Optical Module Solutions for 5G&5.5G Network Deployment

As 5G technology continues to advance, we are on the brink of entering an even more exciting era—5.5G. Compared to the current 5G networks, 5.5G offers higher data transmission rates, greater connectivity, enhanced security, and improved stability. As an indispensable component of network infrastructure, optical modules play a crucial role in the deployment of 5.5G networks. This article will delve into the optical module solutions suited for 5G/5.5G networks.

From 5G to 5.5G

The primary characteristics of 5G networks—ultra-high speed, low latency, and large capacity—enable higher data transfer speeds, more densely connected devices, and a broader range of applications. 5.5G, also known as 5G-Advanced (5G-A), is a mobile communication technology that serves as a significant upgrade to 5G networks and paves the way for the development of 6G.

While cellular networks largely rely on 5G to support billions of connected devices, the transition from 5G to 5.5G marks a shift from simply enabling connectivity to achieving intelligent connectivity, addressing the increasingly diverse and complex demands of full-scenario IoT applications.

Though 5.5G is built upon the foundations of 5G, it must also ensure compatibility with all existing 5G devices. Unlike 5G, which primarily operates within the SUB-6GHz spectrum, 5.5G requires flexible utilisation of the sub-100GHz spectrum. In essence, 5.5G aims to deliver more efficient connections and reduced latency, further enhancing overall network performance.

Application of Optical Modules in 5G Networks

In line with the standards set by 5G, base stations have been restructured into three main components: AAU(Active Antenna Unit), CU(Centralized unit) and DU(Distribute Unit), with the option to deploy CU and DU either together or separately. These changes impose new demands on optical modules to meet the high bandwidth and distance requirements associated with key links in the 5G network architecture. Based on different network layers and transmission distances, the application of optical modules can be categorised into three main scenarios: Fronthaul, Midhaul, and Backhaul networks.

Fronthaul Networks

Fronthaul networks are responsible for connecting small cells and Remote Radio Units (RRUs) within 5G networks, playing a crucial role in ensuring network coverage and signal transmission. Due to the dense deployment of small cells, fronthaul networks must handle a large volume of short-distance data transmission. To accommodate the increasing data traffic, fronthaul network optical modules need to support high bandwidth, typically using 25G or even higher-speed modules.

Midhaul Networks

Between fronthaul and backhaul networks, midhaul networks aggregate data from small cells and transmit it to higher-level network nodes. To ensure data integrity and transmission efficiency, optical modules in midhaul networks typically support high speeds of 50G or 100G and are capable of long-distance transmission. Additionally, to meet the dynamic requirements of 5G networks, these modules must offer excellent compatibility and flexibility to adapt to various network architectures and deployment scenarios.

Backhaul Networks

Backhaul networks are a vital conduit connecting base stations to the core network, handling substantial data transmission tasks. With the significant increase in data traffic brought by 5G networks, backhaul networks face greatly increased bandwidth demands. Optical modules must support transmission rates of 100G or higher, with excellent resistance to interference, ensuring the stability and reliability of data transmission.

Different Types of Optical Modules in 5G

5G Fronthaul: 25G/100G Optical Modules

The need for higher base station density in 5G networks drives the demand for high-speed optical modules, making 25G/100G modules the preferred choice for fronthaul networks. The eCPRI protocol interface, typically operating at 25.16Gbps, is used to transmit 5G base station signals, making fronthaul networks heavily reliant on 25G optical modules.

Given that 5G AAUs are often deployed outdoors, 25G optical modules in fronthaul networks must meet industrial-grade temperature requirements (-40°C to +85°C) and dustproof standards. Grey optical modules are suitable for point-to-point fibre connections, offering a cost-effective and straightforward solution, although they lack network protection and monitoring capabilities. Colour optical modules, mainly used in passive and active WDM/OTN networks, connect multiple AAUs to DUs via a single fibre. Passive WDM equipment is easy to maintain but has limited functionality, while active WDM/OTN offers advantages such as low latency, high bandwidth, and network protection, albeit at a higher construction cost.

5G Midhaul: 50G PAM4 Optical Modules

The 5G midhaul network requires 50Gbps optical modules, available in both grey and colour variants. The 50G PAM4 QSFP28 optical module, which uses an LC optical port and single-mode fibre, can double the bandwidth over a single-mode fibre link without the need for a wavelength division multiplexing filter. These modules can transmit over distances of up to 40km, supported by shared DCM and BBU site amplification.

5G Backhaul: 100G/200G/400G Optical Modules

The 5G backhaul network will need to carry significantly more traffic than its 4G counterpart, due to the higher performance and bandwidth of 5G NR (New Radio). Consequently, the aggregation and core layers of the 5G backhaul network require coherent 100G/200G/400G optical modules, typically operating in the C-band, with transmission distances generally within 200km. Low-cost coherent 100G optical modules are considered foundational technology, which, when combined with wavelength division multiplexing, can achieve even higher transmission bandwidths. Currently, the most pressing need in 5G networks is for 100G optical modules, while service providers require 200G and 400G bandwidth to achieve the throughput necessary for 5G deployment.

Opportunities for Optical Modules in 5.5G Era

In the 5.5G era, optical modules will see significant advancements, with the front-haul segments moving towards 50G/100G standards and the mid-haul segments evolving to 200G/400G, fully aligning with the demands of 5.5G networks. This evolution will drive a substantial increase in demand for high-end optical modules. Looking ahead, 6G networks are expected to further advance front-haul optical modules to 100G/200G and mid-haul modules to 400G/800G.

Comprehensive Range of Optical Modules

FS is dedicated to providing high-performance optical modules through professional and reliable expertise. All modules are tested with specialised equipment to ensure both performance and quality. FS offers a wide range of optical modules from 1G, 10G, 25G, 40G, 50G, 100G, 200G, 400G, to 800G, widely used in enterprise networks, data centres, and telecommunications operators. These modules support various application scenarios, from infrastructure to high-performance computing, meeting the diverse needs of different users. Should you require further assistance, please get in touch with our sales team to customise your solution.