Coverage Enhancement Mode Change in Wireless Communication
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Solution Overview
Problem
Current wireless communication systems, such as LTE, face challenges in efficiently managing coverage enhancement modes, particularly in scenarios requiring adjustments to resource allocation and repetition levels for optimal signal transmission and reception, especially for low-complexity UEs in extreme coverage scenarios.
Innovation Solution
A method for changing the coverage enhancement (CE) mode in a wireless communication system involves determining the CE mode level, transmitting a CE mode change request message to the network, and receiving a CE mode change message via a physical downlink control channel, using different channels and messages based on the mode level change, such as the physical uplink control channel, MAC layer message, random access preamble, or RRC re-establishment procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coverage enhancement mode is changed to improve signal reception in extreme coverage scenarios, then coverage and reliability are improved, but device complexity and resource allocation complexity increase
Solution Approach 1:
The UE autonomously determines its own CE mode level based on downlink signal quality measurements (RSRP/RSRQ) and compares it with the currently applied CE mode level, triggering mode changes without continuous network intervention. This self-service mechanism reduces network signaling overhead and simplifies overall system complexity while maintaining reliable coverage enhancement.
Solution Approach 2:
The CE mode level is made dynamic and adaptable, allowing the UE to transition between different CE mode levels (CE level 0, 1, 2, 3) based on real-time signal conditions. The system dynamically adjusts repetition levels and resource allocation parameters according to the determined CE mode level, enabling flexible adaptation to changing coverage requirements without fixed configuration.
2Adaptability or versatility
If different channels and messages are used for CE mode change requests based on mode level, then adaptability and versatility are improved, but device complexity and protocol complexity increase
Solution Approach 1:
Different uplink channels and message types are selectively applied based on the specific CE mode level transition requirements. For example, MAC CE messages are used for certain mode changes while other signaling methods are used for different scenarios. This localized optimization ensures that the most appropriate signaling method is used for each specific mode change situation, improving adaptability while managing complexity through context-dependent selection.
Solution Approach 2:
The system changes signaling parameters and message formats based on the CE mode level being transitioned to. Different CE mode levels trigger different uplink signaling approaches, allowing the protocol to adapt its complexity to the specific coverage enhancement requirements. This parameter-based adaptation enables versatile mode changes while keeping implementation complexity manageable through conditional logic.
3Reliability
If resource allocation and repetition levels are adjusted for optimal signal transmission, then coverage enhancement is improved, but loss of time and signaling overhead increase
Solution Approach 1:
The network pre-configures multiple CE mode levels with associated repetition levels and resource allocation parameters before the UE needs to change modes. When the UE determines that a mode change is needed based on signal quality measurements, it can quickly switch to a pre-determined appropriate mode level without extensive real-time negotiation. This preliminary configuration reduces the time loss associated with mode changes while maintaining optimal signal transmission quality.
Data Source
AI summary
A method for changing a coverage enhancement (CE) mode at a user equipment (UE) in a wireless communication system in a wireless communication system is disclosed. The method includes steps of determining a CE mode level to be changed, transmitting a CE mode change request message to a network based on the determined CE mode level, and receiving a CE mode change message from the network via a physical downlink control channel. Especially, when the determined CE mode level is greater than a current CE mode level, a random access preamble associated with the determined CE mode level is transmitted to the network as the CE mode change request message.