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ADAPTIX Glossary
- 802.11
- A type of radio technology used for wireless local area networks (WLANs),
developed by a working group of the IEEE (see IEEE). Also known as Wi-Fi. 802.11 is
composed of several standards operating in different radio frequencies: 802.11b
operates in the 2.4-GHz frequency range with a bandwidth of up to 11 Mbps; 802.11a
operates in the 5-GHz frequency range with a bandwidth of up to 54 Mbps; 802.11g
also operates in the 2.4-GHz frequency range but with a bandwidth of 54 Mbps.
- 802.16
- A family of wireless specifications developed by a working group of the IEEE
(see IEEE). Covers 10-GHz to 66-GHz wireless networks. The first broadband wireless
access standard to be developed and released by an accredited standards body, 802.16
features a protocol-independent core, supports high-bandwidth on-demand environments
and hundreds of users per channel, and can handle either continuous or bursty traffic.
- 802.16d
- A consolidation of the 802.16a and 802.16c standards into a single WiMAX standard.
The new version also supports MIMO (see MIMO) antennas, which increases reliable range
amid multipath.
- 802.16e
- A working specification under the 802.16 wireless specification to enable
connections for mobile devices. Until 802.16e, the .16 standard was for fixed connections
only.
- ARQ
- Automatic repeat request. The standard method of checking transmitted data, used on
virtually all high-speed data communications systems.
- CDMA
- Code-Division Multiple Access. A standard mobile wireless service providers use
to allocate bandwidth for subscribers of digital wireless services, such as cellular
service and messaging. CDMA distinguishes between multiple transmission-carried
simultaneously on a single wireless signal. It carries the transmissions on that
signal, freeing network room for the wireless carrier and providing interference-free
calls for the user. Several versions of the standard are still under development.
CDMA promises to open up network capacity for wireless carriers and improve the quality
of wireless messages and users' access to the wireless airwaves. It's an alternative
to GSM, which is popular in Europe and Asia (see GSM).
- CDMA 1XEV-DO
- A third-generation wireless protocol that is a stepping stone in the evolution of
CDMA2000 (see CDMA2000). 1XEV "data optimized" is a data-only overlay that
uses a 1.25-MHz channel to provide a peak data rate throughput of 2.4 Mbps.
- CDMA2000
- Code Division Multiple Access 2000. A third generation (3G) wireless system,
trademarked by Qualcomm, offering 3G capabilities within a single 1.25-MHz channel,
effectively doubling the voice capacity of the standard's predecessor and offering
data speeds of up to 307 Kbps.
- ADAPTIX OFDMA/TDD
- The ADAPTIX scalable OFDMA operating system that drives the NewHorizonTM software
defined radio platform. OFDMA (see OFDMA) alone does not automatically lead to higher
network capacity. The ADAPTIX OFDMA/TDD architecture captures the potentials of OFDMA
by marrying it with an intelligent MAC (media access control) layer. In particular,
the MAC is designed to be channel- and application-aware so that individual radio
resources (frequency, time, space) are utilized to their limits AT ALL TIMES. The
ADATPIX OFDMA/TDD architecture is a fully pre- WiMAX and WiBro compliant engine that
delivers multifold capacity gain over regular OFDMA systems.
- FDD
- Frequency Division Duplexing. A transmission method that separates the transmitting
and receiving channels with a guard band (some amount of spectrum that acts as a buffer
or insulator). Allows two-way data transmission by, in effect, opening two distinct radio
links. Contrast with Time Division Duplexing (see TDD).
- FFT
- Fast Fourier transform. A signal processing term for a common computer implemetation
of Fourier transforms. The FFT will always result in a finite series of sine and cosine
waves as an extremely close approximation of the possibly infinite series described
by the purely mathematical application of the Fourier Transform.
- GSM
- A wireless communications protocol that allows large numbers of users to access one
radio frequency by allocating time slots for use to multiple voice or data calls. A
standard for how data is coded and transferred through the wireless spectrum. The
European wireless standard also used in Asia, GSM is an alternative to CDMA. GSM digitizes
and compresses data and sends it down a channel with two other streams of user data. The
standard is based on Time Division Multiple Access (see TDMA).
- IEEE
- Institute of Electrical and Electronics Engineers. A nonprofit organization of engineers
that holds conferences, publishes literature, and develops standards for electronics.
Its membership spans over 150 countries.
- IPv6
- Internet Protocol Version 6. The "Internet Protocol" is a standard that
defines how data is transmitted over the Internet. IP bundles data—including e-mail,
faxes, voice calls and messages, and other types—into "packets" in order to
transmit it over public and private networks. IPv6 is a replacement for IPv4 and includes
support for flow ID in the packet header, which can be used to identify flows of
transmission traffic.
