2.4 Megabit Cellular Modem 176
lew writes: "Ars has a review of a cellular modem that provides 2.4 megabits / second downsteam and 153 kilobits / second upsteam... and it works! Check it out" How much for unmetered service on such a system? :)
check monet wireless for service with this card (Score:4, Informative)
Here [cdg.org] is more info on the 1xEV-DO network.
Re: Metered service (Score:4, Informative)
I miss Ricochet. I ended up moving into an area where they offered service -- 6 months too late. (Dammit.) They were the only ones offering flat-rate service, although only at 128-256 Kbit. Yes, I know they're trying to re-light the network, but that's not happening up here -- at the last I'd heard.
1. THIS WAS A SERVICE TEST. They set up a few cell towers just for this engineering test.
2. Fat chance any cell provider will give you an all-you-can-eat plan! That's for businesses, you don't need that! You're just a consumer so take our advertising and consume!
Feh.
I've become so cynical regarding cellphone companies and their greed that I can easily see them crippling this service to the point where it's no fun for any of us. I expect:
Re:that's PER CELL (Score:5, Informative)
Try reading the entire article. Page 3 [arstechnica.com], near the bottom, does a nice job of explaining this, and why it's not such a big deal:
Re:that's PER CELL (Score:2, Informative)
Re:that's PER CELL (Score:4, Informative)
Re:Slow transmissions. (Score:5, Informative)
Collisions. Same reason your upstream is often capped on a cable modem. On shared media you will get a lot of collisions from the individuals on the network as they choose to transmit at random times.
From the downstream perspective this is simple to control; you have one broadcast point, you simply queue things to be sent, and there are no collisions. On the upstream side, you need to know when someone else will be transmitting, and this is harder.
I imagine one way of doing this is to assign time slices to groups of people; you do not transmit unless it is your turn, and you compete with far fewer people (the others in your group). If you have 2.4Mbps available and you, say, divide this by 16 groups, you get a ~153Kbps window to transmit in (plus 9.6Kbps left over on the spectrum possibly for out of band housekeeping duties).
This is what is probably happening here.
Another options (and a long shot), but perhaps they are just plain mean (or not confident in their ability to control who uses their service) and want to discourage people from using the system to host anything. "Hey, our security is lousy, we know people will start stealing our wireless service to host copyrighted material/launch dos attacks from, maybe if we lock the bandwidth down at the tower this will not be attractive and the phreaks will go elsewhere".
umm, slight mirror since it's being slashdotted... (Score:3, Informative)
The System
The particular 3G technology under examination in this review is called 1xEV-DO, which is a CDMA (Code Division Multiple Access) technology developed by Qualcomm. Picking apart the acronym is instructive. If you ask an engineer, the "1x" stands for "single carrier," which means it operates in a single 1.25 MHz frequency band just like existing CDMA cellular systems. If you ask a marketing rep, "1x" means the "first phase" of the third-generation wireless systems, implying more good things to come. The "EV" is for "Evolution," meaning the technology is an outgrowth of the base 1x standard, functioning as an interim solution for high-speed data while waiting for the "3x" multi-carrier systems being standardized by the ITU. "DO" stands for Data Only (the marketing guy would say "Data Optimized"), meaning that the entire 1.25 MHz channel is dedicated to data traffic and not shared with voice calls. So the present system implements the data-only variety of the evolution of the first phase of the third generation of wireless cellular technology. Got it?
If acronym soup isn't your bag, simply "fast" will do. 1xEV transmits in the same frequency bands as existing cellular systems and uses similar radio-frequency transmission equipment (the cell sites you see popping up everywhere), but employs packet-switched connections and a new radio link protocol optimized for high data throughput. The maximum speed of 1xEV -- no drooling now -- is 2.4 Megabits per second on the download link and 153.6 kilobits per second on the upload link. As you're probably thinking, that kind of bandwidth is on par with broadband wired connections like cable or DSL -- and the system delivers.
I was given the opportunity to test out an engineering prototype of a 1xEV-DO wireless cellular modem called the HDR Hornet, developed by Qualcomm as a reference design for their 3G chipsets. HDR is short for High Data Rate, Qualcomm's internal name for 1xEV. Qualcomm just makes the chips and does not sell retail devices, so you will not see this modem on the market. What you will see is a plethora of devices incorporating Qualcomm chips, from cell phones to PDAs to PC Cards to notebooks and devices that have yet to be conceived. Of course, any cellular technology without an appropriate infrastructure is about as useful as a frozen brick; Qualcomm also develops chips and software for cellular base stations, and the HDR modem under review was provided as part of a small over-the-air field trial conducted by Qualcomm in conjunction with the University of California, San Diego. There were three 1xEV cell sites set up on top of Qualcomm and UCSD buildings in the La Jolla, California area for the purpose of stress-testing the system in real-world conditions. Free bandwidth, in range of the beach? One stress test coming up!
