CDMA is characterized by high capacity and small cell radius,
employing spread-spectrum technology and a special coding scheme.
Capabilities of cdmaOne evolution have already been
defined in standards. IS-95B provides ISDN rates up to 64 kbps.
The next phase of cdmaOne is
a standard knows as 1XRTT and enables 144 kbps packet data in a
mobile environment.
Other features available are a
two-fold increase in both standby time and voice capacity. All of
these capabilities will be available in an existing cdmaOne
1.25 MHz channel.
The next phase of cdmaOne
evolution will incorporate the capabilities of 1XRTT, support all
channel sizes (5 MHz, 10 MHz, etc.), provide circuit and packet
data rates up to 2 Mbps, incorporate advanced multimedia
capabilities, and include a framework for advanced 3G voice
services and vocoders, including voice over packet and circuit
data.
This phase of the standard will be
complete by 4Q99.
There are now a number of flavours
of CDMA:
|
Composite CDMA/TDMA |
Wireless
technology that uses both CDMA and TDMA. For large-cell
licensed band and small-cell unlicensed band applications.
Uses CDMA between cells and TDMA within cells. Based on
Omnipoint technology. |
| CDMA |
In addition to
the original Qualcomm-invented N-CDMA (originally just
'CDMA', also known in the US as IS-95. See N-CDMA
below). Latest variations are B-CDMA, W-CDMA and composite
CDMA/TDMA. Developed originally by Qualcomm, CDMA is
characterized by high capacity and small cell radius,
employing spread-spectrum technology and a special coding
scheme. It was adopted by the Telecommunications Industry
Association (TIA) in 1993. The first CDMA-based networks
are now operational. B-CDMA is the basis for 3G UMTS (see
below) |
| cdmaOne |
First
Generation Narrowband CDMA (IS-95). See above. |
| cdma2000 |
The new
second-generation CDMA MoU spec for inclusion in UMTS.
Click HERE for more
technical details... |
|