emand grows for LTE-A, engineers developing and testing base stations (eNodeB) need to be able to verify network performance against the latest 3GPP specifications as soon as they are introduced.
The TM500 LTE-A Test Mobile tracks the 3GPP roadmap, providing a fully software-upgradeable path from functional single user equipment test, through multi-UE, to load testing based on the emulation of thousands of UEs working in multiple cells. TM9 is the latest step in this roadmap, enabling the testing of 3GPP Release 10 enhancements including the potential for higher order MIMO and beamforming.
The TM500 LTE-A Test Mobile is based on the industry-standard TM500 platform, which is already used by all the world's major infrastructure vendors and most small cell vendors. With TM9 support, the TM500 LTE-A Single-UE Test Mobile now allows testing of key TM9 features in a single-cell configuration, allowing its functional performance to be verified. The TM500 provides demodulation of downlink data based on the demodulation reference signal and calculation of channel state information feedback from the UE. This information consists of the Pre-coding Matrix Indicator, Rank Indicator, and Channel Quality Indicator, which are based on the newly-introduced reference signal (CSI-RS).
Logging of both Rel-10 related protocol messages and power levels of these newly-defined reference signals, CSI-RS and DMRS, has been added, to ease debugging of the feature.
The TM500 LTE-A Test Mobile now includes all the features necessary to demonstrate and verify the benefits of TM9, and to measure its performance in a single cell FDD 2 x 2 DL MIMO scenario, said Nicola Logli, product manager at Aeroflex. The system is scalable, and the capability of combining TM9 with higher order MIMO will be provided in the near future, to enable testing of the most demanding MIMO configurations.
More about Transmission Mode 9
TM9 is a new transmission mode introduced with 3GPP Release 10 (LTE-A), which enables the enhancement of network capabilities and performance with minimum addition of overhead. TM9 is designed to combine the advantages of high spectrum efficiency--achievable through higher order MIMO--and cell-edge data rates, coverage and interference management, which can be achieved through the use of beamforming. Flexible and dynamic switching between single-user MIMO and an enhanced version of multi-user MIMO is also provided. A new Downlink Control Information format - known as format 2C - is used for TM9 data scheduling.
Two new reference signals are defined in TM9: Channel State Information Reference Signal and Demodulation Reference Signal. The first is used from the UE to calculate and report the CSI feedback (CQI/PMI/RI), while the latter is an evolution--providing support for more layers--of the UE-specific reference signal that is already used for beamforming in Rel-9, and is used for signal demodulation.