User's Manual

2-28
BreezeACCESS 4.0 Operations and Administration
Manual Revision: 1.01
! Hopping Shift –Displays the current Hopping Shift parameter and
allows entry of a new value. Available only in AUs. All the associated
SUs learn the value of the Hopping Shift parameter from the AU
during the association process. The Hopping Shift parameter is
used to provide different operational hopping sequences when
several co-located Access Units use the same set of hopping
frequencies and the same scrambling method (and hence the same
basic hopping sequence). Correct selection of different hopping shift
values for adjascent AUs will minimize the cross interference
among these AUs and will allow for better spectrum utilization.
When setting this parameter, consider the following relationship:
Max. Hopping Shift (channels) = Number of hopping frequencies-1.
The method of using the Hopping Shift for generating the actual
hopping sequences depends on the method used for defining the
basic hopping sequence: ISM Standard Sequence, Standard
Scrambling, Enhanced Scrambling or Manual Sequence Definition.
" ISM Hopping Sequence:
If ISM US FCC or ISM International hopping standard is
used, the shift operation is performed on the channels
(frequencies) of the basic hopping sequence. The actual
hopping channel (frequency) is calculating by adding the
value of the Hopping Shift to the channel (frequency) of the
basic hopping sequence. Note that the sequence is cyclic,
meaning that adding 1 to channel 80 which is the highest
channel, will result in channel 2 which is the lowest channel
in the sequence. See Table 2-3 for an example of the actual
hopping sequence with a hopping shift of 3.
When using the ISM hopping standard, it is recommended
that the difference in the values of the hopping shifts used
by the units in any two adjacent sectors will be 3 (e.g. 0, 3,
6, …) to minimize cross interference.