PRACH Preamble Alignment with ECP Data Signals to Reduce Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In current NR communication systems, the use of an extended cyclic prefix (ECP) in data signals leads to misalignment of random access preamble signals with data signals, increasing interference and affecting communication performance.
Innovation Solution
A communication method where a terminal device aligns random access preambles with an integer quantity of OFDM symbols using an ECP by adjusting parameters such as cyclic prefix length, subcarrier spacing, and PRACH duration based on configuration information from a network device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extended cyclic prefix (ECP) is used in data signals, then the ability to handle large subcarrier spacing and reduce multipath interference is improved, but the alignment between random access preamble signals and data signals deteriorates, increasing interference between channels
Solution Approach 1:
The patent changes the cyclic prefix parameter from the conventional NCP format to an ECP format specifically for random access preamble signals. This parameter change enables the random access preamble to be aligned with data signals using ECP, thereby maintaining the ability to handle large subcarrier spacing while eliminating the misalignment interference between PRACH and PUSCH channels
Solution Approach 2:
Instead of aligning the random access preamble with NCP format as in conventional technology, the patent inverts the approach by aligning it with ECP format. This inversion allows the random access signal to match the data signal structure when ECP is used, converting the harmful misalignment into a beneficial alignment
2Adaptability or versatility
If a short cyclic prefix (NCP) is used for random access preambles to maintain alignment with conventional data signals, then the compatibility with existing systems is improved, but the performance when large subcarrier spacing is used deteriorates
Solution Approach 1:
The patent introduces dynamic adaptability by enabling the random access preamble to use ECP format when large subcarrier spacing is employed. This dynamic adjustment of the cyclic prefix format allows the system to maintain optimal performance across different operating conditions, transitioning from fixed NCP to flexible ECP selection based on subcarrier spacing requirements
3Reliability
If the cyclic prefix length is increased to handle larger multipath delays, then the robustness against inter-symbol interference is improved, but the time duration of the random access preamble increases, affecting access efficiency
Solution Approach 1:
The patent applies ECP format which provides sufficient cyclic prefix length to handle typical multipath scenarios without excessive extension. This partial action approach achieves the necessary robustness against ISI and ICI while avoiding the excessive time duration that would result from overly conservative CP extensions, thus balancing reliability and access efficiency
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of this application provide a communication method and a communication apparatus. According to the method, a terminal device receives configuration information from a network device. The terminal device determines, in a first parameter set based on the configuration information, a parameter corresponding to a random access preamble. The terminal sends the random access preamble to the network device based on the parameter corresponding to the random access preamble and the configuration information. A CP length in any parameter that is of the random access preamble and that is in the first parameter set is aligned with an integer quantity of OFDM symbols with an ECP. Therefore, when a CP type used for a data format in a data signal is an ECP, a random access preamble signal on a PRACH is enabled to be aligned with an integer quantity of data signals on a PUSCH. In this way, a probability that the terminal device successfully sends a message 1 (the random access preamble) in a random access process is increased, an access delay is reduced, and interference between a random access signal and a data signal is reduced.