Research On Cooperative Resources Sharing Method Based On Contract In Mobile Edge Computing

Mobile Edge Computing(MEC)is able to reduce network load and transmission delay and improve user service experience by offloading computing tasks to edge servers.Therefore,MEC has been widely concerned by the industry and has become one of the key technologies of 5G.As the main research problem of MEC,resource allocation is of great significance in improving energy efficiency,shortening task delay and saving costs.In 5G networks,there are a large number of mobile devices with rich computing resources or communication resources,so each device may be surrounded by some devices with idle resources.However,when the available communication and computing resources are unevenly distributed on nodes,how to make full use of idle resources is an effective way to solve the resource imbalance problem in MEC system,which has been largely ignored in previous studies.Therefore,this paper proposes a contract-based cooperative computing and communication resource sharing strategy.Different from the previous models based on currency exchange,the model proposed in this paper allows the RN to contribute its communication resources in exchange for using the computing resources of the ST.Therefore,how to design a contract for RNs is the key to realizing cooperative resource sharing.Due to the lack of private information of RNs,this problem is very challenging.The main contributions of this paper are as follows:(1)Cooperative resources sharing method based on contract theory with single-source.This work first considers a MEC system with single ST and multiple RNs.RNs have sufficient communication resources,but lack computing power,while the situation of ST is just the opposite.In order to solve this resource imbalance problem,a contract-based cooperative computing and communication resources sharing strategy is proposed for both complete and incomplete information scenarios.ST provides a contract including computing time and relay power,and RN forwards the calculation results of ST in exchange for the use of computing resources.For complete information scenario,this work obtains the optimal contract to maximize ST’s utility,and proves the existence and uniqueness of the optimal contract.When ST doesn’t know the private information of RNs,such as channel gain and relay cost,this work further studies the characteristics of feasible contracts under incomplete information scenario,analyzes the necessary and sufficient conditions for a feasible contract,and proposes a sequence optimization algorithm to obtain the optimal contract.Finally,the feasibility and optimality of the contract are proved by the simulation results.(2)Cooperative resources sharing method based on matching-contract theory with multi-ST.This work further considers a MEC system with multiple STs and RNs.Compared with single ST system,in multi-ST scenario,STs that can interact with RNs are not unique,so the competition between STs needs to be considered.On the other hand,different RNs exchanging resources with different STs will produce different effects,and it is necessary to find the best ST for each RN.In order to solve the above problem,a cooperative resources sharing method based on matching contract is proposed.Firstly,the interaction between ST and RN is modeled as a matching problem between schools and students.By constructing the preference lists of STs and RNs,an iterative algorithm is designed to obtain stable matching results.Then,according to the matching results,taking one ST as an example,the properties as well as the necessary and sufficient conditions of feasible contract are further analyzed,and the optimal contract design scheme is obtained.Finally,the simulation experiment proves the stability of the matching algorithm and the effectiveness of the designed contract.