Specifications

Basic Cell Planning 19
For handover times with different security settings on particular WLAN infrastructure, see the ap-
propriate configuration notes in respective VoWiFi configuration manual.
The following security functions are not recommended:
• WEP is not recommended.
• Shared key authentication should be avoided since this authentication scheme makes it easier
to crack the encryption key.
• MAC address filtering is not recommended because it does not provide any real protection, only
increased administration.
• Hidden SSID is not recommended because it does not provide any real protection and it makes
it more difficult for WLAN clients to roam passively.
Certificate
NOTE: Only applicable for handset.
In addition to above security measures, the use of a certificate can help to secure the wireless con-
nection. Once downloaded to the handset, the certificate gives as a permanent access right au-
thentication to the specific user of the handset.
The reverse of the medal is that the handling of the handset is troublesome when using a certifi-
cate. A Site Administrator has to handle the administration, which can not be done by the user (it
requires the PDM software and the OpenStage WL3 Desktop Programmer cradle ). The Adminis
-
trator must also avoid mixing the handsets when handing them out to the right user.
NOTE: When using a certificate in a handset, the shared phone function cannot be used.
Basic Cell Planning
Cell planning for traditional cordless telephony systems (DECT) deals with coverage and addition-
al capacity reinforcement. Normally, a sufficient number of channels are available to plan the cells
for frequency reuse at a distance large enough to limit the effects of co-channel interference.
2.4 GHz-radio b/g/n, Handsets
IEEE 802.11 operation in the 2.4 GHz band only provides the use of three non-overlapping chan-
nels, channel 1, 6 and 11. Use of other channels than 1, 6 and 11 has a negative impact on per-
formance in the system since those channels will interfere with each other. The usage of channels
other than 1, 6 and 11 will cause a performance reduction. This is not only due to RF interference,
but also due to the protocol specification.
Existing systems deployed using four channels (1, 5, 9 and 13) may still may be used. When four-
channel systems are used (and 802.11b rates are enabled) there is a risk of increased adjacent
channel interference and packet loss, especially when other (three-channel) systems are in the
proximity. This may increase with higher channel utilization and traffic load.
NOTE: The use of 802.11n 40 MHz double channels is not recommended since the amount of
channels will be reduced to only two (ETSI) or one (FCC).
5.0 GHz-radio a/n, Handsets
In the 5 GHz band there are plenty of non-overlapping channels to choose from. The specific us-
age and amount of channels that can be used varies with country regulations. The support of the
802.11d in an AP and in the handset will automatically adjust the usage to the so called regulatory
domain.