Beam Reference Signal Block Segmentation for Channel Estimation
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Solution Overview
Problem
In wireless communications networks, beam-formed transmissions face interference issues that lead to poor channel estimation and reduced performance due to interference from other radio-network nodes, especially when the channel is frequency selective, making it difficult to measure Beam Reference Signals (BRS) accurately.
Innovation Solution
The solution involves creating BRS blocks with adjacent subcarriers spread over a bandwidth in the same OFDM symbol, allowing for robustness against channel fading and interference suppression by correlating the BRS over a wider bandwidth, thereby improving channel estimation and network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If BRS are transmitted in frequency selective channels with beam forming, then beam-formed transmission capability is enabled, but interference from other radio-network nodes increases and channel estimation accuracy deteriorates
Solution Approach 1:
The patent segments the BRS transmission into multiple blocks, where each block contains BRS from different radio-network nodes. By separating the BRS of different nodes into different blocks and using orthogonal cover codes within each block, the system enables beam-formed transmission while reducing interference between nodes, thereby maintaining channel estimation accuracy in frequency selective channels.
2Reliability
If BRS are transmitted over wide bandwidth to achieve frequency diversity, then robustness against channel fading improves, but interference from other nodes increases due to more frequent collisions
Solution Approach 1:
The patent divides the wide bandwidth BRS transmission into multiple blocks, with each block occupying a portion of the total bandwidth. This segmentation allows the system to achieve frequency diversity across blocks while reducing interference collisions within each block through orthogonal cover codes, thus maintaining reliability without excessive interference.
Solution Approach 2:
The patent applies orthogonal cover codes locally within each BRS block to provide interference suppression. By making the local structure of each block orthogonal, the system achieves frequency diversity over the wide bandwidth while maintaining low interference characteristics within each local block.
3Productivity
If BRS blocks are transmitted in the same OFDM symbol to reduce latency, then transmission efficiency improves, but interference suppression becomes more difficult due to simultaneous transmission
Solution Approach 1:
The patent assigns orthogonal cover codes to different BRS blocks transmitted in the same OFDM symbol. This creates local orthogonality within each block, enabling the receiver to separate and estimate channels for different radio-network nodes simultaneously. The local quality differentiation through orthogonal codes allows efficient simultaneous transmission while maintaining interference suppression.
Data Source
AI summary
Embodiments herein relate to a method performed by a radio-network node (110) for handling Beam Reference Signals, BRS, of a beam transmitted by the radio-network node (110) in a wireless communications network. The radio-network node creates BRS blocks, wherein each BRS block comprises a respective group of adjacent subcarriers for the BRS belonging to a port of the beam, wherein the BRS belonging to the port is carried over each subcarrier in the respective group of adjacent subcarriers of each BRS block. Furthermore, the radio-network node transmits the BRS blocks spread over a bandwidth in a same Orthogonal Frequency Division Multiplexing, OFDM, symbol.