LTE Advanced Receiver Interference Measurement via Coordinated Reference Signals
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Solution Overview
Problem
Current LTE systems face challenges in managing interference in dense small cell deployments, particularly in heterogeneous scenarios where backhaul latency is high, and existing interference coordination techniques do not effectively utilize advanced receiver capabilities for interference cancellation or suppression.
Innovation Solution
The implementation of coordinated reference signals, such as orthogonal DMRS ports and zero power CSI-RS configurations, among cells to facilitate accurate interference estimation and cancellation, leveraging advanced receivers to improve interference mitigation in small cell scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If advanced receiver capabilities are implemented for interference cancellation, then interference suppression performance is improved, but device complexity increases
Solution Approach 1:
The patent introduces reference signals as intermediary elements that mediate between the transmitted signal and the received signal. These reference signals carry channel state information that enables the advanced receiver to estimate and cancel interference without requiring complex real-time processing of all received signals, thus improving interference suppression while controlling receiver complexity
Solution Approach 2:
The patent implements preliminary channel estimation using reference signals before the actual data reception and interference cancellation processes. By pre-establishing channel state information through dedicated reference signals, the receiver can more efficiently perform interference cancellation without needing to process all signals in real-time, reducing the computational burden and device complexity
2Measurement precision
If coordinated reference signals are used among cells, then interference estimation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent designs reference signals that serve multiple functions simultaneously: they are used for channel estimation, interference estimation, and demodulation across different cells. This multi-functionality allows coordinated reference signals to improve interference estimation accuracy without proportionally increasing signaling overhead, as the same signal structures fulfill multiple measurement and communication needs
Solution Approach 2:
The patent employs parameter changes in reference signal configurations, such as adjusting cyclic shifts, orthogonal cover codes, and resource element allocations, to enable differentiated interference estimation across cells. By manipulating these parameters, the system achieves accurate interference estimation without requiring additional dedicated reference signal resources for each cell, thus controlling signaling overhead
3Productivity
If dense small cell deployment is implemented, then network capacity is improved, but interference levels increase
Solution Approach 1:
The patent implements feedback mechanisms where channel state information estimated from reference signals is fed back to the network, enabling dynamic interference coordination. This feedback loop allows the system to adapt to changing interference conditions in dense small cell deployments, maintaining high network capacity while actively managing and reducing interference levels through coordinated resource allocation and power control
Solution Approach 2:
The patent converts the harmful interference inherent in dense small cell deployments into beneficial information by using it for interference estimation and cancellation. The reference signals enable the receiver to characterize and exploit the interference patterns, transforming what was previously a detrimental effect into a source of channel state information that improves overall system performance and capacity
Data Source
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AI summary
A method for receiving a PDCH is provided. The method comprises: receiving, by a UE, information identifying a plurality of resource elements that are transmitted with zero power in a resource block containing the PDCH; receiving, by the UE, a first DMRS on a first DMRS port transmitted from a first cell; and receiving, by the UE, the PDCH that is transmitted on the first DMRS port.