Base Station CDD Weighted Processing for Coverage Holes
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Solution Overview
Problem
In power division networks, ensuring radio frequency channel consistency between a base station's RRU and antenna systems is challenging, leading to reduced beamforming performance and coverage capability due to phase errors caused by power splitters and cable length differences.
Innovation Solution
The base station performs cyclic delay diversity (CDD) weighted processing on signals to introduce time diversity and densified beam weighted processing to increase the number of beams, thereby improving coverage and channel transmission performance without relying on consistent radio frequency channel responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power splitter is used to connect one RRU to multiple antenna systems, then the base station can support multiple antenna systems, but radio frequency channel consistency cannot be ensured due to phase errors from power splitters and cable length differences
Solution Approach 1:
The patent changes the signal processing parameters by introducing cyclic delay diversity (CDD) with different delay values for different antenna ports. This transforms the physical channel inconsistency problem into a signal processing solution, where the delay parameter D is adjusted to compensate for phase errors and create consistent effective channels across multiple antenna systems.
Solution Approach 2:
The patent introduces an intermediary signal processing layer (CDD processing) between the RRU and the antenna systems. This intermediary processing compensates for the phase errors introduced by the power splitter and cable length differences, effectively mediating the inconsistency without requiring physical channel calibration.
2Device complexity
If traditional beamforming is used without CDD, then the signal processing is simpler, but coverage capability is reduced due to coverage holes and poor beam coverage smoothness
Solution Approach 1:
The patent applies periodic cyclic shifts to the signal across different antenna ports, creating multiple beams with different spatial distributions. This periodic action in the time domain translates to beam diversity in the spatial domain, improving coverage reliability without requiring complex adaptive beamforming algorithms.
Solution Approach 2:
The patent introduces a time domain dimension (cyclic delays) to the traditional spatial beamforming. By adding delays in the time domain, the system creates temporal diversity that translates to spatial beam diversity, effectively adding another dimension to the beamforming approach and improving coverage without increasing spatial complexity.
3Manufacturing precision
If cable lengths are adjusted to ensure channel consistency, then radio frequency channel consistency can be improved, but device complexity and installation difficulty increase
Solution Approach 1:
The patent replaces the mechanical adjustment approach (physically adjusting cable lengths) with a signal processing approach (CDD in the baseband domain). This substitution eliminates the need for precise physical installations and cable length adjustments, reducing installation complexity while maintaining channel consistency through digital signal processing.
Data Source
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AI summary
A communications method and apparatus are provided, to improve channel transmission performance when channel consistency cannot be ensured in a power division network. The method includes: generating, by a base station, a first signal, performing CDD weighted processing on the first signal to obtain a second signal, and performing densified beam weighted processing on the second signal to obtain a third signal, and sending the third signal, by the base station via an antenna. According to the foregoing method, the CDD weighted processing is performed on the first signal generated by the base station, so that time diversity can be obtained when the first signal is transmitted, thereby improving a coverage capability of the base station. In addition, the densified beam weighted processing is performed on the second signal obtained after the CDD weighted processing, so that a quantity of beams scanned by the base station can be increased. In this way, coverage of the base station is smoother, and a coverage hole does not occur, thereby further improving the coverage capability of the base station. In this way, the channel transmission performance can be improved when the channel consistency cannot be ensured.