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August 29, 2004
UMTS stands for Universal Mobile Telecommunications System. It's an evolution of GSM (internal link), previously TDMA based, now, with UMTS, CDMA. Why the change? Capacity, CDMA can process more calls than TDMA. There are other reasons, too, but none more important than permitting more calls. This is a wideband CDMA scheme, compared to the narrowband plan of cdma cdmaOne (internal link) that we discussed below. Next week I hope to explore more of this change with GSM.
August 27, 2004
Question and answers with Ken Schmidt and Mark van der Hoek
Q. I'm in a rural location next to an interstate highway with poor to non-existent cellular coverage. What if I put up my own cell tower? Would that get a wireless carrier interested in my property?
The cell phone tower itself is not the problem, it's your location. You'd need to be within 1/2 mile of the interstate to even be considered. But it is not just one tower or cell site the carrier would need to build, they'd need several to connect to their next, closest location. Traffic counts on most interstates just don't merit this construction expense. Ken.
Q. Okay, what if I build a tower to handle point to point microwave traffic? There's a housing development coming soon and the local telco might be interested in using my tower. Right?
A. This is not Field of Dreams! They might be interested but a professional tower can cost $100,000 to build. You'd be doing some reckless investing. T-1 carrier over microwave might not provide the capacity to handle traffic from those new homes. If the telco trenches in a few strands of fiber from their nearest switch your tower will be bypassed. Caution! Mark.
August 26, 2004
I've just read Murray's Wireless Nation: The Frenzied Launch of the Cellular Revolution in America, and Galambos and Abrahamson's Anytime Anywhere, Entrepreneurship and the Creation of a Wireless World. I haven't read Corr's Money from Thin Air but I understand it is of the same ilk. All three titles maintain Craig McCaw succeed (he sold McCaw Cellular to AT&T for $11.5 billion) because he clearly saw the future of wireless. Nonsense.
McCaw and his cronies came out well because they bought and sold spectrum licenses on the hunch they might be valuable later on. Does a financial hunch make a vision? No, the licenses were a commodity, a limited resource, something to be bought, hoarded, then sold later on. McCaw's team were commodity brokers, in other words, and not wireless visionaries. They bought as much spectrum as they could, financing and leveraging their deals however possible, using money from people like Michael Milken. Their story reminds me of the Texas Hunt brothers, who in 1979 and 1980 tried to corner the silver market. McCaw and company did the same thing with the wireless market: buy enough spectrum and you'll drive up your license prices. Pardon me if I am not impressed.
After selling out to AT&T, McCaw went on to other wireless projects. He funded broadband provider XO Communications which quickly went into bankruptcy, owing five billion dollars. He put tons of money, the amount still unknown, into the Teledesic satellite project, which after eight years of doing nothing is essentially dead. He also infused cash into Nextel, which continues to flounder. Wireless visionary or high tech rug merchant? You decide.
August 25, 2004
I must go out of town today so I can only write this short note. I'll have something on the history of CDMA in cellular radio soon. I must first sort out the self-serving corporate histories and the self-promoting bios. And the omissions. Nothing on Phil Karn at Qualcomm's website? Are you people already forgetting who developed your own technology? Hello!
In reading the history of cellular you'd think everyone was a visionary. Vision this! Were Huntington, Stanford, Crocker, and Hopkins transportation visionaries? Or robber barons? Yes, the railroads were good for the country, wireless is too, but don't try to convince me that these people thought a primary motive was the public good.
"Anything that is not nailed down is mine. Anything that can be pried loose is not nailed down."
It's said the first rule of business is to make money. Wrong. It's to legally make money. You make an ethical decision to not be a criminal. Most of us then try not to skirt the law. We choose not to sell worthless medical cures, cars that will soon break down, or plans to bilk people out of their life savings. These three things may be legal but we don't do them. The history of wireless to me is not a study in entrepreneurship but a study of what one could get away with. More later.
August 24, 2004
A sense of place. J.R. Snyder Jr. comments on how telecom views geography as wireless and landline areas and markets. Click here to go there (internal link). More in the coming days.
Q&A by Mark van der Hoek on 1XRTT/CDMA2000 1X
Q: Whose behind all these crazy names with CDMA?
A. Who is behind EVERYTHING CDMA? :D Qualcomm, of course. It was originally called a 2.5G technology, but Qualcomm muscled the ITU to call it 3G. After all, who wants 2.5 when you can have 3?
A. Coherent detection on the reverse link. Just like the cell sites have a pilot, now the mobiles have a pilot. That enables much better power control on the mobiles, which means greater capacity on the reverse link. Add to that now we have "supplemental channels". Instead of assigning just ONE traffic channel, now we can assign up to 7 to one mobile. The data is fed in parallel across all of them, thus increasing the data throughput. There are also some differences in coding schemes.
Q. Are data rates measured while the cell phone is moving or stationary?
A. Probably stationary.
Q. And do those data rates continue throughout the handoff?
A. No, supplemental channels are not handed off -- just the fundamental channel. However, the supplementals are added back right after handoff, so you shouldn't notice much.
