Dr. Dobb's Journal May, 2005
Bluetooth and the "no wires" short-range networks you can build with it has always sounded like a great idea. First engineered by handset companies as a way for mobile phones to talk to headsets, Bluetooth 1.0 (and, soon after, 1.1) was, for a long time, a solution in search of a problem. While Bluetooth looked like a great way to build a Personal Area Network of all the gear you might carry, it sold tens and tens of units in the U.S. True, millions of Bluetooth-equipped handsets sold, mostly in Europe, but there were few accessories, and it wasn't easy to configure. Early Bluetooth protocol stacks were buggy and had security problems.
That's finally changed. Lots of GSM phones come with Bluetooth, there are dozens of Bluetooth headsets for sale. Mac laptops and HP TabletPC's have supported it for two years, and we have Bluetooth GPS receivers. The PalmOne Treo 650 has Bluetooth. More importantly for DDJ readers, Windows XP directly supports Bluetooth 1.1 devices, and many Windows laptops have it built-in. Chaos Manor Associate Editor Dan Spisak uses his Sony/Ericsson Bluetooth-enabled phone as an Internet link for his 15-inch PowerBook. In short, it's a viable communications technology, though its configuration is still more complex than it should be.
While we weren't looking, Bluetooth 2.0 arrived. The first news we saw was from Apple, which refreshed its PowerBooks with "Bluetooth 2.0 + Enhanced Data Rate" (http://www.apple.com/bluetooth/), supporting up to 3-Mbps conversations. Of course, you'll need another device supporting Bluetooth 2.0 to take advantage of this improvement. Alas, we can't find any now, but you can expect announcements at CTIA (http://www.ctiawireless.com/), the big cellular communications show.
A quick check of the Bluetooth official site confirms that the 2.0 spec was announced in November 2004 (http://www.bluetooth.com/news/sigreleases.asp?A=2&PID=1437&ARC=1&ofs=), with chipsets available now from Broadcom and CSR, and upcoming from RF Micro Devices. Assuming the promises aren't overhyped, the higher performance of Bluetooth can keep it relevant, particularly for headsets and phone-to- computer networking, for which Wi-Fi is ill suited. It's also fast enough to support new devices, like tiny Bluetooth-enabled video cameras (both a blessing and a curse in my book).
There's no real reason to go out looking for Bluetooth 2.0 yet, but since it's backward compatible, you don't need to avoid it either. Like gigabit Ethernet, it's coming, and you probably don't have to pay much attention. One day, you'll just have it.
When it Just Works, Wi-Fi is a boon, a blessing, more than a convenience. Too often, though, range limits, dropouts, and interference cause me to mutter under my breath and look for an Ethernet port. Chaos Manor isn't tiny; from the Great Hall upstairs to the back of the house where we watch TV is about 75 feet and several thick walls away. The TabletPC just doesn't connect to an access point (AP) from that far. My wife is understanding, but even she would find the idea of scattering four or five access points in the house objectionable, merely so I could check e-mail from the back of the house.
Many 802.11b/g add-in cards and most advanced access points have dual antennas, using a voting receiver to choose the best signal for whatever device they're talking to. This "diversity receiver" approach is common in large radio systems, from cellular to public safety. The antenna with the largest signal "wins" with radio sites atop multiple mountains or big masts.
Just as Bluetooth has evolved, so has Wi-Fi. We have some good news from the front, in the form of the Belkin Pre-N Wi-Fi Access Point (AP) and PC Card (http://catalog.belkin.com/IWCatProductPage .process?Product_Id=184316). These devices use three receive and two transmit antennas. The AP combines them into three stubby (4-inch) antennas sticking up from the front of the unit. (The PC Card has a slightly thicker than usual "bump" with the antennas in it, but is otherwise unremarkable.) More antennas mean more possible antenna paths from sender to receiver, which are checked for the strongest signal multiple times a second. This technology is called "Multiple Input/Multiple Output" (MIMO) and our tests show that it's more than hype.
We installed the Belkin AP in the Great Hall, which is upstairs and in the front of Chaos Manor. Associate Editor Dan Spisak was impressed with the AP's setup; he set up WPA (Wi-Fi Protected Access) for security, I associated the Compaq/H-P TabletPC with the network, typed in the WPA passphrase, and was immediately connected using the TabletPC's built-in 802.11 networking—MIMO is backward compatible with both 802.11b/11g. I then carried the TabletPC to all parts of the house, out in the yard, back behind the pool, and down the back street. Connectivity was ridiculously good, three bars of signal strength way down past the next door neighbor's house in a place that had zero signal using a D-Link system, even though that one had an external doughnut antenna.
