RMSI Repetition and Slot Aggregation for Edge Coverage
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Solution Overview
Problem
The limited coverage of remaining minimum system information (RMSI) messages in millimeter-wave communications is due to the use of wide broadcast beams that do not provide sufficient gain for UEs at the edge of the coverage area.
Innovation Solution
Implementing RMSI repetition, which involves transmitting multiple repetitions of the RMSI message, and RMSI slot aggregation, which divides the RMSI message into multiple portions transmitted across different slots, to enhance coverage and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide broadcast beams are used to transmit RMSI messages, then coverage area is expanded, but signal gain becomes insufficient for UEs at the edge of coverage area
Solution Approach 1:
The RMSI message transmission is segmented into multiple repetitions across different time slots. Instead of transmitting a single wide broadcast beam, the system divides the transmission into multiple instances, allowing UEs at coverage edges to accumulate signal energy across repetitions and achieve reliable reception despite lower per-slot signal gain.
Solution Approach 2:
The RMSI message is transmitted periodically through multiple repetitions in different time slots. This periodic transmission approach allows edge UEs to capture the message in at least one of the repetitions, compensating for the insufficient signal gain of wide broadcast beams through temporal diversity and signal accumulation.
2Reliability
If multiple repetitions of RMSI message are transmitted, then reliability of reception is improved, but transmission time and resource usage increase
Solution Approach 1:
The system transmits multiple repetitions of the RMSI message, using more transmissions than the minimum single instance. This excessive action ensures that at least one repetition is successfully received by edge UEs, compensating for the insufficient signal gain of wide broadcast beams. The number of repetitions is optimized to achieve sufficient reliability without excessive time consumption.
3Area of stationary object
If RMSI message is divided into multiple portions across different slots, then coverage is enhanced through slot aggregation, but message reception complexity increases
Solution Approach 1:
The RMSI message is segmented into multiple portions transmitted across different time slots through slot aggregation. Each slot contains a portion of the complete message, and UEs need to combine these portions to reconstruct the full message. This segmentation enables enhanced coverage by distributing the message transmission across multiple time instances, allowing edge UEs to accumulate sufficient signal energy.
Solution Approach 2:
The message transmission is extended from a single time slot to multiple time slots, adding a temporal dimension to the transmission. This dimensional expansion allows the system to overcome the coverage limitations of wide broadcast beams by distributing message portions across different time instances, enabling UEs to aggregate signals from multiple slots.
Data Source
AI summary
This disclosure provides systems, methods, and apparatuses, including computer programs encoded on computer storage media, for wireless communication. In one aspect, a method of wireless communication performed by a user equipment (UE) includes receiving, from a base station, a remaining minimum system information (RMSI) physical downlink control channel (PDCCH) that includes downlink control information (DCI). The DCI indicates a configuration of resources associated with RMSI repetition or RMSI slot aggregation. The method further includes monitoring for one or more RMSI messages based on the configuration of resources. The monitoring includes monitoring for multiple repetitions of an RMSI message based on the configuration of resources being associated with RMSI repetition and monitoring for a single RMSI message that is divided across multiple slots based on the configuration of resources being associated with RMSI slot aggregation. Other aspects are also claimed and described.