| dc.description.abstract | In order to overcome the problem of frequency reuse in communication systems in uplink, we propose the Device-to-Device communication (D2D Communications) to improve the problem of crowded resource.D2D communications allows user in close proximity to communicate directly without through the base station (BS). After construct the D2D communications network, we face new interference problems, e.g. the interference from D2D user to BS, interference between difference D2D pairs and the interference from cellular user to D2D pair’s receiver. In order to clear up the new interference problems, quoting the game theory, which usual use in economics, to model new interference problems. In game theory, we can find Nash equilibrium (NE) to decide each D2D users transmit power.
The users in strategic game distinguish D2D users and cellular users. By establish payoff function in strategic game make overall systems can achieve maximum total payoff. However, undesigned payoff function wills not existent or reach inefficient NE. So the pricing function is necessary to be introduced into the payoff function to ameliorate original methods. A choice of pricing function we can follow difference demands in our D2D network. In this thesis, beginning with protect cellular users and control interference between D2D groups to set up pricing function. According to mathematical analysis, the proposed payoff function exist at least one NE. Therefore, we can start from two distinct ways to grouping users in same resource.
First, by means of power control make distinct mode users share same resource and the interference between each user are acceptable. In this way, we can find a lot of user group and compare the Nash equilibrium in each user group to decide which group is the most efficiency. Second, in situation of fixed maximum power constraint. According to the distance of between difference users to grouping user, choosing user group which has NE. By simulation results, both methods have uniqueness of NE. | en_US |