Extremely Low Latency Interactive Streaming over an 802.11 Wireless Link

Globally, interactive streaming services including AR/VR streaming or cloud gaming are getting more and more attention. To support a smooth and natural experience during the service, a client’s actions should be quickly reflected on the screen in 20 ms while the video frames are generated from the server. To achieve this, the end-to-end latency should be shrunk as much as possible. While most of the works are focusing on reducing the encoding/decoding time or the volume of the video data at the application layer assuming the other layers are reliable, we try to give attention to the other layers. Considering that most streaming users prefer the use of wireless devices, it is important to study the performance of low latency streaming over wireless networks. In this work, we show that the use of general 802.11 (Wi-Fi) wireless networks might cause a long latency which impedes smooth and natural experience during extremely low latency streaming services. Especially with a poor wireless condition, the number of link-layer retransmissions increases resulting in long latency. To relieve the problem, we limit the number of link-layer retransmissions and complement its side-effect by using application layer forward error correction (AL-FEC). From the extensive evaluation on a real wireless testbed, we show that the proposed method could achieve constant low latency service even with a poor wireless condition.