In ambient backscatter communication (AmBC) systems, passive tags connect to a reader by reflecting an ambient radio frequency (RF) signal. However, the reader may not know the channel states and RF source parameters. The traditional energy detector (TED) appears to be an ideal solution. However, it performs poorly under these conditions. To address this, we propose two new detectors: (1) A joint correlation-energy detector (JCED) based on the first-order correlation of the received samples and (2) An improved energy detector (IED) based on the p-th norm of the received signal vector. We compare the performance of IED and TED under the generalized noise model using McLeish distribution and derive a general analytical formula for the area under the receiver operating characteristic (ROC) curves. Based on our results, both detectors outperform TED. For example, the probability of detection with a false alarm rate of 1\% for JCED and IED is 22.97\% and 5.41\% higher, respectively, compared to TED for a single-antenna reader. Using the direct interference cancellation (DIC) technique, these gains are 34.92\% and 3.7\%, respectively. With a four-antenna array at the reader and a 5\% false alarm rate, the JCED shows a significant BER improvement of 28.68\% without DIC and 48.21\% with DIC.

翻译：在环境反向散射通信（AmBC）系统中，无源标签通过反射环境射频（RF）信号与阅读器建立连接。然而，阅读器可能无法获知信道状态和射频源参数。传统能量检测器（TED）看似理想的解决方案，但在上述条件下性能欠佳。为此，我们提出两种新型检测器：（1）基于接收样本一阶相关性的联合相关-能量检测器（JCED）；（2）基于接收信号向量p-范数的改进型能量检测器（IED）。我们采用McLeish分布，在广义噪声模型下比较IED与TED的性能，并推导出接收机操作特性（ROC）曲线下面积的通用解析公式。结果表明，两种检测器均优于TED。例如，在单天线阅读器场景中，当虚警率为1%时，JCED与IED的检测概率分别比TED提高22.97%和5.41%。采用直接干扰消除（DIC）技术后，增益分别提升至34.92%和3.7%。当阅读器配置四天线阵列且虚警率为5%时，JCED在不使用DIC时误码率显著改善28.68%，使用DIC后改善幅度达48.21%。