The communications in MANETs, VANETs and DSRC/WAVE systems are adversely affected by the link failures in the network layer, and by the hidden station, mobile hidden station, neighborhood capture and asymmetric radio link problems in the MAC layer. All the problems are highly affected by mobility of the stations. This book addresses the characterization and solution of these problems. Couple MAC protocols are analyzed with respect to the mentioned problems. This book also addresses how the DSRC/WAVE systems are affected by the above mentioned problems, and how a cross-layer treatment can be applied to make safety critical information dissemination in DSRC/WAVE systems efficient. Discrete time Markov chain (DTMC) and OMNeT++ are used as analyzing tools.