Outdoor IEEE 802.11 cellular networks: MAC protocol design and performance

We explore the feasibility of designing an outdoor cellular network based on the IEEE 802.11 specification. Since the standard is intended for wireless local-area networks (WLAN), there are many technical challenges when applying the air interface to the outdoor environment. We study how the 802.11 medium access control (MAC) protocol can be applied and how it performs in the outdoor network. By exploiting the fact that timeout intervals are not explicitly specified, without modifying the standard, we propose a new timing structure for the distribution coordination function (DCF) and the handshake of request-to-send (RTS) and clear-to-send (CTS) to handle increased signal propagation delay in the outdoor network. We find that the DCF and RTS/CTS protocols as specified in the standard continue to work properly for a link distance up to 6 km. Our analysis reveals that the DCF performance degrades slightly in the 802.11 network with a cell size of 6 km when compared with the 600 m WLAN. Thus, as far as the MAC protocol is concerned, the 802.11 outdoor, cellular network with 6 km cell size is feasible.