Real-world measurements are essential for building statistical channel models and for modeling realistic propagation effects and mechanisms at mmWave frequencies. The NYU WIRELESS channel sounder has evolved to be flexible across multiple frequency bands and RF bandwidths. The latest millimeter-wave (mmWave) channel sounder was developed to support both a wideband sliding correlator mode and a real-time spread spectrum mode, also known as wideband correlation or direct-correlation. Both channel sounder modes are capable of absolute propagation delay (time of flight) measurements with up to 1 GHz of radio frequency (RF) null-to-null bandwidth and can measure multipath with a 2 nanosecond (ns) time resolution. The sliding correlator configuration facilitates long-distance measurements with angular spread and delay spread for up to 185 dB of maximum measurable path loss. The real-time spread spectrum mode is shown to support short-range, small-scale temporal, and Doppler measurements (minimum snapshot sampling interval of 32.753 microseconds) with a substantial dynamic fading range of 40 dB for human blockage and dynamic urban scenarios.
The channel sounder is built with National Instruments digital-to-analog (DAC), analog-to-digital (ADC), and FPGA PXI modules in addition to QuickSyn frequency synthesizers for the intermediate-frequency (IF) and local oscillator (LO) sources of the superheterodyne architecture. Low phase noise Rubidium (Rb) standard references are configured for frequency and time synchronization, and absolute time delay measurements. The LabVIEW and LabVIEW-FPGA environments allow for rapid development and flexibility to modify and improve power delay profile (PDP) acquisition code and algorithms, and the mechanical control of transmitter (TX) and receiver (RX) antennas in the azimuth and elevation planes and along a linear track for small-scale fading and translation measurements.
The mmWave channel sounder may be used for accurate spatial and temporal ray-tracing calibration, for identifying individual multipath contributions, for measuring antenna patterns, and for constructing spatial profiles of mmWave channels using directional antennas. To date, the latest channel sounder has been used for a macro-diversity measurement campaign in Brooklyn at 73 GHz, for 28 GHz and 73 GHz small-scale spatial fading and autocorrelation measurements, and for dynamic human blockage measurements.
- Large-dynamic range measurements with up to 185 dB maximum measurable path loss in dense urban environments
- Small cell base station-to-mobile or base station-to-base station measurements with 4 meter pneumatic masts to elevated RF front-ends to lamppost heights.
- Indoor and outdoor centimeter and mmWave diffraction measurements for various materials at 2.4, 10, 20, 26, 28, 38, 60, and 73 GHz.
- Base station or access point diversity scenarios with absolute propagation delay measurements (true time of flight), enabled by the integration of low phase noise high stability rubidium references.
- Dynamic blocking measurements with wideband correlation allow for a minimum periodic power delay profile (PDP) recording interval of 32.752 microseconds for up to 41,000 consecutive PDPs. This system configuration allows for dynamic human blocking measurements between the TX and RX at various mmWave frequencies over very short time intervals for observing and modeling rapid fading events.
- Small-scale fading and autocorrelation measurements for MIMO analysis
|G. R. MacCartney, Jr. and T. S. Rappaport, “A Flexible Millimeter-Wave Channel Sounder with Absolute Timing,” IEEE Journal on Selected Areas in Communications, vol. 35, no. 6, pp. 1402-1418, June 2017.||5G Channel Models, Channel Sounder, Millimeter Wave 5G Prototype, mmWave Channel Models, mmWave MAC, mmwave rappaport, ns3||2017/06/01|
|G. R. MacCartney, Jr. and T. S. Rappaport, “A Flexible Wideband Millimeter-Wave Channel Sounder with Local Area and NLOS to LOS Transition Measurements,” in 2017 IEEE International Conference on Communications (ICC), Paris, France, May 2017, pp. 1-7.||100 GHz, 5G Channel Models, Channel Sounder, Dynamic Channel Models, Macro-diversity, Millimeter Wave 5G Prototype, MmWave cellular system design, mmWave Channel Modeling, mmWave Channel Models, mmwave rappaport, Prototyping and simulation software, Spatial Channel Estimation and Tracking||2017/05/01|
|S. Sun, H. Yan, G. R. MacCartney Jr., and T. S. Rappaport, "Millimeter Wave Small-Scale Spatial Statistics in an Urban Microcell Scenario," 2017 IEEE International Conference on Communications (ICC), May 2017.||100 GHz, 5G Channel Models, Channel Sounder, Millimeter Wave 5G Prototype, MmWave cellular system design, mmWave Channel Modeling, mmwave rappaport, Prototyping and simulation software||2017/05/01|
|M.K. Samimi, T.S. Rappaport, S. Sun, G. R. MacCartney, Jr. “28 GHz Millimeter-Wave Ultrawideband Small-Scale Fading Models in Wireless Channels,” in 2016 IEEE Vehicular Technology Conference (VTC2016-Spring), 15-18 May, 2016||5G Channel Models, Channel Sounder, Millimeter Wave 5G Prototype, MmWave cellular system design, mmWave Channel Models, mmwave rappaport||2016/02/22|
George R. MacCartney, Jr. and Theodore S. Rappaport