Motorola 5440AP User Manual - Page 13

Canopy 400 Series OFDM AP and SM User Guide service area and using one of the many radio analysis and mapping tools or on-line calculation tools for calculating downtilt. 3.3 WEATHER RADAR Spectrum between 5600 and 5650 MHz (sometimes called the "weather notch") is used by some weather radar and is not allowed for use by regulations in some regions, including Canada and, for new equipment, Europe. When the Canopy module is set to one of those regions (configured on the "Configuration => General" page of the module), it will not allow configuration of the appropriate frequencies, as shown in Table 2. Even in regions where use of the spectrum between 5600 and 5650 MHz is allowed, such as the US, the best practice is to not use these channels if there are any other usable channels available. Only use the channels in this "weather notch" after performing long-term site surveys (minimum of a week) to ascertain the spectrum is clear and that there don't appear to be any weather radar in the area that will cause interference to your Canopy system. 3.4 RANGE AND THROUGHPUT PLANNING Canopy 400 Series APs can provide 21 Mbps aggregate throughput at distances of 1.25 mi (~1 km) in RF environments with clear line-of-sight and low background interference levels. Additional performance details are shown in Table 1 on page 11. RF environments with occluded Fresnel zones or higher background interference levels may give lower, but still give very good, performance, depending on the specifics of the environment. Similar to standard Canopy, at any given instant, any radios not operating at 3X take twice (for 2X) or three times (for 1X) as much "air time" to transmit a given amount of data as if they were running at 3X. Similar to standard Canopy, Canopy 400 Series modules may see reduced total throughput when handling traffic with a high percentage of small packets. The effect of this, again similar to standard Canopy, is that at any given instant total throughput depends on • Mix of links running at 3X, 2X, and 1X • Mix of packet sizes 3.5 COLLOCATION WITH STANDARD 5.4 GHZ CANOPY FSK When locating 5.4 GHz Canopy 400 Series OFDM APs near 5.4 GHz standard Canopy FSK APs (especially on the same tower, but also in the same geographical area), the following practices should be followed to avoid interference between the two systems: • Plan spacing between OFDM and FSK channels to provide 25 MHz center spacing, which gives a 10 MHz guard band between the 10 MHz OFDM channel and the 20 MHz FSK channel. • Coordinate Downlink Data %, Range, and Control Slot settings using both the OFDM and the FSK frame calculators The following paragraphs give more details on these recommended practices. 3.5.1 Channel Spacing Center spacing of 25 MHz between collocated FSK and OFDM APs provides a 5 MHz guard band between the 20 MHz and 10 MHz channels, which has proven useful and needed in field testing. Alternatively, in cases where channel planning is severely restricted and the 5 MHz guard band (25 MHz spacing) is not possible, using vertical separation of 5 feet or more between the OFDM and FSK APs may allow collocation with no guard band (20 MHz spacing) in some deployments. Version 1, April 2008 Page 13 of 40