RECEIVER SENSITIVITY AND LINK COVERAGE

For given modulation scheme and propagation medium the desired Bit Error Rate (BER) gives the required SNR at the receiver input. In this work BER of 10-4 is considered and sensitivity of the receiver is defined by the minimum SNR of the input signal for which BER of the receiver becomes 10-4. Agilent N5182A mixed signal generator is used to generate GFSK modulated signal of known bit sequence. The bit sequence consists of six bytes of preambles, four bytes of synchronization word and 256 bytes of information. Modulated signal is fed to RF input of RTL-SDR using RF cable. Received signal is then demodulated by the receiver as given in section-3 and BER is computed. Power of modulated signal is decreased in steps and corresponding BER are obtained. SNR for which BER is of the order of 10-4 is then recorded as receiver sensitivity.
Measured sensitivity of the receiver for various modulation parameters are given in Table 6.
Table 6: Receiver sensitivity for different modulation parameters