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FCC Ponders Wireless 10GE Plan

3/3/2014 09:00 AM EST
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rick merritt
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What would you do with a wireless 10GE link?
rick merritt   3/3/2014 10:57:00 AM
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I'd love to hear about challenges delivering this technology and opportunities for using it.

y_sasaki
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Wireless 10GE
y_sasaki   3/3/2014 1:02:12 PM
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"10Gbps wireless" sounds fantastic, but you cannot expect it as faster alternative of microwave (2.4 or 5GHz) WiFi. Short wavelength milimeter radiomagnetic wave acts more like laser beam rather than radio wave. Practically it only can be use in clear line-of-sight (LOS) setup. Even though it is still possible to establish "over the bend" communication by using reflective multipass, it reduces (already short) practical range.

It will make sense to use milimeter wave for rather static, point-to-point wireless link (backhaul). Still it is questionable to me what application really exists for short-distance wireless link. Range will be less than 100ft (30m) even under ideal point-to-point, line-of-sight environment (estimated from 105GHz, 25dBm TxP, -70dBm RxS, 6dBi ANT gains). Practical distance may be about half.

Note that I could rather too skeptic about "Ultra highspeed, short distance" radio possibility, because of my experience on ill-fated UWB (Ultra Wide Band).

Bert22306
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Sounds like a misnomer
Bert22306   3/3/2014 4:46:40 PM
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What the article describes is a point-to-point link, at high rate. This isn't Ethernet. Ethernet implies multiple access, and the closest wireless equivalent that actually works is called WiFi (IEEE Standard 802.11, rather than 802.3).

Not sure why such a point-to-point link should be unusual, except maybe the high capacity. This can also be done with optical IR, laser, or other such.

matthelm
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Re: Wireless 10GE
matthelm   3/3/2014 5:04:35 PM
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With "flat ground" (no hills or buildings), even with only 5 meters of tower at each end, LOS is ~3K.   Add a real tower and you should have a ~40K or more LOS!   Or even better, one of the "blimp" based wireless systems.  This is not for mobile, it's for permanent/"temporary fixed" high speed connections.

 

BTW, you do know that LOS microwave has been used for long range point to point for over 60 years (started in the 1940s, and are 40-50 miles apart)???  It is MUCH less common now that they have fiber trunks between most major cities, but it is still used in some locations.

 

The systems you are comparing them to are all omnidirectional, and yes, have VERY limited range.  These would also be using a Parabolic reflector at each end, which normally have gains around 30-40db for a simple one.  (maybe be slightly lower to increase beam width, to help aiming)

 

matthelm
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Re: Sounds like a misnomer
matthelm   3/3/2014 5:16:21 PM
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Um, Ethernet at the phy layer is point to point.  That's why you have to have a switch (or hub) if you want more that 2 machines to talk to each other.  It's only at the higher levels that allow multi point and broadcast.

y_sasaki
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Re: Wireless 10GE
y_sasaki   3/3/2014 5:50:41 PM
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I agree with you that theoritically it can achieve siginificantly long range if it used with high-gain antenna (30-40dBi). My caliculation shows it can reach 12Km with 30dBi anntenas each ends. However I'm skeptic if such highly sensitive directional antenna (half-width beam angle is about 5deg) be practical for consumer product. How to connect radio to anntena will be a big issue. I don't think coax cable will work with 100GHz frequency.

Bert22306
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Re: Sounds like a misnomer
Bert22306   3/3/2014 6:25:14 PM
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Well, Ethernet defines both the PHY and MAC layers, and the PHY of Ethernet options, aside from 10BROAD36, is not designed for RF propagation. Yes, a new PHY layer can be developed, of course, but why pretend this has anything to do with Ethernet?

For point-to-point RF, optical, or laser links, you don't need to invoke Ethernet anything. Just define your p2p link, and send any kind of frame format over that link that your heart desires.

The point of invoking Ethernet in switched Ethernet networks is to make sure that the frames can be correctly switched throughout the network fabric, and also to ensure backward compatibility with older Ethernets that used collision detection and carrier sensing for muliple access. None of that is needed if all you want to do is create an RF or optical point to point link! For example, your IP over Ethernet connection MAY even involve a satellite link. Does IEEE 802.3 include anything about satellite comms? That part is transparent to "Ethernet."

rick merritt
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Beyond wireless GE
rick merritt   3/3/2014 8:39:08 PM
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Anyone familiar with the existing wireless GE pt-to-pt nets (for backup and backhaul I assume) and the potential for 10GE versions?

Bert22306
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Re: Beyond wireless GE
Bert22306   3/4/2014 2:16:45 PM
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Rick, not related to "wireless," but instead with respect to the opical links used, there is a reason why these new superfast Ethernets have been going hand in hand with SONET. Starting with 10 Gb/s metro Ethernet, they share the same fiber optic links as SONET. SONET got to 10 Gb/s and 40 Gb/s first, and then Ethernet said "me too." And used the same optical transceivers.

That's why I don't see anything credibly "Ethernet-specific" in any wireless variant.

krisi
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Re: Sounds like a misnomer
krisi   3/4/2014 4:37:04 PM
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I agree Bert...I am equally confused...also attenuation at 100 GHz is very high

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