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WipLL Radio Technology - Physical Layer System Description
2-30 Airspan Networks Inc. 25030311-08
2.6.4.1.3. Fix Sub-Channel Assignment
In some scenarios—mainly licensed bands in which available spectrum is limited—
it is possible to create a set of “hopping” tables, each based on a single sub-channel.
Using this approach, the hopping nature of the system is actually disabled, so that
synchronization is not required. The trade-off of this approach is loss of frequency
diversity, discussed previously as a means to overcome frequency-selective fading.
Interference analysis in this mode is identical to any FDMA system.
2.6.4.2. Frequency Allocation
Figure 2-8 presents frequency allocation for three adjacent cells for the FDD and
TDD schemes. This frequency allocation is relevant only for synchronized
frequency hopping or fix sub-channel assignment options. For the unsynchronized
frequency hopping option described previously, orthogonal frequency tables are
assigned instead of specific sub-channels (or phases). As described in Section 2.6.3,
“Interference Analysis”, 60-dB isolation between co-located BSRs is assumed for
the TDD allocation.
Figure 2-8: Frequency Allocation FDD (left) and TDD (right)