发表机构
Institute of Information Technology, Technische Universität Ilmenau（信息技术研究所，埃尔朗根-纽伦堡工业大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对千兆采样SDR传输瓶颈，提出用RDMA替代UDP，实现采样数据直接内存访问，消除主机处理负担，保留信号处理核心任务。
AI 中文摘要
软件定义无线电（SDR）前端在单代产品中采样率提升了一个数量级，而承载其输出的传输方式并未改变：采样数据被打包成以太网数据报，并由主机处理器重新组装。在千兆采样率下，这种方式在两方面同时失效：耗尽了主机处理每个数据包的时间以及用于复制的内存带宽，任何调优或内核旁路都无法同时挽回这两方面。负担反而被转嫁给了用户，用户必须提供与无线电无关的操作系统专业知识。我们证明，远程直接内存访问（RDMA）能够消除这一问题，而非仅仅转移问题。SDR将接收到的采样数据直接放入主机已注册的内存中，并在转换器需要时从该内存中获取用于传输的采样数据。处理器在两条数据路径上均退出，每个采样字节仅穿越内存总线一次，传输路径也摆脱了始终伴随的硬实时节拍问题。留给用户应用程序的只剩下信号处理本身，而这正是SDR所应具备的全部，即使在千兆采样率下也是如此。
英文摘要
Software-defined radio (SDR) front ends have gained an order of magnitude in sample rate within a single product generation, while the transport that carries their output has not changed: samples are packed into Ethernet datagrams and reassembled by the host processor. At gigasample rates this fails on two counts at once, exhausting the time the host has per packet and the memory bandwidth it has for copying, and no amount of tuning or kernel bypass recovers both. The burden has instead been passed to the user, who must supply operating system expertise that has nothing to do with radio. We show that remote direct memory access removes the problem rather than relocating it. The SDR places received samples directly into memory the host has registered, and fetches samples for transmission from that memory when its converters require them. The processor leaves the data path in both directions, each sample byte crosses the memory bus once, and the transmit path loses the hard real-time pacing problem that has always accompanied it. What remains for the user application is the signal processing itself, which should be all an SDR requires, even at gigasample rates.
