IT trends impacting IP video: 802.11n wireless

Having reshaped consumer tech, 802.11n reaches the professional security industry


In October of 2009, the IEEE announced the amended 802.11n-2009 standard for wireless access, increasing the bit rate of wireless communications up to 400 percent over existing 802.11 offerings. Taking advantage of this increase in bandwidth, the consumer electronics market quickly incorporated this technology in access points and other edge computing products. Today 802.11n chipsets represent a little more than a third of all wireless devices sold in the 802.11 suite of products -- but it’s predicted that 802.11n offerings will surpass all others in sales in 2011.

The fastest adoption rate will continue to be in the consumer market, with the technology being added to television set-top boxes, cellular phones, laptops and tablet computers such as the iPad and all its inevitable competitors. But as typically happens today when consumer technology paves the way, commercial and enterprise adoption rates should increase as well, which will enable higher bit rates to be applied to business applications. As the electronic physical security industry continues to mature towards IP-based solutions, the repurposing of the 802.11n standard will have a measurable impact on the solutions we deploy.

The 802.11n standard specifies data transmission rates up to 600 Mbits using a technology called multiple-input multiple-output (MIMO), which incorporates multiple antennas that are used to transmit and receive data from point-to-point as well a point-to-multipoint installations. Existing implementations today deliver half that amount. Like its predecessors, the technology operates on the 2.4GHz or 5 GHz spectrum but increases channel width from 20MHz to 40 MHz, doubling the physical layer data exchange. In addition, in order to achieve higher data throughput rates, the radios all need to operate at 5GHz which limits the backward compatibility. Distance limitations have almost doubled with 802.11n -- with up to 230 feet of range indoors and 820 feet outdoors -- and manufacturers are able to increase this through task-specific antennas.

Without a doubt, any wireless technology enables the security practitioner greater flexibility for video surveillance applications by offering cost effective means of deploying cameras in areas that traditionally have been difficult or impossible to install. So what specifically does 802.11n offer the security industry?

For starters, it delivers more bandwidth. This directly impacts the security professional’s options for protecting assets and maintaining life safety by increasing the coverage area simply through the deployment of more network cameras. A direct ratio can be calculated that represents the number of cameras associated with a wireless access point based on a combination of specified resolution, frames per second, level of motion in the scene and the compression technique selected. If all the parameters are equal, that ratio increases favorably when deploying 802.11n access points compared to earlier standards. For instance, retail establishments have traditionally embraced the use of video surveillance within the confines of the facility but rarely maintain the same level of coverage for their parking lots. If viewed from a pure technology standpoint, increasing wireless bandwidth enables more cameras to be installed throughout the parking lot on the same network, migrating risks that were not addressed before.

Another aspect of increasing the bandwidth deals directly with the quality of imagery delivered. While a VGA or 4CIF video stream will consume significantly less bandwidth than a 1080p HDTV signal, it obviously does not deliver the same color fidelity, aspect ratio, or resolution. In fact, in the case of 1080p, this represents a five times increase resolution compared to VGA or 4 CIF. The improvement in image quality increases the bit rate generated, resulting in a need for more bandwidth. At times, this ratio has limited the deployment of cameras capable of delivering this high level of quality. The availability of wireless access points based on 802.11n gives the security professional another set of options when designing solutions.

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