Intelligent reflecting surface (IRS) has been considered as an efficient way to boost the computation capability of mobile edge computing (MEC) system, especially when the communication links is blocked or the communication signal is weak. However, most existing works are restricted to narrow-band channel and ideal IRS reflection model, which is not practical and may lead to significant performance degradation in realistic systems. To further exploit the benefits of IRS in MEC system, we consider an IRS-enhanced wideband MEC system with practical IRS reflection model. With the aim of minimizing the weighted latency of all devices, the offloading data volume, edge computing resource, BS's receiving vector, and IRS passive beamforming are jointly optimized. Since the formulated problem is non-convex, we employ the block coordinate descent (BCD) technique to decouple it into two subproblems for alternatively optimizing computing and communication settings. The effectiveness and convergence of the proposed algorithm are validate via numerical analyses. In addition, simulation results demonstrate that the proposed algorithm can achieve lower latency compared to that based on the ideal IRS reflection model, which confirms the necessary of considering practical model when designing an IRS-enhanced wideband MEC system.

翻译：智能反射面（IRS）被认为是提升移动边缘计算（MEC）系统计算能力的有效途径，尤其在通信链路受阻或通信信号较弱时。然而，现有研究大多局限于窄带信道和理想的IRS反射模型，这并不符合实际情况，并可能导致实际系统性能显著下降。为在MEC系统中进一步挖掘IRS的潜力，我们考虑了一个采用实际IRS反射模型的IRS增强型宽带MEC系统。以最小化所有设备的加权时延为目标，我们联合优化了卸载数据量、边缘计算资源、基站接收向量以及IRS无源波束成形。由于所构建的问题是非凸的，我们采用块坐标下降（BCD）技术将其解耦为两个子问题，以交替优化计算与通信配置。数值分析验证了所提算法的有效性与收敛性。此外，仿真结果表明，与基于理想IRS反射模型的方案相比，所提算法能够实现更低的时延，这证实了在设计IRS增强型宽带MEC系统时考虑实际模型的必要性。