This paper presents the results from a network performance analysis of WiMAX in order to meet growing needs of public safety agencies for outdoor broadband wireless communications technology.
In this report, the authors present the results from their network performance analysis of Worldwide Interoperability for Microwave Access (WiMAX), a communications technology for use by public safety agencies, to meet growing needs for outdoor broadband wireless technology. They deployed an 802.16d WiMAX network that operates at 4.9GHz, the spectrum reserved for public safety at Clemson University, and worked in collaboration with the local police department. The WiMAX standard leaves key areas of the protocol unspecified, including packet scheduling, frame packing, and modulation/coding adaptation. Using knowledge of the equipment’s implementation choices, the authors derived theoretical application throughput for both TCP and UDP protocols and correlated expected results with empirical results. The authors observed TCP throughput in range from 5.2 Mbps to 0.66 Mbps and showed that the measured average TCP and UDP application throughput was within 1.0% of the expected values. Using a coverage tool, the authors monitored the WiMAX for a period of six months and found that an operational link required near line-of-sight between the subscriber station and the base station, was highly sensitive to the level of foliage present at the time of data collection. The authors conclude that despite spectrum difficulties, a WiMAX network can support applications used by law enforcement.