Task-Oriented Multimodal Token Transmission in Resource-Constrained Multiuser Networks

Despite the promising paradigm enabled by integrating semantic communication (SemCom) with multimodal large models (MLMs) for transmitting and utilizing multimodal data, efficiently fusing and exploiting cross-modal information still remain challenging. Moreover, widely adopted transformer-based architectures inevitably produce excessively long token embeddings for transmission, which result in higher bandwidth consumption, increased power usage, and greater latency, rendering them impractical in resource-constrained networks. In this letter, we propose a task-oriented multimodal token transmission scheme for efficient multimodal information fusion and utilization. To improve inter-modal consistency and task-relevant token transmission, we design a two-stage training algotithm which involves cross-modal alignment followed by task-oriented fine-tuning. Meanwhile, token compression is performed using a sliding window pooling operation to conserve limited communication resources. To balance the trade-off between latency reduction and performance degradation caused by compression, we formulate a weighted-sum optimization problem over latency and inference performance. We jointly optimizes bandwidth, power allocation, and token length across users by using an alternating optimization method. Simulation results demonstrate that the proposed algorithm outperforms the baseline under different bandwidth and power budgets. Moreover, the two-stage training algorithm achieves higher accuracy across various signal-to-noise ratios than the method without cross-modal alignment.