Rate Matching Circular Buffer Asymmetry TDD Special Subframes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in LTE, the existing rate matching techniques face inefficiencies due to unequal frequency of transmitting data portions caused by large multiples of data versions, leading to imbalanced repetition gain and inferior decoding performance, especially in MTC communications where a large number of repetitions are required.
Innovation Solution
The implementation of a circular buffer approach for rate matching, where the mapping of coded bits onto special subframes starts from different respective positions, allowing for different redundancy versions and repetitions across subframes, thereby balancing the frequency of data transmission and improving decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing rate matching techniques are used with large multiples of data versions, then data can be transmitted across multiple subframes, but the frequency of transmitting certain data portions becomes unequal leading to imbalanced repetition gain
Solution Approach 1:
The patent applies asymmetry by intentionally introducing different starting positions (offsets) for mapping coded bits onto special subframes. Instead of using identical starting positions for all data versions, the system uses different starting positions to create asymmetric mapping patterns that balance the overall transmission frequency across repetitions
Solution Approach 2:
The patent implements preliminary action by pre-calculating and pre-determining the different starting positions for mapping coded bits onto special subframes. The starting positions are determined in advance based on the version number and configured offsets, allowing the system to proactively balance repetition gain before transmission occurs
2Reliability
If a large number of repetitions are required for MTC communications, then coverage is extended, but the number of radio frames increases and delay increases
Solution Approach 1:
The patent applies parameter changes by modifying the mapping parameters (starting positions) for different data versions. By changing the starting position parameter based on version number and configured offsets, the system achieves more efficient packing of data portions across radio frames, reducing the total number of frames needed while maintaining required repetition gain for coverage
3Productivity
If data versions are transmitted with unequal frequency, then transmission can proceed through multiple subframes, but repetition gain becomes imbalanced leading to inferior decoding performance
Solution Approach 1:
The patent applies local quality by making each data version have different local characteristics (different starting positions in the circular buffer). This local differentiation ensures that when data portions are repeated across subframes, the combination of different starting positions creates balanced overall frequency distribution, improving both throughput and reliability
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to transmitting and receiving data in a wireless communication system employing time division duplex, and in particular to a rate matching for the channels which are mapped onto special subframes such as uplink /downlink switching subframes in TDD. Accordingly, at the transmitter, a data block is stored in a memory unit which is to be operated as a circular buffer, the data block is transmitted in a plurality of subframes including special subframes, a special subframe containing an uplink portion and a downlink portion separated from each other by a switching portion; and before the transmission a rate matching is performed by mapping the stored data block onto the plurality of subframes using the circular buffer, wherein the mapping of bits onto two different special subframes starts from different respective positions in the circular buffer. Moreover, a corresponding receiving apparatus and a transmitting and receiving method are provided.