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The Wireless Networking Question Roundup...
Which 802.11b-enabled PDA?
Kent Brewster asks: "I've retired my Palm 7 due to sudden lack of all-you-can-eat service and lots of free WiFi in the area. Right now, I'm looking at HP's iPAQ h5455, Toshiba's e750, Palm's Tungsten C, and Sharp's as-yet-to-ship Zaurus 5600. What I'm after is the best possible mobile Web experience first and PDA functions second. Opinions, please?"
802.11b Issues for Apartment Complexes? (Revisited)
johaninroseville asks: "I am in the planning stages to build a wireless network to provide an apartment complex with last mile Internet access. There are about six hundred units, but only one to two hundred interested people. For those curious as to the general layout of the apartments, here is an overhead picture.
My experience with radio frequencies, antennas, and especially how well radio waves can penetrate walls etc is rather limited. My game plan is to get a feed into the POP / MDF, and have a rather strong omni antenna mounted on the roof of that building. The coverage of that omni antenna will provide the links to the seven APs that will probably be needed, mounted on the rooftops around the complex. The seven IDFs, (or APs or what ever you want to call them) will each have a Point-to Point connection to the big omni antenna. Hardware used for the seven IDFs is planned to be: directional antenna (for link to omni in POP) connected to bridge, bridge connected to AP, AP connected to a sectored panel antenna that will provide end-user access (to their PCMCIA/PCI/CF/USB Cards, or to their access point).
My biggest questions are what antennas to use? What strength? How well can the radio waves from an omni antenna and/or a sector antenna penetrate multiple walls, if at all? How far can one of these antennas cover, and then penetrate walls?
I would appreciate any help at all in this matter. Maybe somebody has done something similar, or have some useful links."
Ask Slashdot last covered wireless apartment complexes about a year ago, and it would be interesting to note if any of the new technologies, introduced in the interim, will make this job any easier.
Outdoor Enclosures for 802.11b Equipment?
And finally, this question from ETEQ: "I need to operate a small amount of networking and wireless equipment (Router, Cable Modem, and 802.11 access point) in an outdoor setting, but the problem is that I live in Minnesota, where temperatures can drop far below freezing and stay that way for weeks (not to mention frequent heavy snow)... Are there any outdoor enclosures that can be purchased on a Home or SOHO budget?"
make a waveguide antenna with a coffee can. it should last ok, and if it rusts, it is easy to replace.
Am I the only one picturing a lawn gnome with a wire coming out of his butt?
Many apartments have pretty thick ceilings and floors so the signal shouldn't get too far vertically, though the neighbor on the other side of the wall might want to bum some free internet and pr0n downloads on your expense. Solution: secure that network.
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Free your mind.
couple things to consider:
the main problem in my experience is wall penetration. Don't count on more than 3 walls (and this is stretching it if they are concrete). Consider mounting the antenna outside a bit away from the building, essentially hitting the outside wall. This will give you only one wall for all apartments.
Don't forget about accountability and security. Even if billing is not an issue, you don't want someone in your building to go wild and start a hacking crew. Static IPs are a bit accountability help, NAT is though
---- join dshield.org Distributed Intrusion Detec
Since it is a wireless system no string or twine is neccessary. You'll find that with a little imagination The Tin Can System is effective at several kilometers.
for wireless pdas, the ipaq 5455 is really the way to go. wifi, bluetooth and finger print recognition. add to that, the ipaqs have tons of accessories, so you can even use a gsm card and use the ipaq a cell phone (and gprs / gsm data services). also, the ipaq along with a t68 or nokia 3650 is a pretty good combo too.
cheers,
pt
If the fine folks at Tupperware/Rubbermaid can't help, how about Coleman or Igloo coolers?
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A couple of weeks ago, I got a chance to dink around with the Tungsten C at CompUSA and browsed around to a couple of sites, including Slashdot, and the web browser seems to render pages a lot better than Pocket IE included with the Pocket PC OS. Pocket IE is closer to IE3/IE4 than current versions of IE (though IE in CE.NET, which isn't available for Pocket PC hardware, is closer).
Either browsers do not support pop-up windows, which is both good (for pop-up and pop-under ads) and bad (if you are using a webmail system that depends on pop-up windows). Also, trying to read something on a 320x240 screen is a wee bit difficult. The Tungsten C's display (320x320) gives a little more real estate for rendering web pages, though the fonts used my take a little getting used to if you are used to Verdana, Times or Bitstream's Vera.
