Antenna Port Pair Selection for ePDCCH Reception Quality
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Solution Overview
Problem
In LTE-Advanced systems, the shortage of resources in the PDCCH region leads to a decrease in system throughput due to the inability to map control signals, especially when using MIMO transmission technology and relay stations.
Innovation Solution
The proposed solution involves configuring either a first antenna port pair, where reference signals are not code-multiplexed, or a second antenna port pair, where reference signals are code-multiplexed, based on the reception quality of the terminal, to improve reception characteristics during transmission diversity using two antenna ports in ePDCCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control signals are mapped in the PDCCH region, then control signal transmission is enabled, but resource shortage occurs leading to decreased system throughput
Solution Approach 1:
The patent maps control signals (ePDCCH) from the traditional PDCCH region to the data region (PDSCH), effectively moving the control signal transmission to a different dimension of the resource space. This allows control signals to be transmitted without occupying PDCCH resources, thereby resolving the resource shortage problem while maintaining control signal transmission reliability
Solution Approach 2:
The patent introduces an intermediary mapping mechanism where control signals are transmitted through the data region using ePDCCH, rather than directly through the PDCCH region. This intermediary approach allows control signals to share the data region resources, enabling better resource utilization and increasing system throughput
2Measurement precision
If reference signals are code-multiplexed in antenna ports, then channel estimation accuracy is improved, but reception characteristics deteriorate in certain conditions
Solution Approach 1:
The patent dynamically selects between code-multiplexed and non-code-multiplexed antenna port pairs based on reception quality feedback from terminals. When reception quality is good, code-multiplexed ports are used for better channel estimation; when reception quality is poor, non-code-multiplexed ports are used for more robust reception, thus adapting the system to varying channel conditions
Solution Approach 2:
The patent changes the antenna port configuration parameter based on reception quality. The base station receives reception quality information from terminals and switches between different antenna port pair configurations (code-multiplexed vs. non-code-multiplexed), thereby optimizing the balance between channel estimation accuracy and reception characteristics
3Reliability
If transmission diversity is implemented, then reception reliability is improved, but resource consumption increases
Solution Approach 1:
The patent makes the antenna port configuration universal by supporting both code-multiplexed and non-code-multiplexed modes within the same ePDCCH framework. This allows the system to maintain transmission diversity benefits while adapting resource consumption to actual channel conditions, avoiding unnecessary resource usage in good channel conditions
Data Source
AI summary
This invention is a transmission device capable of enhancing the reception characteristics of a terminal when employing transmit diversity using two antenna ports in an ePDCCH. In a base station (100) that transmits a reference signal to a terminal (200) using two antenna ports, a setting unit (102), on the basis of the reception quality of the terminal, sets as the aforementioned two antenna ports either a first antenna port pair for which DMRS (reference signals) do not undergo mutual code multiplexing, or a second antenna port pair for which the DMRS do undergo code multiplexing. A transmitter (109) transmits the DMRS from the two antenna ports set in the setting unit (102).