The HSN is utilized to characterize the hopping sequence from one recurrence list. It is a number that characterizes the recurrence hopping algorithm. It can fluctuate from 0 to 63, i.e. there are 64 hopping algorithms to be utilized in GSM. The hopping sequence decides the frequencies in the MA-list are to be utilized. The HSNs 1 – 63 are pseudo irregular successions utilized in the arbitrary hopping while the HSN 0 is held for a consecutive arrangement utilized in the cyclic hopping.