Point-Dependent CSI-RS Resource Configuration in Heterogeneous Cells
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Solution Overview
Problem
In heterogeneous wireless communication networks, existing methods for allocating and using reference signals are inefficient, particularly in scenarios with multiple transmission points sharing the same cell identifier, leading to interference and suboptimal channel state information feedback, which affects scheduling and resource allocation.
Innovation Solution
The solution involves transmitting channel-state-information reference symbols (CSI-RS) using different resources on various transmission points within the same cell, with the network reconfiguring these resources based on the UE's proximity to each point, ensuring that the UE measures CSI-RS from the strongest transmission points, thereby optimizing channel state feedback and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reference signals are transmitted using the same resources from multiple transmission points, then resource utilization is improved, but interference increases and measurement accuracy deteriorates
Solution Approach 1:
The patent segments the reference signal resources by associating different transmission points with different reference signal resource configurations. Each transmission point uses distinct resource allocations (time-frequency resources, scrambling codes, or resource blocks) for their reference signals, thereby eliminating interference while maintaining high resource utilization across the network
Solution Approach 2:
The patent applies local quality by configuring reference signal resources specifically tailored to each transmission point's characteristics and location. The network can assign different resource patterns, power levels, or scrambling sequences to reference signals from different transmission points based on their local interference conditions and channel properties, optimizing measurement accuracy for each specific point
2Object-affected harmful factors
If static frequency separation is used between macro and pico cells, then interference is reduced, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic resource allocation where reference signal resources for macro and pico cells are not statically separated but can be dynamically configured and adjusted. The network can change resource assignments, time-frequency allocations, and power levels adaptively based on traffic conditions, channel state, and interference measurements, allowing efficient resource sharing while maintaining interference management
Solution Approach 2:
The patent changes key parameters of reference signal transmission including frequency allocation, time scheduling, power spectral density, and scrambling codes. By dynamically adjusting these parameters based on network conditions, the system can switch between interference-avoidance modes (static separation) and resource-efficiency modes (shared resources with coordinated allocation)
3Device complexity
If all transmission points use the same reference signal resources, then device complexity is reduced, but the ability to identify dominant transmission points deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring distinct reference signal resources for each transmission point before the UE performs measurements. The network prepares and transmits reference signals with unique resource signatures (different resource blocks, scrambling codes, or time patterns) from each transmission point, enabling the UE to easily distinguish and measure the dominant transmission point without complex processing
Data Source
AI summary
A high-power point and one or more low-power points transmit signals associated with the same cell-identifier in a heterogeneous cell deployment. Coverage areas corresponding to the low-power points fall at least partly within the coverage area for the high-power point, so that mobile stations within range of a low-power point are also within range of the high-power point. Channel-state-information reference symbols, CSI-RS, are transmitted using different CSI-RS resources on different transmission points within the cell, while configuration of CSI-RS measurement resources is conducted on a UE-specific basis. The choice of measurement resources to be used is determined by the network, based on the properties of the channels from the transmission points to the UE. As the UE moves around within the cell, the network tracks the channel properties and reconfigures the CSI-RS resources measured by the UE, to correspond to the resource of the closest transmission point or points.