Silent Resource Element Grid for Interference Measurement
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately measuring inter-cell interference, which limits the accuracy of data channel quality indicator (CQI) computation and interferes with intra-cell interference estimation, especially in multiuser-MIMO systems, due to limited interference samples and differing statistics between reference symbols and data channels.
Innovation Solution
Introducing a cell-specific, time-varying silent resource element (RE) grid where no data is allocated, allowing for interference measurement from inter-cell signals alone, and using a pseudo-random sequence to generate and synchronize the grid layout with minimal signaling overhead, enabling accurate inter-cell interference statistics collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference measurement is performed on data resource elements, then interference statistics can be obtained, but the limited number of samples significantly penalizes the accuracy of the statistics estimate
Solution Approach 1:
The patent segments the resource elements into different categories: data REs, control REs, and reference signal REs. By segmenting the measurement resources, the system can specifically identify and measure interference on data REs separately from other signal types, thereby improving the accuracy of interference statistics estimation with sufficient sample size.
Solution Approach 2:
The patent performs preliminary actions by having the UE detect data symbols and estimate channel response before measuring interference. This preliminary processing enables the UE to subtract the contribution of desired signals from received signals, isolating the interference component for accurate statistics collection.
2Measurement precision
If interference measurement is performed on reference symbols, then interference can be estimated, but the statistics of interference on reference symbols significantly differ from the interference on the data channel
Solution Approach 1:
The patent applies local quality by making different measurements on different resource element types. Specifically, interference is measured on data REs rather than reference signal REs, because the interference characteristics on data REs are representative of the actual data channel conditions. This localized measurement approach ensures that the interference statistics accurately reflect the data channel quality.
3Productivity
If multiple users are assigned the same data resource elements in multiuser-MIMO systems, then resource utilization is improved, but the UE cannot separate inter-cell interference from intra-cell interference
Solution Approach 1:
The patent extracts the inter-cell interference component from the total received interference by utilizing the known structure of intra-cell signals. Since the UE knows the scheduled data REs and can detect intra-cell interference through channel estimation and signal detection, it can subtract this known component from the total interference, leaving only the inter-cell interference for measurement and reporting.
4Ease of operation
If common reference symbols are used in neighboring cells, then synchronization is simplified, but the interference characteristics from reference symbols differ significantly from data signaling interference
Solution Approach 1:
The patent introduces an intermediary measurement approach by using data resource elements as the measurement medium rather than reference symbols. The data REs serve as an intermediary that experiences the same interference conditions as the actual data transmission, providing accurate CQI information. The UE measures interference on data REs and uses this information to compute CQI, thereby bridging the gap between reference signal reception and data channel quality assessment.
Data Source
Figure 1A
Figure 1B
Figure 1C-1
AI summary
A receiving unit or a transmitting unit of a wireless network for facilitating noise and interference measurements on an air interface. The receiving unit includes a network interface which obtains information relating to a time-varying layout of a silent resource element (RE) grid. The receiving unit includes an electronic memory having code in communication with the network interface which stores the information. The receiving unit includes a processing unit in communication with the electronic memory that takes a presence of a silent RE grid into account in the reception of a control or a data channel. In the transmitting unit, the processing unit takes the presence of a silent RE grid into account in the transmission of a control or a data channel. A method in the receiving unit or a transmitting unit of a wireless network, for facilitating noise and interference measurements on an air interface. The method includes the steps of obtaining information relating to a time-varying layout of a silent resource element (RE) grid. There is the step of taking a presence of a silent RE grid into account in the reception of a control or a data channel.