Motorola 5440AP User Manual - Page 12

Canopy 400 Series OFDM AP and SM User Guide 3 Planning Canopy 400 Series products use a 10 MHz channel size configurable on 5 MHz centers. This channel size, along with some different characteristics due to the use OFDM carrier technology and QPSK, 16 QAM, or 64 QAM modulation, supports somewhat different channel planning than for standard Canopy. (For reference, standard Canopy uses 20 MHz channels configurable on 5 MHz centers, single carrier technology, and 2-level and 4-level FSK modulation.) 3.1 TOWER CHANNEL PLANNING For a single cluster of 4 APs on a tower, 2-channel re-use with channels on 10 MHz channel center spacing gives good performance. In channel design parlance, this can be stated as ABAB channel planning, with no guard band needed between A and B. A typical arrangement might be to use radios configured for 5480 MHz aimed north and south, and radios configured for 5490 MHz aimed east and west. (For reference, standard Canopy uses 2-channel re-use with clusters of 6 APs on a tower with channel center spacing of either 25 MHz for Advantage APs or 20 MHz for non-Advantage APs. This is ABCABC channel planning, with 5 MHz guard band between the 20 MHz channels for Advantage APs and no guard band needed for non-Advantage.) Available channel center frequencies for each region are shown in Table 2. These vary by region due to • different band edge RF specifications (for example, between Canada/US and Europe) • requirements in Europe and Canada to not impinge on the frequencies between 5600 and 5650 MHz, which are frequencies on which some weather radar operate Table 2: Channel Center Frequencies, by Region Region US Canada Europe US FSK (for comparison) Canada FSK (for comparison) Range of Center Frequencies Available (MHz) (on 5 MHz centers within this range, inclusive) 5480 - 5710 5480 - 5595, 5655 - 5710 5475 - 5595, 5655 - 5715 5495 - 5705 5495 - 5575, 5675 - 5705 The best practice for channel planning for APs is to conduct extensive site RF surveys before choosing channels. For those with the equipment and expertise, use commercial and industrial spectrum analysis equipment. The Canopy 400 Series APs and SMs do not provide a spectrum analyzer in the first release (planned for a subsequent release), but standard 5.4 GHz FSK SMs can be used to give useful information on the RF environment in the planned Canopy 400 Series AP deployment location. 3.2 DOWNTILT The standard AP antenna produces a 3 db beam elevation (up and down) of 5°, with near-in null fill that allows good coverage of close-in SMs that otherwise would be affected by the narrow pattern. This is a narrower pattern than operators may be used to with standard Canopy's 60° 3 dB beam, and may require downtilt on the antenna. The standard antenna has provision for measured downtilt. The operator should estimate downtilt based on antenna height above the Version 1, April 2008 Page 12 of 40