Dynamic Antenna Port Pairing for LTE Downlink Transmit Diversity
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Solution Overview
Problem
Current downlink transmit diversity schemes in LTE fail to differentiate the importance of data symbols during antenna port pairing and subcarrier mapping, leading to important symbols being mapped to low-reliable subcarriers, which results in suboptimal performance and system performance loss.
Innovation Solution
A method and system for dynamic antenna port pairing and subcarrier mapping, where data symbols are sequenced and grouped to prioritize important symbols, with antenna port pairing adjusted based on reference signal distribution to minimize frequency domain distances to reliable subcarriers, ensuring better protection and reduced system performance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed antenna port pairing is adopted to balance protection of SFBC blocks, then reliability of transmission is improved, but important data symbols may be mapped to low reliable subcarriers resulting in system performance loss
Solution Approach 1:
The patent applies dynamics by transitioning from fixed antenna port pairing to dynamic antenna port pairing. The antenna port pairing is adjusted based on the distribution of reference signals and the importance of data symbols, allowing the system to adaptively optimize the mapping of important symbols to high-reliability subcarriers while maintaining transmission reliability.
Solution Approach 2:
The patent applies local quality by differentiating the treatment of different data symbols based on their importance. Important data symbols (such as systematic bits) are selectively mapped to high-reliability subcarriers that are closer to reference signal subcarriers, while less important symbols are mapped to other available subcarriers. This localized optimization ensures that critical information receives enhanced protection without requiring uniform treatment of all symbols.
2Reliability
If important data symbols are mapped to subcarriers closer to reference signals for better protection, then reliability of important symbols is improved, but fixed antenna port pairing constraints prevent optimal mapping
Solution Approach 1:
The patent makes the antenna port pairing dynamic by allowing it to change based on the distribution of reference signals and the importance of data symbols. Instead of using a fixed pairing scheme, the system dynamically determines the optimal pairing for each transmission instance, enabling important symbols to be mapped to the most reliable subcarriers while maintaining the benefits of antenna diversity.
Solution Approach 2:
The patent applies preliminary action by first identifying the distribution of reference signals and determining which subcarriers are high-reliability before performing the symbol mapping. This preliminary analysis of the channel conditions and reference signal locations enables the system to proactively allocate important symbols to favorable subcarriers, rather than reacting to suboptimal mappings after the fact.
3Ease of manufacture
If uniform mapping scheme is used for all data symbols, then simplicity of implementation is maintained, but differentiation of symbol importance is lost leading to suboptimal performance
Solution Approach 1:
The patent applies local quality by implementing differentiated mapping for different types of data symbols. Important symbols (such as systematic bits from channel decoding) are identified and mapped to high-reliability subcarriers closer to reference signals, while other symbols are mapped to remaining subcarriers. This localized differentiation improves performance for critical symbols without requiring complete redesign of the mapping system.
Solution Approach 2:
The patent applies segmentation by dividing the data symbol sequence into different categories based on importance. The channel decoded symbol sequence is segmented into important symbols (systematic bits) and other symbols, which then undergo different mapping processes. This segmentation allows the system to apply optimized mapping strategies to specific symbol groups while maintaining overall system simplicity.
Data Source
AI summary
A data processing method and a base station for downlink transmit diversity are disclosed. One embodiment of the method comprises: obtaining data symbol groups formed by arranging a first type data symbol and a second type data symbol in an interval, wherein the first type data symbol is more important; determining a first antenna port pairing mode corresponding to a current slot; performing, for OFDM symbols including the reference signal in the current slot, an antenna port and subcarrier mapping on symbols in a transmit diversity matrix corresponding to the data symbol groups according to the first antenna port pairing mode, wherein a subcarrier in which a symbol related to the first type data symbol is located is nearer to a subcarrier in which a reference signal at the same antenna port is located; and performing an inverse fast fourier transform and a cyclic prefix insertion processing on symbols mapped to subcarriers and then mapping the time domain symbols to a physical antenna for transmission. According to embodiments of the invention, comparatively important symbols may obtain better protection.