Asymmetric physical layer design for high-speed wireless digital communications

High data rates and portability are conflicting requirements in the design of reliable indoor wireless data communication systems. Asymmetric system d esign addresses this problem by exploiting the major differences in the ava ilability of resources (i.e., energy, spare) that exist between base statio ns and portable units. Such an approach seeks to concentrate most of the si gnal processing tasks involved in the operation of the two-way wireless lin k at the base station. This paper presents and discusses the implications o f a set of techniques for asymmetric physical layer system design based on the nse of channel precoding for forward transmission. System performance i s assessed via simulations using a realistic time-varying channel model. Si mplified two-way antenna diversity implemented exclusively at the base stat ion and the key issue of automatic gain control at the receive side of the preceded link are also addressed and evaluated. Simulation results confirm that the adoption of these techniques enables reliable digital communicatio n at a data rate of 20 Mbit/s an both links while significantly reducing th e power consumption of the portable unit.