X-MIMO: cross-technology multi-user MIMO
X-MIMO: cross-technology multi-user MIMO
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DOI：
10.1145/3384419.3430723
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
Shuai Wang;Woojae Jeong;Jinhwan Jung;S. Kim
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文献类型：
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作者：
Shuai Wang;Woojae Jeong;Jinhwan Jung;S. Kim
多用户MIMO（MU-MIMO）是一种众所周知的、显著提高频谱效率的基本技术。虽然在爆炸性增长的IoT下存在对频谱效率和大规模可扩展性的巨大需求，但硬件限制使得将该机制转移到IoT（例如，ZigBee）域。本文介绍了X-MIMO，一个零成本，纯软件的交叉技术MU-MIMO的商品ZigBee。作为揭示MU-MIMO在商品物联网上的可行性的第一项工作，X-MIMO利用跨技术通信（CTC）将普遍部署的WiFi AP变成MU-MIMO发射机，并行向多个ZigBee发送不同的数据包。X-MIMO独特地利用WiFi CSI来提取ZigBee分组的准确物理层信号和WiFi-ZigBee信道系数。严格的推导表明，X-MIMO的预编码本质上不受商品设备的不确定性的影响，使X-MIMO在实践中具有高度可靠性。最后，提出了频谱有效的仿真，以最大限度地提高频谱重用。我们在商用设备（Atheros AR 9334 WiFi NIC和TelosB CC 2420）以及USRP B210上实现并全面评估了X-MIMO的性能，以进行深入分析。结果表明，X-MIMO在两个和三个流中分别实现了495 Kbps和704.24 Kbps，误码率（SER）<1%和6.1%。吞吐量的近线性增长有效地证明了X-MIMO的可行性。
Multi-user MIMO (MU-MIMO) is a widely-known, fundamental technique to significantly improve the spectrum efficiency. While there is a great demand for spectrum efficiency and massive scalability under explosively increasing IoT, hardware limitations make it particularly challenging for the mechanism to be transferred to the IoT (e.g., ZigBee) domain. This paper presents X-MIMO, a zero-cost, software-only cross-technology MU-MIMO for commodity ZigBee. As the first work to shed the light on the feasibility of MU-MIMO on commodity IoT, X-MIMO leverages on cross-technology communication (CTC) to turn the pervasively-deployed WiFi AP into MU-MIMO transmitter, delivering different packets to multiple ZigBees in parallel. X-MIMO uniquely exploits WiFi CSI to extract the accurate physical layer signal of the ZigBee packet and the WiFi-ZigBee channel coefficient. Rigorous derivation shows that X-MIMO's precoding is inherently immune to the uncertainties of the commodity devices, making X-MIMO highly reliable in practice. Lastly, spectrum-efficient emulation is proposed to maximize the spectrum reuse. We implement and comprehensively evaluate the performance of X-MIMO on commodity devices (Atheros AR9334 WiFi NIC and TelosB CC2420) as well as on USRP B210 for in-depth analysis. Results reveal that X-MIMO achieves 495 Kbps with <1% symbol error rate (SER) and 704.24 Kbps with 6.1% SER for two and three streams, respectively. Near-linear increase of the throughput effectively demonstrates the feasibility of X-MIMO.