The new concept of semi-integrated-sensing-and-communication (Semi-ISaC) is proposed for next-generation cellular networks. Compared to the state-of-the-art, where the total bandwidth is used for integrated sensing and communication (ISaC), the proposed Semi-ISaC framework provides more freedom as it allows that a portion of the bandwidth is exclusively used for either wireless communication or radar detection, while the rest is for ISaC transmission. To enhance the bandwidth efficiency (BE), we investigate the evolution of Semi-ISaC networks from orthogonal multiple access (OMA) to non-orthogonal multiple access (NOMA). First, we evaluate the performance of an OMA-based Semi-ISaC network. As for the communication signals, we investigate both the outage probability (OP) and the ergodic rate. As for the radar echoes, we characterize the ergodic radar estimation information rate (REIR). Then, we investigate the performance of a NOMA-based Semi-ISaC network, including the OP and the ergodic rate for communication signals and the ergodic REIR for radar echoes. The diversity gains of OP and the high signal-to-noise ratio (SNR) slopes of the ergodic REIR are also evaluated as insights. The analytical results indicate that: 1) Under a two-user NOMA-based Semi-ISaC scenario, the diversity order of the near-user is equal to the coefficient of the Nakagami-m fading channels (m), while that of the far-user is zero; and 2) The high-SNR slope for the ergodic REIR is based on the ratio of the radar signal's duty cycle to the pulse duration. Our simulation results show that: 1) Semi-ISaC has better channel capacity than the conventional ISaC; and 2) The NOMA-based Semi-ISaC has better channel capacity than the OMA-based Semi-ISaC.

翻译：针对下一代蜂窝网络，本文提出了一种新型的半集成感知与通信（Semi-ISaC）概念。与现有全部带宽用于集成感知与通信（ISaC）的技术相比，所提出的Semi-ISaC框架提供了更多自由度，允许部分带宽专门用于无线通信或雷达探测，而剩余带宽则用于ISaC传输。为提升带宽效率（BE），我们研究了Semi-ISaC网络从正交多址接入（OMA）向非正交多址接入（NOMA）的演进。首先，我们评估了基于OMA的Semi-ISaC网络性能：针对通信信号，我们分析了中断概率（OP）和遍历速率；针对雷达回波，我们刻画了遍历雷达估计信息速率（REIR）。随后，我们研究了基于NOMA的Semi-ISaC网络性能，包括通信信号的OP和遍历速率以及雷达回波的遍历REIR，并进一步分析了OP的分集增益与遍历REIR的高信噪比（SNR）斜率。分析结果表明：1）在两用户NOMA-based Semi-ISaC场景下，近用户的分集阶数等于Nakagami-m衰落信道的系数m，而远用户的分集阶数为零；2）遍历REIR的高SNR斜率取决于雷达信号占空比与脉冲持续时间的比值。仿真结果验证：1）Semi-ISaC的信道容量优于传统ISaC；2）基于NOMA的Semi-ISaC的信道容量优于基于OMA的Semi-ISaC。