Motorola 5440AP User Manual - Page 25

Canopy 400 Series OFDM AP and SM User Guide Similarly for the AP, enter the antenna gain in the External Antenna Gain field. The standard antenna sold with the AP has a 17 dBi gain. Typical External Antenna Gain values are shown in Table 5. Table 5: Typical "External Antenna Gain" Values For this installation Canopy 400 Series AP with standard connectorized 17 dBi antenna Canopy 400 Series AP with other antenna Canopy 400 Series SM Enter this value in the "External Antenna Gain" field 17 The dBi of the antenna 17 The value entered in the External Gain field does not affect the transmitter power. The radio transmits at the level entered in the Transmitter Output Power. The module only uses the values entered in the External Antenna Gain field to adjust DFS sensitivity, not to change transmitter power. 4.5 OTHER CONFIGURABLE PARAMETERS Other parameters are configured the same as they are in standard Canopy. These include, High Priority/DiffServ, NAT, DHCP, VLAN, MIR, and CIR. MIR and CIR work the same as in standard Canopy, but the operator may (or may not) want to take advantage of the higher MIR possible to provide greater bandwidth to a given SM. 4.6 PARAMETERS THAT ARE NOT CONFIGURABLE Canopy 400 Series radios use FEC (Forward Error Correction) to extend the range of the modules. They use Reed-Solomon error correction optimized at 3/4 coding. The coding rate is not settable by the operator. OFDM technology uses a cyclic prefix, where a portion of the end of a symbol (slot) is repeated at the beginning of the symbol (slot) to allow multipathing to settle before receiving the desired data. The initial release of Canopy 400 Series radios use a cyclic prefix of 1/4 that is not configurable by the user. This means that for every 4 bits of throughput data transmitted, an additional bit is used. Future releases may offer lower cyclic prefixes to allow the operator to trade off between multipathing resistance and throughput. Version 1, April 2008 Page 25 of 40