The reason behind this is that many companies constrain their costs to those services required for business. Whilst these have included the lucrative roaming service for business travellers, they usually don't extend to entertainment or other premium applications.

Many staff entitled to mobile phones pay for premium models out of their own pockets. Whilst some people simply swap the SIM card and use their own phone for work, restrictions to premium services devalues the capabilities of their premium phone.

This reason, together with the preference to have a separate mobile phone number for private use, drives the growing duplication of work and personal mobile phone subscriptions.

A few mobile network operators offer services which aim to address this problem. A single phone with two phone numbers (work and personal), with separate billing accounts, service configuration and privileges for each is possible. Callers to your business number might go directly to voicemail, whilst personal callers get through.

Examples include Orange UK, NTT DoCoMo in Japan and Optimus Portugal. However, there are some limitations with each of these services. Sometimes all the features do not work transparently when roaming abroad, text messages may appear to originate from one number only, codes may have to be used to switch between the private and work modes.

In order to be successful, these services really have to be promoted by the network operator through the employers via their enterprise sales teams. Deals have to be done with businesses whereby everyone in a client business gets a dual subscription and probably at least basic phone model. In mature marekts, both prepaid and postpaid billing options need to be available for the personal calls and premium services.

At the moment, there is often no loyalty or connection between the network providers for work and personal phones. There is typically no incentive for workers to choose the same network when selecting their personal mobile phone subcriptions.

How does this affect the market success of femtocells?

Probably the two most common scenarios are oriented around who pays for the fixed network broadband subscription at home.

Scenario 1 is for the femtocell to be provided by the network operator for use domestically. We'd expect this to be associated with the personal subscription, rather than the work one. The sale might be tied to purchase of the broadband service from the same provider, and could also be bundled with mobile subscriptions for other family members.

It seems less likely that network operators would provide and subsidise femtocells for subscriptions related to business users, for use in their homes on their own domestic broadband service. However, there is a need for this. I certainly know of several people whose business mobile phones don't have good coverage when they work from home.

Scenario 2, where companies already/also provide a dedicated broadband service to home workers, adding a femtocell o the services provided is quite feasible. But for the more casual (or more cost-concious) homeworker arrangement, there isn't the commercial incentive here.

Scenario 3 is where customers continue with separate work/personal phones on separate networks, and have two femtocells at home. Since they operate at different frequencies, this is quite feasible.

A more radical thought is that some people deliberately choose their personal mobile phone network to be the same as their work network, despite having poor domestic coverage. By installing a femtocell associated with their personal subscription, they would also benefit from better coverage on their work phone.

However, this does seem a bit of a stretch. If you are disatisfied with the network coverage, why choose the same operator for multiple phones?

These scenarios are summarised in the table below: