PLS62-W DL rate using the main antenna only? | Telit Cinterion IoT Developer Community
March 20, 2019 - 6:32am, 2091 views
Due to space constraints we would like to use the Cinterion PLS62-W without the diversity antenna (i.e. only the main antenna would be connected).
UL peak data rates would not be affected as the diversity antenna is for reception only. Would still the maximu peak DL data rates be achievable?
The purpose of diversity antenna is to to improve signal quality and reliability. In case of very good conditions it could probably be possible to achieve *** throughput. But please also take into consideration this not from our documentation:
'The LTE Cat.1 standard is designed for two antennas. It is mandatory to connect/apply the Rx diversity antenna to an existing antenna. The minimum efficiency shall be better than 50%.'
If you need to certify your device, please make sure that it will be possible with a single antenna. As far as I know it is not 100% clear in 3GPP documentation but only Cat 1bis devices can have a single Rx antenna only.
Thanks for pointing out this statement in Gemalto’s documentation.
I only asked this question on this forum because I wasn’t convinced by a response, I received from my local Gemalto’s support. Their response suggested that with one receive antenna only there wouldn’t be any decrease in the maximum downlink rate.
Now, I have done my own research and see that could only be the case with a strong signal. With a weak signal the diversity antenna could make a difference whether a connection could be established or not in extreme cases. Or what DL rate could be achieved with a given SNR.
My statement that the UL data rate wouldn’t be affected could be too simplistic as well. With a weak reception there could be many re-transmissions which would slow down the overall UL transfer rate despite the UL data being transmitted at the peak rate.
Would you agree with the above?
I can agree.
The answer for the question if it would be possible to achieve the maximum transfer rate with one antenna could be yes if the network conditions are good enough. But as the diversity antenna improves the reliability it should do a good job in case of worse signal quality. In case of uplink transmission it would also be affected by signal quality and maybe downlink retransmissions may additionally have some influence.
That answers my question. It's better to allow for the use of both antennas rather than to exclude it right from the start.