Enhanced CQI to Boost the Performance of 5G-Advanced XR With Code Block Group Transmissions

One of the rapidly emerging services for fifth-generation (5 G)-Advanced is eXtended Reality (XR), which combines several immersive experiences and cloud gaming services. Those services are demanding as they call for relatively high data rates under tight latency constraints, sometimes also referred to as dependable real-time applications. Supporting many XR users per cell requires highly efficient radio solutions. We utilize code block group (CBG)-based transmissions to enhance the XR performance, via smarter link adaptation and to reduce the retransmission overhead. We propose an enhanced channel quality indicator (CQI) that allows controlling the number of failed CBGs per transport block (TB) to its near-optimal value, as compared to using legacy CQI schemes that correspond to 10% TB error rates. We present both an analytical analysis of the related problems and solutions, as well as an extensive dynamic system-level performance assessment, to document the performance benefits of our proposals. Our results show an increased XR system capacity of 17% to 33% as compared to what can be supported by current 5 G systems with baseline CQI schemes. We also present enhanced CQI complexity-reducing techniques based on derived closed-form expressions that are attractive to the user equipment implementation.