Europe : With 3G set for widespread launch in 2004 across Europe, operators are already thinking about the post 3G world and what comes next. According to a new report from mobile industry analysts, ARC Group, the technologies making the largest immediate impact on the post 3G world will be the upgrades to 3.5G and integration of WLAN into wide area networks.

3.5G is an upgrade of 3G which uses technologies like High Speed Downlink Packet Access (HSDPA), Time Division Duplex (TDD) and proprietary technologies like Flash OFDM. Despite the slower than expected uptake of 3G, operators are already interested in 3.5G with NTT DoCoMo planning on launching HSDPA services in 2005 and several Chinese operators looking at using UMTS TDD in 2007. 3.5G technologies are forecast to reach 9.1 million subscribers by 2008.

In the run-up to 4G - which is not expected until 2010 at the earliest - operators will look for ways to enhance network performance through evolutionary upgrades in the same way EDGE and 1xRTT have been used in the 2G world. HSDPA is expected to become the most popular of 3.5G technologies due to its support from major vendors like Nokia. HSDPA uses adaptive modulation and a new shared downlink transport channel type to achieve a two-fold increase in air interface capacity and a five-fold increase in data speeds in the downlink direction.

With the advent of WLAN enabled PDA's and smartphones, there is likely to be more competition from PWLAN providers for broadband mobile revenues. However, rather than compete head on, PWLAN will be subsumed into the network mix, supplementing the 3G/3.5G network for data intensive applications. Despite this, mobile subscribers using PWLAN services over their mobile device will only make up around 50 million users by 2008, less than 20% of total 3G subscribers.

Chris White, Telecoms Consultant at ARC Group comments: "Too much attention has been paid to how PWLAN will compete with 3G rather than looking at the benefits of combining both network technologies. Independent PWLAN operators have found it hard to put a viable business case together but with the involvement of mobile operators and the widespread availability of WLAN capable mobile devices, the case looks much stronger."

Further integration of WLAN into the mobile network mix is one of the vital stepping stones to 4G. The so-called access pyramid model, where multiple networks coexist allowing users to seamlessly switch between the most appropriate network for the device and situation, will not substitute the need for a 4G network. At the heart of everything will be the core network, be it 3G or 4G, which will be supplemented by PAN and WLAN offerings and by network upgrades in the medium-term.