Much of the talk, according to Raajit Lall, at the Mobile World Congress (MWC) is about LTE-Advanced, even though the first implementation of the standard is only a few months old.

Lall is product manager for National Instruments' rf group and saw most interest on the NI stand revolve around a demo using the company's latest Vector Signal Transceiver (VST), the PXIe-5645R, which was introduced at the show. "The target for this module is anyone who is trying to test RF and baseband at the same time," explained Lall. "Previously they would have needed a separate box for vector signal generation, a separate box for analysis, another box for digitising for analysing and another for generating the baseband signals. This combines these four separate instruments in to one four slot PXI module." One aspect of LTE Advanced is cellular aggregation where it takes different LTE carriers and aggregates them in order to improve the data rates on LTE signals - important as market applications for LTE Advanced is for mobile phones where there is demand for HD streaming and HD video games. The required speed and functionality was demonstrated by NI's MWC exhibit, which showed the 5645R generating and analysing LTE Advanced signals and then at the same time generating the I/Q of the baseband LTE Advanced signal and analysing that using a digitiser. Lall commented: "This test would not have been possible in a PXI format before due to delays across the backplane circuitry and there are a lot of applications which require the baseband to be tightly synchronised with the RF signal. Using the same instrument with the same FPGA means you are essentially synchronising within a few pico seconds." Other features of the PXIe-5645R include 65 MHz to 6 GHz frequency range, 80 MHz instantaneous bandwidth and 24 channels of high-speed digital I/Q. It has a baseband I/Q interface with 16-bit data sampled at 120 MS/s with up to 80 MHz of complex bandwidth, configurable as differential or single ended. It also has user-defined functionality by virtue of its FPGA.