Hello Everyone,
I am an Electronic engineer working for a company called “SECOND BRIDGE”, We are based on Paris.
In our applications, We are measuring distance between two 10 layer PCB’s through 802.15.4 protocol. To achieve this, We are using mainly
1. IMX6 Processor (Main processor)
2. SAM4E (Secondary processor) 
3. RF215 + Antennas for RF ranging section
Our issue is when we just measured distance between two PCB by putting the IMX6 in ideal state we are able to range upto 90M (Refer the attachment1) but when we activate the IMX6, ranging is reducing to 40M (50 % performance reduction). 
Can anyone explain this RF interference phenomenon? If possible please suggest us the possible ways to solve this problem like some reference sites or some reference documents?
Thank you.
Regards,