Speed-wise, the Tungsten C seems a bit faster and more responsive when browsing the web than an iPaq with the same processor, memory and built-in WiFi. For me, the location of the navigation disc is a bit too low for me, but after using it for a couple of minutes, I got used to it.
As far as a previous poster's question on why 802.11b instead of 802.11g? I think there are a couple of reasons right now: 802.11g eats up more power (thus run a bit warmer) and the chips used for it aren't as compact as 802.11b chips... that and I'm not sure how much I/O is provided between the processor and the bus that the WiFi controller would connect to (which could end up being a bottleneck). That and I think almost all of the 802.11g PC Cards available right now are CardBus only, which I don't think any PDA (clamshell or not) supports.
... it won't work. At least, it won't work very well.
There are only 3 non-overlapping 802.11b channels, or 4 if you do it right. Either way though, that isn't 7.
However, if you can get it down to 3 or 4 links, don't use omnis anyway - use some little 8dBi-14dBi patch antennas, and do highly directional links to the radios you're bridging to. You only want to use omnis for client (think people moving around, unknown target direction) access.
The above is what the traditional thinkers would say. And what you were probably thinking, given the fact you said "point to point" link for the omni -> client links.
You can get around that barrier, however, if you do a single AP at your POP, and the bridged radios are simply looking to the AP for client access. The downside to this is that all the bridged radios will be sharing the bandwidth of a single channel, but you can have 7 (or more) links from your central antenna this way.
And if you're going to do it that way, get two 15dBi 180-degree sector antennas (cell-site quality), put them back-to-back, and do a combiner feed to your AP box.
You'd better let the residents know that they shouldn't be using 2.4 GHz cordless phones on the premises, or they'll be knocking out the wireless connections for computers in the area.
Here is a link to acompany that proved useful that last time I was installing wireless LAN's.
http://www.hyperlinktech.com/index.html. They have a full assortment including heated outdoor enclosures and antennas and amplifiers and AP's and more!
Or am I feeding the trolls again?
Forward, retransmit, or republish anything I say here. Just don't misquote me.
I have built two splashproof computers for marine surveying on small boats. Pelican cases are what I used. You only need to seal the one or two through-case holes that you will need to run your wires.
I would post a link to some pics, but my home server can't handle the Slashdot effect.
I had the "pleasure" of using the 5455 and I found it to be completely useless. Unless you are somehow attached to the ipaq style or whatever (and you come from Palm) I would not suggest this as the Wifi Pocket PC of choice.
I would suggest the Tungsten C. I borrowed it from a friend for a day and was utterly impressed. The Palm OS 5 is very peppy with the new processor and the battery life is simply amazing. Most Pocket PC devices can only last about 7-10 hours, and only 2-3 with wifi on. However, the C can last up to a week, or a good 11 hours with Wifi. Not only that, but it does a better job rendering. Considering you are coming from a Palm device, I would recommend this C because programs will also be compatible.
This is my digital signature. 10011011001
I am running an open node in my apartment with a broadband Net connection. A co-worker in the same building has wireless, but no Net connection and was hoping to use mine, but the signal was too weak. The other day he was checking the signal again and found yet another 802.11B AP that gave him a good signal and had a Net connection.
My point is this: Just encourage as many people as you can to set up open AP's using off-the-shelf AP's and whatever Net connection they have. Don't tell the providers. Don't worry about setting up complex routing or other network stuff (except making sure the AP's are on different frequencies to avoid stepping on each other). Don't sweat the details. Don't worry about who pays for what. Just do it.
The amazing thing about 802.11B is that it will probably work fine.
- -
Are you an SF Fan? Are you a Tru-Fan?
one of the WISPS here in Iowa throw the equipment into an old cooler, then water proof it with silicone. Not sure if straight Styrofoam or like a Coleman one. I just remember the guy saying it has survived -20 and +100 degrees on op an old grain silo.
For the low budget solution that you request, I'd say to build your own. Further, I feel that you should use a small "log cabin" design so that it is environmentally friendly, or at least asthetically pleasing. You could build your log cabin out of these inexpensive logs and if the weather gets too cold, just put a match to it.
My choice is PocketPC for several reasons. First up, lets not beat around the bush. Palm is currently playing catch up when it comes to having multimedia and Internet capabilities on their PDAs.
