  We present an NS-2 module, Physical Channel Access (PCA), to simulate
different access methods on a link shared with Multi-Frequency Time Division
Multiple Access (MF-TDMA). This tech- nique is widely used in various network
technologies, such as satellite communication. In this context, different
access methods at the gateway induce different queuing delays and available
capacities, which strongly impact transport layer performance. Depending on QoS
requirements, design of new congestion and flow control mechanisms and/or
access methods requires evaluation through simulations.
  PCA module emulates the delays that packets will experience using the shared
link, based on descriptive parameters of lower layers characteris- tics. Though
PCA has been developed with DVB-RCS2 considerations in mind (for which we
present a use case), other MF-TDMA-based appli- cations can easily be simulated
by adapting input parameters. Moreover, the presented implementation details
highlight the main methods that might need modifications to implement more
specific functionality or emulate other similar access methods (e.g., OFDMA).
