A QoS control scheme using dynamic window size control for wide area ubiquitous wireless network

This paper describes a quality-of-service (QoS) control scheme for a wide-area ubiquitous wireless network which is designed to accommodate many wireless terminals (WTs), such as sensors and actuators, in a large cell area. The purpose of this paper is to establish a QoS control scheme in a medium access control (MAC) layer that can hold the transmission delay of high-priority class traffic within a predefined value regardless of how much low-priority class traffic there is. Several QoS control schemes for wireless communication use have been proposed. However, in the wide-area ubiquitous wireless network, an access point (AP) accommodates many WTs and the AP traffic volume often drastically changes. Therefore, conventional schemes sometimes cannot control the QoS of high-priority traffic. To solve this problem, we propose a QoS control scheme that calculates a suitable initial back-off window size of random access for each QoS class by using equations derived from a Markov chain behavior model. The proposed scheme adjusts the window size so as to prevent increased transmission delay of high-priority traffic. The scheme's performance is clarified by computer simulation. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.