Towards an asymmetric air interface protocol for wireless Internet access

An asymmetric air interface protocol is one which allocates more capacity for one direction of data transfer (in our case, the downlink) than the other. In this paper we report ongoing work on the need and initial design calculations for an asymmetric indoor air interface protocol which is suitable for integrated voice and data applications, and specifically for wireless Internet access. As an example we consider PACS-UB, a symmetric protocol for voice communication in the isochronous unlicensed PCS band (1920-1930 MHz), and present a mechanism for making it statically asymmetric, as well as dynamically asymmetric in response to traffic demands. We also present a simplified worst-case two-dimensional model of co-channel interference when the air interface protocol is dynamically asymmetric. The quantitative results of the model indicate that an asymmetric protocol can result in significant gains in spectral efficiency. In the worst case downlink co-channel interference can be significant, and we discuss possible mitigating techniques that could be used.