Radio Communication Apparatus Adaptive Pilot Symbol Placement
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Solution Overview
Problem
In radio communication systems, the transmission of feedback information for pilot symbol placement constrains channel capacity, particularly when high data amounts like in moving picture and music distribution, leading to potential communication quality deterioration.
Innovation Solution
A radio communication apparatus that acquires parameters indicating the propagation environment to select optimal pilot patterns in the frequency and time domains, minimizing feedback information and maintaining information transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the proportion of pilot symbols in a frame is increased to improve data symbol reception accuracy, then the accuracy of propagation path compensation improves, but the proportion of data symbols decreases and information transmission efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the pilot symbol insertion positions variable rather than fixed. The receiving apparatus determines optimal pilot insertion positions on the frequency axis based on reception quality measurements, and the transmitting apparatus adapts to these positions. This dynamic adjustment allows the system to optimize pilot symbol density in specific frequency regions where propagation path variations are more significant, thereby improving data symbol reception accuracy without uniformly increasing the overall proportion of pilot symbols and maintaining information transmission efficiency.
2Measurement precision
If adaptive determination of pilot symbol insertion positions is implemented to improve reception accuracy, then the accuracy of propagation path compensation improves, but the amount of feedback information increases enormously
Solution Approach 1:
The patent extracts only the essential information needed for pilot symbol placement from the complete channel state information. Instead of feeding back all channel characteristics, the receiving apparatus identifies and feeds back only the specific frequency positions where pilot symbols should be inserted. This selective extraction of critical information achieves accurate propagation path compensation while minimizing the amount of feedback data required.
Solution Approach 2:
The patent applies local quality by determining pilot symbol insertion positions specifically in frequency regions where propagation path variations are significant, rather than uniformly distributing pilot symbols across all frequencies. The receiving apparatus measures reception quality at different frequency positions and identifies local regions requiring enhanced pilot coverage. This localized approach improves compensation accuracy in critical frequency regions while reducing the overall number of pilot symbols and associated feedback information.
3Measurement precision
If feedback information is transmitted to determine pilot symbol positions, then the accuracy of channel estimation improves, but the channel capacity is constricted particularly on the downlink channel
Solution Approach 1:
The patent applies partial action by implementing adaptive pilot symbol placement only in frequency regions where propagation path variations are significant, rather than adapting the entire communication system. The receiving apparatus identifies specific frequency positions requiring enhanced pilot coverage and feeds back only this partial information. This selective adaptation achieves improved channel estimation accuracy in critical regions while minimizing the impact on overall channel capacity and data transmission.
Data Source
AI summary
A radio communication apparatus is disclosed that enables the influence of the feedback information on the channel capacity to be kept to the minimum without reducing the transmission efficiency of information by transmission of pilot symbol. In the apparatus, a delay dispersion measuring section (272) generates a delay profile using the received signal, and measures delay dispersion indicative of dispersion of delayed versions. A moving speed estimating section (274) estimates moving speed of a mobile station apparatus that transmits a pilot symbol based on the variation in reception power of the pilot symbol. An other-cell interference measuring section (276) measures other-cell interference caused by signals transmitted in cells except the cell to which the apparatus belongs. Corresponding to the delay dispersion, moving speed and other-cell interference, a pilot pattern information generating section (278) selects a pilot pattern such that placement of pilot symbol is optimal in a frame, and generates the pilot pattern information.