Redesigning Fronthaul for Next-Generation Networks: Beyond Baseband Samples and Point-to-Point Links

TL;DR

This paper proposes a novel fronthaul architecture for 5G networks that supports diverse payloads, flexible topologies, and differentiated latency, enabling advanced network functions and cooperation beyond traditional point-to-point links.

Contribution

It introduces a new perspective on fronthaul design that moves beyond I/Q samples and point-to-point links, supporting diverse traffic, topologies, and latency guarantees.

Findings

Proposes a reference architecture with four logical layers.

Utilizes technologies like decoupled synchronization and packet switching.

Enables point-to-multi-point and flexible topologies for 5G fronthaul.

Abstract

The fronthaul (FH) is an indispensable enabler for 5G networks. However, the classical fronthauling method demands for large bandwidth, low latency, and tightly synchronized on the transport network, and only allows for point-to-point logical topology. This greatly limits the usage of FH in many 5G scenarios. In this paper, we introduce a new perspective to understand and design FH for next-generation wireless access. We allow the renovated FH to transport information other than time-domain I/Q samples and to support logical topologies beyond point-to-point links. In this way, different function splitting scheme could be incorporated into the radio access network to satisfy the bandwidth and latency requirements of ultra-dense networks, control/data (C/D) decoupling architectures, and delay-sensitive communications. At the same time, massive cooperation and device-centric networking could be effectively enabled with point-to-multi-point FH transportation. We analyze three unique design requirements for the renovated FH, including the ability to handle various payload traffic, support different logical topology, and provide differentiated latency guarantee. Following this analysis, we propose a reference architecture for designing the renovated FH. The required functionalities are categorized into four logical layers and realized using novel technologies such as decoupled synchronization layer, packet switching, and session-based control. We also discuss some important future research issues.