Research On Resource Optimization Algorithm For Massive MTC

With the rapid development of mobile communication,the 5th generation mobile communication(5G)will not only support traditional voice and data services,but also support new communication modes,such as Internet of Things(IoT)and other applications.As an important supporting technology of IoT application,machine-typecommunications(MTC)will become the main component of future mobile communication network.Traditional MTC system mainly rely on short-range transmission.For the increasing number of MTC devices,short-range wireless communication can no longer meet the current needs.Therefore,future MTC system must rely on cellular network infrastructure that can provide wide-area connectivity.Particularly,massive MTC(mMTC)is defined as one of the three application scenarios of 5G network by 3rd Generation Partnership Project(3GPP).It is hard for traditional radio access technologies to provide adequate services for meeting mMTC requirements.Thus,in order to adapt to massive access of machine-type communication in cellular network,this paper proposes two single-hop relay schemes for mMTC scenarios:1)Nearest Principle Relay Algorithm(NPRA).2)Load Balancing Relay Algorithm(LBRA).Firstly,this paper describes the research progress of the 5G and the research process of mMTC scenario,and briefly describes the content and research results of this paper.Secondly,this paper presents the relay system model in mMTC scenario.The mMTC relay node(MTG)captures the transmitted packets of one or more mMTC devices(MTD)and relay their information to the base station,thereby reducing the signaling overhead of the cellular network.In order to improve spectrum utilization,MTD uses parallel transmission,so there will be interference between MTDs.In the traditional research,it is often assumed that the interference value of each link is known,but in practice,the interference value is unknown.Therefore,this paper adopts Stochastic Geometry to characterize the received signal and interference power to get closer to the actual situation.Then,the Nearest Principle Relay Algorithm(NPRA)is researched in this paper.The NPRA can minimize the congestion of control channel and provide the highest access opportunity for MTD.Assuming that each active MTD is sent on a randomly selected channel,MTG attempts to capture the MTD packet only if the MTD is associated to the region of MTG which can be represented as Poisson Voronoi.Because multiple MTDs can simultaneously transmit data over the same channel,the probability of successful MTG decoding depends on interference from other MTDs.The condition that MTG can successfully decode MTD Signal is that the MTD is closest to the MTG and the signalto-interference Ratio(SIR)of the MTD signal received by the MTG is higher than the pre-set rated threshold.The scheme requires minimal coordination between MTD and MTG,that means only timing synchronization is required.Thus,a very effective control channel is maintained.In addition,the scheme reduces the energy consumption caused by clustering and does not require any complex user equipment.But at the same time,there will be much more or much less MTD in the network cell of each MTG,that means the number of MTD is divided unevenly,so this scheme will cause some congestion problems.Finally,this paper is concerned with the Load Balancing Relay Algorithm(LBRA).LBRA is a modification of the recent principle relaying,which prevents an MTG network cell from having much more or much less MTDS,thus providing better performance management.Similar to the NPRA,MTD randomly selects the channel to be sent,and the MTD belongs to the region of MTG Voronoi-diagram,the packet can be sent only after secondary load balancing.There are two methods of load balancing: device transfer and dynamic resource allocation.Method 1 can be divided into two algorithms LBRA1 and LBRA2 according to the difficulty of device transfer.LBRA1 and LBRA2 are load balancing methods for device transfer in uplink leading link,and congestion problem will not occur due to the large number difference value.Method 2 called LBRA3 algorithm,the resource block is conducted upward on the link in the uneven distribution of rational utilization of wireless resource to reduce the interrupt probability,avoiding the resource block divide the MTG network caused by the cell within the MTD too much network congestion problem,thus significantly reduce the overload originally in the MTG connections,and support a higher density of MTD.To sum up,this paper deduces the expression of interrupt probability and analyzes and calculates the maximum transmission capacity under interrupt constraint.In addition,in order to obtain the maximum transmission capacity,this paper also proposes the optimal allocation method of spectrum resources on "MTD-relay" and "relay-BS" links.