Mobile Sands

February 4, 2009

More on White Spaces: IEEE 802.22 and CogNeA

Filed under: white space — AJ @ 5:56 am

IEEE 802.22

People researching technology options for TV white spaces should read an article on the status of the IEEE 802.22 Working Group in the January 2009 issue of IEEE Communications magazine.  Launched in Nov 2004, IEEE 802.22  was charged with developing a standard for cognitive radio based air interface in TV white space spectrum.

 Before this article was published in the Communications magazine, information on the status of this standard was difficult to find unless you were a member of the working group.  Though I cannot do justice to summarizing this article in a blog post, here are a few key takeaways:

  • The objective is to create a standard for fixed point-to-multipoint communication. No mobility (or portability) is envisioned
  • The network architecture, MAC and PHY are derived from 802.16 (WiMAX)
  • In order to work within TV white spaces, both the base station and CPE must:

           –  Support spectrum sensing with a 10m high outdoor antenna
            – Automatically determine its location using GPS (or Galileo)
           – Connect to a database of incumbent TV channels

  • The standard is being designed to operate with one 6, 7 or 8 MHz channel in TDD mode. MIMO is currently not supported
  •  Multiple 802.22 systems can co-exist in the same region as long as they transmit a “co-existence” beacon to identify each other.

 From a business point of view, this standard will be uncompetitive in any place other than the most remote rural areas, for the following reasons:

  1. As proposed, this standard will offer much lower data rates than competing OFDM standards (WiMAX and LTE) because it operates in a 6 MHz TDD channel. Compare this to the 20 MHz spectrum that Verizon (and AT&T) have in the 700 MHz band for LTE deployment.
  2. Unlike LTE or WiMAX, 802.22 does not support any mobile or portable operation. On the contrary, it requires every CPE to have a 10m external antenna for spectrum sensing.
  3. The only advantage that 802.22 has is operation in a lower frequency band (500 – 700 MHz). This advantage is nullified by FCC’s requirement that even fixed white space devices have a maximum EIRP of 4 W.

The standard also seems to have some technical discrepancies, like it expects the CPE, which does not have an Internet connection, to connect to an incumbent TV database.  And its completion data is uncertain.  In any case, I would be surprised if there are any companies building equipment or CPE for 802.22.  If there are any, I would be really interested in hearing from them.

CogNeA

At this stage, it look like  most of the interesting activity in standardizing systems that utilize TV white spaces has shifted out of IEEE 802.22.  In December 2008, Philips, Samsung, HP, TI, ETRI and GeorgiaTech announced the formation of a new group called the Cognitive Networking Alliance (CogNeA). CogNeA aims to drive the definition and adoption of an industry-wide standard for low power personal and portable devices to operate over TV White Spaces in the Ultra High Frequency (UHF) television bands. Notice the focus on personal/portable devices rather than providing broadband.

This group does not have a website yet, though they shared some of their plans at the Software Defined Radio Forum’s meeting in San Diego last week.  If you are following this space, add CogNeA to your Google Alerts!


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