ASCOM Myco 3 - Page 20

The Handset as a WLAN Wireless Client
TROUBLESHOOTING GUIDE
Ascom Myco 3
The list of recommendations includes the following:
1. Limit the number of channels to scan in order to shorten the scan time and improve both the handset
and
the system performance:
− Enable 802.11k in infrastructure.
When 802.11k is used, each AP holds a list of the channels used by its neighbours, and sends this list
to newly associated clients. Then the handset only needs to scan the channels present in the latest
received Neighbour List when trying to roam from an AP. In this setup, a full scan of all channels will
only be performed if the Ascom Myco 3 has failed to find a roaming candidate in the Neighbour List.
It is of vital importance to the roaming performance that the APs deliver a good quality
Neighbour List when 802.11k is used.
Similar functionality is achieved with the part in 802.11v standard called BSS Transition
Management. With this functionality the handset will ask the AP for the best roaming
candidates and then scan in a way similar to when receiving a neighbour list.
− The amount of channels enabled on the handset should be minimized to the channels that are used
in the WLAN system. For information on how to limit the amount of channels, please refer to
Configuration Manual, Ascom Myco 3, TD 93309EN.
− Only use a limited number of channels for all AP in the installation, preferably limit the amount upto
eight channels. This is especially important when 802.11k is not used.
2. If possible, avoid using DFS channels where only time-consuming passive scanning can be performed.
3. If possible, avoid using channel bonding i.e. 40 or 80 MHz channels, as it will increase the use of DFS
channels as well as increase the scan time.
4. Use 802.11r fast roaming to ensure lowest roaming times and best audio performance when moving
between APs.
The table below gives an overview of the configuration recommendations to achieve optimal performance
for VoWiFi and/ or transmission of critical mission data.
VoWiFi and / or mission-critical data
802.11 krv Number of
channels
1
DFS Channel
bonding
Band 802.11ac
Optimal Used Limited to 8 Not used Not used 5GHz Used
Allowed Used Limited Used as few
as possible
Preferably
not used
5GHz and
2.4GHz
Used
Not optimal Not used Not limited Used Used
5GHz and
2.4GHz
Not used
1. Regardless of number of channels used, the amount of channels enabled on the handset should be minimized to the channels
that are used in the WLAN system. For information on how to limit the amount of channels, please refer to Configuration Manual,
Ascom Myco 3, TD 93309EN.
14
TD 93297EN / 19 December 2019 / Ver. B