ETech: Any Time, Anywhere: High Speed Mobile Data Technology Overview



I’m back in real-time notetaking at the moment.  I’ll catch up on the notes taken with a text editor earlier.

Rob Gilmore from Via Telecom is talking about upcoming mobile data tech.  I’ve had spotty access to my VPN, and don’t feel comefortable sending passwords in the clear over wireless, especially with all of the sniffing going on.

Rob is going over the current cellular technology, such as CDMA, GSM/GPRS/EDGE, and the current/near-term stuff CDMA20001x, 1xEV-DO, and WCDMA  Of the latter group, WCDMA is nowhere to be found in the US, but is all over Europe, Japan, and Oceania.  1xEV-DO can pull down up to 1.5Mbit down, though only 64kbit up.  That’s going to be a huge crutch, just as current GPRS/EDGE is optimized for download, and if you want to send data, you’ve got a small pipe.

Anywhere/anytime is the Next Big Thing.  There are some technical hurdles that still need to be worked out.  Korea is expected to get 1xEV-DV by the end of 2004.  1xEV-DO will be upgraded to address the lower reverse link in the near future.

Cellular and WLAN (think: Multiradio) working together is going to be big.  You might be able to use WLAN to supplement your data services when it is available, possibly by connecting hot spots into hot zones.  A business model needs to be figured out for this to happen though.  Operators need to make money in order for it to be worth their while.  I would love it if my cel phone would use local WLAN instead of GPRS for data if it is available (both present and billable).

Right now range and interference are two big things holding back 802.11 from being more useful.  We’re suffering through that right now, with 802.11b, 802.11g, and Bluetooth all fighting for our computers’ attention.

802.11n could be the next big thing.  It’s still quite immature tech, but could offer greater than 100Mbit throughput to the user (rather than the usual speeds which include overhead)  MIMO (multiple input, multiple output) antennae might make this possible.  It’s going to require a lot of signal processing though.  It would occupy one WLAN channel, and be in compliance with the 802.11 standards.  One access point could speak 802.11a/b/g/n.

WLAN and 3G roaming.  It’s possible using Mobile IP.  Technical hurdles include handoff, security, billing, etc.  Mobile IP allows for this, but the infrastructure isn’t there yet.  Using Mobile IP, you would have a home agent located at home, which would maintain the location for each of your mobile, and hand off to 3G if neccesary.  A Mobile IP foreign agent wold facilitate roaming.

The slides are flying by too quickly to write it all, but the devices would talk to a foreign agent, which would communicate with the home agent, and would work out connectivity.

WMAN is another possibility for future high bandwidth access.  802.16 is Line-of-Site, which could offer between 2-155Mbit.  802.16a supports mesh, and can go 75Mbit and is non-line-of-site.  Obligatory mention of the last mile.  DSL-like services, interconnecting WLANs, etc.

802.16e is another standard that might help out mobility.  It is based on 802.16a and aimed at carrying signals for PDAs and laptops.

802.20 is packet based, and greated that 1Mbit with a radius of 15km.

Next up, CDMA the next generation.  1xEV-DV (data and voice), and 1xEV-DO (data optimized) are two ways of going about it.  EV-DV does both but has to optimize voice and data differently.  I love this technology.  CDMA is like time-sharing revisited.

EV-DV (which is fun to say) has a single 1.25MHz bandwidth share between voice and data.  It’s 3.1Mbps peak download.  The scheduling is very complex.  Voice users are usually scheduled first.  Dynamic allocation of the unused basestation power is then distributed to data users.  This makes doing multiple things on one channel quite easy.  The second rev of EV-DV (Rel D) will significantly increase the upload (reverse link) bandwidth.  Subsiquently, the next rev of EV-DO (Rel A) will increase the reverse link to up to 1.5Mbit peak.

The EV-DV scheduler is really really complex.  Really complex.

CDMA is really complex too.  I miss GSM.

It will be interesting to see how things pan out EV-DV vs. EV-DO.  EV-DV seems to have its advantages, but EV-DO is here now.  EV-DV has a smoother upgrade path from IS-2000, whereas EV-DO requires new antennae, hardware, etc.

EV-DO is due for upgrades soon (in a month or two), and EV-DV has upgrades coming out, even though it’s not even here yet.  Via is working hard on EV-DV.  1xEV-DV is due out in Q4 2004, and in the US test trials may start by the end of the year.  EV-DV might be in place en masse by 2005-2006.

EV-DV headsets will be made by Nokia, samsung, LG with chipsets by Qualcomm, TI, and VIA.

This presentation has been quite informative, but acronyms abound.