8.In
Usually, DECT wave is attenuated by reflection indoors. In order to minimize attenuation, when you install a base station on the wall, give at least
The best communication environment is when a base station and a user are in the same height. In office environment, however, it is desirable to consider office furniture to minimize reflection, diffraction and scattering of DECT wave when you set the position of a base station.
The appropriate position for a base station is where 1.8meter above from the floor and 0.5 meter below from the ceiling. The top of iron office furniture such as a cabinet or a desk is not a good position. Keep away from electronic equipment such as a copy machine, a printer or a computer. And the lower wall of a corridor where many people pass by, corner of a wall, and narrow indoors also should be avoided.
Attenuation
When determining the location of base station, you should consider the effects of attenuation. Attenuation is the loss of strength of a RF signal due to distance, antenna positioning, and obstructions. The guidelines provided in Location of Base Station on
The magnitude of change in signal strength is measured in decibel(dB). Increasing or reducing of 3dB results in doubling or halving signal power strength.
Distance
[Table 3.6.1] shows the signal attenuation caused by distance in direct line of sight condition.
Distance | Attenuation (dB) |
1 meter | 0 |
10 meters | 20 |
100 meters | 40 |
1000 meters | 60 |
[Table 3.6.1] Signal Attenuation in Direct Line of Sight Condition
Obstructions
RF signals are also attenuated by obstructions in their paths. [Table 3.6.2] shows the attenuation caused by common materials in a building. You should try to limit the loss to 60dB.
Object | Approximate Loss in dB |
|
|
Concrete | 15 |
with metal siding | 30 |
with window | 8 to 9 |
Venetian blinds | 10 |
Open | |
Closed | 20 |
Soft partitioning | 3 to 4 |
|
|
[Table 3.6.2] Signal Attenuation Caused by Building Materials
Although signals can travel through obstacles, you should place base stations so that signals begin their travel with a clear line of sight and travel through obstacles afterwards. In the example shown in Figure 3.6.12, the base station is placed to maximize line of sight in both corridors.
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