OFDM Reference Signal Arrangement for Wireless Communication
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Solution Overview
Problem
In wireless communication systems using OFDMA, the mixing of reference signals from base station devices and mobile station devices within the same OFDM symbol restricts frequency shifting and leads to unnecessarily low data signal power, degrading cell edge throughput and channel estimation accuracy.
Innovation Solution
A wireless communication system that arranges reference signals and data signals within resource blocks to prevent mixing within the same OFDM symbol, or adjusts power to equalize reference signal and data signal power, and allocates unused resources to increase reference signal power without degrading data signal power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reference signal specific to each base station device and the reference signal specific to each mobile station device are mixed within one OFDM symbol, then the resource block structure is simplified, but the frequency shifting restrictions become stringent and channel estimation accuracy degrades
Solution Approach 1:
The patent divides the resource block into different OFDM symbols, separating the reference signal specific to each base station device from the reference signal specific to each mobile station device. This segmentation allows independent frequency shifting of each reference signal type without mutual interference, thereby maintaining channel estimation accuracy while simplifying the overall structure.
2Reliability
If the power of the reference signal specific to each base station device is increased to improve cell coverage, then cell coverage and cell edge throughput are improved, but the power of data signals in mixed OFDM symbols becomes unnecessarily low
Solution Approach 1:
The patent applies different power levels to different OFDM symbols based on their specific content. In OFDM symbols containing only the reference signal specific to each base station device, the power is increased to improve cell coverage. In OFDM symbols containing both reference signals and data signals, the power is maintained at appropriate levels to ensure data transmission quality. This localized power adjustment resolves the contradiction between cell coverage and data signal power.
3Adaptability or versatility
If the reference signal specific to each mobile station device is moved to a different OFDM symbol to avoid mixing, then frequency shifting restrictions are relaxed, but the number of available data signals in mixed OFDM symbols decreases
Solution Approach 1:
The patent dynamically arranges the reference signals and data signals in different OFDM symbols based on the specific communication requirements. This dynamic arrangement allows the system to optimize both frequency shifting flexibility and data signal transmission efficiency by adapting the symbol allocation to the actual operational needs rather than using a fixed pattern.
Data Source
AI summary
A reference signal specific to each base station device and a reference signal specific to each mobile station device are not mixed within one OFDM symbol of a resource block, and OFDM symbols including the reference signal specific to each mobile station device are arranged at regular intervals on a time axis. By using such a signal arrangement pattern, it is possible to overcome the problems in Non-Patent Document 1 mentioned above caused by mixing a reference signal specific to each base station device and a reference signal specific to each mobile station device in one OFDM symbol. Thus, it becomes possible to prevent the reference signal specific to each base station device and the reference signal specific to each mobile station device from being mixed within one OFDM symbol of a resource block.