The IEEE 802.16m standard for Advanced mobile broadband wireless access provides a seamless application connectivity to other mobile and IP networks like UMTS, LTE and WLAN. In order to meet the ubiquitous service delivery for users, Wimax 16m supports integration of these diverse networks which are having great difference in terms of data transmission rate, Coverage, cost and supporting of service types. Here, buffer allocation is the major problem to be handled for offering Quality of Service (QoS). The lack of buffers increases the packet loss and queuing delay. In order to overcome these issues, in this paper we propose a fuzzy based dynamic buffer scheme to improve RRM in WiMAX 16m network. The base station (BS) estimates the parameters such as number of user requests, flow rate, queue length and received signal strength for each user and updates them periodically. When a request arrives at BS, buffer allocation factor is estimated by applying fuzzy logic over these parameters. Then the flow request with high buffer allocation factor is admitted first and rest of the flow requests waits in a queue. Upon new request arrival, if its buffer allocation factor is low, the request is rejected. Otherwise, the pending request packet in the queue is emptied on analyzing their channel condition and buffer is allocated for new request. By simulation results, we show that the proposed technique FBDBM achieves better utilization when compared with MWRR scheme, while increasing the traffic flows.