High Latency & Request Time Out from client side

I have a small WISP. I am using a 433AH routerboard with 3 R52H card with 17 dbi setorial antenna. In client side I will use low costing TP-link CPE (501G and 543G ) and I will use 2.4Ghz frequence. I am facing lots fo problem with my network. There was very high latency and RTO also but there was only few client (5-15) only.Signal strength is also high & medium in client side ( -30 to -75 ). I will implement firewall rule which is given in mikrotik manual.But till date i have this problem. Please help me if anybody solve this type of problem.

Hi, low tx power to reach almost -55 to -75.. You have too much signal doing interferences to your cpes.