STDMA for NS-3 is an implementation of the Self-Organized Time Division Multiple Access (STDMA)-protocol for the open source network simulator NS-3. Traditionally, a CSMA/CA based approach is used in 802.11 networks where a station first listens to the channel whether a transmission is ongoing before transmitting themselves. In case the channel is sensed as busy a random timeout is waited before a new transmission attempt is performed. STDMA on the other hand employs a reservation scheme where nodes communicate their next transmissions, resulting in less random elements. The coordination which node is allowed to transmit at which point of time is, contrary to traditional TDMA approaches, not done by a central station, but in a decentralized fashion by all participating nodes.
For a detailed description of STDMA we refer to the paper "In-depth Analysis and Evaluation of Self-Organizing TDMA" (see publication list) where besides the protocol description a transmitter-based comparison to CSMA is presented.
The STDMA code can be easily integrated and configured as a MAC protocol in NS-3 and enables the simulation of (already existing) beacon-based VANET applications. The code itself, a documentation of available parameterization can be found on GitHub.