Alpha Omega Wireless Blog

Unlicensed 24GHz Point to Point Wireless Backhaul Option

Posted by Joe Wargo on Fri, May 28, 2010 @ 09:17 AM

Point to point wireless backhaul can be either a licensed microwave link or an unlicensed wireless Ethernet bridge. The terms "unlicensed wireless" (also called "license exempt) and "licensed microwave" refer to the radio frequency spectrum characteristics set by the FCC or equivalent national government regulatory body. Licensed microwave communication products require regulatory approval before a wireless installation can take place while unlicensed wireless Ethernet bridges can be deployed without any regulatory approval.

SAF Lumnia 24GHz

Most common unlicensed wireless bridges operate in the 900MHz, 2.4GHz, 5.3GHz, 5.4GHz, and 5.8GHz frequency bands. Unlicensed wireless backhaul is susceptible to wireless interference. See article "Wireless Interference - The Effect on Unlicensed Wireless Backhaul." There is also millimeter wave 60GHz band used for gigabit wireless backhaul that is unlicensed. Licensed microwave links typically operate in 6GHz, 11GHz, 18GHz, and 23GHz. See article "Licensed Microwave Wireless Backhaul." There are a few bands like 4.9GHz public safety band and the 80GHz E-Band that are registered with the FCC but are not truly licensed.

Then there is a part of the spectrum that is mostly overlooked and forgotten about. 24GHz is an unlicensed frequency that can be used for microwave communication for point to point wireless backhaul. For a wireless Ethernet bridge, 24GHz offers some great advantages. Because of the ERIP 24GHz is identical to 23GHz band and can be used for shorter range wireless links (typically under 2 miles) but it has tremendous advantages. First it's rarely used so there is virtually little to no wireless interference. Manufactures that make 24GHz microwave communication radios are those that manufacture 23GHz licensed microwave links and use the same carrier grade microwave radio platform adjusted to operate at 24GHz. As a microwave backhaul link systems can do up to 366Mbps full duplex using 256QAM at 56MHz wide channels. That's 720Mbps aggregate throughput!

Like licensed microwave links, a point to point wireless Ethernet bridge in the 24GHz unlicensed wireless band provides carrier grade wireless backhaul. 24GHz wireless backhaul is ideal for point to point wireless bridges in areas where there is a lot of wireless interference. The unlicensed wireless 5.8GHz band is becoming heavily saturated and it's becoming difficult to deploy wireless Ethernet bridges in many areas. Because the 24GHz band is unlicensed a wireless installation of a 24GHz point to point wireless link can be deployed in a day without the need to wait for a FCC license.

There are many applications that need 100Mbps full duplex connectivity or greater. Millimeter wave 60GHz gigabit wireless radios are also great for shorter applications, but not ever client needs gigabit wireless connections. Most 24GHz microwave communication links can be installed as a 100Mbps full duplex wireless backhaul and can be software upgrade up to 360Mbps full duplex (720Mbps aggregate throughput) protecting the CAPEX investment.

If you need a point to point wireless backhaul that can provide 99.999% reliability, need full duplex connectivity, and are worried about wireless interference then take a look at 24GHz!

Tags: Point to Point Wireless, Licensed wireless, General, Wireless 101