The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.
This application claims benefit of 60/449,602 Feb. 24, 2003 and claims benefit of 60/466,448 Apr. 29, 2003 and claims benefit of 60/472,320 May 21, 2003 and claims benefit of 60/472,239 May 21, 2003.
A Dynamically Reconfigurable Dynamic Wireless Network for connecting a local area network ("LAN") to wireless Mobile Stations. Backbone Access Points ("Backbone APs") are physically connected to the LAN. Levels of Wireless Access Points ("Wireless APs") are daisy-chained together and connected to the Backbone AP, providing an extended area of network coverage. Mobile stations are connected to either Backbone APs or Wireless APs. Dynamic Reconfiguration prevents single point failures. Each AP contains a router, Address Resolution Protocol ("ARP") cache, and Distributed Routing Table ("DR Table"). The DR Table maintains the Media Access Control ("MAC") address and the Internet Protocol ("IP") address of each AP below it in the Distributed Routing Tree. Additionally, each DR Table also maintains the IP address for the device each AP is connected. The Distributed Routing Tree is dynamically reconfigured to minimize transmission hops or to maximize signal strength between Mobile Stations and the LAN.
Disclosed herein is a multi-band ZigBee transceiver for supporting IEEE 802.15.4 wireless communications. In the multi-band ZigBee transceiver, a Multi-Mode Modem (MMM) selects any one of a European version standard using 860 MHz band, a US version standard using 920 MHz band, and a worldwide version standard using 2.4 GHz ISM band among IEEE 802.15.4 standards. A frequency synthesizing unit variably adjusts a carrier frequency according to the transmission standard. A transmission unit receives a digital modulated signal, low-pass-filters the digital modulated signal with a bandwidth thereof being variably adjusted, and up-converts the filtered digital modulated signal into an RF modulated signal corresponding to the selected transmission channel. A receiving unit down-converts the RF modulated signal into a BB modulated signal using the carrier frequency, low-pass-filters the BB modulated signal with a bandwidth thereof being variably adjusted according to the selected transmission standard, converts the filtered BB modulated signal into a digital modulated signal, and outputs the digital modulated signal to the MMM. A transmission/reception switch unit outputs the RF modulated signal, input from the transmission unit, to an antenna, or outputs the RF modulated signal, received from the antenna, to the receiving unit.
The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.
