Need help with my wireless router board

Recently I have been making some wireless router board by using AR9341. The part of WIFI wireless is entirely according to the referential design and AR9341. However,The signal is not stable.There are some specific performance:
1).When two different personal computers link,the feedback time of data in the packets is 3ms.It’s a little slow and lost packets.
2).One of the PCs is stable after the router changed a new environment.
3).One of the PCs which can’t link the WIFI effectively,is able to link about 20 seconds if it’s solved by WIFI repair function.
I has a limit knowledge about wireless design,anybody can tell me how to adjust or solve it ?
Thank you in advance!

Which LEDE version are you talking about?