Wireless Signals and Signal Processing

 Signal Processing: The Science Behind Our Digital Life

- Advanced Signal Processing Helps 5G Achieve Speed Targets

The current generation, 4G, works well for individuals, but can suffer bottlenecks when large groups of people in the same area use a network simultaneously. The new standard solves this congestion problem, potentially offering a 1 000x capacity improvement compared to 4G.

The use of smaller base stations, exploitation of higher frequencies and millimetre waves, and the expansion towards massive multiple‐input multiple‐output makes beamforming one of the most important key technologies in 5G systems. Besides the energy efficiency enhancements because of the narrower beamwidths, it reduces the broadcasting probability by adaptively steering the signals towards the targeted receivers while reducing the reception for nearby receiver, that is less interference. It also increases the energy efficiency of the signals because of the narrow beamwidth. 

Regarding radio communications, a range of radio frequencies is called a band. Each user, or antenna, is allocated a certain small slice. It is like how individual radio stations are described as broadcasting on a certain allocated frequency (called centre frequency), yet in fact they broadcast slightly to either side of that as well. 

In current systems (4G/LTE), only one centre frequency can be used at a time, because otherwise transmissions would interfere with each other. The 5G approach allows duplicate use of each frequency by introducing controlled directionality to the transmission and reception radio beams.