Millions of homes already have wireless networks that generally do a superior job delivering broadband connections to PCs and laptops. But those networks may need to be replaced or at least upgraded when consumers begin to adopt new Internet Protocol video and attempt to distribute video throughout the home from any source.
The main contender is the forthcoming upgrade to the versatile 802.11 wireless local-area network (WLAN) standard. The IEEE Standards Task Group is developing a high-speed version known as 11n. A draft version is now available, and a final version is expected in March 2008.
Meanwhile, chip vendors and equipment manufacturers are offering pre-n or draft-n products that mostly comply with the expected final 11n standard, though some variations are likely to occur. Most manufacturers say draft-n versions will be compatible and/or upgradeable. The Wi-Fi Alliance is even beginning to certify the interoperability of draft-n products.
In addition to providing the extra high speed that 11n promises, some chip vendors are offering products that go beyond the standard to improve range, quality of service (QoS), and speed, such as new chip sets from Metalink Ltd. and Raylink Technology.
METALINK WLANPLUS
Metalink's second-generation draft-11n chip set, WLANPlus, comprises the MtW8151 RF IC and the MtW8171 baseband IC (see the figure).
The 8151 is a complete RF multiple-input/multiple-output (MIMO) front end with three receivers and two transmitters (2x3). It operates in the 2.4- and 5-GHz unlicensed Wi-Fi bands. It's compatible with 802.11n draft standards, but it's also fully backward compatible with 802.11a/b/g. And, this new physical-layer (PHY) chip features a Near Maximum Likelihood (NML) slicer that effectively doubles the coverage area.
The 8171 is a full implementation of an integrated lower and upper media-access controller (MAC) that dramatically reduces the required processing power and memory allocation from the host application processor. This greatly simplifies the integration with consumer electronic devices and helps reduce the total cost.
Another range-extending feature is its low-density parity check (LDPC) forward error correction (FEC), which provides advanced coding gain. It also supports the channel bonding specification with both 20- and 40-MHz channels. Furthermore, its QoS capability makes it fully compatible with the IEEE's 802.11e QoS standard, which is critical for both high-quality voice and video services.
The 8171 implements other QoS mechanisms as well, such as Enhanced Distribution Channel Access (EDCA) with Admission Control and Fast Link Adaption (FLA). The Dynamic Link Adaption features save 50% on airtime and increase network efficiency. Host bus interfaces include CardBus, mPCI, and PCI 2.3.
As for security, the chip set supports the IEEE 802.11i standard as well as all the usual WLAN security modes, such as 64/128-bit WEP, AES, TKIP, WPA, and WPA2. The set also delivers multiple HDTV streams to any location within a radius of 100 ft while maintaining full QoS performance at a data rate to 300 Mbits/s.
WLANPlus exceeds the de facto HDTV802.11n streaming critical requirement for delivering 60-Mbit/s effective throughput to a distance of 60 ft at 5 GHz. This capability will support the multiroom networking of multiple HD video streams. Expected applications include laptops, digital media adapters (DMA), HDTV sets, DVRs, and residential gateways.
Metalink has reference designs for a mini PCI card (type111B), CardBus, and residential gateway. Production is expected by mid-2007 with volume expected in the second and third quarters. Check with Metalink for volume pricing.
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