Random Access Method for 5G Bandwidth Parts
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Solution Overview
Problem
In 5G wireless communication systems, the introduction of bandwidth parts (BWP) in the new radio (NR) system complicates contention-based random access, as the base station cannot uniquely determine the DL/UL BWP for transmitting a random access response, leading to impaired access procedures.
Innovation Solution
A method where the network device receives a preamble from a UE and determines the corresponding DL BWP for transmitting a random access response, ensuring proper access by using indication information carried in the preamble or random access request.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DL/UL BWPs are configured for different UEs, then the system can support diverse traffic requirements and improve adaptability, but the base station cannot uniquely determine the DL BWP for transmitting random access response, worsening the reliability of random access procedure
Solution Approach 1:
The patent applies preliminary action by having the UE indicate its active UL BWP before performing random access. The base station uses this pre-provided information to determine the corresponding DL BWP for transmitting the random access response, thus resolving the ambiguity problem before the access procedure fails.
Solution Approach 2:
The patent introduces an intermediary mechanism where the UE's random access message carries indication information about the active UL BWP. This intermediary information enables the base station to infer the corresponding DL BWP, bridging the gap between multiple configured BWPs and the specific BWP needed for response transmission.
2Device complexity
If the base station cannot determine the DL BWP for random access response, then the system complexity increases due to ambiguous resource allocation, but the access procedure efficiency decreases
Solution Approach 1:
The patent applies self-service by enabling the UE to automatically indicate its active UL BWP in the random access message. This self-provided information allows the base station to autonomously determine the corresponding DL BWP without additional signaling or complex coordination, thus improving access efficiency while maintaining manageable system complexity.
3Reliability
If indication information is carried in the preamble or random access request, then the base station can accurately determine the DL BWP improving access reliability, but the message overhead increases
Solution Approach 1:
The patent merges the indication information about the active UL BWP into the existing random access message structure. By combining this additional information with the standard random access preamble or request message, the patent achieves accurate DL BWP determination without requiring separate signaling channels or additional message exchanges, thus minimizing the overhead increase.
Data Source
AI summary
A terminal includes: a processor circuit configured to: configure at least two uplink bandwidth parts (UL BWPs) and at least two downlink bandwidth parts (DL BWPs); determine an active DL BWP of the at least two DL BWPs, the active DL BWP having a corresponding UL BWP of the at least two UL BWPs, wherein the corresponding UL BWP is configured with at least one time-frequency resource to transmit a preamble; select a time-frequency resource from at least one time-frequency resource allocated for preamble transmission in the corresponding UL BWP corresponding to the active DL BWP; and select a first preamble from at least one preamble allocated for preamble transmission corresponding to the active DL BWP; a transmitter configured to transmit the first preamble, on the selected time-frequency resource, to a network device; and a receiver configured to receive a random access response (RAR) on the active DL BWP.