Robust Optimal Resources Allocation For The Wireless Relay Networks

With the development of wireless communication technology,the wireless communication will have faster communication rate and better communication quality in future.Relay technique has an army of advantages such as lower cost and easier networking.The relay technique improves the communication quality and expands the cover range.In the cooperative relay communication networks,relay node also need consume power and frequency spectrum at the time of transmitting information for the user node.Therefore,how to reasonably allocate communication resources according to the requirements of system is a vital issue for improving the communication quality of system.The communication environment is always changing in practice and has a variety of uncertainty parameters.Meanwhile,relay nodes located at different positions have diverse communication conditions,it does not necessarily have a very good result through selecting relay node randomly.As a consequence,how to develop the optimal relay selection strategy to improve the system spectrum efficiency is also particularly important.In this paper,we have a detail research about the resource optimization of wireless relay communication under the uncertainty channel gain information.Firstly,for the case of uncertain channel gain,which is affected by estimation errors,we assume that estimation errors obey a certain distribution.Then,a robust power control problem based on probability threshold constraint is established.At the same time,a robust game problem based on the non-cooperative game is used to reduce information exchange of the overall system.The formulated optimization problem achieves the target through the optimal power allocation.Power will make the corresponding adjustment as the changing of channel environment.Therefore,the system has a strong robustness.Secondly,for the case of uncertainty channel gains,which are affected by fast fading and path loss,we set up a channel gain model subject to Rayleigh distribution.We formulate a robust power control problem based on proportional fairness to improve the satisfaction of customer.Then,a distributed robust power iteration algorithm is developed to reduce the information exchange capacity.The simulation results show that our proposed algorithm has a strong robustness and scalability.We realize the optimal power allocation of the system.Finally,for the case of channel gain distribution,which is hard to obtain in some certain communication environment,we consider that uncertainty channel gains are changing dynamically in a closed set range.In order to improve the transmission rate with lower energy consumption,we set up a utility function model based on energy efficiency maximization.Then,an optimal relay selection strategy is formulated to improve the spectrum efficiency of system.From the simulation results,we can see that the proposed optimization problem effectively realize the optimal power allocation and relay selection under the condition of uncertainty channel gain.Our proposed relay selection algorithm has a better performance advantage compared with other algorithms.