Random Access Uplink Data Transmission TBS Selection
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Solution Overview
Problem
In the 3GPP R13/R14 protocol, the random access and RRC link establishment process in cellular networks leads to significant transmission delays and high power consumption for terminal devices, especially in NB-IoT, due to large interaction times and excessive signaling, resulting in inefficient uplink data transmission.
Innovation Solution
A method where a terminal device autonomously selects a target transport block size (TBS) from candidate TBSs based on the allowed TBS indicated by the network, reducing packet padding and improving resource utilization by matching the TBS to the size of the uplink data, thereby enhancing transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device uses the largest TBS indicated by the network device for transmitting uplink data in message 3, then the network device can receive the data without knowing the exact size in advance, but when the actual data size is far less than the indicated TBS, large-ratio packet padding is required at the MAC layer, wasting uplink resources and increasing power consumption
Solution Approach 1:
The patent changes the TBS parameter from a fixed largest value to a dynamically selected value from multiple candidate TBSs. The terminal device selects an appropriate TBS from candidate values (e.g., 256, 512, 1024 bits) based on the actual data size, thereby optimizing the transmission parameter to reduce padding and power consumption while maintaining reliable delivery
2Reliability
If the terminal device uses the largest TBS indicated by the network device, then the network device can allocate resources without knowing the exact data size, but this results in uplink resource waste and reduced transmission efficiency
Solution Approach 1:
The patent optimizes transmission efficiency by allowing the terminal to select from multiple candidate TBS values (e.g., 256, 512, 1024 bits) rather than always using the largest indicated TBS. This parameter optimization reduces unnecessary resource allocation while ensuring reliable delivery, thereby improving overall transmission efficiency
3Reliability
If the terminal device completes random access and RRC link establishment before transmitting uplink data, then the connection is properly established, but this requires relatively long interaction time and exchanges large amounts of signaling, causing significant transmission delay
Solution Approach 1:
The patent applies preliminary action by enabling the terminal device to transmit uplink data in message 3 during the random access process itself, before completing the full RRC link establishment. This allows data to be sent in advance alongside the random access preamble, significantly reducing the overall transmission delay while maintaining connection reliability through subsequent confirmation messages
Data Source
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AI summary
This application provides a method and an apparatus that are for transmitting data in a random access process. The method includes: sending a message 1 to a network device; receiving a message 2 sent by the network device, where the message 2 includes uplink grant information, the uplink grant information includes first indication information, and the first indication information is used to indicate a largest transport block size TBS allowed for a message 3; determining a target TBS in candidate TBSs based on the allowed largest TBS, where the target TBS is less than or equal to the allowed largest TBS; and sending the message 3 to the network device, where the message 3 includes uplink data transmitted based on the target TBS. This application can improve efficiency for transmitting uplink data in a random access process.