User's Guide

LE910 V2 HARDWARE USER GUIDE 1VV0301200 Rev.8 • 2016-10-07 66 of 84
Reproduction forbidden without Telit Communications PLC written authorization – All Rights Reserved
When using the LE910 V2, since there's no antenna connector on the module, the
diversity antenna must be connected to the LE910 V2 Diversity Antenna pad (F1) by means of a transmission line
implemented on the PCB.
The second Rx antenna should not be located in the close vicinity of main antenna. In order to improve Diversity
Gain, Isolation and reduce mutual interaction, the two antennas should be located at the maximum reciprocal
distance possible, taking into consideration the available space into the application. For the same reason, the Rx
antenna should also be cross-polarized with respect to the main antenna.
Isolation between main antenna and Rx antenna must be at least 10 dB in all uplink frequency bands.
Envelope Correlation Coefficient (ECC) value should be as close as possible to zero, for best diversity
performance. ECC values below 0.5 on all frequency bands are recommended.
6.5.1 Single Antenna Operation
In 2G and 3G mode second antenna (Diversity) is optional and secondary receiver can be disabled. In 4G LTE
mode, 3GPP standard does not include single antenna operation because MIMO is the standard downlink
configuration in this cellular system and because of reduced overall downlink performance when one or more
neighbor cells are present.
Nevertheless, LE910 V2 might be used with second antenna removed or not connected if this degradation in
performance is accepted: for some MNOs, for example, a single receive antenna could be permissible with Cat.1
devices that operates at very low data rates (integrators should always refer to their network-provider to double
check requirements applicability conditions).
When possible, add a 50ohm (or 47ohm) resistor in order to terminate correctly the secondary receiver input and/or
to provide antenna connection for test/debug purposes.