The Personal Transporter (PT) came into the market in 2002. Formally known as the Segway, some projected that it would have a similar impact on society as the personal computer. But the PT has experienced several highs and lows since its launch. While celebrities such as Jackie Chan ride on the PT as an alternative transportation device (with great publicity), George W. Bush famously fell off one in 2003. In Britain, the PT can be used only within private property, but it is legal in several other European countries. In the United States, PTs are only approved for limited use in many states.

Electrical digital signal processing (DSP) is already a very cost-effective and powerful technique for wireless communications. Here we introduce its applications into the field of 100-Gbit/s coherent optical communications, which may replace the current expensive optical techniques and also improve the system performance in the presence of fibre degrading effects.

Due to demand for higher data rates in wireless communication systems, operating frequencies are being pushed higher and higher. Millimetre wave frequencies, such as 40 GHz and 60 GHz, are now considered for short-range, high data rate communication systems and positioning systems.