Playout buffer and rate optimization for streaming over IEEE 802.11 wireless networks

Abstract

Most streaming rate selection and buffer optimization algorithms are developed for wired networks and can perform poorly over wireless networks. Wireless MAC layer behavior, such as rate adaptation, retransmissions, and medium sharing, can significantly degrade the effectiveness of current streaming algorithms. This article presents the Buffer and Rate Optimization for Streaming (BROS) algorithm to improve streaming performance. BROS uses a bandwidth estimation tool designed specifically for wireless networks and models the relationship between buffer size, streaming data rate, and available bandwidth distribution. BROS optimizes the streaming data rate and initial buffer size, resulting in a high data rate but with few frame losses and buffer underflow events, while still keeping a small initial buffer delay. BROS is implemented in the Emulated Streaming (EmuS) client-server system and evaluated on an IEEE 802.11 wireless testbed with various wireless conditions. The evaluation shows that BROS can effectively optimize the streaming rate and initial buffer size based on wireless network bandwidth conditions, thus achieving better performance than static rate or buffer selection and jitter removal buffers.