WiFi is preparing to ride the unlicensed 900 MHz band, reports EE Times. Chips for the upcoming IEEE 802.11ah standard are expected to hit the market starting in 2015. They will have to compete with numerous other protocols for home and building automation in the unlicensed 900 MHz band, including Zigbee and Z-wave.
The 802.11 standard is the most broadly used form of wireless local-area networking. IEEE has already developed a 1 Gbps standard for 5 GHz (IEEE 802.11ac) and a 7 Gbps standard for the 60 GHz band (802.11ad). Those compete against other protocols for home video connectivity.
While 2.4 GHz WiFi commonly uses a total of three 20 MHz channels (in the available 85 MHz of spectrum), the 802.11ah standard uses a more restricted 902-928 MHz band (in the United States).
The new 802.11ah standard allows twenty-six 1MHz channels or thirteen 2MHz channels. In Japan, the available band is within 916.5-927.5 MHz, with eleven 1MHz channels. In China the available band will be within 755-787 MHz, with thirty-two 1 MHz channels.
EE Times says the spec aims to support a range of options from throughput of 150 Kbits/s with a 1 MHz band to as much as 40 Mbits/s over an 8 MHz band. Distances supported could be about 50 percent longer than those of the streamlined 802.11n products now targeting the sector with throughput up to 72 Mbits/s.
The main use of 802.11ah is expected to be sensor networking. It will not use the TV white space bands (54-698 MHz in the US), which are instead targeted by the IEEE 802.11af standard.
A first vote on
A first vote onthe 802.11ah standard could come as early as the end of September, says EE Times, although a final standard is not expected until January 2016. That makes 2014 the time frame for development of new silicon for end nodes and access points.
A host of companies have been working on the .11ah spec led by a Qualcomm engineer who chairs the group. Other participants come from companies including Broadcom, Huawei, Intel, LG, Marvell, NEC, Samsung, and ZTE.
The PHY transmission in IEEE 802.11ah is an OFDM waveform consisting of a total of 64 tones/sub-carriers which are spaced by 31.25 kHz. The modulations supported include BPSK, QPSK and 16 to 256 QAM. It will support multi user MIMO and single user beam forming.
As many as a dozen 900 MHz protocols are now crowded into the space of building and home control networks. “That’s the biggest problem — you need separate hubs or base stations for each of them, and that means extra costs, and if you add IP to these devices there are more costs,” according to Adam Lapede, a senior director of product management at Qualcomm Atheros.
The .11ah standard is expected to deliver up to 10-20 Mbits/s around the home. It will also help WiFi vendors extend into large building networks supporting up to 8,000 connections.
In another interesting wrinkle, Amazon plans to test terrestrial low-power service (TLPS) which would use both the upper 2.4 GHz unlicensed band and Globalstar’s terrestrial-use spectrum (2473-2495 MHz). The idea is to take the upper 2.4 GHz unlicensed band that isn’t now available for Wi-Fi, and combine it Globalstar’s terrestrial-use spectrum, creating a new service operating on 2473-2495 MHz.
Engineer Steve Crowley says they apparently plan to use 50 Linksys WRT54GL access points, 10 Ubiquity UniFi access points, 10 Ubiquity XR2 client cards, and 10 Ubiquity SR-71-12 client cards.
Meanwhile, Google plans an experimental license to use the 2524-2546 MHz and 2567-2625 MHz bands. Those frequencies are owned by Clearwire, a company that Google had invested in until last year. That’s a lot of unpaired bandwidth (40 MHz & 58 MHz) respectively.
Google is also taking over the Starbucks Wi-Fi network from AT&T, while nationwide cable Wi-Fi networks are linking up as well, using Hotspot 2.0 for seamless roaming between systems.
Free Mobile, a French carrier, has built a mobile network using Wi-Fi hotspots provided by its wireline broadband subscribers, and has proven to be a success.
Carriers and cellular will become the mortar while Wi-Fi will be the bricks“,” said David Morken, CEO of Bandwidth.com, which owns Republic Wireless, a Wi-Fi-based phone network.
Anyfi wants to turn any Wi-Fi access point into a virtual extension of mobile networks. The Swedish startup has raised $1.5 million to enable the construction of large Wi-Fi networks that would allow operators to easily build hybrid cellular-Wi-Fi networks like the ones deployed by France’s Free Mobile and by Japan’s Softbank.
Amazon, Google, Facebook and Microsoft may be angling for spectrum. Combining higher frequencies (2.4-2.6 GHz) with lower frequencies (600 MHz-900 MHz) might be one strategy to deliver always on connectivity. It could also be useful for M2M devices like watches and headgear that don’t require high speed connectivity.
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