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：本文研究了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。我们探讨一个分布式监测系统，其中多个信息源各自观测一个物理过程，并向具有异质性目标的多个监测器提供状态更新数据包。首先提出了两种语义过滤方案，作为根据数据包与目标相关的重要性来允许或丢弃到达数据包的手段——这种重要性取决于信息的内在和外在属性以及每个实际结果的发生概率。随后，每个传感器处被允许的数据包经过编码并通过块衰落无线信道传输，使得被服务的监测器能够及时实现其目标。推导出了一种截断式差错控制方案，该方案允许发射机根据数据包的重要性丢弃或重传未送达的数据包。接着，我们构建了及时信源编码优化问题，并解析推导出分配给被允许数据包的最优码字长度，该长度最大化所有通信传感器与监测器对的语义效用函数加权和。我们的分析与数值结果为不同到达率提供了最优设计参数，并凸显了采用所提出的语义过滤、信源编码和差错控制方案在及时状态更新传递方面的性能提升。