In this paper, we propose and analyze an opportunistic ambient backscatter (AmBack)-assisted decode-and-forward (DF) (i.e., ODF-AmBack) relaying scheme, where the relay can not only forward the signal from the source as in the traditional DF scheme but also backscatter/transmit the signal of the tag embedded in the relay. Motivated by the fact that the capacity is dominated by the “weak” link in the traditional DF scheme, we are able to split the received power at the relay or the transmit power of the relay to support the AmBack transmission while the DF relaying is not affected, by exploiting the “extra power” due to the power difference between the first-hop link and the second-hop link. For comparison, both the traditional AmBack and the DF schemes are also investigated for performance benchmarks. Since the exact closed-form expressions of the ergodic capacities are difficult to obtain for the proposed ODF-AmBack scheme and the traditional AmBack scheme, their lower bounds are derived to facilitate our analysis. Simulations results show that significant performance gain can be achieved in the proposed ODF-AmBack scheme compared with benchmark schemes, and confirm the tightness of the derived expressions.

中文翻译：

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一石两鸟：利用解码转发中继实现机会性环境后向散射

在本文中，我们提出并分析了一种机会性环境反向散射 (AmBack) 辅助解码转发 (DF)（即 ODF-AmBack）中继方案，其中中继不仅可以像在传统 DF 方案但也反向散射/传输嵌入在继电器中的标签的信号。受传统DF方案中容量以“弱”链路为主的驱动，我们可以将中继接收的功率或中继的发射功率分流来支持AmBack传输，而DF中继则不由于第一跳链路和第二跳链路之间的功率差异，通过利用“额外功率”而受到影响。为了进行比较，还研究了传统的 AmBack 和 DF 方案的性能基准。由于对于所提出的 ODF-AmBack 方案和传统的 AmBack 方案难以获得遍历容量的精确闭式表达式，因此推导出它们的下界以方便我们的分析。仿真结果表明，与基准方案相比，所提出的 ODF-AmBack 方案可以获得显着的性能提升，并证实了导出表达式的紧密性。