BWP Selection for Random Access Ambiguity in 5G NR
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Solution Overview
Problem
In 5G NR networks, ambiguity occurs during random access procedures due to different User Equipment (UEs) using the same Uplink (UL) and Downlink (DL) Bandwidth Parts (BWPs), making it difficult for the network to identify which UE sent a random access preamble or received a response, leading to indeterminate UE behaviors.
Innovation Solution
A method and apparatus for selecting associated UL and DL BWPs to be active for performing random access procedures, ensuring that the UE selects one active UL BWP and one active DL BWP based on their association, thereby eliminating ambiguity by coordinating wireless transmissions and receptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple UEs use the same UL BWP for random access, then resource utilization is improved, but ambiguity occurs in identifying which UE sent the preamble
Solution Approach 1:
The patent applies local quality by associating specific DL BWPs with specific UL BWPs, so that each UL BWP has a corresponding DL BWP with unique identification characteristics. This allows the network to identify which UE sent the preamble by determining which DL BWP the UE should monitor, resolving the ambiguity while maintaining resource utilization
2Productivity
If multiple UEs operate on separate DL BWPs and same UL BWP, then spectral efficiency is improved, but the network cannot decide which DL BWP to send the random access response
Solution Approach 1:
The patent applies preliminary action by pre-establishing associations between UL BWPs and DL BWPs before the random access procedure. When a UE sends a preamble on a specific UL BWP, the network can immediately determine the associated DL BWP to send the response, eliminating the decision-making delay while maintaining spectral efficiency through separate DL BWP operation
3Adaptability or versatility
If UEs are configured with different UL and DL resources, then adaptability is improved, but ambiguity occurs in random access procedures
Solution Approach 1:
The patent applies feedback by using the DL BWP association as a feedback mechanism. The DL BWP configuration provides implicit feedback to the UE about which UL BWP it should use for random access, and conversely, the UL BWP selection provides feedback to the network about which DL BWP to use for the response. This feedback loop maintains reliability despite flexible resource configuration
Data Source
AI summary
A User Equipment (UE) including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless transmission and reception to and from a service network. The controller selects one of one or more uplink (UL) Bandwidth Parts (BWPs) to be an active UL BWP, and selects one of one or more downlink (DL) BWPs to be an active DL BWP according to an association between the UL BWPs and the DL BWPs. Also, the controller performs a random access procedure on the active UL BWP and the active DL BWP via the wireless transceiver.