Taiwanese manufacturing giant Hon Hai has big plans for 5G private networking that include the deployment of its own equipment.

It will run 5G trials in 38 factories across China next year using its self-developed small basestations and core network, according to research by Zijinshan Technologies.

Hon Hai, the world's largest contract manufacturer with more than a million employees, says it has been developing the equipment and software for the past three years.

An unnamed executive is quoted as saying the company would not use other vendors' equipment in its private networks.

But like other industrial firms keen to take advantage of 5G in China, it has the awkward problem of no available spectrum.

The national spectrum agency SRRC is weighing the allocation of frequencies to support the industrial Internet, but it is meeting some pushback from operators such as China Mobile.

Some analysts expect that the 4.4GHz-4.5GHz range, which has been set aside for for 5G but not allocated, will be assigned to industry, though under what terms has not been decided.

Facing this uncertainty, Hon Hai needs to find ways to access operators' licensed spectrum.

The company said it was willing to cooperate with all parties "with an open mind," but says it rejects network slicing, claiming it does not provide strong security and adds end-to-end complexity.

It said its current solution is to embed the core network functions into the private network and connect with the public 5G network through a firewall.

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If the core network were outside the factory site the company would lose control, making its production lines vulnerable to "unthinkable consequences" should a major fault occur, Hon Hai said.

Zijinshan analysts had a similar view. The self-built 5G private network is the costliest but also the most reliable solution, it found.

A China Unicom exec conceded that "for a small number of enterprises," a 5G private network combining a self-built core and leased basestations was a workable solution.

But he said in general businesses should not build 5G by themselves because they lacked the scale to manage the high costs. "For most enterprises, private network requirements can be achieved through network slicing."

Luo Wei, the head of Hon Hai's 5G+ Industrial Internet Research Institute, said in a recent presentation that the company is currently running a 4G network architecture through which all traffic was routed, regardless of the requirements of the LAN.

"This network architecture is not suitable for low-latency, broadband closed-loop network scenarios," he said.

Private networking is not Hon Hai's only 5G play. It recently invested another $328 million in Taiwan operator Asia-Pacific Telecom (APT) to increase its stake to 40%.

— Robert Clark, contributing editor, special to Light Reading