Towards 6G Data-Oriented Uplink RSMA Systems: Delay-Outage Ratio Analysis

The so-called data-oriented approach has gathered significant attention in the context of short-packet communications in fifth-generation (5G) and beyond networks. Specifically, it introduces a transient performance metric for small data transmissions, where the amount of data and available bandwidth play crucial roles. Such data-oriented approach has recently been introduced in downlink rate-splitting multiple access (RSMA) system context, which represents a flexible and promising non-orthogonal multiple access paradigm. Building upon such prior-art, this paper introduces the data-oriented approach to uplink RSMA systems under the finite blocklength regime. Specifically, we consider rate-adaptive and power-adaptive uplink RSMA mechanisms, under the data-oriented approach, and derive analytical expressions for the delay-outage ratio (DOR) metric. The analytical derivations are validated through corresponding Monte Carlo numerical simulations. The numerical results show that the DOR performance is directly linked with the transmit antenna diversity, while being also dependent on the accuracy of the channel state information as well as on the power budget of the uplink users. The obtained results highlight the importance of the new data-oriented DOR metric for efficient design of the uplink RSMA mechanism in future networks.