RAR Window Segmentation for SUL and NR Carrier Identification
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Solution Overview
Problem
In wireless communication networks, particularly in 5G, the existing LTE random access response (RAR) framework struggles to distinguish between RARs associated with Supplemental Uplink (SUL) carriers and New Radio (NR) carriers, leading to reduced network performance due to ambiguities in identifying the carrier used for preamble transmission.
Innovation Solution
The proposed solution involves differentiating the RAR window to allocate specific subframes or slots for RARs from SUL and NR carriers, allowing wireless devices to identify the carrier used for preamble transmission even if it cannot be deduced from the Random Access Preamble Identity (RAPID) and Random Access Radio Network Temporary Identifier (RA-RNTI), thereby enhancing network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing LTE RAR framework is used without differentiation, then the system maintains simplicity and compatibility, but wireless devices cannot distinguish between RARs from SUL and NR carriers, leading to ambiguity and reduced network performance
Solution Approach 1:
The RAR window is segmented into separate time positions for SUL carrier RARs and NR carrier RARs. This allows wireless devices to distinguish between RARs from different carriers by monitoring specific time positions, thereby improving carrier identification accuracy without fundamentally changing the RAR framework structure
Solution Approach 2:
The patent introduces a time dimension to differentiate between SUL and NR carrier RARs. By allocating specific time positions within the RAR window for each carrier type, the system enables carrier identification without adding complexity to the existing RAR message structure or requiring additional signaling dimensions
2Loss of information
If separate RAR windows are allocated for SUL and NR carriers, then wireless devices can accurately identify the carrier used for preamble transmission, but the RAR procedure becomes more complex and requires additional configuration
Solution Approach 1:
The RAR window is divided into distinct time positions for SUL and NR carrier responses. This segmentation ensures that carrier identification information is preserved by providing clear temporal separation, while the configuration complexity is managed through systematic allocation rules
Solution Approach 2:
The network configures the RAR window structure in advance, specifying which time positions correspond to SUL carrier RARs and which correspond to NR carrier RARs. This preliminary configuration allows wireless devices to proactively monitor the correct time positions based on their preamble transmission, reducing the need for complex runtime decision-making
Data Source
AI summary
Embodiments herein relate to e.g. a method performed by a radio network node for handling communication of a wireless device in a wireless communication network. The radio network node receives, from the wireless device, a preamble of a random access procedure on a first carrier or a second carrier. The radio network node further transmits, to the wireless device, a random access response (RAR), wherein the RAR or transmission of the RAR indicates the carrier out of the first carrier and the second carrier the preamble was received on.