[Excellent article on integration of 3G, LTE, Wifi and land lines i.e.- 5G networking.
The only thing missing is this article is the 5th “G” – green networking. With so much overlapping coverage from the different wireless and wired nodes you don’t need five nines reliability for each node. Individual nodes can therefore be powered with small solar panels and micro wind mills. This is also great opportunity for R&E networks to partner with carriers like Vodafone and others who are building integrated Wifi/LTE networks and use Eduroam to extend reach of their networks for personal health research applications, sensor networks built around smart phone etc. For more details please see http://goo.gl/W9mla and http://goo.gl/a1Lpz – BSA]
21st Century Triple Networks: Ubiquitous 4G, WiFi, & Wires
The best engineers on the planet are coming to the same conclusion: a hybrid 4G/WiFi/landline network is the way to meet mobile demand. Folks like John Donovan of AT&T and Masayoshi Son of Softbank in Japan had this vision around 2007-2008. As the iPhone/iPad/Android made the coming demand clear, networks planners around the world evolved similar strategies.
• 4G gives wide coverage but is limited in capacity.
• WiFi actually provides far more capacity, because the range of perhaps 100 meters means the spectrum can be reused thousands of times in a major city. (China Mobile is putting 20,000 WiFi hotspots across Beijing.) A network builder tells me "WiFi is a solution to off load 'portable' traffic where possible and rely on 3G/4G for 'mobile' traffic." Femtos and perhaps small cells will play a significant part.
• Landlines effectively have 10x the capacity of a similar wireless network and are already ubiquitous from both telco and cable. A top engineer tells me "The general rule is the quicker you can get the byte of information onto a hard facility (copper, fiber) the cheaper it is to operate the network." Randall Stephenson of AT&T explains "You're always going to have to have a fixed line capability to offload this traffic."
So cell tower 3G/4G ideally is supplemented with local WiFi/femto. Cell towers cover large areas, allowing comprehensive coverage except for a few dead spots. They offer limited bandwidth over that entire area, with a network like Verizon's LTE offering perhaps 35 megabits to share. WiFi is much lower power, limiting range to a typical 100 meters or so, less with obstructions. Within that range, the capacity is high; 3x3 MIMO 802.11N can carry 100's of megabits in a small area. Locally, 802.11 uses spectrum more efficiently, incorporated a limited set of "spread-spectrum" type features.
WiFi was in few phones two years ago because it ran down batteries too quickly and cost too much. Moore's Law now enables low power, low cost WiFi. The latest chips from RALINK/Trendchip, for example, cost less than $5. Off mode power consumption is 0.012 mw, transmit power is 19dBm, and the chips are 5 to 7 mm square. Easily 3/4ths of the phones sold by a carrier like Verizon will soon have WiFi as do just about all tablets. As Qualcomm, Broadcom and others include WiFi on their primary cellphones chips it will become ubiquitous.
Carriers are choosing different strategies to get from where they are today to triple networks. Vodafone, Europe's largest wireless company, is adding millions of DSL customers through unbundling and giving them femto+WiFi gateways. Sky in Britain is buying a WiFi network named "The Cloud." Free.fr enables WiFi on their millions of DSL connections and bought a wireless license. AT&T is putting WiFi hotspots from Times Square NY to San Francisco with expansion plans. China Mobile is adding 1,000,000 hotspots.
Green Internet Consultant. Practical solutions to reducing GHG emissions such as free broadband and electric highways. http://green-broadband.blogspot.com/