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