Canopy (wireless)

Motorola Canopy is a wireless networking system designed for WISPs (wireless internet service providers) that operates in both the point-to-point and point-to-multipoint architectures. Canopy can be deployed in various network topologies such as star, bus, or ring configurations. The line includes the original Motorola-designed products (frequencies starting at 900 MHz, plastic cases, "real" speeds of 4.4, 7 and 14Mbit/sec, and using the Canopy protocol) and PtP backhauls (speeds over 22Mbit/sec, 2.5 GHz or higher, using a different proprietary protocol) which were rebranded from Orthogon Systems which Motorola has now acquired.

A typical Canopy setup can include a cluster of up to 6 co-located standard access points, each with a 60 degree horizontal beamwidth antenna, to achieve 360 degree coverage. Also included would be one or more backhauls or otherwise out-of-band links (to carry data to/from other network locations) and a Cluster Management Module (CMM) to provide power and synchronization to each Canopy AP or Backhaul Module (BM). Customers of the system receive service through subscriber modules (SMs) aimed towards the AP. The SMs should be mounted on the tall point of a building to get a reliable connection else Fresnel zone obstruction will weaken the signal.

Under ideal operating conditions connections at distances up to 3.5 miles can be achieved using equipment with integrated antennas. Network operators can opt to install reflector dishes or use Canopy models that accept external antennas at one or both ends of the link to increase coverage distance.

Most Canopy equipment receives its power using Power over Ethernet however like the SkyPilot Networks range of products, it does not comply with the IEEE 802.3af standard and instead uses its own pinout.

Canopy-protocol products have many advantages over wi-fi and other WLAN protocols:
* transmission timing is explicitly controlled, so that all APs on all towers can by synchronized by GPS to prevent interference. APs of the same band can even be placed right next to each other, something which isn't possible or recommended with most other protocols.
* designed for WISP use; so polling-based (prevents one station from "hogging" bandwidth), good interference rejection, easy management (all SMs report their names and statistics to their AP).
* simple to install and configure - about a dozen protocol settings are available in all - and highly reliable.Their main disadvantage is being proprietary - therefore limited to Motorola's (usually expensive) products.

The Motorola canopy PtMP product is available in the 900 MHz and 2.4, 4.9, 5.2, 5.4 and 5.7 GHz bands. In general, the 900 MHz version is more effective for use in outlying areas because of its ability to penetrate through trees. [citepaper|title=Motorola Canopy Wireless Broaband - 900 MHz Modules|url=http://motorola.canopywireless.com/support/library/|publisher=Motorola|accessdate=2008-02-16] However, this signal does not provide as high speeds as the other bands due to its reduced bandwidth (8 MHz instead of 20 MHz), and it requires careful installation due to its suceptabilty to interference.

The 5.7 GHz is the most popular frequency because it does not interfere with existing wifi installations or other sources of interference. WISPs that use the 2.4 GHz or 5.7 versions can use a variety of add-on products (such as reflector dishes or external antennas) to get more gain, allowing communications at distances of up to 30 miles, throughputs of 14 Mbit/s, and latencies of 7 ms.

Point to point connections are capable of throughput ranging from 7 Mbit/s to 300 Mbit/s with latency of 2 ms.

Other sources of information include [http://www.wisptech.com http://www.wisptech.com] and the primary Motorola website [http://www.canopywireless.com http://www.canopywireless.com] discussion email lists are available from trade groups such as [http://www.wispa.org http://www.wispa.org] and [http://part-15.org http://part-15.org]

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