Reference Signal Sequence Generation for Inter-Cell Interference Reduction
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Solution Overview
Problem
In existing communications systems, inter-cell interference caused by identical narrowband positioning reference signals (NPRSs) in multiple radio frames leads to increased interference power, compromising data recovery and channel estimation accuracy.
Innovation Solution
A method for generating reference signal sequences based on the frame number of a radio frame, where the sequence is associated with the frame number, ensuring that reference signals in any two radio frames are different. This is achieved by using a pseudo-random sequence, such as a Gold sequence, and selecting parts of the sequence corresponding to the frame number, thereby randomizing inter-cell interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same NPRS sequence is used in multiple radio frames for enhanced coverage, then the receiving device can perform in-phase combination to improve signal quality, but inter-cell interference is accumulated and interference power increases
Solution Approach 1:
The patent applies dynamics by making the NPRS sequence variable across radio frames through the parameter v_shift, which changes with the radio frame number. This dynamic adjustment allows the sequence to adapt to different time instances, enabling interference randomization while maintaining the benefits of repeated transmissions for signal combination.
Solution Approach 2:
The patent changes the parameter v_shift in the Gold sequence generation formula based on the radio frame number. By modifying this parameter dynamically, the sequence values change across frames, which randomizes inter-cell interference while preserving the ability to perform coherent combining at the receiver.
2Device complexity
If a limited number of frequency position offset modes are used for NPRS mapping, then the system complexity is reduced, but inter-cell interference randomization performance is insufficient when there are many cells
Solution Approach 1:
The patent introduces a time-varying parameter v_shift that is derived from the radio frame number. This parameter is incorporated into the Gold sequence generation process, effectively increasing the number of distinguishable sequence patterns without adding complex mapping structures. The approach maintains simple mapping patterns while achieving better interference randomization through parameter variation.
Data Source
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AI summary
This application provides a reference signal sequence transmission method. The method includes: generating a reference signal sequence based on a frame number of a radio frame; mapping at least a part of reference signals in the reference signal sequence to a resource position that corresponds to the radio frame and that is used to transmit the at least a part of reference signals; and sending the at least a part of reference signals or an orthogonal reference signal at the resource position, where the orthogonal reference signal is obtained by multiplying the at least a part of reference signals by a preset orthogonal code. When the reference signal sequence is generated, the reference signal sequence is generated based on the frame number of the radio frame, so that reference signal sequences in any two radio frames in each cell are different. Therefore, when a receiving device performs in-phase combination on received reference signal sequences in a plurality of radio frames, interference caused by a reference signal of an interfering cell to a reference signal of a local cell is reduced.