Wi-Fi/802.11
What is Wi-Fi?
The IEEE 802.11 Working Group has defined a family of international standards for high speed wireless Ethernet networks. Products based on these standards have seen explosive growth in the past two years and are widely deployed in coffee shops, business campuses, retail outlets, warehouses, airports, residences, home offices, and urban areas. Some analysts predict that Wi-Fi access will be nearly ubiquitous in a few years replacing 3G cellular networks for data applications.
Wi-Fi Applications
There are a growing number of 802.11 standards targeting different applications:
- 802.11b or Wi-Fi is the most widely deployed technology using direct sequence spread spectrum (DSSS) in the 2.4 GHz band. Data rate is up to 11Mbps per channel.
- 802.11g also operates in the 2.4 GHz band, but supports data rates up to 54 Mbps per channel by using orthogonal frequency division multiplexing (OFDM) a more efficient modulation technique. 802.11g networks are typically backwards compatible with 802.11b adapters.
- 802.11a also uses OFDM at 54 Mbps data rates, but operates in the 5.15-5.35 and 5.725-5.825 GHz bands. There are more channels available in this band so 802.11a can support higher network capacity. On the other hand, the higher frequency does not penetrate walls as well. 802.11a hardware is not usually comaptible with 802.11b or g hardware although some tri-band access points are available.
- Other versions: Recently the FCC approved spectrum in the 4.9 GHz band for public safety applications. In addition, spectrum around 5.9 GHz has been approved for Intelligent Transportation Systems (ITS). Both applications are expected to use 802.11 type networks. In addition, the IEEE802.11 Working Group is preparing a wideband standard for 100 Mbps or more.
Applications include:
- Internet access
- Enterprise networking
- Home networking
- Inventory collection
- Virtual private networks
- Public safety networks
- Point of sale terminals
Key features include:
- Data rates to 54 Mbps
- Widespread infrastructure deployed
- Star topology
- Relatively high current consumption
- Range: 100m nominal (without repeaters)
Services We Provide
The high volume deployment of 802.11 networks has enabled development of chipsets, modules, end products, and software stacks by a number of vendors. As an independent design team we select the best components for your application and develop products that meet your requirements.
Project Example:
A client wants to offer location based services to individuals in automobiles.Taking advantage of the growing deployments of Wi-Fi access points, this can be implemented by integrating a GPS receiver, an 802.11b PCMCIA card and a PDA, for the display and user interface.
As part of the development, we purchase a GPS OEM module from a vendor in France, select an appropriate PDA platform and an 802.11b PCMCIA card. These components are integrated into a single housing appropriate to installation into an automobile. Antennas for 802.11 and the GPS receivers are integrated into a single antenna housing to be mounted outside the vehicle. Application software is developed based on the clients requirements.
Bluetooth
What is Bluetooth?
Bluetooth is increasingly a standard interface for cell phones and laptop computers. An exciting new application is streaming audio, providing wireless CD-quality audio for MP3 players, CD players and internet radio.
Bluetooth Applications
Bluetooth was developed as a cable replacement for connections between cell phones and computers. It is primarily a short range link connecting a few nodes.
Applications include:
- Cell phone hands-free
- Printer cable replacement
- Streaming audio from MP3 player or computer
Key features include:
- 700 kbps or less data rate
- <10 nodes
- Short range, 8m
- 2.4 GHz band
- Low cost
Services We Provide
There are many Bluetooth chipsets, modules and software stacks from a variety of vendors. These products implement Bluetooth profiles for streaming audio, hands free cell phones, remote control, multimedia and computer peripherals. As an independent design team we select the best components for your application and develop products that meet your requirements.
Project Example:
A manufacturer of high fidelity speakers would like to offer wireless surround sound speakers. The Bluetooth Advanced Audio Distribution Profile (A2DP) is perfect for this application.
To reduce development costs and get to market quickly, we license a software stack and an OEM module from a third party and integrate the module into existing surround sound speakers from our client. The client is in production with this solution in three months.
ZigBee
What is Zigbee?
