7 Things I Know About… what Open RAN means for Small Cells

Peter Claydon, President of 5G small cell chipset developer Picocom, says that the Open RAN movement aligns well with market drivers for small cells.

Pete Claydon Picocom1. The problems of a closed RAN ecosystem

Around 80% of the market is supplied by just three vendors – Ericsson, Nokia and Huawei. This market landscape has made mobile operators reliant on these vendors to set up and even operate networks and to dictate the pace of new features and service introductions. Even where operators have theoretical “vendor diversity”, say by splitting up a network geographically between vendors, they are often limited in their ability to introduce a service because vendors implement features differently. The different parts of the network develop according to vendors’ own closed, proprietary profiles.

That’s where the Open RAN movement offers promise. Interoperable RAN functions from different vendors would make operators less reliant on the roadmaps of just a few suppliers. That could mean the introduction of newer, smaller companies, but it could also include the likes of some of the web scalers, for example, coming into this market.

2. Open RAN itself is not without risks

Even with the Open RAN movement, there is a risk it could become dominated by one or two large vendors contributing the majority of the code, or by the migration paths of just a few major network operators. Also, there are cost implications. Using COTS hardware for higher RAN processing layers is okay but not necessarily for L1 processing where commercial hardware can be expensive and power-hungry. Finally, Open RAN potentially puts a more significant system integration burden on the network operator.

By disaggregating the base station architecture, you can upgrade networks in a more targeted way, deploying a best of breed vendor policy for a specific function.


3. In-building and new ownership and service models will drive demand

The nature of 5G, with operation in higher frequency bands, means that in-building coverage will become essential. Small cells will be the means to achieve that. But deploying multi-operator coverage cannot be achieved economically unless the basebands themselves can support multi-operator operation.

Open RAN also offers the ability to upgrade features to just specific parts of a network, without requiring a massive macro-level license upgrade. For example, you wouldn’t deploy URLLC capabilities across a whole network, instead prioritising specific locations such as industrial campuses. By disaggregating the base station architecture, you can upgrade networks in a more targeted way, deploying a best of breed vendor policy for a specific function.

4. Open RAN and the small cell

An Open RAN small cell has support for defined open interfaces between the various 3GPP “split” elements of the baseband and radio units.

The Small Cell Forum has developed a standard protocol, nFAPI, for split 6. This split is between the MAC and PHY layers, with the PHY being in the small cell radio unit, S-RU. It has achieved significant backing in Europe for in-building solutions.

The O-RAN Alliance has defined a protocol (Open Fronthaul) for split 7.2, which is between the upper and lower PHY. This provides for a lower cost RU, but needs a higher bandwidth and lower latency connection to the RU, so it is becoming a popular option for deployments in Asia Pacific where buildings have more fibre to exploit for fronthaul between the DU and RU.

So we see these as the two primary standards. A key enabler to both is the availability of test equipment and test specs so that if a piece of equipment passes the tests it will be guaranteed to interoperate with equipment from other vendors.

5. Silicon will be key – companies need their SoCs

We have seen before that the success of a technology ultimately comes down to the silicon. History is littered with examples where silicon ended up being the most important thing, as it is the thing that underpins everything else. 5G Open RAN infrastructure needs optimised SoCs.

Arguably Nokia fell behind in 5G because of its silicon design decisions compared to Ericsson and Huawei. We are seeing that L2 and above can operate as software on standard processor architectures. But for L1, you need a different architecture. Intel’s FlexRAN shows L1 on what appears to be a purely standard architecture, but any of those solutions ultimately include FPGA-accelerated offload. XEON servers cost money and burn lots of power.

There’s a real competitive advantage on cost and power from a baseband SoC, and that’s our sole focus and area of expertise and heritage.

6. Picocom’s upcoming small cell SoC

Picocom is providing a competitively priced open solution that enables a variety of vendors to enter the 5G market. We will sell the products we are developing in the open market, licensing Picocom software with that. However, we will also be licensing source code so people can use it as the basis of their own differentiated offerings.

The concept of our first chip is an SoC that is optimised for small cell DUs. It uses the FAPI protocol to communicate with the MAC layer and O-RAN fronthaul, based on eCPRI to connect to remote units (RUs). It can offload the entirety of the small cell PHY processing when connected directly into an ARM or Intel-based server.

Early equipment based on a combination of general-purpose processors and FPGAs are workable for trials and small-scale deployments; however, cost and power consumption make them unviable in large-scale network deployments. There’s a real competitive advantage on cost and power from a dedicated baseband SoC – that’s our core focus and area of expertise driven by our heritage. Picocom is the 5G Open RAN baseband semiconductor and software specialist.

7. We know Open RAN, and back its success

Picocom is active in the O-RAN Alliance, contributing to Open Fronthaul in the O-RAN fronthaul group, and very much involved in the SCF 5G FAPI and nFAPI definitions as well. And in that capacity, we see many other companies that are supportive as well.

Despite some potential pitfalls, we really do believe that Open RAN can change the way people put networks together. A dedicated baseband SoC for Open RAN small cells will be a vital part of that change and enabling new vendors to enter the market.



Picocom is a semiconductor company that designs and markets Open RAN standard-compliant baseband SoCs and carrier-grade software products for 5G small cell infrastructure. It empowers wireless innovation by delivering class-leading technology and products, enabling its customers to compete in the rapidly evolving disaggregated telecoms RAN market. The company’s first 5G Open RAN small cells SoC products are expected to be available first-half of 2021.

If there’s anything further you’d like to know about 5G Open RAN please feel free to reach out to Peter Claydon by email .

You can also find more information on Picocom here.