In this paper, we develop a hybrid multiple access (MA) protocol for an intelligent reflecting surface (IRS) aided uplink transmission network by incorporating the IRS-aided time-division MA (I-TDMA) protocol and the IRS-aided non-orthogonal MA (I-NOMA) protocol as special cases. Two typical communication scenarios, namely the transmit power limited case and the transmit energy limited case are considered, where the device's rearranged order, time and power allocation, as well as dynamic IRS beamforming patterns over time are jointly optimized to minimize the sum transmission delay. To shed light on the superiority of the proposed IRS-aided hybrid MA (I-HMA) protocol over conventional protocols, the conditions under which I-HMA outperforms I-TDMA and I-NOMA are revealed by characterizing their corresponding optimal solution. Then, a computationally efficient algorithm is proposed to obtain the high-quality solution to the corresponding optimization problems. Simulation results validate our theoretical findings, demonstrate the superiority of the proposed design, and draw some useful insights. Specifically, it is found that the proposed protocol can significantly reduce the sum transmission delay by combining the additional gain of dynamic IRS beamforming with the high spectral efficiency of NOMA, which thus reveals that integrating IRS into the proposed HMA protocol is an effective solution for delay-aware optimization. Furthermore, it reveals that the proposed design reduces the time consumption not only from the system-centric view, but also from the device-centric view.

翻译：本文通过将智能反射面辅助时分多址（I-TDMA）协议和智能反射面辅助非正交多址（I-NOMA）协议作为特例，提出了一种面向智能反射面（IRS）辅助上行传输网络的混合多址接入（MA）协议。考虑两种典型通信场景，即发射功率受限和发射能量受限情况，联合优化设备的重排顺序、时间和功率分配，以及随时间变化的动态IRS波束赋形模式，以最小化总传输时延。为阐明所提出的IRS辅助混合多址接入（I-HMA）协议相较于传统协议的优越性，通过刻画I-TDMA和I-NOMA对应的最优解，揭示了I-HMA优于两者的条件。进而提出一种计算高效的算法，以获得相应优化问题的高质量解。仿真结果验证了理论分析，证明了所提设计的优越性，并得出若干有益启示。具体而言，研究发现所提协议通过将动态IRS波束赋形的附加增益与NOMA的高频谱效率相结合，可显著降低总传输时延，从而表明将IRS集成到所提出的HMA协议中是实现时延感知优化的有效方案。此外，研究还表明所提设计不仅从系统中心视角，而且从设备中心视角均可降低时间消耗。