Min-Max Latency Optimization for IRS-Aided Cell-Free Mobile Edge Computing Systems

Nana Li, Wanming Hao, Fuhui Zhou, Zheng Chu, Shouyi Yang, Osamu Muta, Haris Gacanin

Research output: Journal PublicationArticlepeer-review

1 Citation (Scopus)


Mobile edge computing (MEC) is expected to provide low-latency computation service for wireless devices (WDs). However, when WDs are located at cell edge or communication links between base stations (BSs) and WDs are blocked, the offloading latency will be large. To address this issue, we propose an intelligent reflecting surface (IRS)-assisted cell-free MEC system consisting of multiple BSs and IRSs for improving the transmission environment. Consequently, we formulate a min-max latency optimization problem by jointly designing multiuser detection (MUD) matrices, IRSs' reflecting beamforming vectors, WDs' offloading data size and edge computing resource, subject to constraints on edge computing capability and IRSs phase shifts. To solve it, an alternating optimization algorithm based on the block coordinate descent (BCD) technique is proposed, in which the original nonconvex problem is decoupled into two subproblems for alternately optimizing computing and communication parameters. In particular, we optimize the MUD matrix based on the second-order cone programming (SOCP) technique, and then develop two efficient algorithms to optimize IRSs' reflecting vectors based on the semi-definite relaxation (SDR) and successive convex approximation (SCA) techniques, respectively. Numerical results show that employing IRSs in cell-free MEC systems outperforms conventional MEC systems, resulting in up to about 60% latency reduction can be attained. Moreover, numerical results confirm that our proposed algorithms enjoy a fast convergence, which is beneficial for practical implementation.

Original languageEnglish
Pages (from-to)8757-8770
Number of pages14
JournalIEEE Internet of Things Journal
Issue number5
Publication statusPublished - 1 Mar 2024
Externally publishedYes


  • Cell-free network
  • intelligent reflecting surface (IRS)
  • min-max latency
  • mobile edge computing (MEC)

ASJC Scopus subject areas

  • Signal Processing
  • Information Systems
  • Hardware and Architecture
  • Computer Science Applications
  • Computer Networks and Communications


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