New 802.11n Wi-Fi chips unveiled at the recent Computex conference in Taipei, Taiwan, look to boost data rate, range, and link reliability, as well as improve video transmission around the home. What’s their secret? Developed by Atheros, Broadcom, Quantenna, and Ralink, they all feature 3x3 and 4x4 multiple-input multiple-output (MIMO).
The Atheros Communications AR9300 family of 802.11n solutions is based on the company’s XSPAN technology. Called Signal Sustain Technology-3, or SST3, it produces 450-Mbit/s physical-layer (PHY) rates derived from its three-stream 11n MIMO configuration. The product boosts range that sustains signal strength over a very wide area when combined with a unique set of enhancement features:
- Low density parity check (LDPC) guards against packet loss at every point on the link.
- Maximum likelihood demodulation (MLD) optimizes MIMO demodulation to boost signal strength at close range.
- Transmit beamforming (TxBF) focuses transmit signals to the receiver to enhance the link rate at mid-range on the link continuum. This technique conforms to the 802.11n standard.
- Maximal ratio combining (MRC) enables the receiver to optimally combine the MIMO signal paths, aligning time and phase of the signal receive to extend link reliability at longer range.
Backward-compatibility with 11g- and 11a/g-based devices is a given feature. Also, the AR9300 chip sets are dual-band devices covering both the 2.4- and 5-GHz unlicensed bands. Concurrent dual-band is an important feature for high-end consumer routers and enterprise access points (APs).
Using both the 2.4- and 5-GHz frequency bands multiplies the available bandwidth, maximizing the Wi-Fi network. For example, a Wi-Fi user could dedicate the 2.4-GHz band for e-mail, Web browsing, and data applications, while simultaneously using the cleaner 5-GHz band for latency-sensitive applications like video, voice, and gaming.
Thanks to MIMO, Wi-Fi is evolving to meet the stringent requirements of media-based applications like Internet Protocol television (IPTV) and whole-home video distribution. Whereas traditional wireless local-area networks (WLANs) are designed to provide the highest possible throughput for data applications, today’s media-centric networks must provide more reliable connections that minimize the number of video and audio packets lost during transmission. Packet loss and latency can lead to video glitches, unsynchronized audio, and delayed gaming responsiveness.
Finally, all of the XSPAN with SST3 devices support the Wi-Fi Direct Connect feature. As a result, notebooks can connect multimedia content directly to other client devices without transmitting through an access point. With a 450-Mbit/s PHY rate, Direct Connect transfers high-definition (HD) content simultaneously to multiple clients, while concurrently being connected to the Internet.
The AR9300 family is designed for certain products and markets. These include PCs as well as high-end laptops, home networking platforms for video, and enterprise/small business applications for dual-band Ethernet access. Specific target areas for the family members include:
- AR9380/81: single-band/dual-band Gigabit Ethernet AP/Router platforms (Fig. 1)
- AR9380: DSL, cable, set-top box, and TV carrier gateway and consumer electronics platforms
- AR9390: dual-band Gigabit Ethernet Power over Ethernet Enterprise/SMB AP/router platforms
- AR9380: dual-band PCI Express notebook and desktop platforms
Atheros is sampling the family now. Evaluation boards are available. Production is expected in the third quarter.
Another single-chip, 802.11n, dual-band 3x3 wireless solution comes by way of Broadcom Corp. The BCM4331, the newest member of the company’s Intensi-fi product family, targets home multimedia applications.
The Wi-Fi chip achieves 450-Mbit/s data rates in client devices and 600-Mbit/s-plus throughput (TCP/IP) in 3x3 AP/router configurations. Its high data rate combined with its range-enhancing features makes possible several wireless multimedia applications, including HD video streaming, backup, storage, multiplayer gaming, audio streaming, wireless printing, and photo sharing.
Continue to next page
Three transmitting and three receiving streams of data, in either the 2.4-GHz or 5-GHz frequency bands, deliver full 3x3 performance. The increased number of data streams and antennas results in faster speeds, longer range, fewer dropped connections, and improved overall wireless coverage (Fig. 2). The new chip addresses designers who want create products that can instantly access broadband video delivered via IP directly to a modern TV set. ABI Research forecasts this IPTV market to exceed 117 million units by 2014.