Browsing has been and continues to be pretty lousy on Palm devices mostly due to the available browsers. Having 802.11 speeds is waisted when your browser can only render text and simple images. PocketPC's all come standard with PocketIE which is basically a light version of IE. It renders pages very accurately (layout wise) considering the available screen real estate. Which leads me to my next point.
Another big plus for PocketPCs is that there is software to increase your screen resolution. So if you wanted, you can rotate the display and bring it up to 800x600 for a better browsing experience. Granted the screen gets pretty blurry at those resolutions but it's still very usable since the tools let you click a button to zoom in and out quickly.
Going beyond web browsing, tools such as SSH clients, FTP applications, network monitors are all much more mature on the PocketPC platform compared to Palm. There's also the added bonus of having native versions of the Windows Media player, the Macromedia Flash 6 player and even the Windows Remote Desktop client for true Mobile computing on a PDA.
Don't get me wrong, I do like the Palm platform. My current PDA is a Handspring Treo 300. But web browsing is definitely sub-par compared to my old iPaq 3600. As far as Linux PDAs are concerned, I'm sure someone else here can comment on those.
Here is a great node on SeattleWireless.net's wiki that details the construction of an outdoor wireless access point, using relatively cheap equipment found at a hardware and/or electrician's store.
o fBoxes
http://www.seattlewireless.net/index.cgi/WaterPro
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And the Angel said unto me, "These are the cries of the carrots! The cries of the carrots!"
Most installations that I've seen use wires to the APs (often with Power-Over-Ethernet, to reduce wiring to a single cable). That way, you have fewer channel collisions, less overall wireless traffic, and significantly lower latency. You can put all of your wires in hallways, basements, and other "public" areas where you can work without going into people's apartments. Too ugly? Use drop ceilings and ceiling-mounted cable runs. Not to mention that it's far harder for a repirman to mess up a cheap 10/100 switch than an elaborate antenna array.
Also, think hard about setting up some sort of monitoring system. You want to have someone on the way to fix a failing AP before the angry calls come in.
Forward, retransmit, or republish anything I say here. Just don't misquote me.
Most of these features--crappy low-res cameras, SMS, e-mail, and simple PDA features--are not technological advances. What they represent is a sort of experimentation; phones are unlikely to get any smaller and still be usable, instead, designers are trying to determine what features are most wanted next to being able to make phone calls.
That said, the processor power in cellphones has remained fairly limited, while that in PDAs like the iPaq or the Zaurus is now greater than many of my still-useful desktops. PDAs are now running nearly-full-fledged operating systems like Windows Pocket PC or Linux. PDAs, just as phones, have to find their niche; designers must figure out what features make a PDA more desirable than just keeping notes and appointments, something which addmittedly has been somewhat supplanted by the phone.
The future is of course the merger of the two, not one beating the other in functionality, as you describe. Many PDAs can be used as phones, and many phones can be used as PDAs. To even make a distinction, or to claim that one category is advancing faster than another, is just silly. You consider a Treo a phone; many consider it a PDA. There will probably come a point, fairly quickly, where the only distinction is not whether it can make a call or not, but how big the screen is and how many added features it has.
You are to 2003 as Richard Nixon was to 1972.
I wouldn't consider it a PDA actually. The Zaurus 5500 is more like a real computer, just small and less powerful (less upgradable too). But nonetheless, it is very powerful and you can have pretty much anything that's compilable.
:) Or watch movies from my NFS server, etc. I don't use other features like agenda or address book so I can't say about those. On the wireless side though, it's excellent. I guess it also depends on the type of card you have. Just make sure you have one that's supported under either the "stock" Zaurus ROM or OpenZaurus (which is way better)
:)
I'm a linux freak (and admin) so this is a nice tool for me. I can ssh to work from my living room and fix stuff at home
Also, since it's Linux based, things like Kismet are ported and work real nice. The only drawback is the battery and I consider buying a less powerful 802.11b card as mine is not power-friendly. Other than that, I get good milage with a base at work and at home. I rarely use it for more than 1-2 hours. I can't wait for the Sharp "C" series to be available as it will have a bigger keyboard. Until then, I'm glad I ditched my Palm Vx, it was useless
-- Leeeter than leet
for wireless pdas, the ipaq 5455 is really the way to go.
It's likely to take the best part of a year (going on past experience) for HP to get Linux working on this model as well as it does on the 3[68]00s. Also bear in mind that there will probably never be native support for SD cards, though MMC cards do instead.
You really, really want to avoid being stuck with PocketPC for any length of time, trust me.
# init 5
Connection closed.
