Studying and comparing spectrum efficiency and error probability in GMSK and DBPSK modulation schemes

Abstract

Gaussian minimum shift keying (GMSK) and differential binary phase shift keying (DBPSK) are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc). Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift ke-ying) modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error pro-bability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when re-covering a signal.

Keywords

• spectrum efficiency
• DBPSK modulation
• GMSK modulation
• error probability