Application-oriented Optimizations On The RLC And MAC Layer In The LTE Network Protocols

The rapid evolution of mobile communication technology and the wide popularization ofsmart terminals provide good transmission channel and bearing platform for mobile Internetapplications. Since different mobile applications have different quality of servicerequirements, behavior patterns and service characteristics, the requirements of applicationsfor the mobile communication networks are also different. In the long term evolution system,services are divided into real time and non-real time types. The real time services aredelay-sensitive and error-tolerable, while the non-real time ones are error-sensitive anddelay-tolerable. Obviously, this simple classifying way doesn’t meet the diverse demands ofmobile applications. Meanwhile, various traffic characteristics and large user scales of mobileapplications make huge impact on the mobile communication networks. Therefore, telecomoperators, terminal manufacturers and service providers need a method to improve the highvalue business, reduce the energy consumption and enhance the user experience.Based on the joint project between Huawei Technologies and Jilin University"Integration research on mobile applications and mobile networks", this paper launchedin-depth study on the LTE protocols and traffic characteristics of mobile applications.Efficient optimization schemes on the mobile applications and networks are proposedconsidering the energy consumption and users experience.At the early stage of the research, the basic problems of current mobile applications andmobile networks are summarized based on the standards of3GPP LTE protocols and the studyof mobile applications’ traffic characteristics. On one hand, the mobile applications with thelargest number of users are instant messaging applications, whose most obvious feature issending "heartbeat information". The heartbeat information is handled by the PDCP, RLC andMAC layer in the LTE protocols, which is unnecessary and causes transmission delay andenergy consumption. On the other hand, delay and packet loss rate are the only related factorsin the LTE network procedures when dealing with packet data, which is imprecise and strainusers experience when the networks are resource-constrained.Faced with these problems, this paper presents optimization schemes on the LTEprotocols and procedures from two aspects of data transmission mode and resource allocation.First, a fast heartbeat information transmission scheme is proposed for instant messaging applications. Through designing and configuring the heartbeat dedicated bearer, the processesfor the heartbeat information in the PDC and RLC layer are ignored, so that the heartbeatinformation transmission delay is decreased. The paper defines a heartbeat informationidentification module at the terminal side, which can identify the heartbeat packets by theindex sent from the application layer. After the heartbeat packets are recognized, it helps tosend the heartbeat data radio bearer request. Meanwhile, the identification module configuresthe PDCP and RLC layer transmission mode into TM. At the eNodeB side, this paper changesthe QCI list in the P-GW. By adding the heartbeat type service, the users are allowed to makea connection for the heartbeat information. Furthermore, the method to reduce the number oftransmission times in MAC layer is also proposed in this paper. This method can decreaseenergy consumption in eNodeB on the premise of keeping users online. Moreover, thecommon heartbeat information transmission flow in LTE networks and the handover processbetween different eNodeBs and MMEs are provided.Second, this paper proposes one optimized token bucket resource allocation algorithm byadding the customization into the QoS defining in order to rise users experience in theresource-constrained scenario. A customized service identification module is designed in thispaper, which can identify the customized service packets by the index. Meanwhile, the paperextends the functions of P-GW. By adding the index parsing and decision-making function,the P-GW can identify the customized service and decide whether a customized service bearershould be established based on the users status. In the optimized token bucket resourceallocation algorithm proposed in this paper, the MAC layer gives priority to the customizedservices’ channels during resource allocation, which can increase the response speed and userexperience. Besides, the establishing, modificating and combinating processes for thecustomized service bearers are designed in this paper.