The Zigbee Alliance and the IEEE 802.15.4 Working Group have defined an international standard for a simple but powerful packet data protocol providing high reliability through message acknowledgement, error checking, prioritized communications, direct sequence spread spectrum, the ability to change frequencies to avoid interference and user-selectable security levels.
Zigbee Applications
Zigbee is optimized for applications that require low throughput, long battery life, low cost and thousands of nodes in a network.
Applications include:
- Low data rate telemetry applications
- Meter reading
- Home automation
- Industrial automation
- Building automation
Key features include:
- Data rates of 10 kbps to 115 kbps
- Mesh topology
- CSMA-CA channel access
- Fully handshaked protocol for transfer reliability
- Dual PHY (2.4GHz and 868/915 MHz)
- Extremely low duty-cycle (<0.1%)
- Range: 10m nominal (1-100m based on settings)
- Low current requirements - 30 ma. transmit, .02 microamps in sleep mode. By operating at a low duty cycle, battery life can be extended to months or even years.
Services We Provide
Zigbee and 802.15.4 standardization have enabled development of chipsets, modules, end products, and software stacks by a number of vendors. As an independent design team we select the best components for your application and develop products that meet your requirements.
Project Example:
An electrical contracting company would like to offer their customers an option of installing energy saving lighting controls in an existing building without major re-wiring. This can be implemented with Zigbee controlled relays added to existing light switches. Battery powered Zigbee switches can be stuck on the wall in any convenient location. The mesh network provided by the relays and switches provides full converage in the building so that lights can be programmed from a central location to turn off on weekends, holidays and at 6:00 pm at night.
To reduce development cost and get to market quickly, we license a software stack from a third party adding some additional application software specific to our clients needs. OEM modules from another vendor are purchased and repackaged with 15 amp relays and flat battery powered light switches. The client is in production with this solution in four months. As volumes increase, a fully customized, cost-reduced product line is developed using chipsets from a third vendor.
GPS/Tracking
GPS/Tracking
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.
GPS Applications
GPS can be used widely for navigation and tracking. It is built in cell phones, automobiles and attached to inventories, wherever the location of a person or an object is of interest
Applications include:
- Navigation
- Inventory tracking
- Fleet control
- Recreational use for outdoor activities
- Emergency response
Networking
In many cases, our client would have an application that needs to have some kind of wireless network. We help our clients find the network requirements and then choose an appropriate network technology, preferably a standard based network. There are three dominant wireless standards available, 802.11, bluetooth, and Zigbee. If one of these is suitable, the implementation would be low cost since many off the shelf components are available.
If none of the standards is suitable for the application, we would suggest using a standard as the base and make changes to the network protocol layers, such as MAC or PHY as appropriate for the application. Off the shelf chip/components would be selected to allow required flexibility.
If none of the standards is suitable, then we would recommend a custom design. We are fully qualified to design a custom network.
Wireless Audio
Wireless audio is one of the important applications of the wireless technology. The wireless audio can be using an analog RF link, or a wireless data network. While Bluetooth has native support for streaming audio, 802.11 is developing a similar support, 802.11e, for synchronous types of service such as streaming audio and video. The physical media can be RF in 900 MHZ, 2,4GHz or 5.8GHz band, or IR.
FCE has developed many wireless audio products for different applications. Some applications are very innovative and make audio available in a very convenient way. With our experience, we have provided solutions with rarely achieved levels of performance.
Wireless Sensors
Wireless sensors can be used in health care, automotive, and telemetry applications.
Wireless sensor network requirements fit quite well with Zigbee technology. The sensor data network is usually low data volume, low duty cycle, and long battery life.
Even though the Zigbee technology is somewhat new, there are already several vendors that provide chip sets.
Custom Design
There are cases where a custom design is called for. This can range from a single analog wireless link to a fully functional wireless network. Before standards were developed, nearly all of wireless projects were of custom design. The First Contact team has developed many such systems in the past, including the CellNet system, GE Space Net Satellite Communications Network, and the Whisper Radio Network. These systems were designed from scratch, first developing a list of requirements, then performing a system link analysis and system architecture definition, and finally completing a full system implementation. Several members of our team were also involved in 802.11 committee work during the forming years of the standard.
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