Wireless Network

Wi-Fi/WiMAX: SDIO, SPI, MiniPCI, USB

Wi-Fi is the brand name for Wireless Local Area Network (WLAN) based on the IEEE 802.11 standards. The legacy 802.11b standard offers a maximum data rate of 11Mb/sec, while 802.11a/g boosted the data rate to 54Mb/sec. 802.11n, still to be ratified, is designed to achieve the maximum data rate of 248Mb/sec.

Wi-Fi allows users to connect to a local network without the drag of requiring network cables, which greatly improves the user experience and mobility. It is widely deployed at company sites and residential homes. With more and more hot spots becoming available at Starbucks, McDonald's, hotels and airports, Wi-Fi has become a low cost, high bandwidth alternative to cellular networks while on-the-go. Most laptops today have Wi-Fi as a standard feature and more handheld devices such as smartphones, personal media players and portable game consoles are being developed with integrated Wi-Fi capability.

Because Wi-Fi was first used in laptops, mini-PCI was the predominant interface for Wi-Fi modules, but more recent generations have started to use SDIO and SPI as the host interface standard primarily due to the cost and board space improvements of having a lower pin count interface. Since miniPCI based Wi-Fi is basically a commodity product, it still offers lower cost and better performance than SDIO and SPI. With the emergence of 802.11n , the requirement of higher throughput also has made USB an attractive option for the host interface to a processor.

Worldwide Interoperability for Microwave Access (WiMAX) is based on the IEEE 802.16 standard, also known as Wireless metropolitan area network, WirelessMAN. It is designed to replace DSL or cable for the last mile of connectivity. WiMAX is also considered one of the leading “4G” mobile data standards along with Ultra Mobile Broadband (UMB) and Long Term Evolution (LTE).

WiMAX offers 70Mb/sec data throughput with longer reach than Wi-Fi. It can cover over 30 miles (48 kilometers) vs. several hundred meters for Wi-Fi. WiMAX directly competes with existing “3G” technologies such as High Speed Packet Access (HSxPA). Sprint and Clearwire are the leading WiMAX providers in the US today with plans for significant expansion of coverage areas in the near future.

Due to its high data rate, the most commonly used interfaces for connecting to WiMAX chipsets are USB, miniPCI and SDIO.

QuickLogic offers a complete interface lineup between Wi-Fi/WiMAX chipsets and application processors, from miniPCI to SDIO to SPI to Hi-Speed USB. It allows system architects to select the ideal interface for their Wireless connectivity to achieve the optimal BOM cost, power consumption and performance.

miniPCI solution supports:

• Leverages low-cost PCI-based Wi-Fi modules
• Up to 264 MB/s PCI bus performance with zero wait states
• Master and target functions for 32-bit data at speeds of 33 and 66MHz
• Fully compliant to PCI specification 2.3, and Cardbus and Compact PCI compatible

PCI Solution

SDIO solution supports:

• High speed SDIO host controller with clock frequency up to 52MHz
• Compliant with the latest Secure Digital 2.0 standard
• SPI, 1-bit and 4-bit modes
• Rx/Tx FIFOs for higher performance and throughput
• DMA Support for reducing processor bus utilization

SDIO Solution

SPI solution supports:

• High speed SPI master controller with clock frequency up to 52MHz
• Low cost, low pin count Wireless connectivity solution
• Simple driver architecture customizable to enhance Wi-Fi performance

High Speed SPI Solution

USB solution supports:

• Hi-speed USB 2.0 OTG with integrated high speed PHY
• 12-signal ULPI interface available through customizable building blocks
• 8 Kbyte SRAM on-chip buffer to improve data transfer performance
• Dedicated DMA controller to offload CPU from heavy data transfer and manipulation

High Speed USB Solution

Applications:

• WiMAX provides fast data access for 4G handsets and data cards to deliver more media rich content to customers
• Wi-Fi offers low cost, high performance data access to smartphones, PMP, PND and data cards
• Wi-Fi enables voice over IP (VoIP) services such as Skype and instant messenger on portable devices
• Wi-Fi supports easy data synchronization such as inventory management, data collection in industrial and retail environment