However, while 4G is viewed by many as a communications technology that will allow one device to roam seamlessly over several different wireless technologies, arguments over the fine detail of what constitutes 4G continue to rage. Jason Ross, senior analyst at AMR interactive, told ZDNet Australia, "everyone was arguing about what 3G is for a while, and you've still got people trying to muddy the waters." However, he said there were a couple of key elements which are required to deliver a legitimate 4G network. First is the ability to roam across different network standards with the one device. "If you've got a mobile phone that's got wireless LAN connectivity, and it's got GSM connectivity, and it's got 3G or 4G connectivity and a Bluetooth capability as well, then you start to see some really interesting things happen," said Ross. The mobile phone (or whichever device is being used) could be programmed to automatically and seamlessly switch to whichever network was the most appropriate, saving the bill payer a lot of money. "There are a lot of problems with that at the moment," adds Ross as a qualifier. "The main problem is the chipset for connecting to those different kinds of frequencies, different channels, are all expensive in their own right -- they're either expensive or they're energy hungry." He pointed out that wireless LAN is very energy hungry, which is why it doesn't work well on laptops. It will have even bigger problems on the smaller mobile phone handsets, with their correspondingly smaller batteries. "History tells us that someone will figure out a way to make it operate without using too much power," said Ross. "It's a question really of when that's going to happen, and they're talking not the next generation but the generation after that of Wi-Fi being much more energy efficient than the current iteration, and therefore it might be useful for that sort of thing." He estimated the technology would be ready around 2008-2010. In addition to the energy problem is the space that would be required to house a Bluetooth chip, a century node or wireless LAN chip, together with GSM capabilities inside a mobile, which would make the handset big and expensive. "Now the way out of that, which is a blue sky solution at the moment but is again being worked on at the moment in various places round the world, is what they call wireless radio," explained Ross. This would involve all the relevant technologies being programmed onto a software configurable chipset, which can reconfigure itself by the moment for each call. The chipset will use one aerial, which after all is just a piece of wire. The second, and most obvious, element of 4G is a higher level of bandwidth. Figures of 100Mbps have been tossed around, but a more reasonable figure to expect is about 20Mbps. This increase in speed will be achieved in two main ways, according to Ross. First, the network will be completely packet-switched, whereas 3G networks have a combination of packet switching and circuit switching, as well as some analogue components. "So [4G] is much more like an IP network, much more efficient [than 3G], and everything is digital in the network," said Ross. The digital aspect of the network will be enhanced with the introduction of time division duplex (TDD), which will allow mobile phone calls to operate on the one frequency. "What we're using at the moment is frequency division duplex -- so when you turn on your mobile phone and talk to someone it sends information on one frequency and it receives the information on another frequency," said Ross. "You can't do it on the same frequency because they haven't really figured out a way yet of allowing you to occupy the same frequency without having elements of the packet interfere with each other...there is interference and static which makes it impossible." He said the industry is trying to remove the interference and send alternate packets on the one frequency, with upstream and downstream packets using the same wavelength. This is a more efficient use of bandwidth, according to Ross. The questions engaging most observers at the moment are just how big is the 4G market going to be, and when can the industry be reasonably expected to invest in a new network after the immense costs dished out recently to kick start 3G -- most of which came in leasing bandwidth from the government. When NewLogic Technologies opened a 4G design centre earlier this year, it estimated that 4G IP-based high-speed mobile systems would account for 14 percent of total mobile data revenues and have 50 million subscribers by the end of 2007. Nokia and Samsung have teamed up to create 4G wireless equipment, a move which not only demonstrates support of the 4G concept, but perhaps an acknowledgement from Nokia that CDMA networks will pose a bigger threat to its native GSM networks in 3G and 4G than in recent mobile systems. Despite all the bustling behind the industry scenes, no telco has admitted to plans to deploy a 4G network.