World's Longest Wi-Fi Connection

axonis writes "The Swedish Space Corporation (SSC) announced today that they have transmitted information via a broadband wireless link over a distance of 310km. They believe that this is the longest distance achieved using wireless connectivity. Alvarion (BreezeCom) is also the original consultant to Ericsson for BlueTooth technology"

Developing Countries

[locarecords.com]

This technology could be a massive boon to poor developing countries in trying to provide technology services and the Internet around their countries. Combined with the cheap 'n dirty homemade wireless links this technology has a *lot* of potential for cheap (or free) Internet access...

Re:Swedes are cheaters

[tigress]

Actually, in Sweden, you're limited to 100 milliwatts on the 2.4GHz band, unless you have a special permit.

Article, in case of /. effect

[Anonymous Coward]

World's Longest Wi-Fi Connection Made by The Swedish Space Corporation Wireless broadband connectivity achieved over 310km using equipment from Alvarion The Swedish Space Corporation (SSC) announced today that they have transmitted information via a broadband wireless link over a distance of 310km. They believe that this is the longest distance achieved using wireless connectivity.

The link was made between a stratospheric balloon that was launched from Esrange near the town of Kiruna in northern Sweden and a base station located near Esrange.

Onboard the balloon was an antenna supplied by Alvarion, the world's most successful provider of broadband wireless products. The antenna was connected to a high-power amplifier with 6 watts power output, a camera and a server. Data, such as environmental conditions and weather patterns, was collected and the information was sent back to Esrange via an Alvarion base station which measured 2.4 meters with 6 watt power output and automatic tracking of the antenna using GPS technology.

Information received at the base station was then sent back to Esrange via the internal network. The information between the balloon and the base station was transmitted over the 2.4GHz spectrum (2480 Mhz which the SSC is allowed to use with higher ERP) with a stable signal strength of -68 dBm.

The round trip ping response at 300Km was 300-500 mSec.

The weather balloon reached a maxium height of 29.7 km and drifted steadily. It finally touched down east of Sodankylä in the northern part of Finland, having travelled approximately 315 Km.

Lars-Olov Jonsson, System engineer RF and microwave, at SSC Esrange commented: "This is an amazing technical achievement, the difficulty of which should not be underestimated. Alvarion has developed extremely robust equipment capable of operating in a very harsh environment. Its technology has helped us save money, time and energy."

Zvi Slonimsky, CEO of Alvarion, said: "Time and time again, wireless is proving to be a genuine option in the broadband arena for enterprises, incumbent and alternative operators looking for alternatives to fibre and satellite to be continued."

About the Swedish Space Corporation
The Swedish Space Corporation is a state-owned, commercial company with about 300 employees at its locations in Solna (near Stockholm) and Kiruna. SSC operates the Esrange facility outside Kiruna for rocket and balloon launches for scientists from the whole world. SSC also operates one of the world's busiest satellite ground stations at Esrange, supporting a growing number of satellites. In Solna, SSC develops state-of-the-art satellites, space vehicle subsystems, payloads for rockets as well as airborne systems for maritime surveillance. These products are sold on the international market. Swedish Space Corporation owns fifty percent of Nordic Satellite AB, which distributes television and offers other telecommunication services on its geostationary Sirius satellites.

About Alvarion
Alvarion is a premier provider of solutions based on Point-to-Multipoint (PMP) Broadband Wireless Access (BWA) used by telecom carriers, service providers, and enterprises worldwide. Alvarion systems provide Internet access and voice and data services in the last mile, cellular network feeding, building-to-building and wireless local area network (LAN) connectivity.

Alvarion offers the broadest range of BWA solutions by market segment and frequency band, designed to address all carriers' and service providers' business models. With its combined market experience, strong customer base, diversified distribution channels and field-proven deployments, Alvarion is a leading BWA pure play provider for every end user profile, from residential subscribers to business customers.

This press release contains forward-looking statements that are subject to risks and uncertainties. Factors that could cause actual results to differ materially from these forward-looking statements include, but are not limited to, general business conditions in the industry, changes in demand for products, the timing and cancellation of orders and other risks detailed from time to time in Alvarion's filing with the Securities and Exchange Commission, including Alvarion's Form F-1.

