To get the most out of upcoming mobile broadband networks based on LTE (Long Term Evolution), the use of femtocells is a key ingredient, according to industry organization the Femto Forum.

Femtocells are small base stations that can improve indoor coverage and increase capacity.

When a user is making calls and surfing the Web with a phone or laptop equipped with wireless broadband, signals are sent via the femtocell and a fixed broadband connection.

They also allow carriers to offload users from the regular mobile network and save money on backhaul capacity.

Operators that roll out LTE networks will be able to use femtocells to increase capacity and improve operator capacity, according to Rupert Baines, the Femto Forum's marketing chairman.

Indoor coverage will be a big challenge for those operators that plan to use the 2.6 GHz frequency band for its LTE networks, but by using femtocells they could get around that, Baines said.

Operators that use spectrum below 1 GHz - U.S. operator Verizon Communications is, for example, planning to use the 700 MHz band - will get better indoor coverage and the ability to cover larger areas per base station.

But large cells will also mean more users per base station, and since capacity in mobile broadband networks is a shared resource users would get less bandwidth, according to Baines.

In this case, femtocells could offload the big base stations, and give users higher speeds, Baines said.

The first femtocells in LTE networks won't be deployed in the home environment, but at offices, coffee shops and airports and compete with Wi-Fi based hotspots, according to Baines.

One advantage femtocells in LTE networks will have over the use of the technology in current 3G networks is better timing. Femtocells are just becoming an option for 3G operators, but most of them have already built their networks.

With LTE the foundations for using femtocells are already part of the standard, and end-to-end support should be a part of the next version, according to the Femto Forum.

However, the operators that are the first to start building LTE networks will have to manage without femtocells.

The first femtocells for LTE networks are expected to arrive in 2011, Baines said.