Belkin claims the best performance, though, if both ends are using Pre-N gear. So Alex installed the Pre-N PC Card in his laptop, a four-year-old Dell Inspiron 7500 running Windows XP. He walked around half the block while running a ping trace, with only a few dropouts the entire time. Even four houses down, with the AP on the other side of the house from him, he got a good enough signal to check e-mail. At extreme range, the link did drop, but it reestablished itself after a few seconds. Reconnections seemed much quicker than with older gear.
We don't know the relative power consumption of the Pre-N gear, but its first-generation PC Card runs hot—too hot to touch when removed after half an hour of use. The PC Card's control panel has a signal strength slider, so you can manually adjust transmit power (and power consumption) as needed.
Belkin has been shipping its Pre-N gear since October 2004; at CES in January, both Linksys and D-Link announced MIMO equipment, with others sure to follow. Linksys's Wireless-G Broadband Router with SRX (http://www.linksys.com/products/product.asp?prid=670&scid=35) has three antennas all at right angles to each other, which my radio engineering acquaintances say could well maximize the chances of a good connection. Still, we've only tested the Belkin gear, and recommend it if you need more range. At the very show where Linksys and D-Link announced their MIMO products, the Belkin Pre-N system was outperforming everything in the room, with signals available way down the hall in another ballroom. We were impressed then, and we remain so.
Pre-N, by the way, refers to equipment designed toward the emerging 802.11n Standard, which should be finalized later this year (see http://grouper.ieee.org/groups/802/11/Reports/tgn_update.htm for the official story). Be warned: There's no guarantee that Pre-N gear will be 100-percent compatible with the new Standard, and it is somewhat more expensive than 802.11g.
The extra range does mean you'll be more vulnerable. With older APs, someone would have had to park right outside Chaos Manor to steal a signal. Bob Thompson points out that a directional receiving antenna made from a Pringles can will let potential intruders intercept your wireless installation from considerably further away, and of course he's right. In any event, the Pre-N gear lights up half the block to any good Pre-N receiving antenna.
This is all the more reason to use WPA, available on both XP and Mac OS X (though there are currently no Mac drivers for the Belkin Pre-N gear). For Mac, just at the moment, you'll have to use the older WEP, which is harder to set up but more secure than nothing. When we were setting up our wireless, we discovered our neighbor has an unsecured wireless net; I could jump onto it and steal his bandwidth were I so inclined.
Regarding WEP: It's better than nothing only so long as you're dealing with nosy neighbors and amateurs. The WEP protocol has been cracked, and there are now downloadable programs for automating the process of breaking into WEP secured wireless systems. Using these requires gathering a significant number of data packets and running the analysis, but none of this is beyond the ability of any serious data or identity thief. (For more on this, see http://www.securityfocus.com/ infocus/1814 and http://www.informit.com/articles/article.asp?p=27666.)
Enough on security. If you want the extra range, and don't want to drop in more APs, we recommend the Belkin Pre-N gear. Just remember to set it up securely, which you should do anyway. Expect further improvements, better compatibility, and higher speed from newer products.
Belkin Pre-N competes well on price, too. We've converted the Chaos Manor wireless establishment to Belkin Pre-N, and there's no part of the house I can't check e-mail from. It's WPA, not WEP, protected. Recommended.
The Game of the Month remains Everquest II. Sony has done this one right. There are still problems with the crafting system: Player made equipment can't really compete with stuff you can get from quests, and that's sad. It's also tedious to do crafting, and the lack of lockers and other conveniences in the crafting establishments doesn't help a bit. Finally, the marketing system sucks dead bunnies: They really need to go over to something like the Star Wars Galaxies marketing system, with vendors accepting wares for sale on consignment in exchange for a small markup. This nonsense about having to sit in your hotel room waiting for customers is boring and needless. On the other hand, Sony has added many new quests and features, and has done well by the adventurer class. Now it's time for them to look at the problems of crafters and merchants.
The first Computer Book of the Month is Small Websites, Great Results, by Doug Addison (Paraglyph Press, 2004; ISBN 1932111905). This is a book for small business people who need a web site to advertise or sell their wares, and haven't the time to learn web design from the ground up. The other Computer Books of the Month are the series from O'Reilly & Associates called "Personal Trainer..." There is one on Windows XP, which I doubt anyone reading this will find useful, but there are two others—PowerPoint 2003 Personal Trainer (ISBN 0596008554) and Excel 2003 Personal Trainer (ISBN 0596008538)—that can be really useful for folks who have to use those programs and don't know much about them.
DDJ