User guide

Canopy

OFDM Backhaul Solutions

Backhaul Solutions for the Most Challenging Locations and Applications

14. What is unique about the OFDM Backhaul radios?

There are many unique features built-in to the hardware and software such as Transmit Diversity, OFDM,

Dynamic Frequency Selection, Dual Polarized Antennae and Adaptive Modulation. The radios offer the

highest system gain in its class through high sensitivity antennae for improved signal recovery. The

radios also feature a Software Defined Radio system that operates on ultra fast digital signal processors

but is controlled by firmware giving the ability to download new firmware when enhancements become

available. The OFDM Backhaul radios have a built-in web server for advanced management capabilities

including detailed radio signal diagnostics.

15. What is Transmit Diversity?

The OFDM Backhaul radios radiate multiple beams from the dual polarized antenna – the effect of which

is to significantly protect against fading and to radically increase the probability that the receiver will

decode a usable signal in the face of multi-path and interference conditions. The effects of Transmit

Diversity combined with OFDM provide a best in class link budget with high reliability in LoS, nLoS and

NLoS conditions.

16. What is Orthogonal Frequency Division Multiplexing?

Orthogonal frequency-division multiplexing (OFDM) is a method of digital modulation in which a signal is

split into several narrowband channels at different frequencies.

17. What do you mean by “near and Non Line-of-Sight?

A wireless connection between 2 points with obstructions, such as buildings, trees, and hills, blocks the

RF signal resulting in two scenarios:

1) near Line-of-Sight – Optical Line-of-Sight between the 2 points, but the Fresnel zone is blocked

Clear Line-of-Sight

Blocked Fresnel

2) Non Line-of-Sight – No optical Line-of-Sight between the 2 points & the Fresnel zone is blocked.

Blocked Line-o

-Sight &

Blocked Fresnel Zone

18. Do the OFDM Backhaul radios support Virtual LANs (VLANs)?

Yes. All Ethernet frames tagged with a VLAN priority greater than or equal to a system administrator

configured threshold, set on the VLAN Configuration web page, will be prioritized for transmission over

the wireless link.

Issue 4, March 2005 Page 20 of 30