This paper focuses on the non-coherent detection in ambient backscatter communication, which is highly appealing for systems where the trade-off between signaling overhead and the actual data transmission is very critical. Modeling the time-selective fading channel as a first-order autoregressive (AR) process, we propose a new receiver architecture based on the direct averaging of the received signal samples for detection, which departs significantly from the energy averaging-based receivers considered in the literature. For the proposed setup, we characterize the exact asymptotic bit error rate (BER) for both single-antenna (SA) and multi-antenna (MA) receivers, and demonstrate the robustness of the new architecture to timing errors. Our results demonstrate that while the direct-link (DL) interference from the ambient power source leads to a BER floor in the SA receiver, the MA receiver can remove this interference by estimating the angle of arrival (AoA) of the DL. The analysis further quantifies the effect of improved angular resolution on the BER as a function of the number of receive antennas. A key intermediate result of our analysis is the derivation of a new concentration result for a general sum sequence that is central to the derivation of the conditional distributions of the received signal.

中文翻译：

---

时间选择性衰落中环境反向散射链路的非相干检测和误码率

本文重点研究环境反向散射通信中的非相干检测，这对于信令开销和实际数据传输之间的权衡非常关键的系统非常有吸引力。将时间选择性衰落信道建模为一阶自回归 (AR) 过程，我们提出了一种新的接收器架构，该架构基于接收信号样本的直接平均以进行检测，这与之前考虑的基于能量平均的接收器大不相同。文学。对于建议的设置，我们表征了单天线 (SA) 和多天线 (MA) 接收器的精确渐近误码率 (BER)，并证明了新架构对定时错误的鲁棒性。我们的结果表明，虽然来自环境电源的直接链路 (DL) 干扰导致 SA 接收器中的 BER 本底，但 MA 接收器可以通过估计 DL 的到达角 (AoA) 来消除这种干扰。该分析进一步量化了改进的角分辨率对作为接收天线数量函数的 BER 的影响。我们分析的一个关键中间结果是推导通用和序列的新浓度结果，这是推导接收信号的条件分布的核心。