Since the 5G mobile network will also use the millimeter wave frequency range, among other things, it must be ensured that mobile devices can still make emergency calls and determine their exact location. Rohde & Schwarz has developed the R&S TS-LBS test system for such tests and used it to verify the performance of assisted GPS (AGPS) in a commercial mobile radio device, for example.
The provider of test and measurement solutions for the 5G mobile network and location-based services (LBS) used the commercial mobile device to test the performance of the integrated AGPS when simultaneously transmitting data via the millimeter-wave frequency band of the 5G mobile network.
5G NR uses the FR1 frequency range (<7.125 GHz) and the FR2 frequency range (>24 GHz). The use of the millimeter wave frequency range FR2 is particularly problematic for mobile devices, as it leads to high power consumption and heat generation. Even though mobile devices in North America, for example, are increasingly accessing the FR2 frequency band, important functions such as emergency calls must be guaranteed at all times and without restrictions.
The new R&S TS-LBS test system consists of the R&S CMX500 test platform, which was specially designed for testing mobile radio devices, and the R&S CMW500 test platform, which is specially designed for verifying wideband radios. This enables seamless and comprehensive testing to determine whether a device is suitable for the LTE and 5G mobile network (in the FR1 and FR2 frequency ranges).
The R&S SMBV100B vector signal generator simulates the satellite constellations used by GPS systems on the L1 and L5 frequencies. The system is also suitable for verifying other GNSS satellite navigation systems such as GALILEO, GLONASS & BEIDOU. In addition, the solution can also be used in conjunction with other positioning systems such as barometric pressure sensors, WiFi and/or Bluetooth. Legacy technologies such as GSM, WCDMA and LTE are supported by the same hardware.
FR2 is a metrological challenge
"Since our TS-LBS test solution can now also be used for the FR2 frequency range, our customers' mobile devices can be certified according to the latest 5G standards," explains Bryan Helmick from Rohde & Schwarz. "Existing LTE-TS-LBS test systems can be easily extended for the 5G mobile network by connecting the R&S CMX500 test platform. The only thing the user then needs to test the devices in the FR2 frequency range is new hardware for the R&S CMX500 test platform and the R&S CMQ500 shielding chamber solution."
The 5G mobile network with a frequency range below 6 GHz (FR1) is the further development of the 4G mobile network. This provides greater bandwidth and ensures greater flexibility at the level of the individual physical layer. This enables all new and additional applications defined for the next-generation mobile network.
The real technical challenge, however, is the 5G-mm wave (FR2), which opens up a new level of complexity in device development. Millimeter wave frequencies imply metrological challenges that require new test approaches.
Rohde & Schwarz is one of the leading solution providers in the fields of measurement technology, broadcast and media technology, aerospace/defense/security as well as networks and cyber security. The Munich-based independent group has around 12,100 employees worldwide and generated sales of €2.14 billion in the 2018/2019 financial year.
