CRS Port Virtualization for Active Antenna Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In active antenna systems, the CRS signal coverage and RSRP/RSRQ measurement issues lead to unsatisfactory cell association and uplink power control due to asymmetric antenna gains and deep spatial fading, particularly in LTE/LTE-A systems using passive antenna assumptions.
Innovation Solution
Implementing multiple CRS ports with different precoding vectors for each port, allowing for port virtualization and simultaneous reporting of RSRP/RSRQ values across multiple ports to improve signal coverage and beamforming alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple CRS ports with different precoding vectors are implemented, then CRS signal coverage and beamforming alignment are improved, but system complexity and measurement processing difficulty increase
Solution Approach 1:
The patent divides the CRS transmission into multiple ports (at least two ports), where each port uses a different precoding vector. This segmentation allows the system to cover different spatial directions independently, improving overall coverage while managing complexity through modular port-based structure
Solution Approach 2:
The patent extends the CRS system from a single-port to multi-port configuration, adding the port dimension to the existing antenna port structure. This dimensional extension enables simultaneous transmission of multiple precoded reference signals, improving spatial coverage without fundamentally changing the underlying transmission mechanism
2Manufacturing precision
If multiple CRS ports are used for port virtualization, then beamforming gains are aligned with data signals, but RSRP/RSRQ measurement and cell association complexity increase
Solution Approach 1:
The patent performs RSRP/RSRQ measurements for multiple CRS ports in advance, before cell association decisions are made. The UE reports these pre-measured values along with the corresponding port indices, allowing the network to select the most appropriate port for data transmission without requiring complex real-time measurements
Solution Approach 2:
The patent introduces port index reporting as an intermediary mechanism. Instead of directly measuring and comparing complex beamforming parameters, the system uses the port index as a simplified indicator that the UE reports alongside RSRP/RSRQ values, making the measurement and selection process more manageable
3Ease of operation
If CRS uses fixed vertical beamforming, then cell association is simplified, but deep spatial fading occurs for UEs at specific antenna heights
Solution Approach 1:
The patent transitions from fixed vertical beamforming to dynamic multi-port beamforming. Each CRS port can be configured with different vertical beamforming characteristics, allowing the system to adapt to UEs at different antenna heights by selecting the most appropriate port, thereby eliminating deep spatial fading while maintaining operational simplicity through automated port selection
Data Source
AI summary
Embodiments of the present disclosure provide reference signal transmitting and receiving methods and devices in an active antenna system. Port virtualization to a transmit antennas may be implemented for multiple cell-specific reference signal (CRS) antenna ports and applying different vertical beamforming vectors to implement port virtualization for the different CRS antenna ports. The User Equipment (UE) reports the maximum RSRP/RSRQ value measured based on multiple CRS ports, or the UE simultaneously reports multiple RSRP/RSRQ values and the information of the multiple CRS antenna ports. Therefore, the coverage problem of the CRS signal and Physical Broadcast Channel (PBCH)/Physical Downlink Control Channel (PDCCH)/Physical Downlink Shared Channel (PDSCH) demodulated based on CRS and the problem of measurement for Radio Resource Management (RRM) in the active antenna system may be avoided. Specifically, the following problems may be solved. 1) Coverage differences between CRS and PBCH/PDCCH/PDSCH demodulated based on CRS transmission and Enhanced PDCCH (E-PDCCH)/PDSCH signal transmission, which is measured based on the CSI-RS or demodulated based on the DMRS may be reduced or avoided. 2) The cell association problem due to the different vertical beamforming technologies adopted by the CSI-RS or DMRS and by the CRS may be avoided. 3) Deep spatial fading state may be avoided for CRS reception and PBCH/PDCCH/PDSCH demodulated based on the CRS.