What are femtocells

What are Femtocells?

Femtocells are fully featured but very low power mobile phone basestations, connected using standard broadband DSL or Cable service into the mobile operator's network. They offer excellent mobile phone coverage at home for both voice and data, but at lower cost than outdoor service.

Standalone or integrated femtocells

Early femtocell products look very much like WiFi broadband modems, needing only two cables - one for power and one internet connection.

Several vendors such as Thomson, Netgear, Pirelli, Cisco and others have integrated the femtocell with other features such as DSL modem, WiFi and even IPTV into a single box. It is expected that in the longer term, most femtocells will be sold in this form.

Locked to a single mobile phone network

Unlike WiFi, these devices use licenced radio spectrum, so must be operated and controlled by a mobile phone company. Thus it will work with only one mobile phone operator, and thus encourages all users in a household to switch to the same network operator.

When in range of the femtocell at home, the mobile phone will automatically detect it and use it in preference to the outdoor cellsites. Calls are made and received in exactly the same way as before, except that the signals are sent encrypted from the femtocell via the broadband IP network to one of the mobile operators main switching centres. Making and receiving calls uses the same procedures and telephone numbers, and all the standard features (call divert, text messaging, web browsing) are available in the same way - indeed data services should operate more quickly and efficiently due to the short range involved.

Low power but high quality

Femtocells operate at very low radio power levels - less than cordless phones, WiFi or many other household equipment. This substantially increases the battery life, both on standby and talktime. Since they are so much closer to the handset or mobile device, call quality is excellent and data devices can operate at full speed. Standard units can handle up to 3 or 4 simultaneous calls from different users depending on the model. Larger femtocell designs intended for business (enterprise) use can handle 8, 16 or even 32 concurrent calls.

Open or restricted access

Restrictions can be applied on who can use the femtocell service. In extreme cases, there may be additional charges for DSL broadband supplier where a quota applies - however this would equate to many long voice calls or data service. Thus, whilst operators will hope that most femtocell users are willing to provide open access to other users, they usually offer the facility to restrict service to a whitelist of up to 50 specified telephone numbers.

Secure and self-managing

The femtocell encrypts all voice and data sent and received from mobile phones and would normally not allow access to the home computer network, so external users cannot break into your computer.

In order to reduce cost, these units are self installing and use a variety of clever tricks to sense which frequency to transmit on and power level to use.

Unlike outdoor mobile phone basestations (masts), femtocells don't require specialist RF planning engineers to design, calibrate or configure themselves - minimising the ongoing cost of maintaining them. They do have remote management from the network operator, who can upgrade the configuration and software as required.

Doesn't require special phones

They are compatible with existing standard mobile phones, although in future some minor enhancements would allow clear indication of when the phone is using the local femtocell (and thus using a free call allowance) - currently this can be provided by tones at the start of each call.


Most of the excitement is based around the new 3G UMTS mobile phone system, which includes the ability for high speed data services. However, vendors have developed femtocells for 2G GSM phones which are the most common globally, and also CDMA systems popular in the US.

So if anyone asks you what femtocells are, you can now confidently reply. Read more about the various femtocell system architectures, vendors and operators on the rest of this site.

