| With the popularity of smart handsets and the advent of the "Internet Plus" era,mobile data traffic presents a growth spurt.New radio access network architectures have been introduced into terrestrial cell mobile communication systems.They use baseband resource pool for centralized management of baseband processing resources.It can reduce the usage amount of BaseBand Units(BBUs)and economize the energy consumption.As the extension and supplement of terrestrial cell mobile communication systems,broadband satellite communication systems need to introduce baseband resource pool architecture to deal with the mobile data traffic demand in the future.This thesis is focused on the design and implementation of broadband satellite communication system protocol stack and the investigation on the processing resource allocation in the baseband resource pool and network design in the General-Purpose Processor(GPP)based baseband resource pool.Firstly,the design and implementation of the broadband satellite mobile communication system protocol stack is carried out.Taking the characteristics of the satellite systems and Long Term Evolution(LTE)protocol stack into consideration,the overall design scheme of the broadband satellite mobile communication system protocol stack is proposed.The module partition and function design of the Medium Access Control(MAC)and Radio Link Control(RLC)software are described in detail.The data transmission funcitons of MAC and RLC are implemented on Digital Signal Processor(DSP)of the hardware platform.Secondly,the processing resource allocation in the baseband resource pool of the broadband satellite radio access network is investigated and reasonable algorithms have been proposed to minimize the usage amount of BBUs.We establish the system model and define the problem of minimizing the usage amount of BBUs.The problem is shown to be a NP-hard problem,and three existing heuristic algorithms for solving this problem are analyzed briefly.In order to overcome the disadvantages of those existing algorithms,we present Improved Spanning Tree Allocation(ISTA)algorithm and Grid-Based Allocation(GBA)algorithm.In the process of those two algorithms,newborn partial solutions are checked immediately and only the best K partial solutions will be kept for the next step.Thus the complexity of algorithms is reduced and the optimal solution is kept as much as possible.Simulation results show that the ISTA and GBA algorithm can achieve a solution which is close to the lower bound by adjusting the value of K.Finally,the network design of the GPP based baseband resource pool for broadband satellite radio access network is investigated.Based on the design and implementation of the protocol stack,we propose the mod-ule partition of the resource pool network.According to the demand of data transmission between functional modules,the resource pool network is divided into bit processing subnetwork and symbol processing subnet?work,which are used to connect the GPP based servers.The topology of those two subnetworks including network addressing and routing strategy is explained and the working flow of the resource pool network is described.At last,the performance of the resource pool network is verified by computer simulation. |
