Supplement to the Canopy System Release 8 User Guide PMP 400

PMP 400 and PTP 200 SeriesCanopy User Guide Supplement2.1.1 NLOS and nLOS Benefits and LimitationsThe use of OFDM technology will help in many cases of NLOS (Non Line-of-Sight) and nLOSnear Line-of-Sight (nLOS) links. LOS (Line-of-Sight ) means the installer can see the AP from theSM and the first Fresnel zone is clear. An example of nLOS is when the installer can see the APfrom the SM, but a portion of the first Fresnel is blocked. An example of NLOS is when theinstaller cannot see the AP from the SM, and a portion or even much of the first Fresnel isblocked, but subsequent Fresnel zones are open. Figure 4 shows examples of such links.Figure 4: LOS, nLOS, and NLOSWhereas multi-pathing degrades a link in some technologies, like FSK, OFDM can often usemulti-pathing to advantage to overcome nLOS and NLOS, especially in cases where the Fresnelzone is only partially blocked by buildings, “urban canyons”, or foliage. OFDM tends to helpespecially when obstacles are near the middle of the link, and less so when the obstacles arevery near the SM, AP, or BH.However, attenuation through walls and trees is substantial for any use of the 5.4 GHz or 4.9 GHzfrequency bands. Even with OFDM, these products should not be expected to penetrate walls orextensive trees and foliage.2.2 APPLICATIONSApplications for the PMP 54400 and PTP 54200 Series systems include• High throughput enterprise applications• NLOS/nLOS video surveillance in metro areas• Extend networks into urban areas• Extend networks into areas with foliageApplications for the PMP 49400 Series systems include• High throughput licensed network for government applications• Municipal network - NLOS/nLOS video surveillance in metro areas• Disaster relief network• Data service network - extend licensed networks into areas with foliageIssue 3, January 2009 Page 9 of 45