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802.11 vs. 3G For Mobile Access
bobdole34 writes: "A new way to give us fast mobile net access spells further trouble for 3G.Imagine being able to surf the net at speeds faster than DSL from anywhere, at any time - you could watch a live video webcast while waiting for the bus, email photos to your friends while sitting in the park, or download the MP3 of the song that's playing in the pub before it finishes. I smelled vapour until I saw a demo of MeshNetworks at 802.11Planet in Philly."
Connecting things in a mesh is all good and well and certinaly more efficient - but is it efficient enough?
:)
Wireless networking occupies a relatively narrow band of the frequency spectrum, and probably less than the 3G ranges offered to telcos.
I highly doubt that an 802.11 mesh will ever provide that much bandwidth - especially once things start relaying in many directions at once.
Imagine splitting it up into cells, each one where a user is. As something transmits from one cell to the next, it'll use bandwidth (or available frequency space) in the neighbouring cells.
Anyway this could work for dense areas but screws over the people living in the country - worse still, it's not dependable. What if you need to make an emergency call and nobody is within range?
I heard nokia were wokring on a hybrid tech that allows you to use mesh networks when they are around and 3G otherwise - that would be cool
Also i could raise the usual problems of accounting for bandwidth use on this kind of net - who pays for it all?
This article, at UltraWideband Planet suggest that 802.11 is doomed. Perhaps most interestingly, the Ultrawideband site is from the same people that offer 802.11-Planet, Internet.com.
Yes yes. What you saw was a step up from vaporware, commonly referred to as a "dog and pony show".
All editorial writers ever do is come down from the hill after the battle is over and shoot the wounded.
Power.
Think about it. You plug a wifi card into your laptop and start surfing. Battery life cuts from 4 hours to 2.
This study examines current 802.11a solutions... chances are there will be some improvements, but it averages 100 microwatts/sec regardless of whether it's in use or not.
OTOH, 3G phones (with their tiny ickle bodies and tiny ickle batteries) consume power at 25 microwatts in TX/RX, and only 1 in idle mode.
This article talks about how 3G power is a challenge for handset manufacturers even now, designing for 3G. You think your phone is gonna be able to cope with 802.11a? You're wrong.
3G and WiFi are both cool. But they are different.
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Your Cisco teacher was referring to fully meshed networks and she was correct. Fully meshed networks, typically based on point-to-point or frame-relay connections such as those that would be used in corporate environments, do not scale well. They very rapidly become far too cumbersome and expensive to maintain due to the fact that these types of networks grow exponentially.
This 802.11 solution would not be a fully meshed network but, rather a series of partially meshed networks which would make them smaller and more manageable. Furthermore, these networks would have the ability to develop new interconnections automatically and dynamically so the management aspect would not be an issue. Also, due to the use of wireless for these connections, rather than physical connections used by point-to-point and frame-relay, cost would not be nearly as big an issue.
In other words, your teacher was correct but, those rules do not apply in this scenario.
this clip is from Business 2.0:
<clip> Ultimately, however, 3G and Wi-Fi should be able to coexist. "The technology is actually very complimentary, because they are not truly competitive technologies," King says. "I expect that mobile carriers will purchase some Wi-Fi providers, and we'll start to see some integration." </clip>
Ok, first you gotta realise that 802.11b (even) by access standards is fast!
With a contention ratio of 50, and giving each user 576K you get:
11,000,000 / 576000 * 50 = 954 users
That's on a single connection, within say 100m of some user.
So even 11b can allow enormous numbers of people 'broadband' capabilities.
Secondly, that's with current technology only- a more advanced technology would allow multiple networks on the same frequency by using directional aerials- this can multiply up the usage maybe 20 times. Then there's the fact that even 11b allows atleast 3 different channels (in practice). We're talking thousands of people, potentially,in little old 1b land alone.
Anyway this could work for dense areas but screws over the people living in the country - worse still, it's not dependable.
Yes, this is the issue. WiFi is basically line of sight, or 100m range. However that's a regulatory issue, mostly. The only reason that WiFi is so restricted is due to power limits. If the users were allowed to shout louder, they would be able to go further, and then country people would be in range of each other anyway (chances are).
What if you need to make an emergency call and nobody is within range?
Cell phone? Who says WiFi is for emergency calls anyway?
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"1. The Telcos start whining to their regulators that they are being deprived of revenue, as point-to-point trunk calls lessen for 802-based communications.
2. The wireless carriers (who still haven't found a stable, profitable business model -- i thought PacBell Wireless was bad -- until Cingular bought 'em) will join in with the trunk owners and scream that their FCC franchise is being devalued by Wireless IP Data and IP Telephony and they need government help (read: R-E-G-U-L-A-T-I-O-N) right now.
3. The Consumer Giants will whine and bitch and snivel about interference issues with 2.5 and 5 GHZ devices they make.
4. The law enforcement/intelligence community will endlessly bitch about their lack of ability to "monitor" this dangerous new technology, and how this creates a national security vulnerablity and therefore, offers a "window of opportunity" to evil-dewars. They will insist on lousy/key crypto and 1.5 bit key algorithms, and their ability to "oversee" the security of this spectrum.
