A Low Transmission Time And High Delay Satisfaction Network Coding Algorithm Based On Relay Selection And Power Control

In traditional wireless networks,beyond the source node and the destination node,the other nodes of the path are only responsible for routing,not processing the packets.This forwarding method is not optimistic while a relay node very busy.Network coding(NC)theory was put forward for in 2000,NC greatly increased the network performance on relay node.In the network coding,when an intermediate node receives some packets,it will try to encode the packets and transmit them.For example,a relay node receives two different packets,the relay node can combine two packets as a coding packet and broadcast the coding packet,and other nodes decode the useful packet form the coding packet.Network coding broke the traditional concept,most investigators suggest that network coding can improve the throughput and network performance.Thus,in wireless networks,it had become a hot topic that how to make use of network coding to maximum performance gains.In this dissertation,we study reducing the transmission time,improving delay satisfaction and without extra energy consumption.First this dissertation introduces the concept of wireless network and network coding,And introduces some network coding algorithm of recent years.Then we proposed two algorithms: high-reliability relay algorithm(HRRA)and encoding algorithm based on power self-adaptation(EAPS).HRRA is proposed to decrease the transmission time based on the network coding in multi-rate environment.The HRRA includes the relay selection algorithm(RSA)and the block transmission algorithm(BTA).Based on the relay reliability of node,RSA chooses the neighbor with the higher link rate as the common relay node and creates more network coding opportunities at the common relay node.Thus,the network coding opportunities and the high-rate links associated with common node could both be exploited in the transmissions of BTA.ESPA is proposed to improve delay satisfaction without extra energy consumption.EAPS includes two sub-algorithms: power optimal algorithm(POA)and encoding selection algorithm(ESA).The POA determines the initial transmission power for each packet by taking advantage of the opportunities in which the transmission power is increased to increase the delay satisfaction but without extra energy consumption.The ESA constructs two linked lists: the delay constraint of packet list(D-List)and the optimal power linked list(W-List)based on the POA,and selects for coding,whenever possible,one packet with tight delay constraint in the D-List and other packets in the same location as the above packet in the W-List to code.