software platform, AT&T developed a new type of channel surveying equipment, and we are using it to develop highly advanced models that will work for our network.”.
The channel survey equipment, internally nicknamed the "Porcupine," is the first of its kind and is owned by AT&T. It allows for real-time measurement and monitoring of channel parameters. Designed by AT&T, the channel survey equipment uses an architecture based on NI's mmWave transceiver system. This unique design offers several significant advantages. It allows angle-of-arrival (AoA) measurements, which would normally take 15 minutes or more to complete (using horizontal-vertical movement units), to be performed in less than 150 milliseconds and the results to be displayed in real time.
The channel survey system uniquely captures channel measurements where all data is acquired and processed in real time. Other channel survey techniques capture raw data and post-process it to characterize the channel while providing a measurement every 15 minutes. In contrast, the "Porcupine" can provide around 6,000 measurements in that time. It's like capturing 15 minutes of action with a video instead of a photo. A video tells the whole story, while a photo shows only a moment.
The real-time measurement capability eliminates the need to repeat experiments or adjust equipment to take multiple measurements from the same location. Because parameter extraction is performed in real time, the collected data can also be evaluated in real time. This means that inaccurate data can be immediately replaced with a fresh set of measurements during the experiment. With other techniques, an entire day of experiments could be lost if the collected data needs to be post-processed.
To our knowledge, the speed and accuracy of this mmWave channel surveyor make it uniquely capable of performing rapid channel measurements. For example, the "Porcupine" allows for the measurement of 5G mmWave frequencies through unit testing. This capability has been beyond the reach of other mmWave channel surveyors. As the 5G ecosystem seeks new use cases for 5G, such as assisted driving, connected cars, and self-driving cars, the ability to study and model vehicular channels will become increasingly critical.
“NI’s mmWave transceiver system and LabVIEW system design software enabled AT&T and NI to define and develop a channel measurement system unmatched in the industry today,” said James Kimery, director of RF research and SDR marketing at NI. “The combination of LabVIEW’s PXIe and FPGA provided the bandwidth, data and signal processing capacity, and flexibility needed to meet mmWave requirements and accelerate 5G development.”.
*Claim based on Nielsen-certified data network rankings. Ranking includes data provided by wireless customers in the Nielsen Mobile Insights survey, Nielsen Mobile Performance network measurements, and Nielsen Drive Test Benchmarks for Q2+Q3 2016 in 121 markets.
**Global coverage claim based on offering discounted voice and data roaming; LTE roaming and voice roaming in more countries than any other US-based carrier. International service required. Coverage not available in all areas. Coverage may vary by country and be limited or restricted in some countries
