Ubee Interactive
Deploying and Troubleshooting the Wireless Network
Ubee DDW3611 Wireless Cable Modem Gateway Subscriber User Guide • November 2012
67
6.4.1
Understanding Received Signal Strength
Received signal strength (RSSI) is measured from connected wireless client devices to
the wireless cable modem. This value can significantly impact wireless
speeds/performance. It is determined by:
Materials (for example, open air, concrete, trees)
Distance between wireless clients and the wireless cable modem
Wireless capabilities of the client devices
To determine the received signal strength, refer to
Using the Access Control Option on
page 65
and review the
RSSI
value. A receive signal strength indicator between 0 and -64
is considered optimal. Levels of -67dBm and lower (for example, -70, -80, etc.) have a
downward impact on wireless data throughput.
6.4.2
Estimating Wireless Cable Modem to Wireless Client Distances
The information in this section helps you to determine how far a wireless cable modem
can be placed from wireless client devices. Environmental variances include the
capabilities of wireless clients and the types of material through which the wireless signal
must pass. When the wireless cable modem and wireless clients reach the distance
threshold between each other, network performance degrades.
Steps
To determine wireless cable modem placement:
1. Connect a wireless client to the wireless cable modem. Refer to
Connecting Devices to
the Network on page 12
if needed.
2. Place the wireless client at around one meter (three feet) away from the wireless cable
modem.
3. Obtain the
RSSI
value for the connected client. Refer to
Using the Access Control
Option on page 65
. This value is used in the formula further below.
4. Use the following table to determine what materials the wireless signal must travel
through to reach the desired wireless coverage distance.
Attenuation Considerations at 2.4GHz
Material
Attenuation
Connector/Cable
3.5dB
Free Space
.24dB / foot
Interior Drywall
3dB to 4dB
Cubicle Wall
2dB to 5dB
Wood Door (Hollow/Solid)
3dB to 4dB
Brick, Concrete Wall (Note 1)
6dB to 18db
