Advantages of MSK,GMSK | Disadvantages of MSK,GMSK
This page covers advantages and disadvantages of MSK or GMSK techniques. It mentions advantages of MSK or GMSK and disadvantages of MSK or GMSK.
What is MSK | What is GMSK
MSK and GMSK stands for Minimum Shift Keying and Gaussian Minimum Shift Keying respectively. GMSK is derivative of base MSK modulation scheme. As we know, sidebands of standard PSK modulated spectrum extend from carrier frequency. This is overcome by MSK and GMSK.
MSK is one type of FSK modulation with less occupied bandwidth.
This leads to less interference to the spectrum. MSK uses half cycle of sine wave for each
symbol. MSK with Gaussian filter gives GMSK signal.
Refer MSK and GMSK basics>> for more information.
Benefits or advantages of MSK or GMSK
Following are the benefits or advantages of MSK or GMSK:
➨The sidebands of PSK modulated spectrum is minimized by this modulation technique. Hence sideband power is reduced.
➨The MSK or GMSK spectrum is less affected by noise and hence leads to good SNR. This helps in achieving very stable and long distance communication. Due to this fact, the GMSK modulation technique is being employed in GSM technology.
➨Above fact, helps in achieving good receiver sensitivity.
➨PAPR is maintained low due to no phase continuities and occurrence of frequency changes at zero cross over of RF carrier. Due to this, highly linear PA (Power Amplifier) is not required.
➨Spectral efficiency is better and higher while demodulator is less complex.
➨GMSK provides constant envelope over the entire bandwidth. Hence it offers excellent power efficiency.
➨It provides good BER performance.
➨GMSK offers self synchronizing capabilities.
➨GMSK is good choice for voice modulation.
Drawbacks or disadvantages of MSK or GMSK
Following are the disadvantages of MSK or GMSK:
➨PSD of MSK does not fall fast and hence Interference between adjacent channels is observed. GMSK uses BT of 0.3 and hence good rejection can be achieved between adjacent channels. Here B is 3dB bandwidth of shaping filter and T is bit duration.
➨Both MSK and GMSK requires more power to transmit data compare to other modulation types such as QPSK.
➨It requires complex channel equalization algorithms e.g. adaptive equalizer at receiver.
➨Inter symbol interference may occur.