The Research Of Packet Scheduling Algorithms In Wireless Networks

In recent years, with rapid development of wireless networks, the demands of the wireless network are also growing fast. The scheduling algorithm of wireless network is the key way to solve this demands, therefore, more and more researchers focus on it.A maximum weight packet scheduling algorithm based on delay and multi-channels(PSADC) and a maximum weight packet scheduling algorithm based on congestion control(PSAC) are proposed in ad hoc networks. Every queue weight is computed according to the length of the queue and delay information in PSADC algorithm. It chooses the queue with a maximum weight and assigns channels for the queue to transmit data packets. The proposed algorithm can keep a high network throughput and reduce the delay of packets. PSAC algorithm joins scheduling algorithm with congestion control, it computes weights of all flows in a node based on the length of the node and the length of the next node,it chooses the flow with maximum weight to schedule and adjusts the transmission rate of the flow according to the network congestion situation. The algorithm can get better fairness for different flows in the networks.Finally, the paper uses the NS2 simulation to analyze the performance of the proposed algorithms. The experiment results show that PSADC can keep a high network throughput and reduce the delay of packets, it balances the relation between the network throughput and packet delay. The paper also compares PSAC with the protocol of TCP and 802.11 MAC, the results show that PSAC has better fairness.