Rsearch On Random Access Of M2M Communication In Internet Of Things

In recent years, with the rapid development of the Internet of things,M2M communication as the main connection method of Internet of things,drawing more and more attention on the research. M2M communication is the machine to machine communication, namely the connection and exchange between machines. The mass terminals and businesses of the Internet of things put forward very high requests on M2M communication,mobile communication network as one of the main methods of M2M businesses, faced with huge pressure and challenge. Traditional H2H communication's random access method is unable to match with M2M communication's mass terminals and businesses. M2M business has these characteristics: mass terminals, small transmission data single time and great network nodes, relatively high time tolerance. Therefore the random access method adapted to the traditional H2H business is facing great challenges, how to improve the existing mobile communication network is the focus research of M2M business.The main contents of this paper can be divided into two parts :First, we aim at the random access's preamble sequence of M2M business and H2H business in LTE and do research on the distribution of the preamble sequence. We firstly analyze the allocation plan of the existing preamble sequence, and then set out from distributing system preamble resources; put forward an improved preamble sequence management scheme basing on resource sharing. This scheme introduces a set of leading sequence resources and supplies the competitive use of M2M and H2H terminals in the random access process. Through the simulation we get that: the improved scheme improves the throughput and utilization of system resources effectively.Second, we do research on the network congestion causing by the access of the huge M2M terminals. Based on the characteristics of the M2M business, we set out from different kinds of businesses which have different sensitivity towards time delay and put forward a packet congestion avoidance scheme based on time delay sensitivity. This scheme divides the M2M businesses which have similar time delay characteristic into one group, broadcasts the message in the system by the base station and pages the terminals' random access request of different business groups. Through the simulation we get that: this scheme can significantly improve the success rate of random access of M2M terminals, solve the network congestion problem caused by a large number of M2M terminals request access effectively, and improve the performance of the system.