The PN sequence generator produces a PN code of 256 chips length, and chip rate
R= 256 kcps (kilo chips per second).
Therefore, the chip rate
needed and the occupied bandwidth required will be independent of the number of aircraft in the network.
To simplify the problem and highlight the differences in BER due to the filters, a quadrature phase shift keying (QPSK) modulator with a chip rate
of 3.84 Mc/s followed by a single filter for each channel was used to obtain the simulation results.
The overall data bit-to-symbol mapping effectively implements a direct sequence spread spectrum (DSSS) scheme with a chip rate
of 2 Mchips/s from a data rate of 250 kbps.
Using hardware or software to create tapped delay lines at the chip rate
allows this chip's transition energy to be integrated.
The long code generator is required to generate spreading sequences at a chip rate
of 1.2288 Mcps for spreading rate 1 and 3.6864 Mcps for spreading rate 3.