User's Manual

Table Of Contents
5 Radio Link Planning and Regulations
81
Table 16 – TDD Structure in TDM Mode
OFDM
Bursts
Radar
Avoidance
Range (km)
30 MHz
Band Range
(km)
15 MHz
Band Range
(km)
10 MHz
Band Range
(km)
5 MHz Band
Range (km)
10:10 1-20 1-43 1-60 1-94 1 -200
20:20 21-63 44-95 61-130 95-200 N/A
30:30 64 -145 96 -150 131 -200 N/A N/A
40:40 146 -200 151 -200 N/A N/A N/A
Secondly, the point at which a modulation mode changes for given RF conditions is more
conservative. In practice, this means that the link will typically stay in a lower modulation
mode, but with increased tolerance to RF variability.
Depending upon the link characteristic that the customer requires, this may very well be the
best choice. It increases consistency of link performance and equality in each direction as a
trade-off against maximum throughput.
CAUTION: In TDM mode, data errors may occur during channel changes on an operational
link. To minimize channel change related data errors in TDM mode, it may be appropriate to
prevent i-DFS initiated channel changes, either by barring all channels except the active
channel, or by configuring for fixed frequency operation. These steps disable the interference
avoidance mechanisms in i-DFS and should not be taken if the risk of errors due to
interference is higher than that due to channel changes.
NOTE: In TDM mode it is recommended to set the Maximum Modulation Mode to 64QAM
0.75 at both ends of the link, but preferably to the minimum mode necessary to carry the
required traffic.