Aeroflex Limited announced that it has added support for 4×2 multi-input multi-output (MIMO) to the 7100 Digital Radio Test Set for the R&D testing of LTE user equipment (UE) being designed with this feature.
4×2 MIMO is used adaptively to offer improved throughput in good signal conditions, and improved resilience in poor signal conditions. When the signal-to-noise ratio (SNR) at the UE is good, the device can make use of spatial multiplexing, where multiple information streams are transmitted simultaneously to improve throughput. When the SNR is poor then transmit diversity is employed. This is where a single information stream is distributed across separately-encoded antenna ports to reduce the variations in SNR experienced by the UE, thus improving the cell coverage. Measurements are made both at the base station and at the UE and these are used to determine how many streams can be supported in the prevailing signal conditions.
Aeroflex
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