Research On Coverage With Multiple Base Station Cooperation

5G(5th Generation)is the next generation of communication system which is aimed to meet the requirements after 2020.It will exceed in many ways compared with 4G,such as the transmitting rate,resource utilization and network throughput.To meet those requirements,the transmitting bandwidth,network architecture and modulation coding scheme also need to be promoted.According to the white paper proposed by NGMN(Next Generation Mobile Networks),the 5G could improve the network performance from both of the architecture and technology by introducing new spectrum and increasing the network density.Those approaches will improve the network capacity and meet the future requirements in a fundamental way.In the Ultra Dense Nerwork scenario,there exist the possibility that a user will exceed the coverage of a certain sector when the user is in movement status.With the increase of the density of base station,the density of user is decreased.So there will be more blank area where there is no user,and it waste lots of energy.We propose a user's trajectory assisted beam adjustment algorithm with the assumption that user is moveable in ultra dense network.The position and velocity of user is collected at the beginning to deduce the trajectory.To assist the assignment process,an affinity valule is defined which is calculated according to 1.the distence between user and base station 2.the angle of user's trajectory and the line between user and base station.With the help of the affinity value,it is easier to choose the proper sector for a certain user.After getting the sector list that a user could attach to,the sector parameters are determined dynamically based on the existing users it already cover.This procedure could guarantee the required minimum receive power at user side,and is optimized to minimize the total transmitting power at base station side.We analyse the power consumption compared with that of the existing beam tracking algorithm and the static coverage method used in nowadays.The system level simulation is also performed to verify the effectiveness of the algorithm in the real world.The simulation results show that our proposed algorithm can meet the the minimum requirement of receive power and SINR at user side,while consuming the least power at base station side.WiFi is a promising technology to offer high data rate network access,and the research on how to combine cellular network and WLAN has gain the attentation.It is necessory to study the influence to the existing cellular network when the WiFi is introduced.In this thesis,we study the influence when a WiFi access point is included in LTE cellular network.The downlink spectrum consists of control region and data region,and the total number of physical modulation symbol is a fixed number under a certain configuration.When multiple user perform the download action directly from LTE network,the control signaling would consume more physical modulation symbol to carry multiple downlink control information.But if the users are connected to a WiFi access point and the WiFi access point is connected to LTE base station,the control information that need to be dispatched is reduced to only one.The data region will increase and the transmitting performance is also increased.The verification of the influence of control region reduction is performed using link level simulation.The system level simulation shows the performance improvement when the user download from WiFi access point.