4. The G, sensing the increased value of this spectrum and their ability to make even more money in licence fees and regulatory overhead will further regulate the spectrum and cause more and more expense to be made to justify their jobs and administration and regulation of it.
no wonder i don't sleep much.....
Ten quid, she's so easy to blind. And not a word is spoken...
Also, is a collection of links on mobile routing protocols, and mesh routing protocols that were originally designed for wired backbone links.
"A new way to give us fast mobile net access spells further trouble for 3G.Imagine being able to surf the net at speeds faster than DSL from anywhere, at any time"
I could imagine that, except I can't get DSL out here, and likely won't be able to at least until the end of the decade. I'm assuming you mean by very limited definitions of "anywhere." More like "anywhere you would care to be."
"you could watch a live video webcast while waiting for the bus,"
"Bus" = "Public transport" = "population density" = "not me."
"email photos to your friends while sitting in the park,"
"Park?" Another one of those things that suggests population density. See, out here we have these things called "back yards"...
"I smelled vapour until I saw a demo of MeshNetworks at 802.11Planet in Philly."
802.11 is a wireless LAN technology. Do I need to remind you what the "L" in "LAN" stands for? Rigging up local transceivers for a single building is a heck of a lot simpler (and cheaper) than an entire city. And that's only for you folks that live in cities (read "for those of you that matter" as far as just about everybody seems to be concerned, even on here).
On the other hand, 3G is essentially a WAN technology, with its much wider tranceiving radius. It may be a cold day in Hell before BellSouth gets off their good-for-nothing behinds to upgrade the local switches for DSL (let alone somebody setting up 802.11 WAPs every few hundred feet along US 90... not that I live close enough to 90 to begin with...), I at least have some access to Sprint's network out here.
I'm sorry, but trying to say that 802.11 can and will compete with G3 is like saying that Gigabit Ethernet is going to edge out the T-3 market.
Oh, and before somebody brings up how Canada has DSL "everywhere" with their larger land mass and smaller population, ever wonder why the United States seems to have twice as many meters of paved highways per person than Canada? Maybe because the Canadian population isn't as dispersed as the American population?
The Mesh Networks Inc protocols are proprietary.
e r.ht ml.
.11 power management is to put the radio in sleep mode (and run the sleep protocol with the AP). This has not been a competitive focal point, but vendors are starting to improve.
.11 radios that are just starting to hit retail channels can operate on both the 11b and 11a bands and with both the 11b and a/g OFDM codecs. The prices for 11a nic cards is under $100 now (79?) and the a/b/g nic cards won't be far behind.
They are a byproduct of military-funded tactical
radio R&D. There is an emphasis onself-organizing topology and route discovery. If every soldier and vehicle is lugging a radio, then the network
has a good chance of continuing to operate even if parts of it are destroyed.
This kind of mesh does have some pathology.Take some number, say 10, of nodes placed in a straight
line. You are at one end of the line and the internet ISP is at the other end. And you have
10 wireless hops between you and the internet. And the people in the middle of the line may not be really happy with you either.
There are non-proprietary approches. Check out the ietf MANET working group at
http://www.ietf.org.html.charters/manet-chart
There are numerous university projects. Try Google(mesh network & university)
or Google(mobile network & university).
There have been numerous failed startup company attempts at mesh networks. One approach that I found very appealing used a self-organizing mesh
that organized itself into rooted tree structures.
The internal tree branches served as backhaul connections to the internet. The leaves represent the clients/users. The internal nodes are not mobile. They are devices to be installed on utility poles or public access locations. They find one another and create an uplink/downlink
infrastructure where uplink means a path to the ISP or other wired infrastructure and downlink
means to the client. I liked this approach because it builds a predictible structure that
can be analyzed and because the routing procedures
within the internal nodes are a lot simpler
than in the completely unconstrained mesh network.
The tree-like organization also seems to avoid
another conceptual problem with the fully
unconstrained network which is bandwidth sharing.
If you are a client in a full mesh, your node
must accept routing traffic from other nodes.
Thus a goodish portion of your bandwidth and battery power may be consumed by traffic going
through your client - but it's not your traffic.
I'd guess that most people would not want to act
as a router and be draining power pretty much
fulltime. Makes more sense to have a wireless
self-organizing infrastructure that can provide
bandwidth to clients that cruise within range.
There were a few misleading comments about power
in earlier emails. Cell phones typical draw
about 2 watts when transmitting. That exceeds
the current capacity of the battery. They actually charge a capacitor from the battery between time slots and drain the capacitor during transmission. 802.11 devices have lower peak current drains, and they continue to get better. The most important technique in
Next-generation
I think it is important to point out that 11b only has 3 channels to operate in. That doesn't give you much routing diversity when you need a lot of overlapping transmitters to create a useful (and thus redundant) mesh. But when you add 11a and can use the higher bandwidth ofdm codec in either the 11a bands or in the 11b bands (where they call it 11g), then you have more than a dozen channels that can be operating simultaneously. It seems obvious to me that this kind of channel diversity will be needed to successfully deploy a good mesh.