Slashdot Mirror

← Back to Stories (view on slashdot.org)

New Wireless Technologies

Posted by ryuzaki0 on from the badger-cmdrtaco-for-a-wireless-topic dept.

Codex The Sloth writes "The Economist has an article on 4 emerging wireless technologies: (1) Smart Antennas for improved base-station capacity, (2) Mesh Networks to make each wireless reciever also be a relay, (3) Ad hoc networking to use network devices as routers, (4) Ultra wideband to transmit 100 mbs wirelessly (but only for distances of 10 feet...). Some of these are already in use while others are still in the lab."

5 of 89 comments (clear)

  1. uwb can go further more than 10 feet... by Anonymous Coward · · Score: 5, Informative

    there are several good articles about uwb at UWBPlanet. It appears the Economist is quite wrong about UWB.

  2. Lasers by Anonymous Coward · · Score: 2, Informative

    Scientific American has an article about the last mile by laser.

    http://www.sciam.com/article.cfm?articleID=00080 69 E-808A-1D06-8E49809EC588EEDF&catID=2

  3. Errors in the post by sheepab · · Score: 5, Informative

    From Slashdot: 4) Ultra wideband to transmit 100 mbs wirelessly (but only for distances of 10 feet...).

    From the article: The FCC ruling limits the range of UWB transmissions to about ten metres, although longer ranges may be allowed in future once the question of interference has been sorted out. However, UWB is capable of a data rate of at least 100 megabits per second over such distances.

    The first thing, the Slashdot post makes it sound like 10 ft is the maximum UWB can go, and second, its 10 METERS not 10 FEET

    --


    In college, really poor, need a flatscreen.
    1. Re:Errors in the post by Beryllium+Sphere(tm) · · Score: 3, Informative

      Interference from UWB may be a real problem, according to some tests reported in the latest issue of Aviation Week.

      Tests were brief and therefore not completely realistic, but showed actual loss of function of aircraft electronics. At 20 dB over typical single-device levels they were completely shutting down some of a 747's navigational equipment. That's 100 times the normal power level, but consider: what if a hundred passengers are carrying UWB devices? Or what if 20dB isn't enough margin to prevent partial interference from a single device?

  4. Re:How do you make an UWB signal!? by ispdrudge · · Score: 2, Informative

    See the papers on timedomain.com.
    Their UWB scheme uses .5 nanosec pulses with a
    gaussian waveform that spreads the signal very
    thinly and evenly over a very large spectrum.
    A 100 kbit/s receiver will listen for these pulses at a sequence of 1 ns wide windows.
    The window sequence is pseudorandom, with something over 100k windows distributed over 1 sec. The
    hard part of the technology comes from :
    very wideband antennas
    syncing ghz oscillators at transmitter and rcvr
    precise timing (they have a dedicated chip)
    establishing the sequence with multiple receivers