We will see throughout this chapter several novel schemes to reduce interference of signals. This is an issue for many forms of wireless technology as the spectrum is unlicensed and shared ( we will discuss this more in the next section). Because of the fact that there may be several devices emanating RF energy in a shared space, interference will occur.
Take Bluetooth and 802.11 Wi-Fi; both operate in the shared 2.4 GHz spectrum but remain functional even in congested environments. Bluetooth Low Energy (BLE), as we will see, will randomly select one of 40-2 MHz channels as a form of frequency hopping. We see in the following figure eleven free channels (three being advertising) on BLE that have a 15% chance of collision ...
