Knowledge Center: F
An alphabetical glossary of terms related to Laird's embedded wireless modules.
Fast is a power save mode that switches between PSP mode and CAM mode, depending on network traffic. For example, it switches to CAM when it is receiving a large number of packets and switches back to PSP after the packets have been retrieved. Fast is recommended when power consumption and throughput is a concern.
Fast Reauthorization, or Fast Reauth, is the expedited WPA key handshake used to reduce roaming time to 125 msec or less.
The Federal Communications Commission is the regulatory agency and standards body for the Americas and parts of Asia. For more information: http://www.fcc.gov/
Laird radios hold the following FCC grants:
The FCC certification process varies depending on the type of device you plan to certify.
When integrating certified wireless modules into end host products, you must consider the specific FCC grant conditions for each wireless module. Common module conditions include:
Type of modular approval:
Frequency-Hopping Sread Spectrum. An FHSS radio does what its name implies: it "hops" from frequency to frequency over a wide band. The specific order in which frequencies are occupied is a function of a code sequence, and the rate of hopping from one frequency to another is a function of the information rate.
FIPS is a National Institute of Standards and Technology (NIST) Federal Information Processing Standard. The standard of interest for Wi-Fi systems is FIPS 140-2, which defines security requirements for cryptographic modules, or modules that provide security services such as encryption to protect data. AES-CCMP, the encryption method defined with IEEE 802.11i (WPA2), is sufficient for FIPS 140-2. Unfortunately, hardware implementations of AES-CCMP found in today's Wi-Fi radio modules such as those from Laird cannot be certified for FIPS 140-2; a FIPS 140-2 cryptographic module nearly always is implemented in software.
Frag Thresh (fragmentation threshold) is an SCU Global setting that indicates the packet size (in bytes) at which the packet is fragmented. For SCU, the Frag Thresh integer range is 256 to 2346 (bytes) with a default setting of 2346 bytes.
Note: For 30AG (SDC-MSD30AG and SDC-SSD30AG) radio modules, this parameter is disabled.
The IEEE 802.11 wireless LAN standards include service on two frequency bands, 2.4 GHz and 5 GHz. 802.11b and 802.11g operate in the 2.4 GHz band. 802.11a operates in the 5 GHz band. 802.11n operates in both bands.
Bluetooth radios transmit and receive by narrowcasting a signal across a pattern of frequencies within a frequency band. This process is known as Frequency Hopping (FH). Wi-Fi radios transmit and receive by broadcasting on a single channel within a frequency band; a process known as Direct Sequence (DS). Adaptive Frequency Hopping (AFH) is a built-in coexistence feature that was developed in version 1.2 of the Bluetooth specification. Prior to AFH, Bluetooth products employed a standard set of hopping patterns which caused occasional interference with other wireless devices operating in the same frequency band.
With AFH, a Bluetooth device is able to identify other sources of interference in the frequency band (such as Wi-Fi radios). Once the device knows on which channel the Wi-Fi radio is operating, it selects a hopping pattern that avoids that interference. By using AFH, Bluetooth and Wi-Fi radios can operate in the same frequency band and in the same physical location with a decreased level of interference and acceptable performance and reliability. AFH is often employed in conjunction with spatial isolation.
Measured in dB, it compares the gain from the strongest point (front) with that of the back on an antenna.
This mode restricts client radios to transmitting on odd numbered frequency hop bins and the server to even numbered frequency hop bins. This can cause overall throughputs to be cut in half.
In object-oriented programming, a function is a piece of code that performs a particular task, and can be called and reused by the program when it is required. The program may jump to and execute the function, and then return to what it was doing. This is more efficient than re-entering the required commands at several locations throughout the program.