In this paper we propose uplink packet transmission scheme based on Synchronized RA. The scheme can afford to support diverse QoS required from diverse multimeda traffics. In order to minimze the collision probability occurred in contention based channel access, we assign a reservation access channel additionally to the traffic channels. Access probability function for controlling collisions occurred in the reservation access channel is applied. Through assigning different access probability to each traffic user with respect to priority issued by his required QoS, the proposed scheme guarantees minimum throughput required by higher priority users in the whole range of system load.