Experimental and Simulation Study of a WiMAX System in the Sea Port Scenario

The paper presents a measurement campaign carried out on a 2.5 GHz Mobile WiMAX test-bed in a sea port scenario, aimed at evaluating the system performance. The analysis of acquired data suggested the definition of a 2-ray pathloss model, which is able to fit the actual behavior of the observed marine channel. In order to evaluate the effects of the proposed pathloss model on system performance the paper presents a simulation study carried out by means of OPNET simulator. In particular, the simulation study is aimed at comparing the throughput at IP level obtained using different pathloss models implemented in OPNET, with that obtained when the proposed 2-ray model is considered. Further, the throughput at IP level obtained by simulation is compared with the one measured in the actual test-bed. This comparison points out that the WiMAX OPNET model is able to reproduce in most cases the system performance observed during the measurement campaign, when the proposed 2-ray pathloss model is used. However, the simulator is not able to predict the behavior of actual system in all situations. Indeed, in the areas where the pathloss presents peaks, the breakdown of system performance, mainly caused by synchronization problems, is not predicted by the simulator.