Qinghua Zhao

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This paper investigates the tradeoffs between source coding, channel coding and spreading in CDMA systems, operating under a fixed total bandwidth constraint. We consider two systems, each consisting of a uniform source with a uniform quantizer, a channel coder, an interleaver, and a direct sequence spreading module. System A is quadrature phase-shift keyed(More)
We consider a CDMA system consisting of an image source coder, a convolutional channel coder, an interleaver, and a direct sequence spreading module. With different allocations of bandwidth to source coding, channel coding and spreading, the system is analyzed over a frequency selective Rayleigh fading channel. The performance of the system is evaluated(More)
This paper analyzes a CDMA system with a continuous uniform source, a scalar quantizer, and a hard decision block channel coder, under the constraint of fixed total bandwidth. The system employs a linear, minimum mean-square-error (MMSE) receiver for interference suppression. We study the performance for both additive white Gaussian noise (AWGN) and flat(More)
As the size of brain imaging data such as fMRI grows explosively, it provides us with unprecedented and abundant information about the brain. How to reduce the size of fMRI data but not lose much information becomes a more and more pressing issue. Recent literature studies tried to deal with it by dictionary learning and sparse representation methods,(More)
This paper investigates the tradeoffs of source coding, channel coding and spreading in CDMA systems. We consider a system consisting of an image source coder, a convolutional channel coder, an interleaver, and a direct sequence spreading module. With different allocations of bandwidth to source coding, channel coding and spreading, the system is analyzed(More)
This paper investigates the tradeoffs between source coding, channel coding and spreading in a CDMA system, operating under a fixed total bandwidth constraint. We consider a system consisting of a uniform source with a uniform quantizer, a channel coder, an interleaver, and a direct sequence spreading module. The system uses binary phase-shift keyed (BPSK)(More)
BACKGROUND There have been few studies focusing on the curve pattern of scoliosis caused by lumbar disc herniation (LDH) in adolescents and the natural history of scoliosis after discectomy. The current study was carried out to identify the curve pattern of scoliosis and investigate the effect of posterior discectomy on the curve improvement in adolescents(More)