Measurement of characteristics of voice over IP in a wireless LAN environment

Voice over IP is becoming very popular in computer communication applications, where quality of service can be evaluated solely by an accurate characterization of packet loss and delay. However, hardware measurement equipment for wireless networks such as 802.11 are essentially unavailable and many software techniques are either inaccurate or imprecise. This paper presents a novel measurement and clock synchronization technique that requires only commercially available software tools to measure the end-to-end propagation delay, delay jitter, and the exact times that packets were lost in the network. This system is capable of measuring the delay of the arriving packets to within 50 microseconds of accuracy. The measurement system is used in a wireless LAN testbed to evaluate the characteristics of voice over IP in an IEEE 802.11 environment.