The big issue with Wi-Fi and video is quality of service (QoS). The 802.11 standard wasn't designed for continuous streaming of data like video or audio. It can result in disruptions of data that make for unacceptable TV viewing. This has led to the 802.11e QoS standard as well as the Wi-Fi Alliance's Wi-Fi MultiMedia (WMM) certification. Based on the 802.11e standard, this new certification ensures that certified devices deliver acceptable performance.
Companies also are developing technology that will help deliver video by Wi-Fi. Kiyon Autonomic Networks has developed software that runs on a wireless router or AP and converts into a multichannel system using TDMA instead of the usual CSMA/CA MAC technology. This software supports two HDTV channels and up to 50 VoIP calls over a fivehop mesh Wi-Fi network.
Another company, Metalink, recently demonstrated its WLANPlus chip set based on the 802.11n standard and MIMO, which can easily stream highdefinition video throughout the home. It's designed for set-top boxes, broadband gateways, HDTV sets, DVD players, and other consumer devices.
Metalink has an agreement with Royal Philips Electronics to use its chips in forthcoming HDTV products.
WI-FI PRODUCTS TO WATCH OUT FOR
The usual suspects—Airgo, Atheros, Broadcom, Intel, and Marvell—will field 11ncompatible chips when the standard is finally ratified. In the meantime, other Wi-Fi chip vendors are rolling out lowpower Wi-Fi chips for portable, batteryoperated consumer products and the cell-phone markets.
Conexant Systems' CX53121 is an 802.11b/g device targeted at any portable or mobile device wishing to incorporate Wi-Fi. STMicroelectronics also delivers similar chips, including its STLC4420, which covers 802.11a/b/g Wi-Fi. A second device, the STLC4550, has only 802.11b/g coverage. Both offer very low power consumption for cell phones, MP3 players, and other portable and consumer items.
In addition, Texas Instruments offers the Consumer Electronics WLAN Developer Kit (CE WLAN DK 2.0). It gives designers of portable and mobile devices everything they need to build a successful product. The kit includes the WLAN chip set comprising the TNET1351 and TNET 3526/5100. The 1351 is the single-chip MAC baseband processor and radio, while the 3526 is an RF power amplifier. The 5100 is a power-management chip. A reference design and software are provided to support both WPA2 security and the WMM/802.11e QoS efforts.