LANCOM FAQ on 802.11n Wireless LAN outdoor application
Where are high-speed wireless links particularly deployed?
High speed links are especially deployed for Point-to-Point, Point-to-Multipoint und reliable Back-up connections for fibre and copper lines.
What speeds can be achieved on the LANCOM OAP-310agn Wireless and the LANCOM L-310agn Wireless and over which distances?
The OAP-310agn can achieve effective data rates of 100 Mbps and the L-310agn can achieve effective data rates of up to 130 Mbps. Depending on the Line-of-sight (LOS) visibility and the mounting height, distances over 20 km can be bridged. Further detailed information can be found by checking the antenna distance calculator.
In which scenarios can the OAP-310agn be deployed in comparison to the L-310agn?
Because of its robust, weather-proof design and extended temperature range, the LANCOM OAP-310agn can be extensively installed and deployed in outdoor environments and is ideally suited for pole mounting. The Access Point can be installed close to the antenna und does not require long antenna cables to be used. The attenuation loss due to long cables is avoided here.
Can MIMO technology be used in outdoor environments, especially when deploying P2P links?
MIMO makes use of the spatial characteristics that are primarily generated by reflections to differentiate between the data streams. However, in outdoor environments where the P2P links have a direct line of sight (LOS) connection between transmitter and receiver; the Fresnel zone will be free of obstructions. Consequently there are no reflections that can be used to differentiate between spatial streams.
For this reason, outdoor applications with 802.11n use a combination of the established polarization diversity method and MIMO technology: MIMO provides the possibility of generating multiple data streams and each stream is assigned a different polarization by using dual polarization antennas such as the LANCOM Airlancer Extender O-D9a , Airlancer Extender O-D60a and the Airlancer Extender O-D80g. For detailed information please refer to the techpaper 802.11n Outdoor.
What antennas can be used in combination with L-310agn and the OAP-310agn Access Points?
Depending on the field of application:
- For high-speed P2P links over several kilometres, the dual polarization antennas LANCOM Airlancer Extender O-D9a Antenna can be used in combination with either the L-310agn Wireless or the OAP-310agn Wireless Access Points.
- For P2P links over shorter distances the Airlancer Extender O-D60g and the Airlancer Extender O-D80g can be used.
- Outdoor campus or hotspot coverage can be achieved by deploying the OAP-310agn in Access Point mode. The Access Point is delivered with a set of three 2.5dBi gain omni antenna.
What is FBWA (Fixed Broadband Wireless Access) and when will it be supported from LANCOM?
FWBA is the frequency band between 5.725 MHz – 5.850 MHz and allows up to 4 Watt (36 dBm) of transmit power.
LANCOM Access Points already support this with UK country setting. For Rest of EU(ETSI), the feature is currently in preparation and will be available as a free upgrade in H2/2008.
What advantages does this frequency band bring to the customers?
As compared to 1 Watt transmit power in Sub band 2, this frequency band allows a transmit power of up to 4 Watts. The signal power received at a particular point is inversely proportional to the square of the distance. So theoretically quadrupling the power to 4 W doubles the distance at which the signal is received.
Please check with the regulatory body of your respective country if the use of this frequency requires prior approval.
What is DFS?
DFS stands for Dynamic frequency selection. In some countries, the European standards organization ETSI requires compliance with the DFS process for automatic channel selection in the 5 GHz band. The DFS mechanism automatically selects a free channel thereby avoided radar pulses.
Which devices are affected by the DFS regulation?
All WLAN devices that operate in the 5 GHz frequency especially devices operating in the upper 5 GHz frequencies.
The following table gives an overview:
| Frequency range* (GHz) |
Indoor / Outdoor | Max. allowed transmit power* | DFS requirement |
|---|---|---|---|
| 5.15 – 5.25 (4 Channels) |
Indoor | 200 mW | not required |
| 5.25 – 5.35 (4 Channels) |
Indoor | 200 mW | required |
| 5.470 – 5.725 (11 Channels) |
Indoor and Outdoor | 1000 mW | required |
| 5.725 – 5.850 (5 Channels) |
Indoor and Outdoor | 4000 mW | required |
Do I need to upgrade my older Access Points to DFS?
No. The regulation affects only those devices which are introduced after 01.04.2008. Devices which have been introduced before this date need not adhere to the new regulation.
Who is responsible for adhering to the DFS regulation ?
Primarily it is the WLAN operator or owner´s responsibilty to adhere to the ETSI. LANCOM WLAN Access Points already support the ETSI 301 893 Version 1.4.1.
Starting which version does LANCOM support DFS and is there a test report available?
Yes, there is a test report available and can be sent upon request.
- From Version 7.30 All LANCOM WLAN Access Points except the L-300 series
- From Version 7.52 L-310agn und L-305agn Access Points
