Terminal Category-Based Resource Mapping for 5G Uplink Timing Offset
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Solution Overview
Problem
The 5G communication system faces performance deterioration due to timing offset errors in uplink transmission, particularly for URLLC and mMTC services, where the initial timing advance (TA) value calculated during the random access channel procedure may not accurately represent the actual transmission timing, leading to interference and increased error rates.
Innovation Solution
A method is introduced where terminals are categorized based on their timing offset values, with first category terminals using normal cyclic prefix (CP) and second category terminals using extended CP to align signals within the FFT window, thereby reducing interference and maintaining orthogonality between subcarriers. Resource mapping is adjusted accordingly, with first category terminals mapping resources to all OFDM symbols and second category terminals mapping to odd or even symbols to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the initial timing advance (TA) value calculated during random access channel procedure is used for uplink transmission, then the information exchange process is minimized, but timing offset error occurs leading to performance deterioration
Solution Approach 1:
The terminals are segmented into first category terminals (using normal CP) and second category terminals (using extended CP) based on their timing offset values. This segmentation allows each category to use appropriate resource mapping patterns, resolving the contradiction by handling different timing scenarios separately without requiring repeated RACH procedures.
Solution Approach 2:
Different resource mapping patterns are applied locally to different terminal categories. First category terminals map resources to all OFDM symbols, while second category terminals map resources to odd or even symbols only. This local differentiation ensures timing accuracy for each category while minimizing overall information exchange.
2Productivity
If terminals at various positions transmit uplink signals simultaneously, then system efficiency is improved, but timing offset causes interference and reduces transmission reliability
Solution Approach 1:
Terminals are segmented into categories based on their timing offset characteristics. Second category terminals with larger timing offsets are identified and assigned different resource mapping patterns (odd or even symbols only) compared to first category terminals. This segmentation enables simultaneous transmission from various positions while maintaining reliability through category-specific resource allocation.
Solution Approach 2:
The solution introduces a new dimension of resource mapping based on terminal categories. Instead of uniform resource allocation, the system maps resources differently for first and second category terminals, adding a categorical dimension to resource allocation that resolves timing offset interference while maintaining system efficiency.
3Measurement precision
If extended cyclic prefix is used to compensate for timing offset, then signal alignment within FFT window is improved, but device complexity increases
Solution Approach 1:
The extended cyclic prefix is applied locally only to second category terminals that require it, rather than universally. First category terminals use normal CP while second category terminals use extended CP. This localized application achieves precise signal alignment for terminals needing it without unnecessarily increasing complexity for all terminals.
Solution Approach 2:
The system dynamically determines which terminals require extended CP based on their timing offset values and categories. This dynamic configuration allows the system to adapt CP length per terminal type, achieving precise alignment when needed while avoiding unnecessary complexity for terminals that can use normal CP.
Data Source
AI summary
The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as long term evolution (LTE). The present disclosure relates to a method for transmitting and receiving a data. A method of a terminal according to the present disclosure includes: generating a signal; identifying a category of the terminal; mapping the generated signal to a resource using resource mapping information determined based on the category of the terminal; and transmitting the signal using the mapped resource.