Product Info

System Description WipLL Radio Technology - Physical Layer
25030311-08 Airspan Networks Inc. 2-29
Figure 2-7 displays a graph depicting the hit or blocking probability as a function of
number of interferers for different table lengths (7, 23, and 79).
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1 3 5 7 9 1113151719
N = 7 N = 23 N = 79
Figure 2-7: Hit probability as a function of active interferers
Note: The probability of collisions with 20 interferers and 79 sub-channels is
only 20%.
2.6.4.1.2. Synchronized Frequency Hopping
In most scenarios, the operator synchronizes between WipLL base-stations located
in the same coverage area. This option provides the best control over intra-system
interferences.
In this mode of operation, the available set of sub-channels is arranged in a single
hopping sequence, common to all transceivers (BSRs and SPRs) in the coverage
area. Since the table ID is identical to all radios, the only parameter that needs to be
assigned is the phase, that is, the starting point within the sequence.
By selecting the sequence appropriately, the relative frequency separation between
the transceivers remains constant over time, so that interference analysis is quite
similar to any Frequency Division Multiple Access (FDMA) system.