NB-IoT PRACH Resource Partitioning for EDT Padding Reduction
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Solution Overview
Problem
Current NB-IoT technologies face high overhead and power consumption due to excessive padding in early data transmission (EDT) with limited transport block size (TBS) granularity, leading to wasted power consumption by user equipment (UE).
Innovation Solution
Implementing a method where a network node schedules multiple grants for EDT during a random access procedure, allowing the UE to select PRACH resources based on wireless communication coverage, and transmitting a message indicating the selected resources to reduce padding and optimize TBS, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed maximum TBS of 1000 bits is used for EDT Msg3, then backward compatibility is maintained, but average padding overhead increases to 500 bits (50% overhead)
Solution Approach 1:
The patent segments the NPRACH resources into multiple subsets, each associated with a specific TBS value from a predefined set (e.g., 240, 360, 480, 600, 720, 840, 960, 1000 bits). This segmentation allows the system to move from a single fixed TBS allocation to multiple granular TBS options, reducing the need for excessive padding while maintaining backward compatibility through the configured TBS set.
Solution Approach 2:
The patent introduces dynamic TBS selection by mapping different NPRACH resource subsets to different TBS values. The UE can dynamically select the appropriate TBS based on its actual data size and coverage conditions, rather than being constrained to a fixed maximum TBS. This dynamic adaptation reduces padding overhead while maintaining reliability.
2Loss of substance
If multiple NPRACH resource subsets with different TBS values are configured, then padding overhead is reduced, but NPRACH resource configuration complexity increases
Solution Approach 1:
The patent creates a universal NPRACH resource configuration framework where a single set of NPRACH resources serves multiple TBS values through the association with different resource subsets. Each subset can be used for multiple purposes (different coverage enhancement levels, different data sizes), reducing overall configuration complexity while enabling granular TBS selection.
Solution Approach 2:
The patent changes the parameter of TBS from a fixed value to a selectable value from a configured set. By introducing TBS as a variable parameter that can be adjusted based on actual data size and coverage conditions, the system reduces padding overhead while managing complexity through predefined TBS sets and systematic resource subset associations.
3Productivity
If UE transmits with larger TBS to avoid padding, then power consumption increases, but data transmission capacity is improved
Solution Approach 1:
The patent enables the UE to change the TBS parameter dynamically based on its actual data size and coverage conditions. Instead of always transmitting with a fixed maximum TBS of 1000 bits (which causes 50% padding overhead and wasted power), the UE can select from a configured set of TBS values (e.g., 240, 360, 480, 600, 720, 840, 960, 1000 bits), transmitting only the necessary amount of data and avoiding unnecessary power consumption from padding.
4Loss of substance
If TBS granularity is increased, then padding overhead is reduced, but system configuration and management becomes more complex
Solution Approach 1:
The patent segments the TBS range into multiple granular values (e.g., 240, 360, 480, 600, 720, 840, 960, 1000 bits) and associates each with specific NPRACH resource subsets. This segmentation provides fine-grained TBS control to reduce padding overhead while managing complexity through systematic association rules between resource subsets and TBS values.
Solution Approach 2:
The patent introduces TBS as a configurable parameter with multiple discrete values rather than a fixed value. By enabling TBS to be changed based on actual data size and coverage conditions, the system achieves granular control over padding overhead while managing complexity through predefined TBS sets and automated selection mechanisms.
Data Source
AI summary
Various examples and schemes pertaining to NB-IoT physical random access channel (PRACH) resource partitioning and multiple grants in random access response (RAR) for early data transmission (EDT are described. A network node schedules multiple grants for EDT during a random access (RA) procedure with a user equipment (UE). The network node transmits to the UE a message indicating the multiple grants mapped to a maximum broadcast transport block size (TBS) configured for each of one or more preamble resource of a plurality of preamble resources. The UE calculates a TBS that fits an uplink (UL) data packet of the UE. The UE selects one or more PRACH resources for EDT for the TBS based on a wireless communication coverage of the UE by the network node. The UE transmits to the network node in the RA procedure a first message (Msg1) indicating the selected one or more PRACH resources.