The Setup
The unit I was supplied with came in a plain white box and a static-proof bag, along with an AC adapter, a dongle to connect the modem to an Ethernet jack, a two-page quick-start guide, and four Velcro stickies to attach it to a laptop. The Hornet itself is something between the size of a DVD movie box and a VHS cassette, measuring 7 1/8" x 4 1/8" x 3/4" HWD (18 cm x 10.5 cm x 1.9 cm) and weighing about 3/4 lbs. (0.35 kg). As you can see, the unit has two 5 3/4" (14.6 cm) antennae that independently swivel up about 200 from alongside the unit, enabling diversity reception for a stronger signal. Keep in mind that this is an engineering prototype; you will probably not see retail devices with this form factor. PC Cards and PDA modules with the same chips inside will likely be the most popular paths to 3G in the near future.
The first thing that struck me about the Hornet is that it looks pretty darn smooth for an engineering reference design, no frills, but all the essentials: AC adapter plug, on/off switch, USB port on the bottom, Ethernet dongle on the right, and four status LEDs on top that wrap around to the back so as to be visible while the unit is stuck to your laptop lid.
Installation and set-up can't be any easier. Taking a cue from the quick-start guide, the process goes something like this:
1. Plug it in.
2. Turn it on.
3. You're good to go.
The unit I was supplied with interfaced via TCP/IP over standard 10 Mbit Ethernet. The Hornet has a built-in DHCP server that automatically serves up the correct TCP/IP settings to your laptop and acts as your default gateway to the network. The connection is "always on" and there is no special dial-up or logon procedure. Having connected this thing to a dozen different computers, I can say that setup was simply a non-issue and took at most two minutes.
USB connectivity was not implemented on the test unit I received, but I can't imagine it being any easier to use than the Ethernet connection. USB will probably be the interface found in most external devices for laptops; unfortunately, this means you are at the mercy of the manufacturer for driver support and you will probably have to install a CD full of video-mail-grandma-with-one-click software to make it work. On the other hand, TCP/IP over Ethernet is standard, well-understood, supported out of the box by every operating system, and already used for Internet connectivity by most laptops. An Ethernet-enabled wireless modem would be a drop-in replacement for a huge installed base of users, but USB + Plug-and-Pray is perceived as being easier for consumers. Go figure. I tested the Hornet through its Ethernet interface with desktops and laptops using a variety of Ethernet cards under Windows 95, 98, and Me, Windows NT4, 2000, and XP, MacOS 8, 9, and X, and Mandrake Linux 7.1 (kernel 2.2.17). All worked flawlessly. A big nod goes to Qualcomm for sticking with open systems and standards. We can only hope retail products will do the same.
Once the unit is connected up and turned on, it takes about five seconds to initialize and then begins searching for a connection. If you're in a covered area, the service light goes green and the receive and transmit lights flash as the fire-breathing modem awakes and stretches its muscles. After living with this unit for a while, the sight of those lights when service comes up is like the geek's version of a well-tuned big-bore Harley's guttural rumble.
Re:that's PER CELL (Score:2, Informative)
No way. If that were true, then Cingular Wireless would actually be USABLE in Los Angeles after 3PM. You're crazy if you think a cellular company is going to willingly spend money on infrastructure.
They will do so, but only when their level of service sinks far below what others provide. And since they are all fairly sucky, that can take a while.
In Los Angeles, Cingular is getting about to that point now. No one I know would ever sign up for Cingular because the service is so bad. Everyone jumps to a different provider as soon as their contract is up.
Re: Metered service (Score:2, Informative)
Not necessarily. Blue Kiwi [mybluekiwi.com] or Speak Zero [speakzero.com] offer flat rate LD to the continental US for $30-35 or so a month. All you can eat.
Re:Slow transmissions. (Score:4, Informative)
Also, that downstream transmitter can push more watts, hence has better signal-to-noise, hence can use more complex modulation techniques and get more bits per Hz of bandwidth. Given 1 MHz of bandwidth for each direction, a base station using 256-QAM modulation has a raw bit rate of 8 Mbps (then subtract out a bunch for forward error correction, framing, etc). The low-powered upstream transmitters may only be able to code at two bits per Hz, for a 2 Mbps total.
Re:Slow transmissions. (Score:3, Informative)
Why do all the new broadband technologies limit the upload to a very slow speed? 2.4Mbps is nice and all, but for it to be useful beyond surfing the web 153Kbps doesn't leave for much of anything else.
Collisions. Same reason your upstream is often capped on a cable modem. On shared media you will get a lot of collisions from the individuals on the network as they choose to transmit at random times.
