11-05-2011, 03:32 PM
[attachment=13567]
[attachment=13567]
INTRODUCTION
Code Division Multiple Access (CDMA) is a form of multiplexing and a method of multiple access to a physical medium such as a radio channel, where different users use the medium at the same time thanks to using different code sequences.
Use in mobile telephony
Coverage and applications
Technical details
Coverage and applications
The size of a cell depends on the power of the signal transmitted by the handset, the terrain and the radio frequency being used
Various companies use different variants of CDMA to provide fixed-line networks using wireless local loop (WLL) technology
Technical details
CDMA exploits mathematical properties of orthogonality between vectors representing the data strings. For example, binary string "1011" is represented by the vector (1, 0, 1, 1).
Example
Macro diversity usage
Soft handover
Hard handover
Roaming
Soft handover
Soft handoff (or soft handover) is an innovation in mobility
As a result, signal quality and handoff robustness is improved compared to TDMA systems
Hard handover
When there are frequency boundaries between different carriers or sub-networks, a CDMA phone behaves in the same way as TDMA or analog and performs a hard handoff in which it breaks the existing connection and tries to pick up on the new frequency where it left off.
Roaming
CDMA2000 bases its roaming capabilities on ANSI-41,Regional, National or International roaming all have several elements that are required in order for CDMA roaming to be facilitated:
CDMA Roaming Business Elements
CDMA Roaming Technical Elements
CDMA Roaming Service Features
Roaming Service Providers
CDMA Roaming Inter-carrier Implementation
CDMA Roaming Carrier Maintenance
Features of CDMA
Narrowband message signal multiplied by wideband spreading signal code
Soft handoff increases capacity
Near-far problem
[attachment=13567]
INTRODUCTION
Code Division Multiple Access (CDMA) is a form of multiplexing and a method of multiple access to a physical medium such as a radio channel, where different users use the medium at the same time thanks to using different code sequences.
Use in mobile telephony
Coverage and applications
Technical details
Coverage and applications
The size of a cell depends on the power of the signal transmitted by the handset, the terrain and the radio frequency being used
Various companies use different variants of CDMA to provide fixed-line networks using wireless local loop (WLL) technology
Technical details
CDMA exploits mathematical properties of orthogonality between vectors representing the data strings. For example, binary string "1011" is represented by the vector (1, 0, 1, 1).
Example
Macro diversity usage
Soft handover
Hard handover
Roaming
Soft handover
Soft handoff (or soft handover) is an innovation in mobility
As a result, signal quality and handoff robustness is improved compared to TDMA systems
Hard handover
When there are frequency boundaries between different carriers or sub-networks, a CDMA phone behaves in the same way as TDMA or analog and performs a hard handoff in which it breaks the existing connection and tries to pick up on the new frequency where it left off.
Roaming
CDMA2000 bases its roaming capabilities on ANSI-41,Regional, National or International roaming all have several elements that are required in order for CDMA roaming to be facilitated:
CDMA Roaming Business Elements
CDMA Roaming Technical Elements
CDMA Roaming Service Features
Roaming Service Providers
CDMA Roaming Inter-carrier Implementation
CDMA Roaming Carrier Maintenance
Features of CDMA
Narrowband message signal multiplied by wideband spreading signal code
Soft handoff increases capacity
Near-far problem
