User:PikkuHiirri98

Binary Offset Carrier (BOC) modulation currently used in Galileo is a square sub-carrier modulation, where a signal is multiplied by a rectangular subcarrier of frequency $$f_{sc}$$ equal or higher to the  chip (CDMA) rate. Following this sub-carrier multiplication, the spectrum of the signal is divided into two parts, therefore BOC modulation is also known as a split-spectrum modulation.

BOC modulation has several variants: sine BOC (SinBOC), cosine BOC (CosBOC) , alternate BOC (AltBOC)   ,, multiplexed BOC (MBOC)     , Double BOC (DBOC) etc. and some of them have been currently selected for  Galileo GNSS signals.

A BOC waveform is typically denoted via BOC(m,n) or BOC$$(f_{sc}\;,f_c)$$, where $$f_{sc}$$ is the sub-carrier frequency, $$f_c$$ is the chip frequency, $$m=f_{sc}/f_{ref}$$, $$n=f_{sc}/f_{ref}$$, and $$f_{ref}=1.023$$ Mcps is the reference chip frequency of C/A GPS signal.

The Power Spectral Density of a BOC-modulated signal depends on the BOC modulation order $$N_{BOC}=2\frac{f_{sc}}{f_c}$$ and its derivation can be found, for example, in