Engineering News Article

Its amazing how a simple idea like the cantenna has grabbed the attention of the media. So far I’ve been interviewed on SABC Africa and by Engineering News (Tin-can bridge to digital society). One would have thought that the technical, innovative stuff we’re doing with ad-hoc networking in the larger project would have more interest. I suppose that its easier to grasp the imagination with simplicity.

IWS2005 Thursday

IWS2005 Thursday
Keynote speech
WLAN, Fixed Wireless and Cellular all have adopted space-time transmit diversity
Only WLAN’s really use special MUX
Celullar may never see special MUX

Cognitive radio may present a challenge to spatial MUX in WiMAX
MIMO in networks is different from MIMO in isolation

Networks not prepared to cut down on power(loose channels) to include spatial diversity

UWB panel discussion
CSEM – built small, low complexity UWB solution
Low data rate
Tx 3.5 mW
Rx 7.5 mW
Radiated power 100uW
Uses analogue spread spectrum and multi-path diversity
Use of other MAC layer may reduce power further, WiseMAC, S-MAC

Delivering Broadband from a high altitude, quasi stationary plane/airship
120Mb/s symmetric links
Delivery to rural areas, blocks of flats and moving train, using steerable antennae
Optical links for backhaul 48/47GHz 31/28GHz
University of York UK, NICT Japan
60Km diameter user area coverage, single or multiple cell
Possible backhaul via satellite
802.16, 802.20, 802.11 , ETSI Hiperaccess, hiperMAN, DVB
802.16sc is best overall choice
WiMAX, possible depending on regulators
17 – 22 Km above the ground
Dish sizes less than 30 cm
Issues: HAP station keeping and moving train
Antennae: mechatronic and smart
Use 8X8antenna array to block out interfering signals

Test system in Sweden delivered 4Mb/s throughput 802.11b and 1.25Gb/s freespace optic link
Dr. David Grace [email protected]
200-300 000 euros for test tethered platform

This has given me an idea!!! Why not put an AP on an advertisement gas balloon as a hop between Jhb and PTA?

Improved Triangulation Method using a Movement model
Localisation done in Bluetooth
Inquiry procedure provides RSSI
Movement model variables: Speed, direction based on previous measurements
Without prior knowledge: Speed truncated normal distribution with a mean of 1m/s and std dev of 0.5m/s
Direction uniform between -180 and 180
With prior knowledge, previous measurements used to determine speed

Planning of Large-scale WLAN infrastructures, Methodius University, Macedonia
Planning either done using educated guesses or with auto planning
Dominant path approach used for propagation modelling
Propogation Modelling, Coverage optimisation and channel alloc optimisation
Wireless Indoor Design Tool, version 1 (WIDT v1) to be released soon
Possible use in indoor mesh?

IWS2005 Wednesday

IWS2005 Thursday
Broadband Rollout and the role of wireless, Steffen Ring, Director Motorola
IEEE802 has 3 categories, Wire line 802.1, 802.3, 802.21 , Wireless 802.11.802.15, 802.16, 802.20 and tech advisory 802.18, 802.19

Enhanced Data rate, 802.11n WLan approx 200+ Mb/s in testing may be able to handle 1000’s of calls and possibly uncompressed video

New mobile extensions to WiMax, 802.16e
Mesh networks 802.11s

802.11a 5GHz 54Mb/s PHY based on OFDM
802.11v 2.4GHz 11Mb/s PHY based on DSSS
802.11f Support for roaming
802.11h European 802.11a
802.11i Security
802.11n High Throughput

802.16 Single Carrier MAC/PHY layer 11-66GHz
802.16e Mobile Broadband Wireless Access
WiMax based on 802.16 and 802.16e

DVB-H as Broadband Access Technology, Reza Tadayoni, CICT, Tech Univ Denmark,
Mobile and Broadcast Convergence
Inband – UMTS and GPRS e.g mibiTV
Hybrid – DVB-H, DMB (Korea), ISDB-T (Japan), MediaFLO (Qualcomm, US)
DVB-H up to 11Mb/s

BREAD project, Broadband access for all in Europe
Mention made of African Cantenna project

