Agilent forges ahead with LTE-Advanced 8×8 MIMO testing

Agilent forges ahead with LTE-Advanced 8×8 MIMO testing Welcome to a Medical Battery specialist of the EXFO Battery

Agilent Technologies is actively engaged in developing LTE analysis and signal generation solutions that will help the industry move forward with development and deployment of LTE systems as the technology evolves from 2×2 to 4×4 to 8×8.

The 8×8 MIMO scheme involves more than just adding additional antennas to 2×2 or 4×4 LTE systems. The LTE-Advanced specification, in Release 10, added Transmission Mode 9 to enable the transmission of higher order MIMO, which is significantly with battery with battery like Li202SX Battery, Li202SX-6600 Battery, Li202SX-66C Battery, Li202SX-7200 Battery, Li202SX-7800 Battery, Li202SX-78C Battery, TSI 8240 Battery, TSI 9130 Battery, TSI 9550 Battery, TSI 9510BD Battery, TSI AEROTRAK APC 9510-02 Battery, Zoncare BAT-120003 Batterydifferent than the previous transmission modes. … One of the main differences is that Transmission Mode 9 is based on non-codebook based precoding. This concept was introduced in previous LTE releases in Transmission Mode 7 for single layer transmissions and Transmission Mode 8 for two-layer (2×2 MIMO), commonly known as single-layer and dual-layer beamforming respectively.

Transmission Mode 9 is really an extension of the dual-layer beamforming technique, adding up to eight layers, and one of the obvious enhancements is the definition of additional antenna ports to handle the eight-layer transmissions. There will be some new challenges associated with operating eight radios simultaneously in a small space. For example, consider the potential interference and cross-talk issues that could degrade system performance. This means that the test equipment will need to support up to eight ports for complete testing. Agilent’s Signal Studio software automatically generates the eight-layer LTE signals and synchronizes multiple signal generators for accurate testing at the receiver.

What is less obvious in Transmission Mode 9 is the inclusion of the UE-specific reference signals, which are transmitted among the sub-carriers used for the transmission of the physical downlink shared channel. They follow the same signal processing (precoding) as the downlink shared channel, and this is what enables the use of non-codebook-based precoding where the mobile handset demodulates the downlink shared channel without knowledge of the precoding that was used, and thus the base station avoids the overhead of specifically signaling this information to the mobile handset. These UE-specific reference signals are already supported by Agilent’s signal creation and analysis solutions to enable testing of this new functionality.

In the codebook based precoding scheme, the cell-specific reference signals are added after the precoding and therefore the mobile handset needs to know explicitly how the precoding is performed since the downlink shared channel will have undergone some additional amplitude and phase changes that the cell-specific reference signals did not. The cell-specific RS definitions from Release 8 were not required to be repeated on the new port definitions since the UE-specific RS are used for demodulation in Transmission Mode 9, which saves resources for transmitting real user data.

However, another function of the cell-specific reference signals is to enable the mobile handset to make measurements of the channel conditions and report them back to the base station, regardless of where or whether a downlink shared channel was scheduled for transmission. To meet the need for reporting the channel conditions, the standard introduced new channel state information reference signals, or CSI-RS, which, for this purpose, thereby saving resources because they do not need to be transmitted as frequently as the cell-specific RS. Agilent’s signal analysis solutions enable testing of the CSI-RS signal quality as well as the proper placement in time and frequency. From the receiver perspective, Agilent’s signal creation software enables the designer to determine if the UE is reporting the correct channel conditions under different propagation conditions.