Ultradense Cell-Free Massive MIMO for 6G: Technical Overview and Open Questions

Ultradense cell-free massive multiple-input multiple-output (CF-MMIMO) has emerged as a promising technology expected to meet the future ubiquitous connectivity requirements and ever-growing data traffic demands in sixth generation (6G). This article provides a contemporary overview of ultradense CF-MMIMO networks and addresses important unresolved questions on their future deployment. We first present a comprehensive survey of state-of-the-art research on CF-MMIMO and ultradense networks. Then, we discuss the key challenges of CF-MMIMO under ultradense scenarios such as low-complexity architecture and processing, low-complexity/scalable resource allocation, fronthaul limitation, massive access,…

• EC
  Excellence Center at Linköping – Lund in Information Technology
• KO
  Knut och Alice Wallenbergs Stiftelse
• V
  Vetenskapsrådet