Offloading data traffic from Infrastructure-to-Device (I2D) to Device-to-Device (D2D) communications is a powerful tool for reducing congestion, energy consumption, and spectrum usage of mobile cellular networks. Prior network-level studies on D2D data offloading focus on high level performance metrics as the offloading efficiency, and take into account the radio propagation aspects by using simplistic wireless channel models. We consider a D2D data offloading protocol tailored to highly dynamic scenarios as vehicular environments, and evaluate its performance focusing on physical layer aspects, like energy consumption and spectral efficiency. We do this by taking into account more realistic models of the wireless channel, with respect to the simplistic ones generally used in the previous studies. Our objective is twofold: first, to quantify the performance gain of the considered D2D offloading protocol with respect to a classic cellular network, based on I2D communications, in terms of energy consumption and spectral efficiency. Second, to show that using simplistic channel models may prevent to accurately evaluate the performance gain. Additionally, the use of more elaborated models allows to obtain insightful information on relevant system-level parameters settings, which would not be possible to obtain by using simple models. The considered channel models have been proposed and validated, in the recent years, through large-scale measurements campaigns. Our results show that the considered protocol is able to achieve a reduction in the energy consumption of up to 35%, and an increase in the system spectral efficiency of 50%, with respect to the benchmark cellular system. The use of different channel models in evaluating these metrics may result, in the worst case, in a sixfold underestimation of the achieved improvement.
翻译:从基础设施到设计设备(I2D)的数据传输从基础设施到设备到设计(D2D)通信,卸载数据传输到设备到设备到设计(D2D)通信,是减少蜂窝网络的拥堵、能源消耗和频谱使用率的有力工具。关于D2D数据先前的网络级研究,将重点卸载在高水平的性能衡量标准上,以此作为卸载效率的卸载标准,并使用简单无线频道模型考虑到无线电传播方面。我们认为,将D2D数据从高度动态的情景中卸载为动态环境,并评价其以物理层方面为重点的性能,如能源消耗和光谱效率等。我们这样做的方法是考虑到更现实的无线谱化频道模式,对于以往研究中普遍使用的简单化模型而言,我们这样做的方法是:首先,量化D2D卸载协议与经典手机网络的性能收益,根据简单化的无线路段通信、能源消耗率和光谱效率的模型;第二,显示使用最差的频道模型可能妨碍准确评估业绩的增益。此外,使用更详尽的模型可以获取有关50个无线路路路路路路路段的更真实的模型,通过最近使用的系统测测测算结果。通过大规模测量结果,在系统测算中,在可能的减量测算。