Oh...
the first Airport products? Because they are selling 802.11g products now so it's quite likely that their cards will continue to be supported wherever 802.11g eventually ends up.
As for browsing from a PDA, I've found Thunderhawk from Bitstream invaluable. I've found it to render pages in about the same time, sometimes even a little faster, although there are delays when scrolling up/down on a page. The big advantage is that it is able to scale a page, rendering it at the equivalent of up to 800x600 on a pocket pc PDA. I can view slashdot, as it looks on a PC, from my iPaq. There is a yearly fee of $50.00, but you can get a one month free trial if you're interested in it.
http://www.bitstream.com/index.html
My $0.02.
If you don't mind Sony and all the baggage that comes with them, their clamshell PDA's are outstanding wireless PDA's. They have a CF slot dedicated to just being used for 802.11b cards (though if you buy a 3rd party driver you can also use CF memory cards in it), and they have the best screen bar none on PDA's to date. 320x480 of web-browsing pleasure (well, relative to other PDA's anyways). That's twice the resolution of any PPC-based handheld.
The ones you'd want to look at if you're interested are the NX60, NX70V (same as NX60 with a crappy camera), and the NZ90 (only if you're really into getting a gigantic PDA with an actually decent digital camera built-in).
The ultimate Wi-FI PDA appears to be the Samsung Nexio S160, with a big, high-resolution screen for Web browsing. It's not officially sold in the USA, it runs WinCE, and it costs as much as a computer, though.
Lurking inside your cellphone is a vastly underused computer. One inventive programmer figured out what to do with it.
by Paul Wallich June 2003
Way back at the dawn of time--say, 30 years ago--when Alan Kay was pioneering windowed displays on a personal computer and Doug Englebart was inventing the mouse, either of them would have killed for a modern cellphone. Not for the instant communication, which would have required another billion dollars' worth of towers, transceivers and switching equipment, but for the computing power. The megabyte or four of memory and the couple of multi-megahertz CPUs that are standard on today's Web-enabled mobiles dwarf what you could find on almost any machine available to the developers of Unix, e-mail or the Internet. Yet most of the time, all that computing power just sits unused.
Therein lies an opportunity.
Most of the current generation of cellphones support Java, a combination of programming language and libraries that lets developers write compact code and run it on many different machines with minimal customization. Obviously, you can't just sit down at the keyboard--so to speak--of your Motorola, Nokia or Samsung and start coding, but building programs for a Java-enabled phone is relatively simple. Download the Java development environment of your choice, snarf a few extra bits of code from the phone manufacturer's Web site, and type away.
When you're done, simply insert a link to the compiled code onto a Web page, download it with your phone's browser and presto! (For hackers who haven't got a new-model cellphone and aren't willing to buy one just to run their code, Motorola, Nokia and others offer emulators you can run on a PC that allow you to see the cramped little images and push illegibly labeled buttons on your screen.)
Since Java-enabled phones became available around the turn of the millennium, thousands of apps have made their way onto the Web, ready for downloading. In addition to retreads of every game that ever graced an 8-bit cartridge system back in the 1980s--from Pong to Space Invaders to Pac-Man--hackers have managed to cram chat clients, low-resolution porn, grocery-list managers, news- headline scanners, webcam viewers and streaming-video clients into people's pockets and onto their belts.
If some of these apps make it seem as if Java-based cellphones aren't fully tapping all that power under the hood, well, that's by design. Victor Brilon, Java applications manager at Nokia, and Charles Chopp, Nokia's media relations manager, laughed when I asked questions about writing Java programs that make full use of a cellphone's computing and communications power. As on PCs, Java apps on cellphones run in a "sandbox" that prevents them from doing damage to their surroundings. So no dialing out, no messing with other programs loaded on the phone, no access to the digital signal processor that encodes and decodes the digits representing your voice, which is by far the more powerful of the phone's two CPUs. There's a legit reason for this good-fences policy: Imagine accidentally downloading a scrap of code that dials 911 every five seconds, or a malicious app that records snippets of your phone conversations to the phone's RAM and then calls random numbers in your address book to play them back.
A revised version of MIDP (Mobile Information Device Profile, the standard for running sandboxed Java apps on handheld gizmos, including cellphones) scheduled to be released this summer allows users to allot more access to their phone's resources to "trusted" apps that have been vetted by the manufacturer or some other industry-approved authority; watch for the first round of train wrecks soon after its release.
