Femtocells can be upgraded, replaced or swapped out. With the launch of new versions, higher speeds and increased functionality, operators need to plan for the full lifecycle of femtocell deployments. Here we’ve considered several of the common scenarios in the femtocell lifecycle, including some that could easily be overlooked.
Linking a single femtocell to its owner
The most common situation is where a residential subscriber buys a femtocell from their operator and installs it at home. The “master phone” number (i.e. the femtocell owner’s mobile phone number) can be captured at the point of sale (which could be the website for online sales).
More commonly, this is done as a separate transaction after delivery. This leads to longer time before the femtocell becomes fully operational, but simplifies the changes in the dealer’s point of sale and associated back office systems.
At this time, the master phone number should be checked to verify it belongs to an active account on the network (not obvious these days due to number portability) and added to the whitelist for the femtocell itself.
Lost or stolen phones
The consequence of a stolen or lost phone being able to use a femtocell is irrelevant – it could make or receive calls from any basestation until the account is blocked. It’s also unlikely a thief would remain in the area where it had been stolen.
As with any stolen phone, a call to the operator can terminate use of both the SIM card (blocking will prevent any further charges on the user’s account) and the phone device itself (blocking will prevent or make use very difficult on most networks by blacklisting the IMEI, the unique device identity). Calls to the phone number can then be diverted either to voicemail or a special announcement as a temporary measure.
Whether it’s worth removing the blocked SIM card number from the whitelist of femtocells where it has been provisioned is also highly dubious.
Lost or stolen femtocell master phones
Where the stolen phone is the registered master phone for a femtocell, it seems unnecessary (even undesirable) to disable the associated femtocell – there are no benefits or security issues, especially once the SIM card has been blocked.
Replacing a phone or SIM card
Where an operator has issued a replacement SIM card and associated it with the previous phone number, the new IMSI (SIM Card Number) needs to be provisioned and downloaded into any femtocells on the network to replace the old number.
Potentially this could affect several femtocells although commonly only one or two.
The self-service page on the operator’s website would continue to allow the femtocell owner to maintain the whitelist for any femtocells they own and manage.
Lost or stolen Femtocells
Where a femtocell is stolen, it is a simple matter for the network operator to disable it. Each femtocell is unique and must have a serial number to identify itself. When switched on, an authorisation check would quickly determine if the femtocell has been deregistered and it could not be used.
The serial number of the femtocell would have been assigned to the customer's account when first purchased or registered, so can be used to disable it from further use.
Upgrading the femtocell
New technology provides us with faster, cheaper and more functional devices all the time. For example, femtocells are now being sold as integrated solutions rather than standalone. At some point, existing femtocell owners may want to upgrade to a new device.
The business process to support this should be straightforward, ideally allowing any personalization such as a whitelist across to the new box in a seamless fashion.
This might be done by a one-off re-registration process involving entry of the serial number of the new box.
A typical example might be a Sprint customer who wants to upgrade from their 2G to the latest 3G data capable device. Since these are provided by different manufacturers and use different standards, some provisioning to different systems may be required.
Transferring the femtocell to someone else
Femtocells can be transferred to any other subcribers who use the same network – they are already bought and sold on eBay. The new owner needs to be able to easily register the device in their name, entering their own whitelist and setting up as if for a new customer.
Retiring the femtocell
Where femtocells are faulty or simply no longer used, some housekeeping process might be used to remove the details of any femtocell that hasn’t been connected to the network for some time. This can actively retire devices, so that if they do reappear they will need to be re-registered as if new.
Some operators may not see the need for this – after all, if any very old 2G phone were to appear on their network, there is no reason it can't be used. The only difference is perhaps that femtocells are commonly upgraded to the latest software version, and in the long term (i.e. after many years) this may not be feasible – some models may be retired and not actively supported.
I’ve heard of some residences that cover large areas and small businesses with extensive premises where a single femtocell can’t provide coverage. Two or more may be installed to ensure 100% coverage and/or capacity. These would ideally be managed with a common whitelist by a single administrator.
Corporate femtocells for home use
Large corporations often have negotiated attractive deals from a single network operator on a national basis. Since any network operator will have some gaps in their coverage footprint, there will be individuals who have poor or inadequate coverage at home but are tied to the operator for their business phone. A femtocell is an attractive solution to the problem.
One issue can be that the administrative rights to the whitelist for femtocells supplied as part of the corporate deal belong to the IT department. This makes it awkward for individuals to make changes at short notice out of hours, for example if a guest comes to stay for a weekend or a colleague visits for an evening.
Individual access to the whitelist for each corporate femtocell owner would solve this problem.
Corporate femtocells for branch use
Sometimes femtocells are deployed in small branch offices. These may be linked to a specific master phone number, such as that of the branch office manager. There may need to be an update process to handle that phone being stolen/swapped/upgraded, or if the office manager changes.
Master phone subscription expires/cancelled/on-hold
What should happen if the master phone subscriber fails to pay their bill and their subscription expires, is cancelled or put on hold? Unless there is a regular monthly fee for the femtocell, it doesn’t seem worthwhile to take action to switch it off. That would adversely affect other users, and may impact customer loyalty further than needed.
Some operators limit ownership of femtocells to postpaid customers only. This may be because they see prepaid customers as those with lower ARPU (Average Revenue Per User), or because they may not be able to easily trace their home. Since use of the femtocell itself is always controlled through the postpaid and prepaid accounts of each individual user, this seems a strange limitation at face value. Why stop customers using the service unless you’ve decided the femtocell subsidy might not be repaid?
One possible reason may be the fact that prepaid customers typically have a separate customer care system, often with a different set of customer care staff. However, the femtocells themselves are typically managed and controlled centrally and don’t depend on the type of subscription.
Where operators do allow the master phone to be a prepaid customer, expired prepaid subscriptions might not affect whether the femtocell can be used or not. A possible measure could be to disable changes to the whitelist until the subscription becomes active again.