Collisions can be managed by assigning time slots for the inbound direction. There'd be some reduction due to variation in turnaround time among customers sharing the bandwidth, but nothing like a 20:1 degradation. (And it can also be managed by smarter schedulers.) You have to do some of this anyhow.
But the upstream doesn't (or doesn't HAVE to) apply to non-shared services like DSL. There the bandwidth is divided between the upstream and downstream link - currently with a fixed ratio though in principle the modems COULD have dynamically adjusted it.
No, I believe the issue is that the network designers just built networks on the assumption that the customers were mainly browsing the web or pulling down content, rather than serving others. For such a content consumer you want the downstream to be as fat as you can afford, and the upstream to be adequate for TCP ACKs URL references, and keystrokes. Then they massively oversubscribed the (symmetrical) network link feeding the local node (DSLAM, cell, what-have-you) and let the users stat-mux themselves. When they have little competition (which, the carrier hopes, is most of the time) they can fill their fat personal downlink pipe to its capacity. They don't lose packets on the uplink (which would break them badly) beacuse they're throttled back so far that the network link doesn't saturate.
Users running servers break that model. They cost the ISP more to support because he can't oversubscribe the network link to such an extreme - or much at all - without degrading their service. Even with the throttle, a few users hosting servers on a DSLAM can start causing other users to lose upbound packets and see download degradation.
Re:No, it's not a big deal. (Score:2, Informative)
Besides, the radio eqipment is the same. I'm not sure how they do it, but I would assume that each radio site is connected back to some kind of central office with racks of routers and whatnot. You don't have to actually do much to each cell site. If anyone has more info on how it's actually connected and what needs to be upgraded, please comment.
Not very spectrally efficient... (Score:3, Informative)
ArrayComm licensed [eetimes.com] some spectrum in Australia, where they plan to roll out a wireless broadband service in the major cities in just 5 MHz of TDD spectrum. It looks like recent FCC rule changes [rcrnews.com] have made some national TDD spectrum licenses available in the U.S. as well
It uses IntelliCell [arraycomm.com] spatial processing and spatial channels to get multiple users on the same spectrum, at the same time. I've been lucky enough to see the i-BURST system in action, and it looks pretty cool, is real, and actually works. There are other smart antenna companies as well that are working on broadband data products, but I don't think any of them are as far along as ArrayComm.
Re:More of a nightmare (Score:3, Informative)
1. Caller ID.
2. Turn the damn thing off.
Not all sites use tri-sectored antennas. (Score:1, Informative)
Check out some panel antenna mfg. and review the beam patterns of Celwave, DB, Kathrein and Andrew.
Newer styles use electronic steering and downtilting to null fill "bad" geo-areas.
even Crunchcraft makes "commercial" antennas for 802.11b, as well as Maxrad, Comtelco, and Antenex(no panels, just omni and yagi for base apps).
Each sector is not added to "your" total throughput, as you can only be in one sector's coverage for "X" amount of time before you are handed off to a new cell/sector, unless you drive in 360s and grab only that one cellsite.
Mod an old Mot. bag phone, use it to scan active data channels, RSSI and you'll see reuse occur within that carrier's POP. Sectoring reduces interference from adjacent sites, that's why you never see the same channels being used within a 5 cell "pattern", and also, you'll not see the same LCR channel active within that grouping either.
We used a dead carrier aimed away from our service area in order to keep a competing carrier out of our coverage pattern, we null that sector, place the carrier there at 1/2 power and let it run, it's also used to keep our service out of the competition's pattern as well, since we both had "A" band licenses for that specific POP.
Sectoring coverage is a great method to strengthen your carrier power where it's needed, while minimizing the return loss due to in-band interference and IMD products(no cheap TTAs here!).(TTA-TowerTop Amplifiers).
Sectoring also keeps the TX power OUT of your RX system as well, sort of like a "separation filter" but not really, due to bandspread of the uplink/downlink frequencies used by cellsites.
We have very limited PCS coverage where I am located, and NO GSM, 3G or the like is going to arrive and take over because the dimwits here love football more, and "modern" technologies are too elusive for them to comprehend in the slightest.
I installed a pair of panel antennas in the Oshkosh, WI. area for a local carrier, simply because they needed the network built and fully operational the next day!
The equipment was already on site, we arived at 6:00 AM with all the necessary equipment and proceeded to spend the next 18 hours getting that microcell up and fully operational, what a pain in the ass that was! This "installation" was FULL, cabling, routing, cutting access holes UP in the signs, programming the site and initial testing one it was complete, not to mention drive-outs to test pattern/coverage.
If you ever get to Oshkosh, WI. stop in at the PLANEVIEW restaurant on Hwy. 41 and look towards the top of the sign, just below the highest sign, the outermost colum has a pair of Celwave 20dB panels mounted to it, facing down the coridor of the highway, that's my installation(it was supposed to be temporary, but no more, the coverage is too hot for them to have me take it down now)!