A multiplexing scheme for multimodal teleoperation

This article proposes an application-layer multiplexing scheme for teleoperation systems with multimodal feedback (video, audio, and haptics). The available transmission resources are carefully allocated to avoid delay-jitter for the haptic signal potentially caused by the size and arrival time of the video and audio data. The multiplexing scheme gives high priority to the haptic signal and applies a preemptive-resume scheduling strategy to stream the audio and video data. The proposed approach estimates the available transmission rate in real time and adapts the video bitrate, data throughput, and force buffer size accordingly. Furthermore, the proposed scheme detects sudden transmission rate drops and applies congestion control to avoid abrupt delay increases and converge promptly to the altered transmission rate. The performance of the proposed scheme is measured objectively in terms of end-to-end signal latencies, packet rates, and peak signal-to-noise ratio (PSNR) for visual quality. Moreover, peak-delay and convergence time measurements are carried out to investigate the performance of the congestion control mode of the system.