Exploiting Multi-Hop Relaying to Overcome Blockage in Directional mmWave Small Cells

TL;DR

This paper introduces MHRT, a multi-hop relaying scheme for mmWave small cells that effectively bypasses obstacles, significantly improving network throughput and robustness by optimizing relay paths and scheduling.

Contribution

The paper proposes a novel multi-hop relaying transmission scheme with relay path selection and scheduling algorithms for mmWave small cells to overcome blockage issues.

Findings

MHRT outperforms existing protocols in throughput and robustness.

Relay path selection improves handling of blockages.

Optimal hop count balances performance and complexity.

Abstract

With vast amounts of spectrum available in the millimeter wave (mmWave) band, small cells at mmWave frequencies densely deployed underlying the conventional homogeneous macrocell network have gained considerable interest from academia, industry, and standards bodies. Due to high propagation loss at higher frequencies, mmWave communications are inherently directional, and concurrent transmissions (spatial reuse) under low inter-link interference can be enabled to significantly improve network capacity. On the other hand, mmWave links are easily blocked by obstacles such as human body and furniture. In this paper, we develop a Multi-Hop Relaying Transmission scheme, termed as MHRT, to steer blocked flows around obstacles by establishing multi-hop relay paths. InMHRT, a relay path selection algorithmis proposed to establish relay paths for blocked flows for better use of concurrent transmissions. After relay path selection, we use a multi-hop transmission scheduling algorithm to compute near-optimal schedules by fully exploiting the spatial reuse. Through extensive simulations under various traffic patterns and channel conditions, we demonstrate MHRT achieves superior performance in terms of network throughput and connection robustness compared with other existing protocols, especially under serious blockage conditions. The performance of MHRT with different hop limitations is also simulated and analyzed for a better choice of themaximum hop number in practice.