NS-2, with its IEEE 802.11 support, is a widely utilized simulation tool for wireless communications researchers.  However, the current NS-2 distribution code has some significant shortcomings both in the overall architecture and the modeling details of the IEEE 802.11 MAC and PHY modules. This paper presents a completely revised architecture and design for these two modules. The resulting PHY is a full featured generic module able to support any single channel frame-based communications (i.e. it is also able to support non-IEEE 802.11 based MAC). The key features include cumulative SINR computation, preamble and PLCP header processing and capture, and frame body capture. The MAC accurately models the IEEE 802.11 CSMA/CA mechanism (without upper MAC management features like beacons, association, etc.), as required for credible simulation studies. The newly designed MAC models transmission and reception coordination, backoff management and channel state monitoring in a structured and modular manner. In turn, the contributions of this paper make extending the MAC for protocol researches much easier and provide for a significantly higher level of simulation accuracy.

The latest code is included in ns-2.34 released on June 17th, 2009