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Centrino Draft N Support

As I mentioned at the beginning of this feature, one of the key benefits of the original Centrino platform was integrated Wi-Fi. The original Centrino utilised 802.11b with a maximum theoretical bandwidth of 11mbps, while the second generation Centrino platform, codenamed Sonoma, implemented 802.11g with a maximum theoretical bandwidth of 54mbps. Santa Rosa moves the wireless game on once more by utilising the Draft 802.11n standard, which offers a theoretical maximum bandwidth of 300mbps!

Anyone who’s been watching the ratification process of 802.11n will be well aware that the process has taken an inordinately long time to come to a conclusion, and even now we have no officially ratified standard. I’m hoping that the fact the Intel has implemented the current Draft N standard into its next generation Centrino platform will push through the ratification and allow 802.11n to become a set standard. It’s worth noting that the original specification for 802.11n stipulated a maximum theoretical bandwidth of 540mbps, or exactly ten times the speed of 802.11g. But pretty much all of the Draft N kit on the market today states 300mbps, and even then, actual real world performance comes nowhere near the theoretical maximum.
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Santa Rosa will ship with Intel’s new Wireless Wi-Fi Link 4965AGN card, which as the name suggests, will support 802.11a, g and n. The Draft N standard makes use of MIMO (Multiple Input Multiple Output) technology, where multiple data streams are sent concurrently to improve throughput. MIMO requires a minimum of two antennae, but performs optimally with three. Despite this, notebook manufacturers will only be required to have two antennae to achieve Centrino certification. So, if you’re concerned with Wi-Fi performance, you better check the number of antennae before you purchase a new laptop.
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Channel bonding is also employed to allow twice the amount of data to be sent. Channel bonding has been common place in the wired networking world for some time, where two Ethernet adapters are employed to send twice the amount of data. A similar system has been used for DSL installations in areas where high bandwidth single line connections aren’t available – two DSL lines are channel bonded to create say, a 2mbps link in an area where only 1mbps is achievable through a single line.
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Meanwhile Payload Optimisation allows for more data to be delivered per transfer, with the network overhead becoming far less significant. One of the key benefits that the Draft N standard will bring is the ability to stream video wirelessly. Of course there are lots of wireless digital media adapters out there now, based on 802.11g, but it really isn’t fast enough to ensure smooth playback of high quality video – Draft N should solve this problem.
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However, encouraging as Intel’s inclusion of 802.11n technology in Santa Rosa is, the theoretical performance is unlikely to reflect the real world performance. Our experience of Draft N hardware shows a real world maximum throughput of around 70mbps, which is still way higher than what 802.11g can offer, but clearly a long way from 300mbps. On thing’s for sure though, the MIMO technology does allow for better wireless range, especially in Europe where houses are built from solid brick walls, rather than wood and paper. Another major plus point for the new Wi-Fi adapter is that Intel assured me that it uses 90 per cent less power than the outgoing module.

Expect Draft N products to start carrying “Centrino Compatible” branding soon after Santa Rosa launches in May, with most of the networking community already working with Intel.
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