Research And Optimization On The Key Technology Of The LTE Specific Network With Small Cell

With the synchronous progress of wireless communication and production requirements, communication was no longer confined to that among people. The reason was that increasingly more tasks should be completed by mutual communication between devices without human intervention, such as smart home, industrial automation, intelligent transmission, medical treatment, intelligent devices, environmental monitoring and natural disaster prediction, etc., which was referred to as Machine to Machine (M2M) communication. LTE network with strong adaptability not only supported IP interconnection and allowed devices to access the network on a large scale, but radio resources could be flexibly distributed. Therefore, it was extensively applied into M2M communication. In this paper, LTE technique was adopted for cable-free seismograph data recovery system and the cable-free seismograph was a kind of sensor node. In a system, data collected were abruptly uploaded to server from masses of sensor nodes under the circumstance of artificial earthquake so as to analyze the distribution of underground minerals. As such a system was strongly temporary, small cell was utilized in this paper to realize rapid deployment of network. As considerable up-going transmission existed during data recovery, uplink scheduling algorithm was studied and improved here to obtain the maximum throughput.Primary tasks of this paper are as follows.(1) A private data recovery network was designed and established in accordance with LTE protocol. By simplifying LTE core network protocols of 3 GPP, core network was designed for the private network and then open source projects were also employed to implement this core network. In this way, a private data recovery network consisting of a core network, a small cell and a subscriber terminal could be set up. In addition, iperf was also utilized to perform functional tests for this private network. Thus, uplink and downlink transmission rates reached 8Mbit/s and 30Mbit/s respectively.(2) The uplink scheduling algorithm was studied together with construction of the corresponding system model. To be specific, the uplink scheduling process could be divided into two stages. One was uplink time domain scheduling; and, the other was uplink resource allocation.Algorithms of both steps were modified separately. As for time domain scheduling, PF algorithm was modified and user delay was taken into account as well; besides, statistical data strengths and weaknesses of the current CQI were assessed by estimating its probability distribution function. Within the scope of LTE system mechanism, uplink scheduler failed to gain user delay. Therefore, a mechanism was developed in this paper to figure out user delay based on BSR. Additionally, RME algorithm of resource allocation was also analyzed and then improved direct at shortcomings of it. In the end, the modified algorithms of both stages were simulated. The relevant simulation results indicated that these algorithms were able to effectively improve system throughput provided that the maximum time delay of users could be guaranteed.