High-Granularity Modulation for OFDM Backscatter
High-Granularity Modulation for OFDM Backscatter
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DOI：
10.1109/tnet.2023.3286880
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发表时间：
2024-02
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影响因子：
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通讯作者：
Xin Liu;Zicheng Chi;Wei Wang;Yao Yao-Yao;Pei Hao;Ting Zhu
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作者：
Xin Liu;Zicheng Chi;Wei Wang;Yao Yao-Yao;Pei Hao;Ting Zhu
正交频分复用（OFDM）已广泛用于WiFi、LTE中，并在5G中采用。最近，研究人员提出了多个基于OFDM的WiFi反向散射系统，其使用相同的基本设计原理（即，码字转换）以传输标签数据。然而，由于WiFi接收机中的相位误差校正可以消除由标签产生的相位偏移，因此码字转换需要可以禁用相位误差校正的特定WiFi接收机。结果，相位误差被引入到码字转换的解码过程中，这显著地增加了标签数据解码误差。为了解决这个问题，我们设计了一种称为TScatter的新型OFDM后向散射，它使用高粒度采样级调制来避免由相位误差校正消除的标签产生的相位偏移。此外，通过利用相位误差校正，我们的系统能够在更动态的环境中工作。我们的设计也有两个优点：更低的误码率（BER）和更高的吞吐量。我们在不同的情景下进行了广泛的评估。实验结果表明，TScatter具有i）当其吞吐量与最新的OFDM后向散射系统MOXcatter相似时，其BER低三到四个数量级;或者ii）当其BER与MOXcatter相似时，其吞吐量高出212倍以上。我们的设计是通用的，并且具有应用于反向散射其他OFDM信号（例如，LTE和5G）。
Orthogonal frequency-division multiplexing (OFDM) has been widely used in WiFi, LTE, and adopted in 5G. Recently, researchers have proposed multiple OFDM-based WiFi backscatter systems that use the same underlying design principle (i.e., codeword translation) at the OFDM symbol-level to transmit the tag data. However, since the phase error correction in WiFi receivers can eliminate the phase offset created by a tag, the codeword translation requires specific WiFi receivers that can disable the phase error correction. As a result, phase error is introduced into the decoding procedure of the codeword translation, which significantly increases the tag data decoding error. To address this issue, we designed a novel OFDM backscatter called TScatter, which uses high-granularity sample-level modulation to avoid the phase offset created by a tag being eliminated by phase error correction. Moreover, by taking advantage of the phase error correction, our system is able to work in more dynamic environments. Our design also has two advantages: much lower bit error rate (BER) and higher throughput. We conducted extensive evaluations under different scenarios. The experimental results show that TScatter has i) three to four orders of magnitude lower BER when its throughput is similar to the latest OFDM backscatter system MOXcatter; or ii) more than 212 times higher throughput when its BER is similar to MOXcatter. Our design is generic and has the potential to be applied to backscatter other OFDM signals (e.g., LTE and 5G).