10-04-2012, 03:04 PM
Power-Distortion Optimized Mode Selection for Transmission of VBR Videos in CDMA Systems
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INTRODUCTION
ACROSS THEWORLD, third-generation cellular communication
systems are being introduced. These systems are
designed to accommodate various multimedia services, which
have a much greater data rate than past voice-only services.
However, the greater data rates required by these multimedia
services requires a greater transmit power for each mobile terminal.
Because the capacity of a code-division multiple-access
(CDMA) system is limited by the multiple-access interference
(MAI), if the power transmitted by each user is reduced,
intracell and intercell interference will be decreased, increasing
the total system capacity [1].
PERFORMANCE COMPARISON
In this section, we compare the performance of the R-D
optimized and P-D optimized mode-selection methods for
CDMA systems. We assume Rayleigh flat fading environment
CONCLUSION AND FURTHER WORK
Because the capacity of a CDMA system is interference limited,
it is important to minimize the total transmit power of the
mobile terminals. However, this must be done without compromising
QoS. To realize this, we have proposed an optimum
mode-selection algorithm for transmitting digital video over a
CDMA channel, which minimizes the distortion for a given
power consumption value. Unlike previous optimum mode-selection
methods, this scheme takes into account time-varying
channel conditions. Furthermore, our scheme remains simple
and can be implemented on resource-constrained MTs at minimal
cost.