Design of a downlink power control scheme in multi-code CDMA mobile medicine system

In this paper, we proposed a downlink power control scheme to apply in the multi-code CDMA mobile medicine system. The mobile medicine system contains: (i) blood pressure and body temperature measurement value, (ii) medical signals measured by the electrocardiogram device, (iii) mobile patient´s history, (iv) G.729 audio signal and MPEG-4 CCD sensor video signal. By the help of the multi-code CDMA spread spectrum communication system with downlink power control strategy to make it possible for transmission media in this system to meet the quality of service of mobile medicine system, and achieve the purpose of the maximum resource utilization. In different media, the power is controlled according to the demand for bit error rate. Higher transmission power is given to the media requesting lower bit error rate. Numerical analysis shows that the ratio of transmission power of voice, video and data virtual channels are approximately 1:2:13 when the bit error rates for the voice, video and data are set at 10^-3, 10^-4 and 10^-7. It is similar to the ratio of SNIR of voice, video and data transmission requirement. Meanwhile, we also test related mobile medical signal transmission and simulation.