So if a hacker can't implement all of Microsoft Office or find the next Mersenne prime on a cellphone, what is it good for? State the question another way: Besides old video games, what really interesting applications accommodate lousy graphics, marginal memory and a user interface consisting of a d
I saw a few posts about cordless phone interference and 802.11 and wanted to add a recent experience. I recently added the MP3 capapbility to my Tivo and was streaming MP3s off my shared drive (linux of course) via 802.11b. Works great. (The Tivo MP3 play functionality sucks but thats a different story). So i'm listening to the music just fine and my wife puts dinner in the microwave. Now we have all heard about microwaves interfering with 802 before but i have never had a problem before. So as soon as she turns on the microwave, the music cuts out. The microwave counts down 3...2...1 and queue the music. While I have run the microwave for years while surfing the web and checking email, I have never noticed the problem. The statelessness of web surfing masks the interference of the microwave. The MP3 streaming highlights the issues of microwave interference. The moral of this story, don't count on 802 for network connectivity.
This is what I do now. I have an open AP on a specially firewalled port, and it only allows web browsing through a proxy server. All other traffic is blocked, except for a few neighbors who know how to authenticate to my firewall and have less restricted access.
My AP is in the top of the house, with a nice omni antenna on the roof covering my neighborhood. I coordinate with several neighbors so our channels don't overlap. One neighbor in a shielded area has put up a yagi pointed at my omni, and gets a 2Mbps (really about 400kbps throughput) signal, which he repeats to several of his neighbors, using a linux box and 2 APs + 2 antennas. They buy me beers from time to time to pay me back. My neighbors are mostly geeks who want to experiment with wireless routing, and swapping emails between our servers without having to go through the internet.
Some evenings I see as many as 4 or 5 people connected. I feel this is the best use of my internet connection, because I'm providing a service which doesn't cost me much and certainly helps people sitting in the local cafe brun working on term paper research while downing a beer.
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
Ok, so now you are probably more confused than when you started. People are bombarding you with stuff like "use different channels", "why not cable each AP" etc. Your basic idea is to avoid ethernet cables to the APs and personally I think this is a good idea, as you may find you have to stick extra APs in all sorts of out-of-the-way places to cover black spots. I'll continue this post on the assumption that you are going to stick with this plan and use radio to feed the APs rather than cable.
(note: your biggest issue in this is going to be which access points to use - more on this later)
Different channels? - This WOULD be an issue if you were cabling each AP to a network behind. But since your APs must talk to each other then ALL your APs must be on the same channel. Now I'll have to start with a couple of disclaimers before everyone jumps on me. This means that your overall bandwidth will be reduced. In an office environment this type of scenario of having many APs sharing the same bandwidth is not acceptable. HOWEVER in your case most of your traffic is going to the internet, and your pipe to the internet is limited anyway. Therefore this isn't a big issue for you. There is an alternative design where you use one set of APs on one channel for your feeder network, and a different set on a different channel for your access network. This doubles the amount you have to spend on APs, and won't make a huge difference in your setup anyway (more later when I talk about APs and their limitations).
Now when your APs talk to each other they are using bridging mode. Many manufactures support bridging mode. When clients talk to the AP they are using what I'll call client access mode. Pretty much all the manufactures support this (naturally). So fine, everything sounds good right?
Well if you really read the fine print (assuming it even exists on the website of the manufacturer) you'll see that there are almost no manufacturers that support both bridging mode and client access mode AT THE SAME TIME IN THE SAME AP. Usually the vendor will propose a design where one AP handles the bridging to the central AP, and this AP is then connected via an ethernet cable to the back of a second AP which provides the client access on a different channel.
But there is good news, there are some APs that can do both modes at the same time.
They are (as far as I know - happy to be corrected here): Cisco 350 (and probably the more expensive ones), a HP model (can't remember the model number), the Apple Airport Extreme, and the Meshbook.
The Cisco 350 is a little pricey but will give you better range due to the fact that it can output the full 100mW. It also supports power over ethernet natively (not an issue in your config though), and is available in a rugged outdoor version. http://www.cisco.com/en/US/products/hw/wireless/ps 458/index.html
I'm not familiar with the HP one, so I won't talk about it here.