Rate Switching in 802.11e, dude from Toshiba
Currently, it is impossible to change the transmission rate during a burst because of Block ACK
4 algorithms proposed to solve the problem
1) link adaptation algorithm for Block ACK
Change and compare ratio of change of rate within a burst
2) Reduce the burst size
4) A tail data packet with a higher rate is attached in every burst

Problem: 802.11 suffers from downlink throughput degradation when uplink traffic increases, cause: AP must transmit all downlink traffic and acquires the channel with the same probability as a single station, therefore to solve the prob, a new scheme is needed.
Solution: In the proposed scheme the AP has a single CSMA/CA function, this lowers prob of collision.
Proposed Scheme compared to DCF and Multiple CSMA/CA
After 26 station Multiple CSMA throughput drops
DCF and proposed scheme seem better, DCF drops off at 50

Current Frame burst handling of frame errors not efficient
Dymanic Queue prioritizing proposed.
Results show that after 30 stations, throughput decreases more in normal round robin than the proposed queue prioritization

IWS2005 Wednesday Afternoon

Power Efficient
Wireless is unrelieable, high BER
Leads to high power consumption
Use Co-operative Diversity (spatial diversity)
Does this lower transmission power of individual nodes?
hardware – Mulitple antenna on every node, minimum distance between antennas should be l/2 = 6.12 cm
software – Space -time codes, two dimensional array
Nodes with single antennas cop-operate to create a virual MIMO, which gives the same effect [Laneman et al]

IWS 2005 Tuesday

Home Networking: Sudhir Dixit, Research Fellow, Nokia Research Center
Home Networking; the next frontier (not the final frontier, coz thats been reserved for space)

DLNA consortium
DLNA Vision, promote interoperaability between home networked devices.

Media Exchange protocols for home networks, Edwin Heredia, Microsoft

Location based services, Paul Wisner, Nokia
Based on Nokia 6630, uses Discovery Protocols: Bluetooth SDP and UPnP
Others: SLP and JINI
Nokia Approach: Everything is aware of its own location, proximity is determined by comparisn
Map location to position, position determined from GPS, WLAN triangulation etc.
Desktop on mobile device shows reachable services

Usable Security in Smart Homes, Saad Shakshir, Nokia Research

Hot Topics: MIMO
What is MIMO?
Definition: MIMO

IWS2005 Tues Afternoon

Duplicate Address Detection in OLSR networks, Thomas Clausen, Inria

MANETS: Mobile Adhoc Networks, do not comply with traditional internet hypothesis
Networks split and re-combine and may cause address conflicts.
DHCP is statefull , server based and sensitive to partitioning
IPV6 also has similar problems
Pro-active protocol
Inspired by NOA OLSR and PACMAN
The proposed solution is to use link state messages to determine the occurance of duplicate addresses and initiate self address change in case of detection

AD-hoc network applcations and technical issues, Dude from Hitachi
3 uses for ad-hoc:
specialized, e.g miltary, emergency, disaster
enterprise e.g. office, home
consumer e.g. community
Town security System with wireless cameras, Tracking, Cellular phones using ad-hoc networking to bypass network
ITS service systems
3 test systems
Security system with 8 olsr nodes, cameras and pda
Car mobile network with auto handover between wilan and cellular, using olsr and mobile IPv6

International Wireless Summit 2005

International Wireless Summit 2005, Aalborg, Denmark

The international wireless summit has just kicked off and I have the privilege of being amongst some of the greatest think-tanks in the wireless arena.

The aim of the IWS is to offer a platform for establishing exchanges of information between universities, industry and science parks. The next summit will be in 2008 in Helsinki, Finland.

International Wireless Symposium aims to exchange research information. 450 papers to be presented on “hot topics”.

Prof. Ramjee Prasad giving introductory speech.

Prof. Ramjee Prasad predicts that the future of wireless comms will be based on single layer technology, not quite sure what is meant by this though.

“Personal Networks are going to be of major importance in future business…”

The next Big thing….

Mobile companies have spotted it a while ago and its already filtered through to service providers in the form of “look-for-me” type services. But one company has just launched location based services and perhaps the Internet to a whole new level; Hello Google Earth. Its been a while since anything in the pc/cyber world has slapped a wow at me and it was worth the wait! The uses are already incredible and the possibilities are amazing. Imagine browsing the net by finding pages based on where they’re physically kept, like spinning the globe to Google headquartes to launch a google search?

Have to interrupt this transmission, but will resume later…