How to reduce RRC congestion in ZTE network

how to reduce RRC congestion in ZTE network. Even though the traffic volume is less but RRC congestion is more than 10 % in ZTE NW. what are the parameters to be check in RNC to reduce the RRC congestion pl

First of all check the reason of the congestion (power dl ,ul or code or CE dl ,ul or IUB or hspa users ) then we will go for the next step.