Q. What's the real speed in practice with Vision or Express? 45 to 60 kbs?
A. That's what Verizon claims for Express, and that's what I've heard from folks in the field. Basically really good dial up. Nothing to get excited about, but usable surfing. I suspect those speeds are stationary, though, and don't expect that at the cell edge.
August 23, 2004
Tom:
1XRTT (CDMA2000 1X) is pretty widespread (discussion below) -- both Verizon and Sprint have it everywhere, just about. Verizon calls it "Express", Sprint calls it "Vision." It's really for data, you buy a wireless modem for your laptop that lets you connect to their networks. You get landline dial-up speeds when everything works right. Price? At least $60 to $80 a month or more, as well as the cost of the modem.
Verizon has EVDO, the next generation in CDMA, in two markets, and is rolling it out pretty quickly elsewhere. Sprint had been insisting they were going to wait for EVDV to be ready, but realized they can't let Verizon get that big of a lead over them. EVDV isn't due out till 2006. By then Verizon will have EVDO in all the major markets, and most of the mid sized ones. That means they'd own the business data market. 95 (B) never really got off the ground. It's here and there, but nobody's bothering to migrate to it now. 1xRTT blew past it.
Your Cellular Friend
August 22, 2004
2.5G Land, more musings on CDMA
Sprint PCS offers upbanded IS-95 (A), that is, IS-95 (A) placed at a higher frequency than conventional cellular. Still, the same technology other carriers have used since the mid-1990s, although now tweaked a bit. They claim their "Vision" service gives data speeds averaging 50-70 kbps, with peak speeds of 144kbps. That 144 would be their network speed, not what you would normally experience. And all of this is one fifth the speed needed to be considered 3G. Let's call their Vision service 2.5G.
Sprint claims greater nationwide coverage than any other carrier. Even here in heavily populated California Sprint does not cover the Highway 50 corridor to Lake Tahoe, barely any of the Sierra Nevada foothills, and little of the Sacramento Delta. It seems you can call yourself a nationwide network if you just list cities around the country, leaving huge gaps between. And how do you fill in those gaps?
How about cell sites costing one half million to one million dollars every seven miles across the entire United States? Yes, that's impossible. There's not enough people making calls to justify building such infrastructure. Better coverage and 3G and all the wonderful wireless services predicted for the last several years will never happen where it does not make economic sense to the carrier. Your nationwide coverage maps will look as they do now: like a slice of Swiss cheese. More later.
August 21, 2004
Other CDMA schemes exist than what's described below. Wideband CDMA, utilizing 5Mhz channels and in many countries newly allocated spectrum, will allow advanced services to emerge and older services to continue. After a decade of denial, the most loyal proponents of TDMA (internal link, typical advocate), will soon admit defeat: CDMA has won. GSM is a fine system (internal link) but its capacity using TDMA is limited. As GSM moves to what's called 3GSM it will convert to CDMA. TDMA and its variants will exist for sometime, another decade possibly, but it is not the future of transmission technology. Although advanced, this is a fine paper on CDMA by Prasad and Ojanperäon. Please read if you want to know more:
http://www.comsoc.org/livepubs/surveys/public/4q98issue/prasad.html (external link)
August 20, 2004
I've added more to the discussion below:
August 19, 2004
Confusing CDMA names
Cellular's original spread spectrum scheme was IS-95. That name comes from the standard (internal link) outlining its operation. It was also called CDMA but that is a generic term which is inherently confusing. IS-95 is CDMA, but not all code division multiple access plans are IS-95.
Capitalizing on CDMA's name recognition, however, the CDG Group now incorporates that acronym into titles for their future spread spectrum plans. These names incorporate revision numbers which make them difficult to relate to and remember. The goal though is straightforward: an always on connection, fast data rates, and an all IP network (internal link, discussion of circuit and packet switching.) .
Graphic from the CDG Group: http://cdg.org/ (external link)
Read how many poor names have been used along the development path. "[We'll introduce the] world's first third generation (3G) services later this year using IMT-2000 CDMA Multi-Carrier 1X technology (1X). This technology has been called many names in its development history - CDMA2000 phase 1, 1XRTT, 3G CDMA 1X - but regardless of the naming convention applied, it is the same set of advanced capabilities that promise to introduce the world to 3G in commercial form." Sheesh.
To back up a little, cdmaOne is the marketing term for IS-95 (A), the original CDMA scheme, and IS-(B). In America we still have IS-95 (A); (B) never got going. Now we come to other CDMA services, some of which we won't see for many years:
"CDMA2000 represents a family of technologies that includes
1) CDMA2000 1X and
2) CDMA2000 1xEV.
CDMA2000 1X can double the voice capacity of cdmaOne networks and delivers peak packet data speeds of 307 kbps in mobile environments.
CDMA2000 1xEV includes:
a) CDMA2000 1xEV-DO. [Data only or optimized] This delivers peak data speeds of 2.4Mbps and supports applications such as MP3 transfers and video conferencing.
b) CDMA2000 1xEV-DV. [Data and Voice] This provides integrated voice and simultaneous high-speed packet data multimedia services at speeds of up to 3.09 Mbps."
"1xEV-DO and 1xEV-DV are both backward compatible with CDMA2000 1X and cdmaOne."
The ski graphics below are my attempt at visualizing the differences between the services.
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