PDCCH Beamforming via CRS Composite Beams
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In massive MIMO systems, the demodulation performance of the PDCCH deteriorates when the coverage of the PDCCH exceeds that of the CRS wide beam due to inconsistent phases, leading to poor channel estimation and reduced beamforming effectiveness.
Innovation Solution
The method involves combining a CRS wide beam with pre-generated CRS narrow beams to form composite beams, allowing for beamforming processing on the PDCCH using a weight that matches the CRS composite beam, thereby expanding coverage and ensuring consistent phases for improved demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If narrow beam weighting is performed on the PDCCH to expand coverage in a particular direction, then the coverage of the PDCCH exceeds coverage of the CRS wide beam, but the phases of the PDCCH and CRS become inconsistent causing deterioration of demodulation performance
Solution Approach 1:
The patent segments the beamforming approach by separately handling CRS and PDCCH beamforming. CRS uses wide beamforming for broad coverage and consistent phase reference, while PDCCH can use narrow beamforming for directional coverage expansion. This segmentation allows each signal type to optimize its beamforming strategy independently, resolving the contradiction between coverage expansion and phase consistency.
Solution Approach 2:
The patent introduces an intermediary mechanism where the CRS wide beam serves as a phase reference for PDCCH demodulation. By maintaining CRS with wide beamforming and allowing PDCCH to use narrow beamforming independently, the CRS acts as a stable phase mediator that enables accurate demodulation even when PDCCH coverage extends beyond CRS coverage area.
2Area of stationary object
If narrow beam weighting is performed on the PDCCH, then coverage in a particular direction is improved, but channel estimation accuracy deteriorates when PDCCH coverage exceeds CRS coverage
Solution Approach 1:
The patent segments the beamforming function between CRS and PDCCH. CRS maintains wide beamforming for accurate channel estimation across the entire cell, while PDCCH uses narrow beamforming for directional coverage enhancement. This segmentation allows channel estimation to be performed accurately using CRS wide beam, while PDCCH benefits from directional narrow beamforming without compromising estimation accuracy.
Solution Approach 2:
The CRS wide beam acts as an intermediary reference signal that provides accurate channel estimation for PDCCH demodulation. Even when PDCCH uses narrow beamforming that extends beyond CRS coverage, the CRS wide beam serves as a reliable phase and channel reference, enabling accurate channel estimation through the intermediary CRS signal.
3Area of stationary object
If wide beam weighting is used for CRS, then coverage is maintained across the cell, but the PDCCH cannot be correctly demodulated in directions beyond CRS coverage
Solution Approach 1:
The patent segments the beamforming requirements of CRS and PDCCH. CRS uses wide beamforming to maintain comprehensive cell coverage and provide phase reference, while PDCCH uses narrow beamforming to extend coverage in specific directions. This segmentation resolves the contradiction by allowing each signal type to use the beamforming approach best suited to its function.
Solution Approach 2:
The patent introduces dynamic beamforming where the base station can independently adjust beamforming weights for CRS and PDCCH. CRS maintains wide beamforming for stable coverage, while PDCCH dynamically uses narrow beamforming for directional coverage expansion. This dynamic approach allows the system to adapt beamforming strategies to meet different coverage and demodulation requirements simultaneously.
Data Source
AI summary
A beamforming method and apparatus are disclosed, to expand coverage of a PDCCH in a particular direction, and improve demodulation performance of the PDCCH. Under this method, a cell-specific reference signal CRS wide beam can be combined by a base station with N CRS narrow beams to form N CRS composite beams. A first beam can be selected by the base station from the N CRS composite beams. Beamforming processing can be performed by the base station on a physical downlink control channel (PDCCH) based on a weight of the first beam to form a second beam. The first beam and the second beam can be sent.