NB-IoT Power Control for Random Access Interference
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Solution Overview
Problem
The NarrowBand-Cellular Internet of Things (NB-IoT) system faces interference issues between user equipment (UEs) with different coverage enhancement levels during random access, affecting detection performance and causing co-channel interference in Small Cell scenarios.
Innovation Solution
A power control method and apparatus that determines the power control mode for user equipment to send preambles on Physical Random Access Channels, considering path loss, maximum transmitted power, and target received power, to reduce interference between UEs with varying coverage enhancement levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If user equipment at different coverage enhancement levels use the same maximum transmitted power for random access preambles, then the system maintains simplicity in power configuration, but interference between UEs with different CE levels occurs and detection performance deteriorates
Solution Approach 1:
The patent applies local quality by configuring different maximum transmitted power values for different coverage enhancement levels. Specifically, UEs at CE level 0 use a first maximum transmitted power value while UEs at CE level 1 use a second maximum transmitted power value, allowing each CE level to have optimized power characteristics suited to its specific coverage requirements and interference profile.
2Reliability
If user equipment at coverage enhancement level 0 uses high transmitted power for random access preambles, then detection performance for CE level 0 UEs is improved, but co-channel interference to CE level 1 UEs increases
Solution Approach 1:
The patent changes the power parameter by establishing a relationship where the maximum transmitted power for CE level 0 is lower than that for CE level 1 (PCMAX,0 < PCMAX,1). This parameter adjustment ensures that CE level 0 UEs do not transmit at excessively high power that would cause interference to CE level 1 UEs, while still maintaining adequate detection performance through appropriate power levels.
3Reliability
If different maximum transmitted power values are configured for different coverage enhancement levels, then interference between UEs is reduced and detection performance is improved, but system complexity in power management increases
Solution Approach 1:
The patent segments the power management system by dividing UEs into different coverage enhancement levels (CE level 0 and CE level 1), with each segment having its own maximum transmitted power configuration. This segmentation allows independent optimization of power parameters for each CE level while maintaining clear boundaries and manageable complexity through level-based categorization.
Data Source
AI summary
Disclosed is a power control method and apparatus. The power control method includes that a user equipment at level i sends a preamble on a resource of a Physical Random Access Channel (PRACH) at level k greater than or equal to i according to a determined power control mode, which includes at least one of: mode one: transmitted power of the preamble of the PRACH at level k is determined according to a path loss between the user equipment and a base station, maximum transmitted power, and target received power of the preamble of the PRACH at level k; mode two: the transmitted power of the preamble of the PRACH at level k is the maximum transmitted power of the user equipment; or mode three: the transmitted power of the preamble of the PRACH at level k is the maximum transmitted power of a user equipment corresponding to level k.