Transmission energy allocation for CDMA applications
Transmission energy allocation (TEA) refers to redistribution of the available transmission energy among the different bits according to their sensitivity. We describe the application of TEA to robust vector quantization in a CDMA environment. We consider an interference-limited environment with negligible interference from other cells. In spite of the apparent incompatibility of TEA with such an environment, we show that it is, in fact, highly beneficial. We first analyze the effect of TEA on multi-user interference. We show that optimal TEA design is not separable from the problems of ordering of the bits of the various users, and the design of power control. We then prove that the jointly optimal solution to the overall design problem is simple and easy to implement. Finally, we provide experimental evidence to substantiate the performance gains of TEA over the standard index assignment, under conditions of severe fading.