Re:6 Watts!?

[MarkTina]

I guess they didn't want to effect anyone else who might be in the covered area. People get narky when their equipment gets interference.

Regards

Mark

Re:Developing Countries

[hcdejong]

This technology may be cheaper than laying 300 km of cable, but it isn't exactly free. The receiving end used a 2.4 m dish with a tracking system, and I expect the receiver was of a rather higher grade than the one in an 802.11 card as well.

Basically, all they have done is show that 802.11 (I assume) communication via satellites (balloons, high-altitude UAVs, whatever) is feasible. Other than the protocol used, that's no big deal.

Re:Swedes are cheaters

[Albinoman]

So basically what youre saying theyre developed this great long range connection that has no purpose for civilians.

Re:6 Watts!?

[klaasvakie]

The moment you transmit high watts wirelessly it becomes potentially dangerous. I don't know on what frequencies the above link operates,but if it is 1-2GHz then it could probably be used as a (slow/small/low power) microwave oven if you would push the watts to say 500W or above. The FCC will prohibit you from transmitting signals with energy more than a few watts. For a comparison, the radio transmitter on the Pathfinder mars probe was 4 watts. amazing eh?

Re:Power 101

[EmagGeek]

This isn't true. The limit is based on your Effective Isotropic Radiated Power, or EIRP. This is formulated by the combination of your output amplifier and your antenna. To get your EIRP, simply add the output power of your amplifier, expressed in dBm (dB referred to 1 milliwatt), to the gain of your antenna, expressed in dB.

So, if you have a transmitter with an output power of +14dBm, and an antenna with a gain of 18dB, then you have an EIRP of 14+18 = 32dBm, which is almost 2 watts.

If you have a transmitter with an output power of 14dBm, an amplifier with a gain of +10dB, and an antenna with a gain of +15dB, then you end up with an EIRP of 14+10+15 = 39dBm. So, in extremely simplified terms, you simply add up all the dB's to get your EIRP.

To convert your EIRP into a "wattage" number, you divide your dBm by 10, and then raise 10 to that number. So, if you have 36dBm, you would do 10**3.6, which is 3.981 Watts.

Some useful things to remember is that adding 10dB is the same as multiplying the output power by a factor of 10. Adding 3dB is the same as doubling your output power. Likewise, subtracting 3dB is halving and subtracting 10dB is decimating.

There are two limits, one for point to multipoint and the other for point to point links. For the former, you're allowed up to 36dBm EIRP, which is to say, 36dB over 1 milliwatt, which is 4 Watts EIRP. For the latter, you're allowed 48dBm, which is just a tiny bit over 50 Watts (50.118).

Re:Bollocks - play on words and terms

[GoRK]

I dont know if this article clarifies it, but the Alvarion equipment used was 802.11 FHSS running at 1 megabit in the 2.4GHz frequencies known as the ISM band here in the US, just like most of their other WLAN stuff. It was not packet radio. They do produce radios in other bands that operate with the exact same technology - ie they would be 802.11 compatible if not for the frequency. The only thing they did that you couldn't do here in the US is use such a high power output on the 2.4 frequencies. (And of course, FCC approval of your amp/antenna system) You could; however, duplicate this sort of work on the 2.5GHz band with Alavarion equipment and an appropriate MMDS license.

~GoRK

Not Wi-Fi, and so what at those power levels

[eggboard]

Wi-Fi is specifically a certified version of 802.11a or 802.11b or both. Not a generic term. It's confusing when used generically.

What's being discussed here is spread-spectrum frequency hopping or direct sequence -- probably FHSS not DSSS. It should be called by its right name as this is Slashdot, after all!

With 6 watts of output power, you could send 802.11b quite far as well using off-the-shelf equipment. This achievement is only remarkable because of the components involved (balloons, etc.), not because of the distance.

Because of the curvature of the earth, you have maximum distances without building huge towers that are only in the tens of miles, even with curving of the 2.4 GHz waves around the globe. The small wavelength means you don't get an enormous bending effect.

If you beam from the earth straight up, you have longer possible distances.