Many people coming to WiMAX are familiar with either WLAN or cellular formats. Mobile WiMAX signals conceptually combine elements of both types of signals, but with many novel aspects. The 5 ms frame timing is similar to GSM, as is the use of a Base Station derived "rubber clock" in the mobile. The use of multiple orthogonal sub-carriers is familiar from WLAN, as are some aspects of the MIMO operation. What's new is a kind of symbol by symbol frequency hopping to provide frequency diversity, and the introduction of "collaborative" MIMO to help spectrum efficiency in the Uplink. This short presentation uses pictures instead of maths to bring out what the resultant signals look like. It also shows how key measurements can be quickly and effectively made on what are some of the most complex radio signals we've yet encountered.
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