Shortened Time Domain Precoding Filters for Multi-Antenna
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Solution Overview
Problem
Existing wireless communication systems face challenges with high peak to average power ratio (PAPR) and pathloss in higher frequency bands, particularly when using multi-antenna precoding with OFDM technologies like DFT-S-OFDM.
Innovation Solution
The implementation of shortened time domain precoding filters by selecting a subset of significant time domain precoding taps and using a transmit channel shortener to reduce the length of the precoding filter, thereby reducing PAPR and maintaining beamforming gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-antenna precoding is implemented with OFDM to overcome pathloss, then beamforming gain is increased, but peak to average power ratio (PAPR) becomes high
Solution Approach 1:
The precoding filter is segmented into multiple time domain taps, and only the significant taps (those with larger absolute values) are selected and retained. This segmentation approach allows the system to maintain the essential beamforming functionality while reducing the overall filter length and consequently lowering the PAPR of the transmitted signal.
Solution Approach 2:
The patent extracts and removes the less significant time domain taps from the precoding filter, keeping only the taps with larger absolute values. This extraction process reduces the filter length and eliminates the contribution of minor taps to the signal's peak power, thereby reducing PAPR while preserving the main beamforming gain from the significant taps.
2Power
If a longer time domain precoding filter is used to maintain beamforming gain, then pathloss is compensated, but device complexity increases
Solution Approach 1:
Instead of using the complete set of time domain taps, the patent applies partial action by selecting and using only the significant taps (those with larger absolute values). This partial approach is sufficient to maintain the necessary beamforming gain while significantly reducing the filter length and associated device complexity for implementation.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) transmits a signal in accordance with a shortened time domain precoding filter for multi-antenna precoding. In some examples, a UE may precode the signal in accordance with a subset of time domain precoding taps. The UE may select the subset of time domain precoding taps from a set of time domain precoding taps in accordance with an absolute value of each of the set of time domain precoding taps. The UE may transmit the signal in accordance with the precoding. In other examples, the UE may select a transmit channel shortener to apply to a channel. The UE may select the transmit channel shortener based on a channel energy of a shortened channel that is associated with the transmit channel shortener. The UE may transmit the signal via the shortened channel.