Resource allocation using ASK, FSK and PSK modulation techniques with varying M

Communicating effectively over a large distance has always been the quest of engineers and scientists and with the transition of modern day systems from analog to digital, has further complicated the scenario. Several modulation techniques like the AM and FM, have been tried and tested in the past century to get the desired analog signal at the receiver. But with the introduction of digital systems we find ourselves in the time of ever increasing demand for high data rates and optimum bandwidth usage. This has forced us to look for better modulation techniques with higher immunity to environmental noise and channel distortion. But implementation of these digital modulation schemes like the Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK) and Phase Shift Keying (PSK) comes with a tradeoff. There is a compromise that needs to be made between the available bandwidth and the number of bits/symbol that can be sent over the line, which in turn limits the maximum data rate on the link. Thus choice of digital modulation schemes is absolutely critical, especially in an environment like the satellite uplink - downlink where resources are very limited and time slots are auctioned at very high rates. The intent of the paper will be to show the effect of varying M, when applied to the modulation schemes, which can be then selected to achieve the best performance in an outer space communication link. Having this knowledge of the resources needed to maintain an acceptable Bit Error Rate (BER), it will be possible to change the modulation scheme during sudden environmental changes, like rainfall, stand storms and tornadoes to sustain the communication link.