- LAN
- Local area network. A data network generally confined to a building or campus environment
and owned by the end user organization.
- MAC
- Media Access Control. The lower of the two sublayers of the data link layer defined by
the IEEE. The MAC sublayer handles access to shared media, such as whether token passing
or contention will be used.
- MAN
- Metropolitan area network. A public network that covers a metropolitan area, which may
extend beyond the official city limits.
- MIMO
- Multiple input multiple output. An antenna technology for wireless communications in
which multiple antennas are used at both the source (transmitter) and the destination
(receiver). The antennas at each end of the communications circuit are combined to minimize
errors and optimize data speed.
- OFDM
- Orthogonal Frequency Division Multiplexing. A modulation technique for wireless
communications. OFDM splits a data stream into multiple RF (radio frequency) channels,
each of which is sent over a subcarrier frequency. Multiple data symbols are encoded
concurrently onto multiple frequencies in a parallel fashion. Other techniques are used to
ensure maximum transmission performance.
- OFDMA
- Orthogonal Frequency Division Multiple Access. A highly flexible multiple-access scheme
based on OFDM modem. OFDMA is the predominant multiple-access scheme of choice for beyond
3G (B3G) generation broadband wireless systems such as WiMAX and WiBro. The major
benefits of OFDMA include simplicity, high scalability, fine granularity, and capacity-achieving
performance.
- QAM
- Quadrature amplitude modulation. A sophisticated modulation technique, or compression
technique, using variations in signal amplitude and phase, that allows multiple bits to
form a single "symbol," which is then impressed on a single sine wave.
- QoS
- Quality of Service. The ability to define a level of performance in a data communications
system. For example, ATM networks specify modes of service that ensure optimum performance
for traffic such as real-time voice and video. QoS has become a major issue on the Internet
as well as in enterprise networks, because voice and video are increasingly traveling over
IP-based data networks that were not designed for continuous speech or video. A high QoS
would ensure that the packets of data all arrive in time for undetectable reassembly.
- SDR
- Software defined radio. A radio in a mobile communications environment whose channel
modulation waveforms are defined in software. That is, waveforms are generated as sampled
digital signals, converted from digital to analog, and then upconverted to RF. The
receiver, similarly, employs a wideband analog to digital converter (ADC) that captures
all of the channels of the software radio node. The receiver then extracts, downconverts,
and demodulates the channel waveform using software on a general purpose processor.
- TDD
- Time Division Duplexing. A transmission method that uses only one channel for transmitting
and receiving, separating them by different time slots. No guard band is used. This increases
spectral efficiency by eliminating the buffer band, but also increases flexibility in
asynchronous applications. For example, if less traffic travels upstream, the time slice for
that direction can be reduced and reallocated to downstream traffic.
- TDMA
- Time Division Multiple Access. TDMA breaks down data transmission, such as a phone
conversation, into fragments and transmits each fragment in a short burst, assigning each
fragment a time slot. With a cell phone, the caller would not detect this fragmentation.
Whereas CDMA (which is used more frequently in the United States) breaks down calls on a signal
by codes, TDMA breaks them down by time. The result in both cases: increased network capacity
for the wireless carrier and a lack of interference for the caller. TDMA works with GSM and
digital cellular services.
- TD-SCDMA
- Time division synchronous code division multiple access. A unique 3G wireless standard
under development in China for use inside China. The spectral efficiency of radio systems is
three to five times higher than that of GSM.
- VoIP
- Voice Over Internet Protocol. The technology used to transmit voice conversation over a
data network using the Internet Protocol. The data network can be the public Internet, a
corporate intranet, or another managed or service provider network.
- WAN
- Wide area network. A public voice or data network that extends beyond the metropolitan
area, perhaps even internationally.
- WiBro
- Wireless broadband. A standard developed for the Korean market that is essentially 802.16d
with limited 802.16e functionality offering support for device mobility at speeds of up to
60 km per hour. The standard is expected to support 1 to 2 Mbps throughput per subscriber,
and will operate in the 2.3-GHz band.
- Wi-Fi
- Wireless fidelity. Another name for a wireless local area network running under the
802.11a/b/g standard in the 2.4-GHz range (see 802.11).
- WiMAX
- A group of broadband wireless communications standards for metropolitan area networks
(MANs) developed by a working group of the IEEE (see 802.16)
- WLAN
- Wireless local area network (see Wi-Fi).
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Resources & Downloads
Corporate Overview 
ADAPTIX Whitepaper: Key technology concepts behind FastSwitching-OFDMA™
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