RSE measurements on LTE devices - 21 March 2012 - Protea Electronics-Comms & Measurement Div

Rohde & Schwarz is taking a completely new approach to measuring radiated spurious emissions (RSE) on LTE devices, in an attempt to make it easier for users to measure RSE in the presence of LTE carrier power. The solution is the R&S OSP open switch and control platform equipped with the new OSP-B155 option – at a price no higher than that of a conventional test setup with notch filters.

Standardisation bodies, such as the ITU or the European R&TTE, specify tests for measuring RSE on wireless devices. Manufacturers perform these tests during development and final acceptance testing. With conventional wireless communications techniques, the high-level radio signal can be filtered out at reasonable effort to enable RSE measurements.

On the other hand, LTE defines 43 frequency bands and can transmit – at full power – in six bandwidths in each band. Filtering out all LTE signals present in each band and bandwidth would involve tremendous effort, requiring a separate cabinet solely to accommodate the 258 filters needed to cover all frequency bandwidth combinations.

The Rohde & Schwarz solution requires only two height units in the control cabinet. The OSP-B155 plug-in module shifts the entire received signal spectrum into the optimum power range to allow full use of the dynamic range of the connected EMI test receiver. The receiver can analyse the entire LTE signal spectrum without requiring a notch filter.

The crucial prerequisite for a successful measurement using this technique is high receiver sensitivity. Only a high-performance EMI test receiver can detect all relevant spurious emissions. Moreover, the test receiver must have a high dynamic range to prevent peak levels of the transmitted wireless signals from distorting measurement results. The R&S ESU EMI test receiver offers high sensitivity of typically -155 dBm/Hz, combined with a high dynamic range of 80 dB in the relevant frequency range, making it an ideal choice for this type of measurement.

The OSP-B155 option fits into two slots on the OSP. It is designed to be used with the ESU EMI test receiver and EMC32 EMC measurement software from Rohde & Schwarz. In combination with the CMW500 wideband radio communication tester, which provides LTE signalling, the new RSE measurement solution seamlessly integrates also into existing applications and systems.

For more information contact Trevor Grundlingh, Protea Electronics, +27 (0)11 719 5700, trevorg@protea.co.za, www.protea.co.za