Adaptive Cyclic Prefix Design for Millimeter Wave Symbol Alignment
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Solution Overview
Problem
Current wireless communication systems face challenges in handling high-frequency signals, particularly in millimeter wave communication, due to issues related to physical properties and timing, such as the need for efficient cyclic prefix design to accommodate large subcarrier spacings and ensure proper symbol alignment across different subcarrier spacings.
Innovation Solution
The proposed solution involves a signaling structure with adaptable cyclic prefix lengths based on subcarrier spacing, allowing for optimized CP design in OFDM systems, where the cyclic prefix length for regular and long symbols is adjusted to ensure alignment and efficient use of time domain resources, particularly by using formulas like q=144×Nfft2048+b to determine CP lengths that do not exceed symbol lengths, and considering multiple long symbols within a half-subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If larger subcarrier spacing is used for high-frequency communication, then bandwidth efficiency is improved, but cyclic prefix length requirements increase causing timing alignment difficulties
Solution Approach 1:
The patent implements dynamic cyclic prefix length adjustment where the CP length is adaptively determined based on the subcarrier spacing. For larger subcarrier spacings typical in high-frequency communication, the system automatically increases the CP length to maintain proper timing alignment, while for smaller subcarrier spacings it uses shorter CP lengths. This dynamic adaptation resolves the contradiction by allowing the system to optimize both bandwidth efficiency and timing alignment requirements according to the operating conditions.
2Reliability
If cyclic prefix length is increased to accommodate large subcarrier spacing, then symbol alignment is improved, but overhead increases reducing spectral efficiency
Solution Approach 1:
The patent changes the parameter of cyclic prefix length from a fixed value to a variable that depends on subcarrier spacing. By establishing a relationship where CP length scales with subcarrier spacing, the system ensures that symbol alignment is maintained (improving reliability) while avoiding the excessive overhead that would result from using a uniformly large CP length. This parameter change allows the system to achieve the minimum necessary CP length for each specific subcarrier spacing configuration.
3Device complexity
If fixed cyclic prefix length is used across different subcarrier spacings, then system complexity is reduced, but timing alignment deteriorates at high frequencies
Solution Approach 1:
The patent applies different cyclic prefix lengths to different subcarrier spacing configurations rather than using a uniform CP length across all cases. This local optimization ensures that each subcarrier spacing has the appropriate CP length tailored to its specific timing requirements, thereby maintaining proper timing alignment at high frequencies without significantly increasing overall system complexity. The system complexity increase is localized to the CP length determination logic rather than affecting the entire system architecture.
Data Source
AI summary
There is disclosed a method of operating a radio node in a wireless communication network, the method including communicating based on a signaling structure, the signaling structure including a number R of long symbols and/or a number Nsym of regular symbols, wherein R and/or Nsym is based on the subcarrier spacing associated to the signaling structure and/or a cyclic prefix length of a long symbol and/or a cyclic prefix length of a regular symbol. The disclosure also pertains to related devices and methods.