Supported under the NSF Special Projects in Communication and Networking, Ohio State University researchers in both the wireless communications and networking areas are working toward achieving significant gains in wireless system performance by leveraging an existing and functioning wireless modem testbed. The narrow-band wireless modem testbed is expected to support both real-time and non-real-time (regular) data applications. The first step is to design and implement an effective medium access control (MAC) protocol that coordinates the transmission activities on the forward and reverse channels. In this paper, we document our design of such a MAC protocol, called OSU-MAC, subject to the physical layer characteristics and constraints. A number of techniques have been proposed to support QoS imposed by the real-time applications, to deal with the asymmetry on the forward and reverse channels and the half-duplex transmission constraint imposed by the physical layer, and to enhance the error control capability of OSU-MAC. We also present simulation results to demonstrate the key, functional characteristics of OSU-MAC. Index Terms: MAC, asymmetric wireless links, wireless WAN, temporal QoS, half-duplex transmission constraints, error control.

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