Research On Node Cooperation Incentive Algorithms In Ubiquitous Wireless Access Environment

With the rapid development of communication technology, various types of communication networks, which overlap and complement each other, compose a wireless ubiquitous access environment. In such environment, the cooperations among multi-network and multi-terminal can achieve service flow migration and network load balance, so as to effectively guarantee QoE of demand nodes in congestion cells. However, terminal nodes often exhibit selfish feature in relaying process, which seriously affects the terminal cooperation. Therefore, this thesis researches on the node cooperation incentive problem in ubiquitous wireless access environment to promote the terminal cooperation. The main works are as follows:Firstly, the related contents of wireless ubiquitous environment are introduced. Furthermore, the root cause of node cooperation incentive problem is analyzed, and then current node cooperation incentive algorithms are surveyed in detail.Secondly, a novel reputation based topology construction incentive algorithm is proposed for service migration scenario. According to characteristics of wireless ubiquitous environment, this algorithm investigates the node incentive problem for achieving the optimal service migration. First, considering the performance parameters of service migration cells and service migration relays, a hierarchical selection model is established, so as to select the optimal service migration cell and relay for a demand node. On this basis, an improved reputation calculation method is proposed, which combines the interaction history based direct reputation with the behavioral similarity based indirect reputation, to accurately reflect the credit of each cooperation node. Furthermore, by using the topology construction algorithm, the neighbor set of each node is updated periodically and the entire network topology is adjusted adaptively, for promoting the node cooperation. Simulation results verify the effectiveness of proposed algorithm.Thirdly, a novel bargain model based bi-level optimization incentive algorithm is proposed for multi-flow parallel transmission scenario. According to characteristics of wireless ubiquitous environment, this algorithm investigates the node incentive problem for supporting high rate services. First, the bargain model based on sub-flow rate and voucher currency is constructed to obtain the preliminary deal relay set and the corresponding preliminary deal results. On this basis, by using bi-level optimization model(i.e. the upper candidate relay selection model and lower deal relay selection model), the final deal relay set and the corresponding deal results can be obtained. In particular, by means of differentiated solving strategy, the above optimization model can be solved quickly, so as to achieve node cooperation with the minimum deal price and high rate service guarantee of each demand node. Simulation results verify the effectiveness of proposed algorithm.