Thanks for your answer and the helpful link you have provided below
I have totality understand the microcell architecture by adding AP's on the room near users , but i think this scenario is not be suitable for me for many reasons
1- i am not planning to renew my infrastructure and i want to use the the existing ap on the hallway
2- i can't put AP on the user room for many reason
which is mean i want to go ahead with hallway deployment with achieving the best performance , is i am able to do this by dual radio ap for ex ap105 on the both end of the hallway
thanks