The N7624B Signal Studio for 3GPP LTE FDD is a powerful software tool that simplifies the creation of standards-based LTE and LTE-Advanced signals compliant with the 3GPP Release 9 June 2010 and December 2010 version. The waveform playback mode of the software creates physical layer and transport channel coded arbitrary waveform files. These waveforms are used for measuring EVM, ACLR, and CCDF for power amplifier testing and for measuring HARQ functionality and block error rate (BLER) for receiver testing.

Signal setup is simplified with the included pre-defined, standard-compliant E-TM and FRC configurations. Extensive flexibility enables testing beyond standard requirements with user-defined signal configurations.

LTE-Advanced signal creation enables uplink and downlink carrier aggregation with flexible configuration of contiguous and non-contiguous component carriers. Power characteristics and spectral investigation for uplink signals are critical to LTE-Advanced, and enhanced uplink is supported through clustered SC-FDMA and simultaneous PUCCH / PUSCH transmission, enabling test of spurious emissions, CCDF, PAR, and other metrics. Pre-defined configurations of carrier aggregation scenarios are included for uplink and downlink waveforms.

The software also creates real-time uplink LTE signals when used with the N5106A PXB. Real-time HARQ (Hybrid Automatic Repeat Request) and timing adjustment feedback from the eNB are used to create LTE signals with dynamically changing characteristics to enable testing of two important characteristics:

• the incremental redundancy capability of the eNB receiver to correctly recover UE data transmitted with different RV indexes and then inform the UE of Acknowledge/Not Acknowledge (ACK/NACK) transmissions
• the ability of the eNB receiver to correctly measure UE transmitter frame timing and then direct the UE to advance or delay the timing of subsequent transmissions

Closed loop HARQ and timing adjustment feedback is required for making the throughput measurements defined in the Performance Requirements in the 3GPP specification. Additionally the real-time signals have data payloads that seamlessly span frame boundaries for making bit error rate (BER) measurements. The N5106A PXB can add to the LTE signal the required fading models along with Additive White Gaussian Noise (AWGN) to simulate realistic propagation conditions in a variety of different environments.