In this paper, we investigate the resource allocation design for integrated sensing and communication (ISAC) in distributed antenna networks (DANs). In particular, coordinated by a central processor (CP), a set of remote radio heads (RRHs) provide communication services to multiple users and sense several target locations within an ISAC frame. To avoid the severe interference between the information transmission and the radar echo, we propose to divide the ISAC frame into a communication phase and a sensing phase. During the communication phase, the data signal is generated at the CP and then conveyed to the RRHs via fronthaul links. As for the sensing phase, based on pre-determined RRH-target pairings, each RRH senses a dedicated target location with a synthesized highly-directional beam and then transfers the samples of the received echo to the CP via its fronthaul link for further processing of the sensing information. Taking into account the limited fronthaul capacity and the quality-of-service requirements of both communication and sensing, we jointly optimize the durations of the two phases, the information beamforming, and the covariance matrix of the sensing signal for minimization of the total energy consumption over a given finite time horizon. To solve the formulated non-convex design problem, we develop a low-complexity alternating optimization algorithm which converges to a suboptimal solution. Simulation results show that the proposed scheme achieves significant energy savings compared to two baseline schemes. Moreover, our results reveal that for efficient ISAC in wireless networks, energy-focused short-duration pulses are favorable for sensing while low-power long-duration signals are preferable for communication.

翻译：本文研究了分布式天线网络（DANs）中集成感知与通信（ISAC）的资源分配设计问题。具体而言，由中央处理器（CP）协调，一组远程无线电头端（RRHs）在ISAC帧内为多个用户提供通信服务，并感知多个目标位置。为避免信息传输与雷达回波之间的严重干扰，我们提出将ISAC帧划分为通信阶段和感知阶段。在通信阶段，数据信号在CP处生成，随后通过前传链路传输至RRHs。而在感知阶段，基于预定义的RRH-目标配对，每个RRH使用合成的高定向波束感知特定目标位置，并通过前传链路将接收回波的样本传输至CP，以进一步处理感知信息。考虑有限的前传容量以及通信和感知双方的服务质量需求，我们联合优化两个阶段的持续时间、信息波束成形及感知信号的协方差矩阵，以最小化给定有限时间范围内的总能耗。为求解所提出的非凸优化问题，我们开发了一种低复杂度的交替优化算法，该算法收敛于次优解。仿真结果表明，与两种基准方案相比，所提出的方案实现了显著的节能效果。此外，我们的研究结果揭示，在无线网络中进行高效ISAC时，能量集中的短持续时间脉冲有利于感知，而低功率的长持续时间信号则更适合通信。