5G fronthaul-latency and jitter studies of CPRI over ethernet

TL;DR

This paper investigates the feasibility of encapsulating CPRI over Ethernet for mobile fronthaul, focusing on delay and jitter performance through FPGA experiments and simulations.

Contribution

It provides experimental and simulation evidence that Ethernet-based CPRI can meet delay and jitter requirements with appropriate scheduling and redundancy.

Findings

CoE encapsulation with fixed frame size requires tens of microseconds.

Scheduling policy reduces jitter significantly with redundant Ethernet capacity.

Ethernet-based fronthaul can be a credible alternative to traditional CPRI.

Abstract

Common Public Radio Interface (CPRI) is a successful industry cooperation defining the publicly available specification for the key internal interface of radio base stations between the radio equipment control (REC) and the radio equipment (RE) in the fronthaul of mobile networks. However, CPRI is expensive to deploy, consumes large bandwidth, and currently is statically configured. On the other hand, an Ethernet-based mobile fronthaul will be cost-efficient and more easily reconfigurable. Encapsulating CPRI over Ethernet (CoE) is an attractive solution, but stringent CPRI requirements such as delay and jitter are major challenges that need to be met to make CoE a reality. This study investigates whether CoE can meet delay and jitter requirements by performing FPGA-based Verilog experiments and simulations. Verilog experiments show that CoE encapsulation with fixed Ethernet frame size requires about tens of microseconds. Numerical experiments show that the proposed scheduling policy of CoE flows on Ethernet can reduce jitter when redundant Ethernet capacity is provided. The reduction in jitter can be as large as 1 {\mu}s, hence making Ethernet-based mobile fronthaul a credible technology.