Summary: | 碩士 === 國立臺灣科技大學 === 資訊工程系 === 105 === As the technology evolves, networking technologies become more and more popular.As an increasing amount of devices are connected to a network, the machine-to-machine (M2M) communication has become pervasive. Because of a better coverage solution provided by the cellular network, it is one of networks which can be chosen for the M2M communication. Although the data size is small, the number of M2M devices is perhaps huge. When a lot of devices are trying to access the network in a short period, collisions are inevitable, leading to communication failure and degradation of service. To address such an issue, how to alleviate collisions in the random access of the long-term evolution (LTE) system is considered when M2M devices are added. We try to propose a random access scheme to enhance efficiency. By splitting the preamble into two sets, it is able to reduce the delay for M2M devices suffering from preamble collisions. The two sets include the one of M2M devices which never tried before and the one of backlogged M2M devices. Additionally, priority is considered for devices which can not tolerate a longer delay and the others. Actually, the coexistence M2M and human-to-human (H2H) devices form an issue to be addressed. This allows us to let H2H devices have a priority higher than M2M devices. Finally, our simulation results demonstrate that our proposed scheme can achieve the goal of delay reduction and access efficiency enhancement regardless of traffic loads within the network.
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