Msg3 Size Reduction via Dynamic MAC Subheaders in 5G Random Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The 5G wireless communication system faces challenges in reducing the size of Message 3 (Msg3) during the random access procedure, which leads to reduced uplink coverage due to its larger size compared to LTE.
Innovation Solution
The method involves identifying whether PRACH occasions are configured for the active uplink BWP of a serving cell and, if not, switching to an active downlink BWP of a special cell, and performing the random access procedure on both the active downlink and uplink BWPs. Additionally, determining the size of the MAC SDU and using a corresponding MAC subheader size (1 byte for CCCH, 2 or 3 bytes for DCCH) to reduce the overall size of Msg3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the Msg3 size is increased to accommodate all RRC messages, then the message capacity is improved, but the uplink coverage is reduced
Solution Approach 1:
The Msg3 is segmented into multiple parts: MAC subheaders and MAC SDUs. Each MAC SDU contains a portion of the RRC message, allowing the total message to be divided into manageable units that can be transmitted efficiently. This segmentation enables the system to handle large messages without requiring a single large transmission block, thereby maintaining uplink coverage while achieving high message capacity.
Solution Approach 2:
The patent dynamically changes the size parameters of MAC subheaders based on the type of MAC SDU being transmitted. For CCCH SDUs, a 1-byte subheader is used, while for DCCH SDUs, either 2-byte or 3-byte subheaders are used depending on the SDU size. This parameter adaptation optimizes the overall Msg3 structure, reducing unnecessary overhead and improving transmission efficiency without compromising message capacity.
2Device complexity
If a fixed MAC subheader size is used for all message types, then the processing complexity is reduced, but the Msg3 size efficiency deteriorates
Solution Approach 1:
The MAC subheader size is made dynamic rather than fixed. The system adapts the subheader size (1 byte, 2 bytes, or 3 bytes) based on the specific requirements of each MAC SDU. This dynamic adjustment allows the protocol to optimize message packaging for different message types and sizes, significantly improving Msg3 size efficiency while maintaining manageable processing complexity through clear conditional logic.
Data Source
AI summary
A communication method and system for converging a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with a technology for Internet of things (IoT) are provided. The communication method and system may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method of a terminal for performing a random access procedure in a wireless communication system is provided. In addition, a method by a terminal for system information (SI) request is provided. A method includes receiving, from a base station, information on resources for SI request including information on a start index of at least one random access preamble for the SI request; receiving, from the base station, at least one synchronization signal block (SSB); selecting an SSB among the at least one SSB; determining a preamble for the SI request corresponding to the selected SSB based on the information on the start index; and transmitting, to the base station, the determined preamble based on a physical random access channel (PRACH) occasion corresponding to the selected SSB.