Next-generation networks

WiMAX technologies may be an important component of future converged or ubiquitous networks due to their reach and relatively high-speed wireless connectivity. WiMAX and competing longer-range technologies could certainly be one component of a multi-platform network that allowed users to have access to a seamless, always-on Internet connection. The implementation of WiMAX in a converged environment may be several years away but elements of converged networks have started to appear in OECD countries. Proponents claim the trend is likely to continue when mobile WiMAX devices appear on the market while sceptics are unsure of the impact of WiMAX in the future market.

The line between different types of broadband access networks is blurring with the introduction of services that work seamlessly across platforms. In Korea, KTs Nespot Swing service provides continuous data coverage as a subscriber moves between KTs Wi-Fi network ieNespotlr and the CDMA 2000.

In the United Kingdom, BTs Project Bluephone has plans to offer a phone that works as a cordless handset on a fixed line at home (via Bluetooth) and as a Global System for Mobile Communication (GSM) phone when out of range of the home connection. Operators have been working on developing seamless handoff technologies that work between disparate networks in order to make these kinds of services possible.

While network operators are working to seamlessly bridge together their fixed and wireless networks, application providers have already announced streamlined services that are platform independent. Skype, the IP telephony provider, currently builds client applications for use on a wide range of PC operating systems and portable devices. Skype users can currently make phone calls via desktops, laptops and pocket PCs.

However, Skype also plans to release a version of their software for Embedded Linux, Symbian or Windows Mobile devices later in 2005 48 . These versions could then be made available on mobile phones over a GPRS, 3G or Wi-Fi data connection. An example of this trend was the announcement by equipment manufacturer Motorola of an alliance with Skype in February 2005 to work towards integrating Skype functionality into Motorola products.

Both fixed and mobile WiMAX technologies may be important components of any converged network, although each will play a different role in the infrastructure of the network Fixed WiMAX technologies will provide similar connectivity to DSL and cable modem technologies, although DSL and cable will provide faster speeds in urban areas. In an economic sense, DSL and cable modem networks will likely be more cost effective per Mbit/s of connectivity where they are already in place.

Some claim that rural and remote areas stand to benefit the most from fixed WiMAX deployments and that holds true in a converged setting. Operators will maximise the efficiency and profitability of the next-generation network (NGN) by moving users to the most cost effective network that will support their current demands at any given moment. operators will likely attempt to connect users via wired connections when possible, given their better cost effectiveness per bit of data transferred.

When users require mobility, some believe that WiMAX will offer higher speeds and cost efficiencies per bit than 3G at all but the highest levels of mobility, while others believe that 3G will be able to accommodate those needs.

Converged networks will likely connect users via the least-cost bandwidth path that service their
usage demands. In rural areas without other broadband options, WiMAX-to-the-home connectivity will likely play the major role in providing irmultiplay services including voice, data and video. In urban environments the role of fixed-WiMAX will likely be more as backhaul for Wi-Fi and other WLAN technologies.

The role of mobile WiMAX technologies may be the most profound in urban areas because they
could fill a connectivity void between 3G data networks and Wi-Fi. 3G networks offer very high mobility but at low data speeds. Wi-Fi offers much higher speeds but in a nomadic setting within a range of 150 metres.

In a converged network, the mobile version of WiMAX may be the most efficient data connection for many users outdoors. 3Gs more limited bandwidth will likely make it the network of choice for users who, at any given moment, require high mobility. For example, users in trains or moving vehicles may only have access to data provided over traditional mobile networks. However, users moving at pedestrian speeds may be best served by mobile WiMAX connectivity.

DO network of KTs sister mobile network, KTF. Users are automatically shifted to the most efficient network via a process where devices first attempt to connect via Wi-Fi (at home or from a public hotspot), and if a signal is not available connect via 3G. Figure 5 shows how the same mobile devices will maintain connectivity either via Wi-Fi from KT or the CDMA 3G network from KTF.