WiMax ( IEEE 802.16) stands for Worldwide Interoperability for Microwave Access and it’s used to do so called “last-mile” connection, taking advantage of MIMO. It is providing a wireless alternative for DSL and cable connections to Internet. It ‘s not same as mobile WiMax ( IEEE 802.16e), it was developed later too, and earlier standard 802.16d did not support mobility. As 802.16 refers to both it can not equal to one of them. For the record Wi-Fi hotspots use this technology to connect to Internet. WiMAX is trying to take over DSL and provide better connection to Internet in countryside.
Ultra-wideband (UWB IEEE 802.15.3a) is used primarily for short range, high performance, low-power data transfer to be used in PAN networks. It uses pulses for transmitting data that occupies the whole spectrum of UWB and this tecnique is also improved by using MIMO. It might interfere other systems if lots of units are used simultaneously in a same place and its unlicenced RF range is 3.1 to 10.6 GHz. It may die because of the high cost.
Is a wireless WPAN tecnology similar to Bluetooth, but ZigBee has a much faster response time and it’s also cheaper than Bluetooth. ZigBees characteristics are, low data rate, long battery life and good security. It operates in a mesh network so it can move data for very long distances, because the units eg. sensors can communicate with each other.
High-Speed Downlink Packet Access (HSDPA) is part of UMTS standard and used for higher data rates. Data rates used are 1,8 Mbit/s, 3,6 Mbit/s, 7,2 Mbit/s and 14,4 Mbit/s. Used beside UMTS based 3G network. It uses QPSK and 16-QAM for modulation.
OFDM and COFDM
These techniques are essentially the same. OFDM stands for (Orthogonal frequency-division multiplexing) and it is used for both wireless and wired communication. This is one of the most used technologies in wireless communincation today. It is used eg. for LTE and WiMAX In COFDM the forward error correction is applied to the signal before transmission.
Wireless USB (WUSB)
Wireless USB is a short-range(3-10 meters), high-bandwidth wireless radio communication protocol and it is pretty similar to Bluetooth and WiFi. It uses frequency band of 3.1 GHz–10.6 GHz and uses Multiband OFDM for modulation.
Near Field Communication is for short range wireless systems. It operates from distance under 0.2m, in 13.56 MHz frequency and it is compatible with RFID and thus has an advantage over Bluetooth. It also has a very short set-up time(0.1 s) as Bluetooth is set-up in 6 s. The short operating distance can also increase security.