| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 102 === Thanks to the prevalence of mobile devices, various wireless applications and services such as online social networking and video streaming are developed and deployed. However, the continuous growth of data demand from these applications and services can no longer be supported by the existing wireless solutions. Long-Term Evolution (LTE) was proposed by the 3rd Generation Partnership Project (3GPP) in the Release 8 as a new network standard to solve this problem. After the Release 10, LTE becomes LTE-Advanced (LTE-A), which is regarded as the 4G standard nowadays.
In LTE-A, new technologies, such as device-to-device (D2D) communication and small cells, are proposed to address the growing data demand. Take D2D communication as an example. Devices in the proximity of each other can communicate directly via a D2D link. Therefore, fewer radio resources are needed. Take small cell as another example. Small base stations (SBSs) can be deployed for increasing resource reutilization by providing better link quality.
Although both D2D communication and small cells can improve resource utilization of LTE-A networks, the latter seems to attract more attentions since communicating UEs are not limited to be in the proximity of each other. However, deploying SBSs incurs a substantial amount of equipment and deployment expenses. Compared with small cells, D2D communication is a ``cheaper solution". Therefore, joint consideration of both technologies may reduce the overall cost while the same performance is achieved. In this thesis, different parameters, such as small cell coverage ratios, traffic patterns of UEs, etc., are used to evaluate both technologies. Our simulation shows that with the help of D2D communication, up to 33% reductions in term of the number of SBSs deployed can be achieved even when most communication links are not proximity links.
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