The apple airport extreme is very interesting because of its low cost. It is the only AP in the low end price range which can do client access and bridging at the same time. You'll have to use an external antenna with it because the internal antenna will not be powerful enough for your needs. It won't output the same power as the Cisco though. If cost is an issue this is the one you want, though with the Cisco you may end up with less access points and therefore save money. http://www.apple.com/airport/
Something that is very interesting is the meshbook at http://www.meshbook.com it is an AP running linux and some open source software which solves a lot of the problems of community networks. When you use a Cisco or Apple AP you are going to be able to use only a single exit point to the internet, but the meshbook is much smarter and a collection of these in a network together will be able to load share to multiple exit points. This way you could get two feeds in at either end of the complex, and if you placed a few extra meshbooks into the design for
Back in the early nineties I spent some months doing indoor radio propagation measurements in the 2 GHz band. Basicly there are a few rules to observe when designing a wireless link:
1: In free space the signal strength is inversively proportional to the square of the distance. Double the distance and the signal drops by 6 dB. Increase the distance by 10 times and the signal drops by 20 dB.
2: Walls, buildings and trees attenuate the signal. As a rule of thumb a concrete wall attenuates the signal by 20 dB. Transmitting around a corner attenuates the signal by 10 dB. Wooden doors and windows will let the signal pass through with a typical attenuation of 10 dB.
3: Big flat surfaces reflect the signal. This means that you might be able to connect to a friend in the same appartment block by "reflecting" off the building on the other side of the road, even if the direct line between you is obstructed by several concrete walls.
Let us assume that the coverage of your wireless link in free space is 500 meters when using omnidirectional antennas. If you increase the antenna gain by 20 dB the coverage will increase to 5 km. If on the other hand you have to pass through a concrete wall then the original 500 meters will be decreased to 50 m. Add another concrete wall and we are down to 5 meters!
As I understand your apartment complex project the users should be able to use their WLAN cards in all rooms of the flats. To be on the safe side you need line-of-sight between the access point and the facade of each flat. This of cause would require quite a lot of access points.
Alternatively you might be able to use a few access points located at high points even if there is not line of sight to each flat. The signal would then be scattered and reflected of the neighboring buildings. This however would attenuate the signals, and your poor users might have to stand by the windows to get a good connection.
With the number of people getting wireless devices for their homes riseing and the people still forgeting to secure their routers and access points to prevent unsigned people from using their connections, an amazing new concept up as popup in my appartment complex. Their is a shared access setup going on. Everyone here has a different type of connection (Cable, T1, DSL, Satelight, and even DialUp) but most of us use a wireless router so we don't have to run 10base-T around our appartments. After booting up and checking for SID broadcasts comming to your card or access point its amazing the number of people who don't secure them. After asking around I found out that they don't secure them for a reason. The arpartment complex is on a shared internet system. Everyone who has a connection opens themselves up to everyone else. It gives us the ablity to go to the pool with our labtops or walk our dogs with our PocketPCs or allow friends to use your connection when your isp is being slow. We respect each others line and know that if we abuse a friends connect that our mac address will get banned. What it has turned is a massive internet shareing community. A wonderful paradise of highspeed access where ever you might go. I wonder if anyone else has done anything like before?
No.
To solve the channel problem, consider this:
.11a gear with directional panels pointed back at the master. Set them to bridge the wireless side to their ethernet jacks. Now you've essentially got "wire" to all your locations, without stepping on the 2.4GHz spectrum.
Use a single 802.11a AP on the roof above the MDF with a decent omni on it. Then, at your other locations around the complex, use more
Then at each location, connect one or more 802.11b/g APs to the ethernet. I say "or more", because you may wish to use several APs with narrow sector antennae, to provide stronger signal to a broad area.
Another poster pointed out, you'll have to make people swear not to use 2.4GHz cordless phones. Since 802.11b isn't really spread spectrum, it doesn't handle interference well.
People in their apartments will need to realize, they're not aiming for the AP on their own building, they're aiming for the building across the way. Explain that 2.4GHz is line-of-sight, so if they can't visually see the AP, they might have problems. Consider marking the rooftop locations with flags.
On the other hand, you won't find many 10-story wood-frame buildings *anywhere*. Building them in earthquake country means using steel beams and rebar, and reinforced-concrete floors are often built on metal decking. That doesn't mean that room-dividing walls are built of decently sound-proof material, but they can be - my mother-in-law's place in LA seems to have cinderblocks for most of the dividing walls, though that may be engineering conservatism (the rest of the construction was nothing special...)
But then, most of the dorms where I went to college were cinderblock, and that didn't mean that you couldn't hear the guy on the first floor with the big stereo, even in the dead of winter.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks