New Carrier Type CRS Down-sampling for Heterogeneous Networks
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Solution Overview
Problem
The use of cell-specific reference signals (CRS) in LTE systems limits advanced techniques for increasing cell capacity, especially in heterogeneous networks where multiple nodes simultaneously transmit within a single cell, due to increased complexities and interference.
Innovation Solution
The introduction of a new carrier type (NCT) that reduces or eliminates legacy control signaling and CRS, enhancing spectral efficiency, supporting heterogeneous networks, and improving energy efficiency by using reduced or eliminated CRS overhead, and employing different CRS configurations for non-synchronized carriers, including down-sampling and pre-defined hopping patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell-specific reference signals (CRS) are used for demodulation in LTE systems, then reliable signal reception is achieved, but spectral efficiency deteriorates and cell capacity is limited due to increased overhead and interference in heterogeneous networks
Solution Approach 1:
The patent extracts and removes CRS from specific resource blocks to create CRS-free resource blocks, separating the reference signal function from data transmission resources. This extraction reduces overhead and interference while maintaining necessary reference signals in other regions, thereby improving cell capacity without completely sacrificing reception reliability.
Solution Approach 2:
The patent segments the frequency spectrum into CRS-containing resource blocks and CRS-free resource blocks. This segmentation allows different transmission strategies to be applied in different frequency regions, enabling advanced techniques like CoMP and enhanced ICIC in CRS-free regions while maintaining backward compatibility in CRS-containing regions.
2Measurement precision
If CRS are transmitted in all resource blocks, then channel estimation accuracy is maintained, but spectral efficiency deteriorates due to excessive overhead
Solution Approach 1:
The patent applies local quality by transmitting CRS only in specific resource blocks where they are most needed for channel estimation, while omitting them in other resource blocks. This localized approach concentrates reference signal resources in critical areas, maintaining estimation accuracy where required while reducing overall overhead and improving spectral efficiency.
3Area of stationary object
If multiple nodes transmit simultaneously within a single cell, then network coverage is extended, but interference increases and device complexity rises due to CRS conflicts
Solution Approach 1:
The patent extracts CRS from certain resource blocks to create CRS-free resource blocks, removing the source of interference that causes complexity in heterogeneous networks. This extraction allows multiple nodes to transmit simultaneously in different resource blocks without CRS conflicts, reducing demodulation complexity while maintaining extended coverage through coordinated multi-point transmission.
4Adaptability or versatility
If legacy control signaling and CRS are used, then backward compatibility is maintained, but energy efficiency deteriorates due to increased overhead
Solution Approach 1:
The patent segments transmission resources into legacy CRS-based regions and new CRS-free regions, allowing UEs to be configured appropriately for their capabilities. This segmentation enables energy-efficient transmission in CRS-free regions for advanced UEs while maintaining backward compatibility in CRS-containing regions for legacy UEs, optimizing overall network energy efficiency.
Data Source
AI summary
Technology for selecting physical resource blocks (PRB) for cell-specific reference signal (CRS) transmission for a new carrier type (NCT) is disclosed. In an example, device operable in an evolved Node B (eNB) to select physical resource blocks (PRB) for cell-specific reference signal (CRS) transmission for a new carrier type (NCT) can include computer circuitry configured to: Determine a frequency bandwidth for the NCT; and select a CRS pattern of PRBs for a transmission of the CRS in the frequency bandwidth, wherein the frequency bandwidth includes PRBs with CRS and PRBs without CRS.