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Wireless Architecture Considerations
Published in Ali Youssef, Douglas McDonald II, Jon Linton, Bob Zemke, Aaron Earle, Wi-Fi Enabled Healthcare, 2014
Ali Youssef, Douglas McDonald II, Jon Linton, Bob Zemke, Aaron Earle
Wi-Fi networks are a marriage between client devices and access points, which are referred to as stations (STAs) and APs, respectively. These entities have a few things in common yet maintain some clear differences. The APs communicate regularly with everyone around him or her, making sure that the STAs have the correct time and notifying the STAs when it is time to wake and do some work. STAs, on the other hand, are either receiving and sending packets or notifying the APs that they are going to sleep to conserve some energy. This analogy is meant to entertain but at the same time drive home the principle that a successful network design balances the needs of the AP and the STA client devices. Let’s start with the AP. The AP is what creates a BSS or Basic Service Set. This is kind of like a date. It is just a concept not an actual measurable entity. If the BSS is extended over several APs, then we can call it an ESS or Extended Service Set. This is a little more like a marriage than a date. An ESS allows the STA to maintain a relationship with the network regardless of which AP it is communicating with. So, the BSS and ESS are a concept that is central to wireless local area network (WLAN) principles. Every BSS will have a BSSID, which is a media access control (MAC) address, of the APs radio and may look something like this: 00-c0-f ee-12-34.
Introduction to Wireless Mesh Networking
Published in Gilbert Held, Wireless Mesh Networks, 2005
The grouping of two or more wireless LAN devices results in the formation of a service set. The actual type of service set that is formed depends upon the type of wireless LAN devices and the manner by which they communicate. When two or more clients communicate directly with each other (known as peer-to-peer or ad hoc communications), they form what is referred to as an independent basic service set. In comparison, when one or more clients communicate via the use of an access point, the AP and clients form an infrastructure service set. Because both an independent service set and an infrastructure service set have the same initials (ISS), we do not use these initial abbreviations due to possible confusion.
A distribute and self-tuning wireless environment monitoring system for buildings based on the Wi-Fi Direct technology
Published in Science and Technology for the Built Environment, 2018
When a new sensor node is added into the network, it will try to find an accessible node. The newcomer would have found more than one candidate superior node in different hierarchies. For example, sensor 9 will find that it can access sensor 5, sensor 4, and sensor 2 within the limitation of received signal strength indication (RSSI) and these nodes are marked as being able to reach the root node. If sensor 4 is busy or the number of subordinate nodes has exceeded the limitation, sensor 9 will try sensor 5 then sensor 3 in random order. When sensor 9 joins a node successfully, it will record the node as its superior point and try to join it next time. A mark will be added to service set identifier (SSID) when a node has joined successfully to tell other newcomers that it can reach the root node.