5G millimeter-wave channel sounding test system targets research
For decades, propagation conditions in cellular networks have been well understood in the frequency bands from 450 MHz to 3 GHz. Starting with the commercialization of GSM systems, channel models were developed based on this knowledge. These are widely used to verify base station and end user device performance in the lab by simulating real-world conditions. In contrast to these legacy frequency bands, knowledge of the radio channel at frequencies above 6 GHz is still limited.
Although a significant amount of channel sounding campaigns have been conducted and many results published, new spectrum in the discussed range from 6 GHz to 100 GHz requires much more measurement data. Multiple research projects as well as the upcoming 3GPP standardization need comprehensive measurement data in order to derive suitable channel models for efficient testing in future.
The test system from Rohde & Schwarz comprises the SMW200A vector signal generator and the AFQ100B I/Q baseband generator on the transmitter end and the FSW signal analyzer on the receiver end. The transmitter and receiver are synchronized and triggered by high-precision clocking units from Fraunhofer HHI, which also serve as absolute time bases with an accuracy of 2 ns.
The SMW200 and AFQ100B provide a wideband sounding signal with up to 500 MHz signal bandwidth and up to 40 GHz carrier frequency. The sounding signal is based on an optimized correlation sequence. The FSW receives this signal up to a carrier frequency of 67 GHz, and demodulates and samples it using its built-in 500 MHz demodulator.
Thomas Haustein, Head of the Wireless Communications and Networks Department, states: "Fraunhofer HHI’s expertise in millimeter-wave channel sounding contributes to a better understanding of radio propagation, making it possible to derive realistic channel models for the relevant wireless use cases. It will therefore provide the basis for standardizing link and system design within the global 5G effort."
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