The IEEE is expected to ratify a Quality of Service (QoS) spec by the end of this year. The 802.11e standard is designed to improve the quality of voice and video in WiFi networks. QoS and multimedia support are viewed as critical to wireless home networks where voice, video and audio will be delivered.
The spec will have two components, WME (Wi-Fi Multimedia Extensions), which can be used by developers to assign priority to packets. In September, the Wi-Fi Alliance will begin certifying products that use the subset of 802.11e (WME), to improve quality of service.
The second piece of the spec is WSM, (Wi-Fi Scheduled MultiMedia), will control resource management for bandwidth. WSM allocates slices of bandwidth to various types of wireless data, and increases that bandwidth as needed for voice or video applications. QoS will be mainly targeted in voice over Wi-Fi applications on VoIP (voice over IP) devices, according to some observers.
Chipmaker Engim’s multi-channel WiFi radio has a novel solution. Their chips can use multiple WiFi channels at the same time. When one channel gets clogged, it uses another one.
Meru Networks improves performance by avoiding the slowdown in throughput when you combine 802.11g clients and 802.11b clients on the same access point. Nancy Gohring reports that the Meru Access Point “virtually” separates 802.11g and 802.11b traffic on a per packet basis.
Because the packets don t see each other, the 802.11g traffic doesn t switch to a backward compatibility mode. That keeps 802.11g clients humming. The Meru Wireless LAN Solution features three major components: Meru Access Point, Meru Controller, and the Meru System Director.
As DailyWireless previously reported, Meru’s AP200 will come with two radios which can be programmed to support either the 2.4GHz or the 5GHz band. But it’s not the dual radios that enable mixed-mode performance enhancement, explains 802 Planet. It’s Meru’s Media Access Control (MAC) layer on their AP that gives them control over the density of clients and the quality of service. Meru uses a single WiFi channel, but controls it more closely.
Delivering over-the-air bandwidth control and quality of service (QoS) capabilities is also the province of Autocell who claims their automatic load balancing system maintains high-quality video streaming in “mesh-like” network architectures. Their software, in clients and APs, automatically enables the client to choose the best available channel and access point.
Chipset company Bermai, is demoing a standards-based, WiFi chipset using 802.11e. The wireless multimedia network was demonstrated at CONNECTIONS The Digital Home Conference and Showcase, in Dallas, TX this May.
Bermai is using two approaches to get high-quality video. The first is implementing the 802.11e draft standard for QoS to assign higher priorities to video streams. The second is MIMO — using multiple antennas at both the base station and the subscriber station to increase the performance of the wireless link.
Intersil and ViXS teamed on a multi-media gateway at last year’s CES. ViXS’ XCode integrated circuit can adjust the bit-rates, resolutions and formats of multiple MPEG video streams in real time, adapting each stream to changing network bandwidth. As a result, products such as digital video recorders (DVRs), media gateways, or set-top boxes can distribute high-quality digital video over WiFi networks.
With ratification expected at the end of 2004, the 802.11e specification may enable PCs and PVRs to become media hubs. WiFi (or something like it) will connect them. Then QOS will be a requirement.
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