Research On The Relay And M2M Random Access Technology Of LTE-Advanced

As one of the three alternative fourth-generation(4G) standard, LTE has attracted far more attentions compared to the other two candidate standards: WiMAX and UMB, and may become the only survived 4G standard. The standardization of LTE has been frozen, currently the work transfers to the advanced version of LTE—LTE-A. LTE-A, as the authentic 4G standard, requires much higher system performance than LTE. Due to the capability of enlarging the cell coverage, solving the problem of coverage hole, improving the overall system spectrum efficiency, Relay has officially been said to be supported by 3GPP. On the other hand, LTE is suffering from the problem that technology surpasss the market requirement, M2M undoubtedly has the potential to solve the problem. However, whether LTE that is designed for H2H can effectively support M2M requires evaluation.LTE-A Relay study mainly focus on how to effectively reduce the change of the standard and how to minimize the interference. Another problem of Relay is that the deployment of relay is static, it cannot satisfy the dynamic requirement of relay service scenario. Because static strategy can only deploy relay at certain zones that the fading is severe or serving a large area as a whole, it eliminate the possibility to serve the area that the fading is not very severe but temporarily need high data rate. In this paper, we research on a CAN Relay scheme, it doesn't need to introduce specific relay node. Instead, it utilizes the feature that most mobile phones have wireless interface:WiFi or Bluetooth and the distribution of mobile phones in a cell is large, lets the UEs with good link condition serve the UE with bad link condition as a relay. This method has the advantage of less standard change requirement, lower cost, no interference introduced high flexibility and more effective coverage. The simulation result shows that it can effectively improve the system performance. M2M is different from H2H communication, it features low communication data, high device number and high burstiness. Whether the traditional random access strategy of LTE can be directly used for M2M need further research. In this paper, we build a simulation platform to evaluate the random access performance such as preamble congestion rate, random access success rate, under the condition of two traffic distribution modes(uniform and beta distribution) and different M2M devices(5000,10000 and 30000). The simulation result shows that LTE random access strategy cannot serve M2M well.