User's Manual

Chapter 3 - Operation and AdministrationBS Menu
Chapter 3: Operation and Administration
BS Menu
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BreezeCOMPACT System ManualBreezeCOMPACT System Manual
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3.7.2.5.4 Ducting Mitigation Mode
Sudden changes in the atmosphere's moisture and temperature profiles can on random occasions make radio signals
propagate hundreds of kilometers and even more, far beyond the normal radio horizon. When a BS suffers from such
tropospheric ducting phenomena, which causes reception of a relatively strong signal transmitted by a very far BTS, the
Ducting Mitigation feature enables increasing the time period between DL and UL transmissions to reduce potential
interference effects. This is achieved by adding DL Silenced Symbols and, if necessary, changing the number of Extra TTG
slots (see below). This results in reducing the actual UL Duration by 1 slot (Medium Ducting Mitigation Mode) or 2 slots
(High Ducting Mitigation Mode) without affecting the number of DL symbols (for the same combination of Configured
Total Uplink Duration and Maximum Cell Radius).
Note that for certain values of configured Total Uplink Duration, the High and/or Medium options are not available since the
minimum uplink duration is 4 slots for a BS bandwidth of 5/10 MHz or 3 slots for a BS bandwidth of 7 MHz.
The options are None, Medium or High.
The default is None.
Table 20: Functionality of Allowed Ducting Mitigation Modes, 5/10 MHz BS Bandwidth
Configured
Total Uplink
Duration
(Slots)
Mitigation
Mode
Maximum Cell
Radius (Km)
Extra TTG
(Symbols)
Added DL
Silenced
Symbols
Actual
Uplink
Duration
(Slots)
DL
Symbols
4 None 1, 2, 4, 8 0 0 5 34
15, 23, 30 2 0 4 32
Medium N/A
High N/A
5 None 1, 2, 4, 8, 15, 23 1 0 5 30
30 3 0 5 28
Medium 1, 2, 4, 8 0 4 4 30
15, 23 2 2 4 30
30 2 4 4 28
High N/A
6 None 1, 2, 4, 8 0 0 6 28
15, 23, 30 2 0 6 26
Medium 1, 2, 4, 8 1 2 5 28
15, 23 1 4 5 26
30 3 2 5 26
High 1, 2, 4, 8 0 6 4 28
15, 23, 30 2 6 4 26