CDMA2000 is an evolution of CDMA technology that provides higher data rates and improved voice quality over CDMA. It spreads signals across a wider bandwidth and uses techniques like multicarrier modulation to support higher data rates. CDMA2000 represents a family of standards that offer both voice and high-speed data services. It provides more efficient use of spectrum and supports advanced mobile services while maintaining backward compatibility.
2. WHAT IS CDMA???
CDMA is a high speed data and voice network solution
for low cost easy to deploy high performance services.
CDMA can support high volume of voice and data traffic.
Instead of being limited to narrow channel structure in a
given frequency, CDMA spreads signal across 1.25MHz
of spectrum and simultaneously transmits uniquely
encoded and encrypted signals over same RF carrier.
Due to its efficient use of spectrum to provide high
quality voice and data services CDMA can be utilised for
fixed voice and data services.
3. CDMA 2000
CDMA 2000 is designed to provide an evolutionary path from
cdma One (or) IS95.
The name CDMA2000 denotes a family of standards that
represent the successive, evolutionary stages of the underlying
technology. These are:
Voice: CDMA2000 1x,1xRTT, 1X Advanced
Data: CDMA2000 1xEV-DO
4. WHY CDMA???
Higher capacity
Improved performance in multipath by diversity
Lower mobile transmit power = longer battery life
Power control
Variable transmission rate with voice activity detection
Sectorization gain
High peak data rates can be accommodated
Combats other-user interference = lower reuse factors
5. FACTS ABOUT CDMA
CDMA is a technology for the evolution of IS-95/IS-
95A to 3G services.
The CDMA2000 cellular technology provides an
evolutionary high data rate upgrade path for current
users of 2G(IS-95)and 2.5G(IS-95A)CDMA technology.
CDMA2000 represents a family of standards.
A key component of CDMA2000 system is a new
packet core network(PCN) that allows for the delivery
of packet data with high speed and better security.
6. CONT..
Multicarrier modulation is applied to 3G voice oriented
cellular network using CDMA technology.
CDMA2000 employs a multicarrier operation in which a user
is allowed to use 1,3,6,9 of the CDMA one channels to
support a more reliable voice and variety of data channels.
The main advantage of using multicarrier modulation is to
provide higher data rates for data applications, wider BW and
consequently better voice quality and backward compatibility
with existing CDMA system.
In CDMA2000 using 16-QAM digital modulation technique
the maximum data rate is increased.
7.
8. CDMA 2000 LOGICAL CHANNELS
Dedicated Traffic Channel
Common Control Channel
Dedicated Signalling Channel
Common Signalling Channel
9. SPREADING AND MODULATION
Uplink – spreading via Walsh functions
Downlink – Downlink carriers can be operated independently –
Each carrier contains a pilot – spreading via Walsh functions –
spreading factors from 4 to 256 – PN sequences and Walsh
functions on parallel carriers are the same
10. USER DATA TRANSMISSION
Fundamental Channel is specified, with a maximum data
rate of 14.4 kbps
For increased data rates, use one or more Supplemental
Channels
– Supplemental Channel is a parallel code channel,
separated with a different Walsh function from the
Fundamental Channel
– Supplemental Channel has a fixed spreading factor for
a given data rate
11. KEY FEATURES
Leading performance.
Efficient use of spectrum.
Support for advanced mobile services.
CDMA2000 technology are compatible with IP having
more flexibility and higher BW efficiency.
Device selection: CDMA2000 offer the broadest
selection of mobile devices and has a significant cost
advantage.
CDMA2000 have been designed for urban as well as
remote rural areas for fixed wireless, WLL, limited and
full mobility application in multiple spectrum bands.
12. ADVANTAGES
Superior voice quality.
High speed broadband data connectivity.
Improved security and privacy.
Multi-mode, multiband global roaming features.
DISADVANTAGES
Channel pollution: there are too many signals from cell sites in
subscribers phone, but none is dominant –degrading call quality.
International roaming: another disadvantage of this technology is the
lack of international roaming capabilities and only CDMA2000
device that can be used internationally must also have a GSM radio.