SRS Resource Allocation for 5G Cell Edge Orthogonality
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Solution Overview
Problem
In 5G communication systems, pilot contamination due to non-orthogonal sounding reference signal (SRS) resources allocated to different cells leads to poor channel estimation and reduced system capacity, especially in massive MIMO systems, where the increased number of antennas exacerbates interference and reduces the gain from massive antenna deployment.
Innovation Solution
A method and apparatus for allocating SRS resources that classify terminals as cell center or cell edge and allocate orthogonal SRS resources to cell edge terminals in one cell relative to adjacent cells, using fractional reuse mechanisms to improve SRS resource utilization efficiency, and employing cyclic shift intervals to ensure orthogonality in code and frequency domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal SRS resources are allocated to terminals in different cells, then SRS resource utilization efficiency is improved, but pilot contamination occurs leading to poor channel estimation and reduced system capacity
Solution Approach 1:
The patent applies local quality by differentiating resource allocation strategies for different terminal types: cell-center terminals use non-orthogonal SRS resources to improve resource utilization, while cell-edge terminals use orthogonal SRS resources to avoid pilot contamination and ensure accurate channel estimation. This localized differentiation resolves the contradiction by optimizing resource allocation according to specific terminal locations and interference exposure.
2Productivity
If the number of antennas is increased in massive MIMO systems, then spectrum efficiency is improved, but interference from non-orthogonal SRS resources is exacerbated reducing the gain from massive antenna deployment
Solution Approach 1:
The patent applies local quality by implementing different SRS resource allocation strategies for cell-center and cell-edge terminals. Cell-edge terminals, which are more susceptible to interference from adjacent cells, are allocated orthogonal SRS resources to eliminate pilot contamination. This localized differentiation ensures that the harmful interference is suppressed where it matters most, allowing massive MIMO systems to achieve their full spectrum efficiency potential without being degraded by pilot contamination.
3Measurement precision
If orthogonal SRS resources are allocated to all terminals, then pilot contamination is avoided and channel estimation accuracy is improved, but SRS resource utilization efficiency is reduced
Solution Approach 1:
The patent applies local quality by implementing differentiated SRS resource allocation: cell-center terminals use non-orthogonal SRS resources to maximize resource utilization efficiency, while cell-edge terminals use orthogonal SRS resources to ensure accurate channel estimation. This localized strategy resolves the contradiction by applying orthogonality only where it is most needed (at cell edges with high interference), rather than universally across all terminals.
Data Source
AI summary
The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as a long term evolution (LTE). Various examples of the present disclosure provide a method of allocating sounding reference signal (SRS) resources. A base station of a target cell receives information of first cell edge terminals in an adjacent cell transmitted by the adjacent cell. The base station allocates SRS resources for a terminal in the target cell according to information of second cell edge terminals in the target cell and the information of the first cell edge terminals, and transmits information of the allocated SRS resources to the terminal. According to the mechanism, when there are cell edge terminals in both the target cell and the adjacent cell, it can be guaranteed that all SRS resources allocated to cell edge devices in the target cell are orthogonal to those allocated to cell edge devices in the adjacent cell. Thus, the impact of pilot contamination on system performances may be remarkably reduced.