EE, the biggest mobile operator in the UK, has struck a 4G network-sharing deal with 3, the smallest.

“The new framework increases cost efficiencies as we continue our roll out of 4G to cover more than 90 per cent of the UK population by the end of the year,” EE said in a statement. “This is part of our £1.5 billion three-year investment to significantly differentiate the EE network in terms of the people we connect and the experience they receive.”

The deal is different to a previous 3G network-sharing arrangement between the two operators.

Under that arrangement, a joint venture – Mobile Broadband Network Ltd (MBNL) – managed the sharing of actual equipment, such as base stations and antennas. It was an ‘active’ network-sharing agreement.

MBNL was formed as a 50-50 joint venture in December 2007 between 3 and T-Mobile UK. Its ownership was expanded when T-Mobile UK and Orange UK merged to form Everything Everywhere (EE).

The 4G deal between EE and 3 UK, however, is a passive network-sharing arrangement – commonplace among 3G operators – where mast infrastructure and backhaul transmission costs, but not the equipment, are shared.

While active deals have the potential to cut costs more than passive ones, active network-sharing requires close alignment of rollout strategy between partners if they are to work. If one operator wants to install new equipment then it would need the agreement of the other.

The advantage of passive network-sharing is that operators can roll out equipment at their own pace.

EE is keen to emphasise the difference in network performance from rivals. The operator, for example, was the first out of the UK traps to offer “double-speed” 4G.

Unlike the previous MBNL agreement, the two operators will have separate antennas, spectrum and core network.

Although it has already upgraded large parts of the network using its own money, EE costs are now to be shared with 3. The Financial Times reported that 3 has committed £500 million to network investment over the next three years.

EE, meanwhile, is on track to cover 70 per cent of the UK population with 4G this month. 3 wants to reach 50 cities by the end of 2014 and 98 per cent coverage by the end of 2015.

In separate network-sharing news, Bouygues Telecom and SFR in France agreed to share part of their mobile networks to improve coverage and save costs.

The shared network of Bouygues and SFR will cover 57 per cent of France’s population, the operators said in a joint statement cited by Reuters.

A joint venture is be created to manage the infrastructure, with each operator having “total commercial independence”. It’s scheduled to be in operation by 2017.

SFR, owned by Vivendi, expects to save around €200 million per year once its network sharing deal with Bouygues Telecom is up and running by 2017-2018, according to a Reuters report.