PARTNER FEATURE: The industry is uniting behind the new 4.3-10 connector standard, with vendors including Huawei and a number of tier-one operators putting their weight behind it.

Attendees polled at Huawei’s 5th Annual Global Antenna & AAU Forum in Paris last month were widely supportive, with almost 80 per cent of respondents either already moving toward 4.3-10 or planning on starting to do so in 2017.

The need for 4.3-10
Ongoing developments in mobile broadband, including the need to support multiple frequency bands and new technologies such as MIMO, carrier aggregation and beam forming, have meant that antenna modernisation is high on the agenda for many operators.

But this comes against a backdrop of challenges with site acquisition, which means that real estate is at a premium. And so, despite demanding more capable equipment, equipment sizes cannot grow to accommodate this.

This restriction has led to demand for smaller connectors, delivering more ports without increasing the space taken up on antennas. The 4.3-10 connector has a clear size advantage: it is 40 per cent smaller than 7/16 DIN, with the recommended minimum distance between ports of 40mm, reduced from 70mm.

But size isn’t the only benefit of 4.3-10.

Another improvement is a reduced influence of coupling torque on performance: while for the old connector, connection torque is advised to be consistent at 30Nm, for the new version this is not an issue. Essentially, the PIM (passive intermodulation) performance is no longer dependent on the torque applied to secure the connection.

And this is a significant factor: according to a presentation by Reiner Berchtold, senior manager of sales and marketing at Spinner, up to 70 per cent of reported PIM failures in antenna feeder lines are caused by insufficiently torqued 7-16 connectors.

“The strength of 7/16 – the high coupling torque – is at the same time the biggest weakness,” he said, noting that “basically, it’s a more than 60 year old connector design”.

Evolution path
Earlier this year, NGMN Alliance launched a taskforce dedicated to issues including the migration of connectors to 4.3-10 in the most efficient way.

Key items on the agenda include avoiding an expensive and time-consuming migration process from 7/16 to 4.3-10 connectors and enabling cooperation between operators and vendors.

And the list of participants indicates how important the issue is to the industry: operators represented include T-Mobile, Orange, Telecom Italia and Telia, with vendors represented including Huawei, Ericsson, Nokia, Kathrein and Commscope.

Huawei is adopting 4.3-10 connectors on its new products, and other vendors are also bringing it to their portfolios as they are updated in 2017 and beyond.

Cumpanas said that as far as radio units and active antennas which have already launched, there will be no switch to the new connector: instead it will be adopted as new products are brought to market. Legacy passive antennas will migrate “according to customer requirements”, with new products again adopting 4.3-10 from the outset.

For distributed antenna systems, which require deployment of a large number of RF connectors, and therefore presenting a high cost if replacement connectors are required, a partial migration can be considered. For example, this applies during an extension (for example, to add new frequency bands), and is applicable to relatively high power RF sections of the network, to provide a reasonable balance between cost and PIM risk.

Heino Cumpanas, 4.3-10 Taskforce Member at industry body NGMN Alliance, also noted some geographic differences, with little impetus (so far) for a shift from, for example, Latin America, where the supply chain still centres on 7/16.

NGMN whitepaper
NGMN Alliance is readying a whitepaper to discuss issues surrounding migration – including scenarios and strategies – which is due to be published soon.

“The whitepaper should push the industry forward to speed up the migration to 4-3.10. I think, honestly speaking, maybe next year we will see a lot of 7/16, but after 2017 most products will come with 4.3-10, and other markets will be thinking about migrating,” Cumpanas said.