What Is the True Value of Dynamic TDD: A MAC Layer Perspective

TL;DR

This paper evaluates the true value of dynamic TDD in small cell networks from a MAC layer perspective, revealing insights into resource utilization despite PHY layer interference issues.

Contribution

It provides the first analytical analysis of DL/UL resource utilization for synchronous dynamic TDD at the MAC layer, offering new understanding for 5G network design.

Findings

Analytical results on DL/UL resource utilization in dynamic TDD

Insights into the trade-offs between resource efficiency and interference

Implications for future 5G small cell network deployments

Abstract

Small cell networks (SCNs) are envisioned to embrace dynamic time division duplexing (TDD) in order to tailor downlink (DL)/uplink (UL) subframe resources to quick variations and burstiness of DL/UL traffic. The study of dynamic TDD is particularly important because it provides valuable insights on the full duplex transmission technology, which has been identified as one of the candidate technologies for the 5th-generation (5G) networks. Up to now, the existing works on dynamic TDD have shown that the UL of dynamic TDD suffers from severe performance degradation due to the strong DL-to-UL interference in the physical (PHY) layer. This conclusion raises a fundamental question: Despite such obvious technology disadvantage, what is the true value of dynamic TDD? In this paper, we answer this question from a media access control (MAC) layer viewpoint and present analytical results on the DL/UL time resource utilization (TRU) of synchronous dynamic TDD, which has been widely adopted in the existing 4th-generation (4G) systems. Our analytical results shed new light on the dynamic TDD in future synchronous 5G networks.