CDMA stands for Code Division Multiple Access, a digital
technology that uses digital encoding "spread spectrum" radio
frequency (RF) techniques, thus providing much better and more cost effective
voice quality, privacy, system capacity, and flexibility than other wireless
technologies
CDMA2000 1X (IS-2000) was recognized by the International
Telecommunications Union (ITU) as an IMT-2000 standard in November 1999. It was
the first IMT-2000 technology deployed worldwide, in October 2000.
1X is the most spectrally efficient wide area network
technology for circuit-switched voice communications and it supports packet
data speeds of up to 307 kbps in a single 1.25 MHz channel.
Key features of CDMA2000 1X includes:
Voice Capacity: Supports 33-35 up to 40 simultaneous voice calls
per single 1.25 MHz FDD channel. A new codec, 4GV, for CDMA2000 1X will
increase voice capacity by 40%.
High-Speed Data: Release 0 supports bi-directional peak data
rates of up to 153 kbps and an average of 60-100 kbps in commercial networks in
a 1.25 MHz channel. Release 1 can deliver peak data rates of up to 307 kbps.
Applications: Supports circuit-switched voice, short messaging
service (SMS), multimedia messaging service (MMS), games, GPS-based location
services, music and video downloads
CDMA2000 1xEV-DO Revision A (Rev A)
Rev A is an evolution of CDMA2000 1xEV-DO Rel 0 that
increases peak rates on reverse and forward links to support a wide-variety of
symmetric, delay-sensitive, real-time, and concurrent voice and broadband data
applications. It also incorporates OFDM technology to enable multicasting
(one-to-many) multimedia content delivery.
Rev. A’s more symmetric uplink speeds enable users to send
large files, email with attachments, high resolution photographs and personal
videos from their mobile devices. With its low network latency, service tiering
with Quality of Service (QoS) and IP-based broadband architecture, Rev A is
able to support time-sensitive applications, such as Voice over IP (VoIP),
Push-to-Talk (PTT) and video telephony. Rev A was launched in October 2006, and
it is the only All-IP, advanced broadband technology commercially deployed
today.
Key features of Rev A include:
Improved broadband speeds: Provides a peak data rate of 3.1 Mbps
in the forward link and 1.8 Mbps in the reverse link in a 1.25 MHz FDD carrier.
In commercial networks, Rev A achieves average throughput of 450-800 kbps in
the forward link and 300-400 kbps in the reverse link
Higher spectral efficiency: Supports1.2 times Rel 0 forward link
sector capacity and3.4 times reverse link sector capacity. Increased rate
quantization on both forward and reverse link enables more efficient use air
link resources, better network utilization and lower cost of delivery
Increased Capacity – On both the forward and reverse link, Rev A
allows operators to support more users and it improves the cost of delivering
voice, data and multimedia services.
Symmetry – By increasing uplink speeds, Rev A is the first
commercially available wireless technology to deliver a true synchronic
broadband experience. Symmetry is important for applications where users send
packets of data as often as they receive them, such as receiving and sending
email with attachments.
Low latency : The average latency of Rev A is below 50
milliseconds, making it ideal for delay-sensitive applications.
Advanced Quality of Service (QoS) mechanisms that support the
prioritization and delivery of individual packets based on the type of application
or user profile. These mechanisms ensure a consistent, high-quality user
experience.
All-IP: Internet Protocol (IP) is the foundation for CDMA2000
radio access networks. Like 1xEV-DO Rel 0, All-IP Rev A networks provide
operators service flexibility and higher bandwidth efficiencies, which
translate into greater control and significant cost savings.
Advanced services: Enables the enhanced performance of real-time
broadband, symmetric data link, and delay sensitive services such as VoIP,
push-to-talk (PTT), push-to-media (PTM), video conferencing, multicasting, and
rich 3D gaming with multiple players.
Backward compatibility: Rev A networks support existing Rel 0
applications and devices. This backward compatibility preserves an operator’s
previous network investments. Rev A it is backwards compatible with 1X and
cdmaOne systems through multi-mode devices.
In addition to the air interface techniques used in CDMA2000 1X
and 1xEV-DO Rel 0, the following new high-speed packet-switched uplink
techniques are incorporated into CDMA2000 1xEV-DO Rev A:
Fast Uplink Rate Control – to efficiently control the
transmission of mobile devices
Fast Hybrid ARQ in Uplink – to acknowledge correct receipt of
data and retransmit erroneous data
Incremental Redundancy Feedback in Uplink – to increase the
effective data rate in the downlink by terminating the transmission of a packet
early if it is decoded earlier than expected
Uplink Channelization – to enable better control of the uplink
data flows
Short Transmission Time Interval (TTI) – to accelerate the
transmission of packets
Information available on this page is culled from various telecom sites, not under the control of Multi-Links. Multi-Links is not responsible for, and makes no representations, warranties or conditions concerning, the contents of this page.
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