Abstract
Development of applications in real-time service promotes more stringent freshness and fidelity requirements for the status update and decision systems. However, the freshness and fidelity of status updates are mutually restrictive, as fresh information requires timely transmission whereas high quantization precision incurs long transmission time. This work improves trade-off between the freshness and fidelity of status updates at periodical decision epochs by selecting appropriate transmission time and quantization precision. Specifically, the age of information (AoI) metric is used to assess data freshness, while distortion that consists of both static and dynamic parts is used to characterize the fidelity of status updates. We first formulate a joint AoI and distortion optimization problem. Then, the optimal transmission time and quantization precision are theoretically analyzed. We further minimize the sum of AoI and distortion by using power allocation strategy which selects a proper budget SNR of the wireless channel. Numerical results show that by using the optimized transmission time, quantization precision, associated with transmit power allocation, the overall freshness and fidelity of status updates can be improved remarkably.