PRACH Preamble Detection for Large Subcarrier Spacing
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Solution Overview
Problem
Current wireless communication systems face challenges in supporting large cell sizes and high subcarrier spacings due to limitations in cyclic prefix and guard time durations in physical random access channel (PRACH) preamble formats, which affect detection accuracy and coverage.
Innovation Solution
The method involves adjusting the PRACH detection window by extending the cyclic prefix duration and allocating additional guard symbols, and using PRACH preamble configurations with reduced sequence repetitions for subcarrier spacings that satisfy specific thresholds, allowing for improved timing alignment and detection in higher frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the cyclic prefix duration and guard time duration are increased to support large cell sizes and high subcarrier spacings, then the supportable cell size and coverage are improved, but the PRACH preamble format becomes less efficient and the number of available resources decreases
Solution Approach 1:
The patent implements dynamic adjustment of the PRACH detection window timing based on the detected subcarrier spacing. When large subcarrier spacing is detected, the system dynamically extends the cyclic prefix duration and adjusts guard time allocation. This dynamic adaptation allows the system to optimize for both large cell sizes and maintain transmission efficiency, resolving the contradiction between increased duration requirements and resource efficiency.
Solution Approach 2:
The patent changes key parameters (cyclic prefix duration, guard time duration, detection window timing) based on the detected subcarrier spacing conditions. By adjusting these parameters dynamically, the system can support large cell sizes with high subcarrier spacings while maintaining acceptable PRACH transmission efficiency, thus resolving the contradiction between parameter requirements for coverage and efficiency.
2Measurement precision
If the PRACH detection window timing is adjusted to accommodate large subcarrier spacings, then the detection accuracy is improved, but the complexity of the detection process increases
Solution Approach 1:
The patent adjusts the PRACH detection window timing parameters based on the detected subcarrier spacing. By dynamically changing the detection window start time and duration according to the subcarrier spacing, the system achieves accurate detection without requiring complex algorithms. The complexity is managed by using parameter-based adaptation rather than complex signal processing, thus resolving the contradiction between detection accuracy and process complexity.
3Loss of time
If the number of sequence repetitions in the PRACH preamble is reduced for large subcarrier spacings, then the transmission time is decreased, but the detection reliability may be compromised
Solution Approach 1:
The patent dynamically adjusts the number of sequence repetitions based on the detected subcarrier spacing. When large subcarrier spacing is detected, the system reduces the number of repetitions to minimize transmission time. This dynamic adjustment, combined with corresponding adjustments to detection window timing and cyclic prefix duration, maintains detection reliability while reducing time loss, thus resolving the contradiction between transmission time and detection reliability.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a physical random access channel (PRACH) preamble configuration that indicates a first preamble format for a first PRACH preamble and a second preamble format for a second PRACH preamble, wherein the first preamble format is different from the second preamble format. The UE may transmit the first PRACH preamble as part of a random access procedure based at least in part on the PRACH preamble configuration, wherein transmitting the first PRACH preamble enables a determination of a symbol boundary offset. The UE may transmit the second PRACH preamble as part of the random access procedure based at least in part on the PRACH preamble configuration, wherein transmitting the second PRACH preamble enables a determination of a symbol timing offset. Numerous other aspects are described.