DTV Primer

Chris Llana, Editor



A-VSB Enhancement to DTV Standard Opens Way for Mobile TV Service

October 3, 2006

Last Thursday Samsung executives met with a group of high-level FCC officials to share their thoughts on a number of topics. One of those topics was a new technology that has the potential to take broadcast TV mobile.

The new technology Samsung is developing is called A-VSB (Advanced Vestigial Sideband). It's an enhancement to the U.S. 8-VSB digital TV broadcast standard that works by adding special tracking information to the broadcast signal. Upgraded TV receivers can use that added information to quickly lock onto the primary signal in environments where there is a lot of motion-generated signal interference.

In other words, adoption of A-VSB would let you take your TV with you and watch it while on the move.

The COFDM standard adopted in Europe for their transition to digital TV has been suited for mobile broadcasting all along. If the A-VSB enhancement is implemented here, the ATSC 8-VSB standard could compete with COFDM-based DVB-T and DVB-H derivatives for the broadcast of TV programming and data to handheld and other portable receivers (perhaps like cell phones, blackberries, iPods, etc.).

This area of technology development also holds the potential to improve smart antenna operation and to facilitate the deployment of Distributed Transmission Systems.

The FCC is working on this latter development, a more efficient system whereby TV stations use, instead of a single large tower, a number of smaller transmission antennas distributed throughout their broadcast area to achieve more uniform signal strength. A-VSB can sort out such multiple single-channel signals picked up by a receiving antenna, and Samsung was careful to point out this benefit of the technology to the FCC policy-makers.

With Samsung pushing A-VSB, it is more likely to be adopted than the similar E-VSB ("E" for enhanced) standard, which ATSC published implementation guidelines for this past April. E-VSB adds extra error correction to digital TV transmissions to improve reception is areas of weak signal strength, but it has not been embraced by the industry.

A-VSB is now under study in the ATSC standards development process, but it has not yet attained "candidate" standard status. FCC backing would obviously expedite its consideration.

The added A-VSB information will be ignored by existing TV receivers and converter boxes, making the technology backward compatible. To take advantage of the A-VSB technology, both the broadcaster and the TV receiver would have to have it built in.