Other BCM4331 features include:
- LDPC code and space-time block coding (STBC) to boost overall range and coverage and an advanced receiver architecture
- Bluetooth wireless coexistence
- Wi-Fi Direct to simplify video streaming between PCs and TVs
- Coupled with the BCM4718, it creates a low-cost, two-chip, simultaneous dual-band 3x3 AP solution for 11n 2.4-GHz data and 5-GHz HD video-distribution applications
- Simultaneous three-stream throughput using the 600-MHz, MIPS74k BCM4706 processor
- 65-nm CMOS PCI Express design that promotes integration and low power consumption
- Broadcom’s OneDriver software support and WHQL-certified driver support for Windows 7, Vista, Windows XP, and Linux
The BCM4331 is sampling now.
While most chip vendors went with the 3x3 MIMO format, Quantenna Communications opted for a 4x4 MIMO format in its third-generation 11n Wi-Fi chipset. It’s designed to deliver whole-home coverage for IPTV services over a wireless network. As of now, the chipsets are in trials with more than 12 service providers worldwide for broadband digital video services.
The third-generation chipset incorporates all specifications in the IEEE 802.11n standard, including, of course, 4x4 MIMO. It also provides extensions to the 802.11n, such as dynamic digital beamforming, and wireless channel monitoring and optimizing. With these features, Wi-Fi home networks can deliver the same quality as wired Ethernet, including supporting up to full HD video with 1080p resolution, anywhere in the home. On top of that, compatibility is guaranteed with existing and future IEEE 802.11n-compliant products.
Error vector magnitude (EVM) and phase-noise performance were enhanced to boost range and reliability, and the chipset’s receiver linearity significantly reduces interference. Furthermore, its 80-MHz channel bandwidth supports higher throughput for such emerging standards as 802.11ac, which is expected to deliver speeds of up to 1.2 Gbits/s.
By implementing Quantenna’s Full-11n technology, standard Wi-Fi can serve as a reliable, carrier-class, whole-home IPTV networking backbone for complementary single-room wireless technologies. Competing technologies are the emerging short-range 60-GHz solutions from companies in the WirelessHD Consortium and Wireless Gigabit Alliance (WiGig).
Quantenna’s third-generation chipset is available now as part of the QHS610 reference design. The reference design includes an evaluation board plus cables for connecting it to an external controller. A complete software developer’s kit (SDK) implements the entire networking and device discovery/connectivity functionality required for a full solution supporting the 802.11n standard. Also included is a full test suite of specialized video-over-wireless RF calibration and performance-characterization software, including an easy-to-use GUI. Pricing for the QHS610 is available upon request.
Ralink Technology’s 3x3 MIMO 11n chipsets come with a twist—they include the company’s DSL and Ethernet features. Known as the TC3182P2V + and TC3182 LEV, these devices provide a xDSL2+ 11n Wi-Fi IAD (Integrated Access Device) solution. The TC3182x series, with its strong cost-to-performance ratio, is designed as an all-in-one solution for service providers targeting rapidly growing markets around the globe.
A telco-class 10/100 Fast Ethernet switch and telecommunication standards-compliant software are integrated on a two-layer printed-circuit board (PCB) that’s 30% smaller than similar PCBs, according to the company. The devices, which are applicable for ADSL single-port 1T1R/2T2R and four-port 1T1R/2T2R 802.11n Wi-Fi gateways, also support a variety of peripherals via a USB2.0 host interface for digital home peripherals and applications (e.g., connecting media server disk drives and optional 3G connections).
Specific features include an ADSL2+ chipset with PCI Express interface for connections to Wi-Fi PCI Express clients ranging from low-cost 150-Mbit/s, 1x1, 2.4-GHz 802.11n to 450-Mbit/s, 3x3, dual-band 802.11n. A multi-threaded MIPS34Kc embedded processor optimizes Voice over IP (VoIP) and IPTV services support. Its flexible IAD platform fulfills telco requirements and applications, and there’s integrated support for a range of voice codec solutions. Also, the memory footprint uses the company’s LiNOS system, which targets triple-play, wireless-enabled gateway and IAD applications.