The bistatic integrated sensing and communication (ISAC) system model avoids the strong self-interference in a monostatic ISAC system by employing a pair of physically separated sensing transceiver and maintaining the merit of co-designing radar sensing and communications on shared spectrum and hardware. Inspired by the appealing benefits of bistatic radar, we study bistatic ISAC, where a transmitter sends a message to a communication receiver and a sensing receiver at another location carries out a decoding-and-estimation(DnE) operation to obtain the state of the communication receiver. In this paper, both communication and sensing channels are modelled as state-dependent memoryless channels with independent and identically distributed time-varying state sequences. We consider a rate of reliable communication for the message at the communication receiver as communication metric. The objective of this model is to characterize the capacity-distortion region, i.e., the set of all the achievable rate while simultaneously allowing the sensing receiver to sense the state sequence with a given distortion threshold. In terms of the decoding degree on this message at the sensing receiver, we propose three achievable DnE strategies, the blind estimation, the partial-decoding-based estimation, and the full-decoding-based estimation, respectively. Based on the three strategies, we derive the three achievable rate-distortion regions. In addition, under the constraint of the degraded broadcast channel, i.e., the communication receiver is statistically stronger than the sensing receiver, and the partial-decoding-based estimation, we characterize the capacity region. Examples in both non-degraded and degraded cases are provided to compare the achievable rate-distortion regions under three DnE strategies and demonstrate the advantages of ISAC over independent communication and sensing.

翻译：双基地集成感知与通信（ISAC）系统模型通过采用一对物理分离的感知收发器，避免了单基地ISAC系统中的强自干扰，同时保持了在共享频谱与硬件上协同设计雷达感知与通信的优势。受双基地雷达显著优势的启发，本文研究了双基地ISAC：发射机向通信接收机发送消息，位于另一位置的感知接收机执行解码与估计（DnE）操作以获取通信接收机的状态。本文将通信信道与感知信道均建模为状态依赖的无记忆信道，其状态序列为独立同分布的时变序列。我们以通信接收机处消息的可靠通信速率作为通信指标。本模型的目标是表征容量-失真区域，即在给定失真阈值下允许感知接收机感知状态序列的同时，所有可达速率的集合。针对感知接收机对该消息的解码程度，我们提出了三种可达的DnE策略：盲估计、基于部分解码的估计和基于全解码的估计。基于这三种策略，我们推导了三个可达的率-失真区域。此外，在退化广播信道的约束下（即通信接收机在统计意义上强于感知接收机），基于部分解码的估计策略，我们刻画了容量区域。通过非退化与退化案例的示例，比较了三种DnE策略下的可达率-失真区域，并展示了ISAC相对于独立通信与感知的优势。