Base Station Subframe Combination for Wireless Signal Demodulation
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Solution Overview
Problem
In wireless communication systems, channel estimation and signal demodulation processes are prone to performance deterioration due to channel value changes and frequency offset during signal accumulation in LTE systems, especially when channel estimation is performed after subframes are accumulated for certain time transmission intervals (TTIs).
Innovation Solution
The method involves performing channel estimation on each subframe and combining subframes using estimated channels of consecutive subframes, allowing for accurate demodulation even in low signal-to-noise ratio environments by determining a TTI group based on communication schemes and configuring weights or windows for channel estimation and combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subframes are accumulated for certain TTIs before channel estimation and signal demodulation, then signal detection capability is improved, but performance deterioration occurs due to channel value changes and frequency offset
Solution Approach 1:
The patent divides the signal processing into separate stages: channel estimation is performed on each individual subframe before accumulation, rather than after accumulating multiple subframes. This segmentation prevents channel value changes and frequency offset from degrading the estimation accuracy, while still allowing signal accumulation to improve detection capability.
Solution Approach 2:
The patent performs channel estimation as a preliminary action on each subframe before the accumulation process. By estimating channels in advance for each subframe individually, the system avoids the performance deterioration that would occur if estimation were performed after accumulation, thus maintaining measurement precision while enabling signal improvement through accumulation.
2Device complexity
If channel estimation is performed after subframe accumulation, then processing complexity is reduced, but signal demodulation accuracy deteriorates due to frequency offset
Solution Approach 1:
The patent segments the channel estimation process to operate on each subframe independently before accumulation. Although this increases processing steps compared to post-accumulation estimation, it prevents frequency offset from corrupting the channel estimates, thereby maintaining signal demodulation accuracy despite the additional processing complexity.
3Productivity
If simple accumulation is performed for certain TTIs, then productivity is improved, but performance deterioration occurs due to frequency offset
Solution Approach 1:
The patent applies preliminary channel estimation to each subframe before accumulation. This preliminary action on individual subframes corrects for frequency offset effects before the accumulation process, allowing simple and efficient accumulation to proceed while maintaining signal demodulation performance that would otherwise be degraded by frequency offset.
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AI summary
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method, by which a base station demodulates a signal in a wireless communication system, according to an embodiment of the present invention, comprises: a step for allowing the base station to receive at least one subframe through at least one antenna from a terminal; a step for allowing the base station to combine the subframe including the continuously same data as much as the predetermined number of data; and a step for demodulating the received subframe on the basis of the combined subframe.