Abstract:

Currently, due to the limitation of hardware for network protocol developing and huge cost of network building in hardware for performance evaluation, most of the literature focuses on software system which limits the results in theory. To solve these problems, a hardware-in-loop simulation system for distributed wireless network MAC (Media Access Control) protocols based on GNU Radio and the second generation of Universal Software Radio Peripheral (USRP2) was designed and implemented. Referring to the standard IEEE802.11 Distribution Coordination Function (DCF) protocol, the designed simulation system adopted the discrete-event simulation technique to realize simulation for multi-node distributed wireless networks with only the least hardware resources (i.e., one Personal Computer (PC) and two USRP2s). In the software, the MAC protocols were implemented using Python language, which is flexible and easy to change or extend. And in the physical layer, modularized modules in C++ language were adopted for signal processing, which further improves the scalability of the simulation system. The experimental results validate the reliability of the hardware-in-loop simulation system, in comparison with the Bianchi algorithm and time slot based saturation throughput calculation model.

Key words: Universal Software Radio Peripheral (USRP), GNU Radio, Software Defined Radio (SDR), hardware-in-loop network simulation, Media Access Control (MAC) protocol

摘要：

目前,由于可供网络协议开发的硬件资源极其有限,而且真实性能评估要求硬件上的组网产生了高额的硬件成本。因此,对于大多数网络协议的研究以及性能评估都是基于纯软件系统进行的,其结果仅局限于理论意义。为了解决这些问题,基于GNU Radio平台以及二代通用软件无线电外设(USRP2)设计和实现了分布式无线网络媒体介入控制(MAC)协议的半实物仿真系统。该系统以IEEE802.11分布式协调功能(DCF)为协议框架,结合离散事件仿真技术,依靠较少的硬件资源(一台个人计算机(PC)和两台USRP2)模拟了多个节点的无线通信网络。实现中,MAC层协议使用简洁的Python语言进行系统开发,具有很大的灵活性,而且扩展性和可移植性强;物理层使用高效的C++语言对信号进行模块化处理,并利用USRP2射频硬件在真实信道上进行数据传输。将系统的节点发送概率以及吞吐量实测数据分别与Bianchi算法以及基于时隙分析的饱和吞吐量计算模型进行了对比,对比结果的吻合性说明了网络仿真平台的可靠性。

关键词: 通用软件无线电外设, GNU Radio, 软件无线电, 半实物网络仿真, 媒体介入控制协议