Random Access Preamble Configuration for High Carrier Frequency Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting random access channels at high carrier frequencies, particularly in terms of subcarrier spacing and sequence length, which affect service coverage and orthogonality in high-frequency environments.
Innovation Solution
The method involves determining a random access sequence transmission period, configuring a random access preamble by inserting a cyclic prefix and guard time, and repeating the random access sequence if its length is shorter than the transmission period, either along the time or frequency axis, to optimize subcarrier spacing and ensure efficient transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the random access sequence length is increased to improve service coverage in high carrier frequency systems, then the orthogonality between sequences deteriorates, but if the sequence length is kept short to maintain orthogonality, then the service coverage is reduced
Solution Approach 1:
The patent divides the random access sequence into multiple segments and transmits them in different time slots. By segmenting the sequence, the system can achieve longer effective sequence length for improved service coverage while maintaining the orthogonality of individual segments. The base station receives multiple segmented sequences and combines them to identify the complete random access preamble.
Solution Approach 2:
The patent employs periodic transmission of random access sequences at different time slots. The same sequence structure is repeated periodically, allowing the base station to receive multiple instances and combine them for better detection. This periodic action enables extended sequence length without compromising the orthogonal properties of each period.
2Productivity
If the subcarrier spacing is increased to improve transmission efficiency in high carrier frequency systems, then the random access channel orthogonality deteriorates, but if the subcarrier spacing is kept small to maintain orthogonality, then the transmission efficiency is reduced
Solution Approach 1:
The patent dynamically adjusts the subcarrier spacing for random access channels based on the carrier frequency. In high carrier frequency systems, the system automatically selects appropriate subcarrier spacing values that balance transmission efficiency and orthogonality. The dynamic adaptation allows the system to optimize performance for different operating conditions.
Solution Approach 2:
The patent changes the subcarrier spacing parameter adaptively for random access channel transmission. By adjusting this key parameter, the system can achieve better transmission efficiency in high carrier frequency environments while maintaining sufficient orthogonality. The parameter change is implemented through configuration of the random access channel parameters based on system conditions.
3Reliability
If the random access sequence transmission period is extended to improve service coverage, then the time required for random access increases, but if the transmission period is shortened to reduce access time, then the service coverage is reduced
Solution Approach 1:
The patent segments the random access sequence transmission across multiple time slots. By dividing the transmission into segments, the system can extend the effective transmission period to cover more service areas while the user equipment only needs to wait for a limited number of segments. The base station combines the segmented transmissions to achieve comprehensive service coverage.
Solution Approach 2:
The patent implements preliminary configuration of random access parameters including sequence length, transmission period, and time slot allocation. By pre-configuring these parameters, the system optimizes the balance between service coverage and access time. The preliminary setup allows for efficient transmission without requiring excessive waiting time from user equipment.
Data Source
AI summary
A method for transmitting a random access preamble at a user equipment in a wireless communication system is disclosed. The method includes determining a random access sequence transmission period using a random access sequence, configuring a random access preamble by inserting a cyclic prefix at a front of the random access sequence transmission period and a guard time at an end of the random access sequence transmission period, and transmitting the random access preamble on a random access channel to a base station. The random access preamble is configured by repeating the random access sequence a predetermined number of times, if the length of the random access sequence is smaller than the random access sequence transmission period.