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#1 Ed said: 
The MOBILE data revolution/evol ution process has begun.... Now.. lets get this FemtoCell technology integrated into WiFi home and business network hubs...it's only natural this would happen.
0 Quote 2010-01-13 16:19
#2 bruce said: 
Hello, I wanted to know about the licensed frequencies used...specific ally in the United States. 'Unlike WiFi, these devices use licenced radio spectrum, so must be operated and controlled by a mobile phone company. Thus it will work with only one mobile phone operator, and thus encourages all users in a household to switch to the same network operator.' What does that mean exactly for consumers? Will I have to buy an AT&T base station to place calls? Will my Femtocell base station have to be set at the same frequency as the AT&T tower?
0 Quote 2010-01-25 21:40
#3 Thinkfemtocell said: 
Hi Bruce, Hope this answers/clarifi es your question: The femtocell must be operated (and connected to) the mobile phone operator's network and will use the same (set of) licensed frequencies. What it means is that if you do buy a femtocell, you can only use it with that one network - i.e. you can't use AT&T's femtocell with a T-Mobile, Sprint or Verizon cellphone. The femtocell will work out exactly what frequency it can use and automatically select the best one, which may or may not be the same as the tower outside. Your cellphone is smart enough to be able to switch frequencies when it leaves the femtocell area and transfer the call to the tower outside.
0 Quote 2010-01-25 21:56
#4 bruce said: 
Thanks for the quick response...I understand that in a way the femtocell is proprietary in the sense of its frequency. ie. T-Mobile phone must use a T-Mobile femtocell. So when I go to the store to buy a femtocell Access Point do I need to buy a specific Access Point or does any box containing the T-Mobile brand work? After that, will the Access Point detect my T-Mobile phone and automatically connect me to my broadband? Thanks in advance
0 Quote 2010-01-26 02:38
#5 Ko Thant said: 
How about R.F output power(in dbm) of enterprise level 2G/3G femtocell?
0 Quote 2010-08-18 14:00
#6 Randy said: 
Femtocells, sounds like this may be the solution to my problems. Can anyone tell me if femtocells work similar to VoIP telephones. I live in a rural area, I do have "high speed Internet"; however, VoIP telephones do not work well because of the speeds offered with satellite service. Would a femtocell base work with the limitations I have?
0 Quote 2010-09-29 16:38
#7 ThinkFemtocell said: 
The femtocell does send voice calls over your wireline broadband Internet connection, so if that can't handle VoIP calls it is pretty unlikely it would support a femtocell. Satellite services don't just suffer from slow speeds, but often send the data over the wireline network using satellite only for downloads. That's fine for web surfing but much less useful for voice or other bi-directional telecom services.
0 Quote 2010-09-29 22:10
#8 Usama Khan said: 
Hi, I want to ask,can we deploy more than 1 femtocells nearby to each other operating at same frequency. If yes then will they be in co-ordinated fashion or unco-ordinated one. Secondly, if unco-ordinated then how would we minimize the frequency interference as all of the feemtocells will be transmitting at same frequency.
0 Quote 2011-04-13 19:35
#9 ThinkFemtocell said: 
@Usama. Almost all femtocells use WCDMA (Wideband Code Division Multiplexing) technology where cellsites and femtocells can share the same frequency. Channels are separated by coding the signal with their own unique "fingerprint" code. Femtocells are also self-organising and self-optimising - they "sniff" their environment and adapt to cope with the other femtocells and cellsites nearby, either using a different code or different frequency. Ubiquisys claim to have unique additional intelligence built into their grid femtocell system where clusters of femtocells can directly talk to each other and self-optimise. In both cases, several femtocells can operate close together, sharing the same frequency without interference problems.
0 Quote 2011-04-13 22:25
#10 Emma said: 
Just wondering if the Femotcells will work with Satellite broadband, i couldn't really establish from the earlier post.
0 Quote 2011-08-19 23:12
#11 ThinkFemtocell said: 
@emma: The short answer is yes - for specialist satellite broadband. This is still fairly new/unusual because most femtocells are installed at home (using DSL or Cable modems) or in the office. But for rural areas or disaster recovery/emerge ncy, then specialist satellite backhaul can be used. That's not the same as domestic satellite broadband services, which sometimes use a standard dialup phone for uplink and satellite for downlink - I believe the latency and jitter would be outside workable tolerances.
0 Quote 2011-08-22 21:25
#12 Dennis said: 
Can femtocells work connected to T-1 line currently used for internet?
0 Quote 2011-09-09 18:16
#13 ThinkFemtocell said: 
@Dennis: Network operators recommend at least 1 mbit broadband internet speed for a residential femtocell, so a t-1 with about 1.5Mbit/s should be more than enough. Some customers have successfully use them over as little as 256kbit/s lines. Commercially, it depends on your network operator, some allow connection via any 3rd party internet while others insist you buy and use their fixed line service. Let us know how you get on and how well it works (I'm always looking for independent customer reviews!)
0 Quote 2011-09-09 18:23
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