The problem of goal-oriented semantic filtering and timely source coding in multiuser communication systems is considered here. We study a distributed monitoring system in which multiple information sources, each observing a physical process, provide status update packets to multiple monitors having heterogeneous goals. Two semantic filtering schemes are first proposed as a means to admit or drop arrival packets based on their goal-dependent importance, which is a function of the intrinsic and extrinsic attributes of information and the probability of occurrence of each realization. Admitted packets at each sensor are then encoded and transmitted over block-fading wireless channels so that served monitors can timely fulfill their goals. A truncated error control scheme is derived, which allows transmitters to drop or retransmit undelivered packets based on their significance. Then, we formulate the timely source encoding optimization problem and analytically derive the optimal codeword lengths assigned to the admitted packets which maximize a weighted sum of semantic utility functions for all pairs of communicating sensors and monitors. Our analytical and numerical results provide the optimal design parameters for different arrival rates and highlight the improvement in timely status update delivery using the proposed semantic filtering, source coding, and error control schemes.

翻译：本文研究多用户通信系统中面向目标的语义过滤与及时信源编码问题。我们考虑一个分布式监控系统，其中多个观测物理过程的信息源向具有异构目标的多个监控器提供状态更新数据包。首先提出两种语义过滤方案，根据数据包基于目标的重要性（该重要性由信息的固有属性与外在属性以及每个实现发生的概率共同决定）来决定接收或丢弃到达数据包。每个传感器被接收的数据包随后经过编码，并通过块衰落无线信道进行传输，以使受服务的监控器能够及时实现其目标。推导出一种截断式差错控制方案，该方案允许发送端根据未传递数据包的重要性决定丢弃或重传。随后，我们构建了及时信源编码优化问题，并解析推导了分配给被接收数据包的最优码字长度，该长度能够使所有通信传感器与监控器对的语义效用函数加权和最大化。我们的解析与数值结果为不同到达率提供了最优设计参数，并揭示了采用所提出的语义过滤、信源编码与差错控制方案在提升及时状态更新传递性能方面的改进。