Voice over WLAN Mobile IP Touch Design Guide R2.0
As stated above, inserting IEEE 802.11b clients such as MIPT terminals, into an IEEE 802.11g network
results in a significant bandwidth reduction. This type of bandwidth sharing also results in a compromise
in the maximum number of simultaneous calls per Access Point. The following table highlights the
impacts of sharing bandwidth for both voice and data clients. Care should be taken during the design
process to ensure that the engineered maximum number of simultaneous calls per Access Point (managed
by the SVP Server) spares enough bandwidth to service data network requirements.
Security Codec
Number
of
sets
Available
bandwidth (Data)
G.711 8
6,5
Mbps
wpa2-psk
G.729 10
5,5
Mbps
3.7.1.3. Voice on 802.11b, Data on 802.11a
Because IEEE 802.11a utilizes the 5 GHz wireless spectrum, it offers no direct radio competition to
VoWLAN solutions that require use of the 2.4 GHz IEEE 802.11b realm. This is an ideal situation that
offers the greatest benefit for both voice and data subscribers. A a result of the lack of frequency
competition, VoWLAN elements are free to utilize the full theoretical 11 Mbps (less overhead and
signaling) of the IEEE 802.11b network. Congestion and competition is reduced or eliminated, resulting
in the highest possible levels of service and voice quality.
This full separation of networks is also of great advantage to data subscribers, as the bandwidth hungry
applications found on data clients can gain access to the full theoretical 54 Mbps of IEEE 802.11a
technology, as well as benefit greatly from the density and coverage capabilities of the 10-13 non-
overlapping channels (depending on local market restrictions) it makes available.
Customers seeking this type of solution can unify the infrastructure elements by using Alcatel-Lucent’s
OmniAccess product suite for both Wi-Fi formats. Alcatel-Lucent’s OmniAccess 70 Access Point can be
effectively leveraged to construct networks for both 2.4 GHz (802.11b/g) and 5 GHz (802.11a) networks
simultaneously. For more detailed product information, visit :
http://www.alcatel-lucent.com/wps/portal/enterprise
.
3.7.1.4. Partially Overlapping Voice and Data Networks on 802.11b/g (isolated applicability)
In some cases, a customer may implement IEEE 802.11b for voice and choose to restrict Wi-Fi data client
access for security or productivity reasons. This same customer may decide that Wi-Fi data access is
desirable in very specific and isolated environments (a shipping dock, cafeteria, large auditorium, etc.)
For cost control and access flexibility the customer may desire to service these isolated data applications
with IEEE 802.11b. This can present channel overlap challenges.
Similar situations can be encountered when a customer network closely neighbors another Wi-Fi
environment. Hot-Spots, Cyber Café, or Wi-Fi radio propagation from the building across the street can
all present direct channel competition. ue to the distinct channel selection options available, with
careful planning it is usually possible to adapt to these types of network settings. Care must be taken to
ensure that the data environment does not pose significant impact to the voice solution.
ESD/ Central Pre Sales / DF/ PH
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January 2007 – Ed 01
