In the practice of communication engineering, the rational selection and optimisation of communication methods are crucial for improving the overall performance of robot control systems. This study compares and analyses the effectiveness of traditional unicast communication methods and broadcast communication methods in modern robot control systems. The study points out that although the traditional unicast method is suitable for specific scenarios and can ensure the exclusivity of communication, it has the disadvantages of inefficiency and high latency in multi-node scenarios. To overcome these shortcomings, this study proposes a broadcast-based communication method, which significantly simplifies the communication process and reduces the consumption of computational resources and latency of data transmission through the “one-to-many” data transmission mode, especially when used in conjunction with the 5G technology, which can better take advantage of the high-speed and low-latency advantages of 5G advantages. Further, in order to improve the controllability of data transmission and the convenience of analysis, the research designed a method of dividing the data frame transmission into N synchronous time slots, which uses preset labels to improve the randomness of the selection of time slots, ensuring the flexibility and security of communication. By establishing a probabilistic model of the data transmitted by the tags in the time slots, the study provides a new perspective for the calculation of the throughput rate of the communication engineering system and finds the optimal number of tags to maximise the system throughput rate through mathematical derivation, thus providing a theoretical basis for the optimisation of the throughput rate in the 5G communication engineering technology. In the experimental analysis section, the study reveals the difference in throughput rate between the two methods under different node sizes by comparing the performance of the robot controller communication method with the traditional communication method under different node numbers and provides strong data support to help make precise technology choices and resource allocation in the construction of communication systems. The experimental results show that with the increase in the number of nodes, the method proposed in this study exhibits higher data transmission and better system performance, which is especially advantageous in large-scale network environments. This study not only highlights the application potential of the combination of 5G technology and robot controller communication methods in communication engineering, but also provides empirical evidence and theoretical guidance for the design and optimisation of future communication systems, bringing innovative solutions to communication engineering, which is expected to drive the industry towards a more efficient, safer, and more reliable direction.