What is a Hopping Sequence Number?

It is a gsm parameter ranges 0-63.It is use to reduce interference.Frequency hopping occurs according to the HSN number within the MA list.

The HSN is used to define the hopping sequence from one frequency list

Hopping Sequence Number is used to define the hopping sequence from one frequency list.It is a number that defines the frequency hopping algorithm, and can vary from 0 to 63, i.e there are 64 hopping algorithms to be used in GSM.

its the code that defines the manner  the signal is hopping around in frequency domain .

Hopping Sequence no defines the algorithm of Hopping frequency i.e 0 means cyclic algorithm. The range of HSN is 0-64 

Hopping Sequence Number or HSN in short, is cell-parameter that defines the frequency hopping sequence. It takes the values from 0 up to 63, where the value 0 means the hopping sequence is cyclic  i,e. ( f1,f2,f3,f4,....,fn where f1,f2,.. are the frequencies available in the MA list ). And the values from 1 to 63 corresponds to pseudo-random hopping sequences.

HSN and MAIO should be planned carefully to ensure minimum probability of two or more TCHs are assigned the same frequency at the same time.

Hopping Sequence Number  (HSN) is a number that defines the sequence of Time Slots (TS) will be used by the users, if equals Zero the TS will be used in order (i.e TS0,TS1,TS2,...)