RIS-Aided Latency-Efficient MEC HetNet With Wireless Backhaul
Yiyao Wang, Jinping Niu, Gaojie Chen, Xiangwei Zhou, Yanyan Li, Shiwei Liu
Abstract
The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mobile edge computing</i> (MEC) <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">heterogeneous network</i> (HetNet) can create a high-performance and low-latency environment for users. However, due to the limitation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">small base stations</i> (SBSs) cache and wireless backhaul transmission capacity, how to make the service caching and task offloading decisions and reduce the task offloading time are still key issues to be addressed to achieve decent system computing delay performance. To this end, this paper investigates a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reconfigurable intelligent surface</i> (RIS)-aided wireless backhaul MEC HetNet system. The joint service caching, task offloading, and resource allocation problem is designed to minimize the total latency. The joint optimization problem is an NP-hard mixed-integer nonlinear programming problem, which is difficult to tackle directly. We decompose the optimization problem into two sub-problems, i.e., the communication and the computing sub-problems, and propose algorithms to solve them. Numerical results show that the proposed schemes can effectively reduce the total delay by 6.79% and 18.29% in wireless backhaul MEC HetNet in comparison with the scheme without RIS and local computing, respectively.