BLE reliability

Question

Hello , 
 We are working to an OEM Security System project that is using BLE. 
 The system contains at least 2 modules that communicate using the BLE technology.
One of this modules is located under the hood (a siren) and the second module is located in car.
The product needs to be approved by Thatcham organization in order to sell it on the UK market. 
 The Thatcham's guys complains that if interference occurs it can affect the connection robustness. 
 My question is :
There is a study or something similar that measure somehow the radio link reliability in automotive environments ? 
 Thank you

Stefan Birnir Sverrisson · Accepted Answer

Hi Florin 
 Not sure about any official research for BLE in automotive environments in particular. BLE is anyhow a bluetooth technology which is already widely used in cars. It uses 3 advertising channels and 36 connection channels in the 2.4GHz unlicenced band. It features adaptive frequency hopping, which means that transmission is continuously taking place on different channels, therefore minimizing impact of disturbances of a single channel, and avoiding those channels that are continuously having interference. 
 BLE is a reliable protocol, which means that every packet that not acknowledged is retransmitted. Retransmission will of course delay packets and decrese maximum throughput, but you can fully configure how many retransmission will take place for a single packet before the device disconnects. Retransmissions will take place on different channels, therefore it is highly probable that a packet will eventually be transmitted on a channel that does not have interference.