Wireless Networks

Wireless Local Area Network (WLAN) links devices via radio signal. WLAN is a handy alternative to cabled LAN, especially when you want to build up an ad hoc network for a judo tournament. WLANs seem to be quite reliable, at least to a certain extent. You should be aware of the following challenges:

  • Co-channel interference. This signal transmission problem occurs when two access points are operating on the same channel and they attempt to transmit at the same time. Many wireless products ship with a default channel of 6 and people do not bother to change it.
  • Interference from other equipment. Cordless microphones or speakers, microwave ovens, and even remote control toys can interfere with your WLAN network.
  • Edge-user and mixed mode problems. An edge user in a cell-based topology is someone who is too far away from the access point to connect at the highest possible data rate. When the connection is eventually made, at a slower speed, other users are forced to connect at a slower speed as well, due to the amount of time required for the edge user to transmit its data packets.
  • Network security. Security in wireless networking systems continues to be a major concern.
  • Tournament site layout. You will have constraints on how to place your equipment. Range of the WLAN may not be sufficient. A general rule of thumb says that 802.11b and 802.11g routers support a range of up to 40 m indoors. Obstructions such as brick walls and metal frames or siding greatly can reduce the range of a WLAN by 25% or more.

Follow these basic rules to enhance the network reliability:

  • Position your wireless router in a central location
  • Move the router off the floor and away from walls and metal objects.
  • Add a wireless repeater. Wireless repeaters extend your wireless network range without requiring you to add any wiring.
  • Change your wireless channel to an unused one. Both channels 1 and 11 do not overlap with the default channel 6.
  • Reduce wireless interference. Avoid wireless electronics that use the 2.4 GHz frequency.

To be on the safe side:

  • Use wired connections between JudoShiai and JudoTimer computers.
  • Wireless connections are suitable only for non-critical applications such as JudoInfo.