The dramatic growth in mobile communications equipment penetration rates over the past few years has created a situation where the vast majority of people have a communications or Internet access device with them at all times. This new environment has provided the stimulus for the development of the Femtocell (also known as a "home base station" or "3G access point"), a miniature base station that is inexpensive, easily installed, highly interoperable, and does not require the user to make any significant changes to their existing communications equipment.
Overview of Femtocell Technology
The Femtocell is an IP (Internet Protocol) based access technology that uses mobile core network packet switching to transmit voice calls and provide other real-time services. By setting up a small, lowpower transceiver inside a house or other building, the user can link their 3G (Third Generation Mobile Communications) handset to this indoor base station to enjoy reliable 3G service indoors.
A Femtocell can access the core network using IP or SIP (Session Initiation Protocol) technology via an Ethernet , broadband or ATM/TDM (Asynchronous Transfer Mode / Time Division Multiplexing) connection. So far, three main solutions have been developed for integrating Femtocells with the core network: lu-b over IP, lu over IP, and IMS (IP Multimedia Subsystem) or SIP based solutions. There is still considerable disagreement among both researchers and telecommunications operators as to which of these three solutions offers the most advantages. Currently, lu over IP based solutions are the most widely used, mainly because of their low cost and relatively low complexity. The establishment of a unified interface standard by the Femto Forum would help to stimulate market growth by encouraging more companies to move into the Femtocell business.
Femtocell 3G home base stations offer the following advantages for consumers:
1. Convenience – consumers do not need to replace thei r exist ing communicat ions equipment
2. Stability and provided better quality of service
3. Improved security compared to conventional WiFi solutions
4. Good signal reception even when traveling at high speed
5. Can be used with free Mobile VoIP services
From the point of view of mobile communications operators, Femtocells can create the following benefits:
1. The integration of Femtocells with DSL (Digital Subscriber Line) and cable networks can help to speed up the expansion of 3G network coverage
2. The density of WCDMA(Wideband Code Division Multiple Access)base stations can be reduced, enabling operators to achieve cost sav ings on networ k deployment and maintenance
3. Femtocells are lower power consumption than WCDMA base stations
4. Having a Femtocell will encourage consumers to make more use of their 3G handset while at home, creating the potential for the mobile phone to eventually replace the conventional fixed-line telephone within the home
5. Potential for boosting revenue through the development of a wider range of personalized value-added services
Conclusions
Forecasts compiled by market research firm ABI Research indicate that, within five years time, the number of Femtocells in use worldwide will have risen to over 100 million. The ongoing development of Femtocell technology will help t make communications networks more efficient, reduce subscriber churn, and improve indoor mobile communications service quality. The availability of Femtocells will also encourage mobile communications operators to introduce more competitively priced home mobile data service packages, while at the same time changing consumers' mobile phone usage habits. From a technical point of view, Femtocell will improve indoor coverage for both WCDMA and HSDPA (High Speed Downlink Packet Access), thereby supporting mobile operators' deployment of these services. However, it will be the consumer who will benefit most from the introduction of Femtocell technology!
(Li Kun-Hung is a Manager with the Mobile Communications Technology Center, Networks and Multimedia Institute. E-mail: jason@nmi.iii.org.tw)
