What Do You Know About Mobile Fronthaul Optical Modules?

NADDOD Jason Data Center Architect Dec 30, 2022

As the name implies, mobile fronthaul optical modules are optical transceiver modules used in mobile base stations, mostly industrial grade.

industrial grade

What is mobile fronthaul?

Mobile Fronthaul, simply put, is the separation of functions within a base station so that some of the functions can be transferred to the tower, thus reducing the equipment, energy and space required in the hut below, also called a distributed base station. There are therefore two types of equipment: a smaller rack-mounted unit called a Baseband Unit (BBU) and a Remote Radio Unit (RRU) or (as it is sometimes called) a Remote Radio Head (RRH) mounted on top of the tower next to the antenna. The link between these two devices is defined as a fronthaul .

What is the role of fibre optics in mobile fronthaul?

In older monolithic base stations, the two parts were connected by an inch or two of copper cable. But since half of the equipment was installed on top of the tower, it was clear that a few inches of copper cable would not suffice. And it was found that even when the BBU was at the bottom of the tower, copper was a poor choice. This is because the signal between the two devices is an RF signal, which is uncompressed and therefore has a fairly high bandwidth.

Statistically, if copper is used instead of fiber, the former is 13 times heavier than the latter. For base stations, we have to take into account wind and ice loads and therefore need cables with a small diameter and light weight. So, even without considering distance, fiber is the better choice as far as basic physical factors are concerned. That was the origin of the mobile fronthaul.

But then people realised: we have fiber optic connections and we can move BBUs; the transmission distance between these two devices can be extended to tens of kilometres if we want to. Then operators could consider aggregating BBUs to a central office serving multiple wireless macrocells, which is called a centralised RAN. centralisation of the RAN reduces costs by saving on house construction, space and power consumption. With the right equipment, processing power can also be dynamically distributed among multiple units to achieve greater efficiency.

Thus, fronthaul solves the multiple benefits of weight, reduced operating costs and investment costs required for future wireless capacity.

What are the ways of mobile fronthaul?

What we currently know from device vendors is a simple point-to-point Grey Optics link. But let me start with the definition of CPRI. As part of the development of distributed base stations, a number of device vendors have defined the way in which signals are transmitted between the BBU and the RRU, also known as the Common Public Radio Interface (CPRI). In the specification they define the minimum requirements for the optical link, indicating that existing optical equipment including several Fibre Channel devices will meet these requirements.

The huge demand is driving strong growth in the performance of mainstream domestic optical module manufacturers. The SFP/SFP+industrial grade mobile fronthaul optical modules developed by NADDOD for 4G and 5G wireless communication base station application scenarios can meet the industrial grade long time stable transmission. With Mobile’s additional investment in 5G networks, domestic mainstream optical module manufacturers are sure to continue to show strong production and sales.