Mobile Wireless Communications Tomorrow
Evolving Today's Networks Towards 3G The 3rd Generation Mobile System will most likely grow out of the convergence of enhanced 2nd generation mobile systems with greater data transfer speed and capacity and 1st generation satellite mobile systems. Evolution to the current generation mobile networks to 3G doesn't necessarily mean seamless upgradation to the existing infrastructure to the 3G. Evolution should also be seen in context of coexis10ce of the 2G and 3G networks for some time, with users able to roam across the new and the old networks, able to access 3G services wherever 3G coverage is available. As mentioned before, a 3G network can have one of the 3 optional air interfaces supporting one of the two GSM MAP and IS-41 network architectures. This results in a range of choices for the existing networks to evolve/migrate towards 3G. Possible convergence of TDMA and GSM networks with EDGE adds another variable to the overall migration paths. Another variable that adds complexity to this already complex list of options is the time frames involved. By the time some of the 2.5 or 2.75G technologies go to field, we may see the emergence of 3G technologies also. So, a lot of thought regarding the costs involved, and/or the viability of 2.5G technologies like EDGE could be questioned. The same is true about the time frames of the so called "4G".Before I talk about evolution/migration paths of all the existing 2G mobile wireless technologies, let me briefly discuss the 3G network architecture and other technology factors involved in the migration to 3G.
3G Architecture The 3G network will have a layered architecture, which will enable the efficient delivery of voice and data services. A layered network architecture, coupled with classicalized open interfaces, will make it possible for the network operators to introduce and roll out new services quickly. These networks will have a connectivity layer at the bottom providing support for high quality voice and data delivery. Using IP or ATM or a combination of both, this layer will handle all data and voice info. The layer consists of the core network equipment like routers, ATM switches and transmission equipment. Other equipment provides support for the core bit stream of voice or data, providing QOS etc. Note that in 3G networks, voice and data will not be treated separately which could lead to a reduction in operational costs of handling data separately from voice. The application layer on top will provide open application service interfaces enabling flexible service creation. This user application layer will contain services for which the end user will be willing to pay. These services will include eCommerce, GPS and other differentiating services. In between the application layer and the connectivity layer, will run the control layer with MSC servers, support servers, HLR etc. These servers are needed to provide any service to a subscriber.
Migration techniques The migration to 3G is not just based on evolving core networks and the radio interface to IMT 2000 compliant systems. Migration towards 3G would also be based on the following steps/technologies:
Network upgrades in the form of EDGE, GPRS, HSCSD, CDPD, IS-136+, HDR etc. Evolution to 2.5G basically will provide support for high speed packet data. Though these technologies are ex10sions to 2G rather than precursors to 3G these will have a major impact either by proving (or not) demand for particular services. Service trials to test infrastructure, handsets and applications etc. Introduction of WAP-based services that bring the web to the wireless phone. In short-term WAP and, in longer term, XML will provide a classical framework for accessing wireless Internet con10t, enabled by 2.5G/3G. The development of mobile web portals Development of microbrowsers and operating systems. Wide acceptance of short-range wireless connectivity technologies like Bluetooth, HomeRF etc.
