Two-Step Random Access Carrier Selection Using Dual RSRP Thresholds
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Solution Overview
Problem
The challenge in two-step random access processes is the high collision probability of MsgA PRACH and MsgA PUSCH signals due to orthogonal or quasi-orthogonal preambles, leading to increased error probabilities in signal parsing.
Innovation Solution
A method involving the use of separate RSRP thresholds for MsgA PRACH and MsgA PUSCH signals, where a broadcast signal carries different RSRP limits for target block error rates, allowing carriers to be determined based on measured RSRP relative to these thresholds, ensuring optimal signal transmission on either SUL or non-SUL carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple preambles are configured to correspond to one PUSCH resource unit to protect against massive payload resource reservation, then the system can handle more users, but the payload has a higher collision probability
Solution Approach 1:
The patent segments the carrier selection process into two independent parts: PRACH carrier selection based on first RSRP threshold and PUSCH carrier selection based on second RSRP threshold. This segmentation allows each signal type to be optimized independently, reducing collision probability while maintaining system capacity.
Solution Approach 2:
The patent introduces different RSRP threshold parameters for PRACH and PUSCH signals. By changing the threshold parameters based on signal type and channel conditions, the system can dynamically adjust carrier selection to reduce payload collision probability while maintaining adaptability for multiple users.
2Measurement precision
If payload parsing requires demodulation and decoding to ensure accurate data reception, then the channel quality requirement increases, but the error probability increases under poor channel conditions
Solution Approach 1:
The patent performs preliminary carrier selection based on RSRP measurements before actual signal transmission. By pre-selecting carriers that meet the required channel quality thresholds, the system ensures that subsequent payload parsing operations are performed on channels with sufficient quality, reducing error probability while maintaining reception accuracy.
Solution Approach 2:
The patent uses RSRP measurement feedback to dynamically select carriers for PRACH and PUSCH transmission. The terminal measures RSRP, compares it with thresholds, and selects carriers accordingly, creating a feedback loop that ensures channel quality requirements are met before payload transmission, thereby reducing parsing errors.
3Reliability
If separate carrier determination is implemented for MsgA PRACH and MsgA PUSCH based on different RSRP thresholds, then the access success rate increases, but the device complexity increases
Solution Approach 1:
The patent manages device complexity by introducing clearly defined parameter thresholds (first RSRP threshold for PRACH, second RSRP threshold for PUSCH). These parameter-based decision rules provide a systematic and automated carrier selection process, making the increased complexity manageable through standardized threshold comparisons rather than complex algorithms.
Data Source
AI summary
Provided is a random access method, including: a broadcast signal sent by a base station on a non-SUL carrier is received, the broadcast signal is parsed to obtain a first RSRP threshold and a second RSRP threshold, the first RSRP threshold being an RSRP limit value at which an MsgA PRACH signal is received and parsed on the non-SUL carrier to reach a target block error rate, and the second RSRP threshold being an RSRP limit value at which an MsgA PUSCH signal is received and parsed on the non-SUL carrier to reach a target block error rate; an RSRP of the broadcast signal on the non-SUL carrier is measured to obtain a measured RSRP; and carriers for sending the MsgA PUSCH signal and the MsgA PRACH signal are determined separately according to a numerical relation between the measured RSRP and the first RSRP threshold and the second RSRP threshold.