WiFi is an IEEE-based specification Ð 802.11a/b/g/n and so on. 802 is the Ethernet specification and WiFi systems are really Ethernet mapped onto a radio system.
Unfortunately, there are fundamental differences (Municipal WiFi continues to struggle). Where Ethernet
detects collisions, WiFi avoids them.
So on a physical local area network, if multiple devices transmit at once, each device knows about it and stops transmitting.
In WiFi, networks have to be cleverly designed so each device can hear all the others; that way, if a device is transmitting, other devices will hear and not transmit themselves.
Hidden nodes can cause network meltdown, and municipal WiFi systems will always have hidden nodes that can't be seen by all other parts of that WiFi network, as nodes are often mobile, such as laptop users. This makes the networks expensive and not particularly reliable.
WiMax gets around these problems as the base station is always in control of who gets to talk, so there's only ever a conversation between the base station and one endpoint at a time.
The other issue is that broadband has become ubiquitous, so homes and businesses are already connected to the internet. When municipal WiFi was first rolled out, broadband was costly and not available everywhere.
Steve Kennedy
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