Evolution of the data aggregation concepts for STS readout in the CBM Experiment

The STS detector in the CBM experiment delivers data via multiple e-links connected to GBTX ASICs. In the process of data aggregation, that data must be received, combined into a smaller number of streams, and packed into so-called microslices containing data from specific periods. The aggregation must consider data randomization due to amplitude-dependent processing time in the FEE ASICs and different occupancy of individual e-links. During the development of the STS readout, the continued progress in the available technology affected the requirements for data aggregation, its architecture, and algorithms. The contribution presents considered solutions and discusses their properties.