Research On Joint Optimization Algorithm Of Access And Backhaul Links In 5G Wireless Network Based On Beamforming

The mobile phone has experienced a rapid development in the past ten years from a device with a small screen and very weak processing ability to one with high resolution,palm-sized screen and the processing power like a laptop.Meanwhile,some burgeoning online-business like e-banking,e-learning and e-health have also been risen gradually.These changes together with the expanding use of cache have demanded for the higher data rate and larger system capacity.According to the prediction,there will be 1000 times of growth on mobile data traffic between 2010 and 2020.In this context,the 4G network currently deployed may not be able to support such vast amounts of data,we naturally think of to develop the next generation mobile communication system —— 5G network.5G is a new generation of mobile communication system to face the mobile communication development beyond 2020 whose aim is more effective,higer data rate and supporting more users,more terminal devices,more service and emerging application scenarios.By deploying a large number of lowcost and low power AP(Access Point),reducing the distance between the network nodes to 10 meters or less,achieving the density even more than density of user node,forming the UDN(Ultra–dense Networks)which is one of the key technology to gain spatial reuse rate of the spectrum resource and improve the per unit area transmission capacity.However,with densely deploying the network,UDN will also face some technical challenges,such as the coupling relationship between access and backhaul links,the allocation of wireless backhaul resouce,reasonable assignment of access points for each user and so on.In view of this,this paper innovatively proposes the research on UDN wireless backhaul technology based-on beamforming,the key breakthrough is the joint optimization problem of the user access point selection in access links and the allocation of wireless resource in backhaul links.We convert the original non-covex problem to a standard convex optimization problem by some methods in mathematical approximation and equivalent transformation and finally solve it out.On the other hand,the wireless revolution has led to the ever-increasing demand for our limited radio spectrum resources,driving us to search for a system with higher spectral efficiency.In a variety of ways to increase the spectrum utilization,IBFD(in-band full-duplex)has received much attention recently.The main idea behind IBFD is that if the wireless terminals can transmit and receive the signal on same frequency bands simultaneously,it will have the potential to make double spectrum efficiency.Although IBFD technology has a very potential,before its widely deployment,there are still some significant challenges in urgent need of solution,and among these challenges,self-interference is no doubt the most critical influence factors.In view of this,this paper studies the problem of joint beamforming design in IBFD relay network.We propose to apply distributed beamforming technology at relays to suppress both self-interference and inter-relay interference.We similarly convert the original non-trivial optimization problem to a convex form,and solve out it by a iterative algorithm.