The Research Of Key Technologies In Signaling Control For LTE/LTE-A Based Machine-Type-Communications

Recently,communications between smart things have been developingrapidly and become the important part of Internet traffic in future.Machine Type Communication(MTC)needspowerful carrier network with ubiquitouscoverage.So far,MTC applications based on Long Tern Evolution/Long Tern Evolution-Advanced(LTE/LTE-A)network have been recognized generally by academia.Signaling control is one of the key technologies and the core foundationsin LTE/LTE-A network which is designed for Human-to-Human(H2H)in heart.However,unlike the communication between peoples,MTC from massivedeviceswith unique featureshave lead to signaling flood inLTE/LTE-A network,which becomes the most serious challenge faced by LTE/LTE-A based MTC applications.How to optimize the key technology of the LTE/LTE-A signaling system,thus supporting the rapid growing number of devices,enhancing the resource utilization,reducing the signaling congestion and improving the service quality of MTC applications,have been playing as a role key for MTC application based onLTE/LTE-A network,the relative research topics also have important theoretical significance and excellent market prospects.Topics in this article come from the National Natural Science Foundation of China.This paperanalyzesthe key requirements and charactors of the MTC applications and tries to solve the top three challenges faced by LTE/LTE-A based MTC,including the congestion management,Quality of Service(QoS)management and mobility management,which makes LTE/LTE-A cellular networkmore suitable for communications between machines,between machine and people.This paper achieves the following three innovations.1.Algorithmes forcongestion management based on signaling optimization are proposedfrom the aspects of air interface and network layerrespctively,to deal with the signaling congestions from massive MTC devices.From the aspect of air interface,a novel mechanism of congestion avoidance based on the signaling shaping is proposed,averagelyspreading MTC concurrent intensive access requests ontothe window in time domain,improving the utilization efficiency of the air interface resources through the periodic statistical prediction method,combined with the conflict withdraw scheme.This mechanism can avoid the signaling congestion as while as reduce the energy consumption of MTC devices.From the aspect of network layer,a novel Group-based SIP Signaling Aggregation Mechinism is proposed.It aggregates all of the smart machineswithin one specificarea as a group unit.Through some new defined SDP attributes,this mechanism efficiently aggregates theSIP messages from individual MTC devices within one group,thus allieviates the MTC signaling interacts,and avoids network congestions.Theoretical model is created with the helpof Jackson's Theorem and Little's Theorem,these two proposalsboth can effectively reduce the network signaling congestion through mathematical theory and experimental analysis.2.A QoS guarantee mechanism for multiple types of MTC service based on the signaling optimization is proposed.Firstly,this article analyzes the characteristics of MTC applications anddivides them into deterministic one and stochastic one.Then it analyzes theoretically the threshold of QoS requirements for different types of services under large-scale access scenario.Then,it usessome novel SDP protocol extensions attributes to achieve resource reservation process optimization,which can solve the low success rate problem in traditional fixed mapping mechanism.By modeling as FIFO queue,simulation results show that the packet loss rate and delay get the effective promotion.3.An innovativeMTC device group mobility management method based on signaling optimization is proposed,which can solve the problem of position migration and network switching froma large number of in-vehicle MTC devicesmove as a group unit.Group mobility management frameworkbased on in-vehicle MTC gateway is firstly proposed,which effectively reduces the signaling interaction load for the LTE/LTE-A cellular network.Then,itproposes a group-based handover decision algorithm under KKT condition,models the group-based handover problem of MTC device as an optimization problem and proves that the problem is a convex optimization problem with the use of Hessian matrix.And using the KKT conditions and the Lagrange multipliers method,a suitable solution is proposed.Meanwhile,a group-basedSIP predictivehandover signaling procedure is achieved,reducing the probability of handover congestions and the latency of handover process.