In order to achieve better fairness on bandwidth allocation among users in GPON

and reduce the packet transmission delay

a new MAC protocol is designed and a novel dynamic bandwidth assignment scheme is proposed.The main idea of the scheme is:the bandwidth that is unused by several users will be allocated dynamically among the users who’s requirements are not satisfied according to the network load.based on the guarantee that each user with different QoS services can obtain the subscription rate to improve the utilization ot bandwidth.It is indicated through the simulation results that the fairness of bandwidth allocation among users can be guaranteed on the precondition that transmission delay can be controlled strictly by the new algorithm