OFDM Interference Measurement Power Control
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately measuring interference levels due to distortion caused by power transmission in orthogonal frequency-division multiplexing (OFDM) symbols, which affects channel quality reporting and data rates.
Innovation Solution
A method is introduced to control distortion in interference measurements by adjusting the power in OFDM symbols transmitted from a network node to a radio device. This involves allocating zero power resource elements (ZP REs) and non-zero power resource elements (NZP REs) in IM symbols, ensuring that the power in subcarriers outside of the set in IM symbols is less than or equal to that in other symbols, thereby reducing symbol power and minimizing power-dependent distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power transmitted in OFDM symbols is increased to improve signal strength and data rates, then transmission performance is improved, but distortion in interference measurement increases
Solution Approach 1:
The OFDM symbols are segmented into two distinct types: IM symbols with reduced power specifically for interference measurement, and non-IM symbols with normal power for data transmission. This segmentation allows the system to maintain high data rates during non-IM symbols while obtaining accurate interference measurements during IM symbols, resolving the contradiction between transmission performance and measurement accuracy.
Solution Approach 2:
IM symbols act as an intermediary mechanism between the conflicting requirements of high power transmission and accurate interference measurement. By introducing these dedicated low-power symbols, the system can measure interference without the distortion caused by high power transmission, while still maintaining overall high data rates through normal power transmission in other symbols.
2Reliability
If power in OFDM symbols is increased to approach channel capacity, then communication performance is improved, but distortion-dependent interference measurement degrades
Solution Approach 1:
The transmission framework is segmented into IM symbols with reduced power to minimize distortion for accurate interference measurement, and non-IM symbols with full power to maximize data transmission efficiency. This segmentation enables the system to reliably measure interference free from distortion while maintaining high communication performance during data transmission phases.
Solution Approach 2:
IM symbols are periodically inserted into the transmission sequence at regular intervals. This periodic structure allows the system to continuously monitor interference levels with minimal distortion while maintaining high overall transmission power, thus achieving both reliable channel quality assessment and high data rates.
3Measurement precision
If power in IM symbols is reduced to minimize distortion, then interference measurement accuracy is improved, but signal strength decreases
Solution Approach 1:
The system segments transmission symbols into IM symbols with reduced power dedicated solely to interference measurement, and non-IM symbols with full power for data transmission. This segmentation ensures that the reduced signal power in IM symbols does not impact overall system performance, as these symbols are specifically designed for measurement purposes only, while data transmission maintains full power for high data rates.
Solution Approach 2:
IM symbols are designed to serve their specific function of interference measurement without requiring high signal power. The reduced power in these symbols is acceptable because their sole purpose is measurement, not data transmission. The system uses these self-dedicated symbols to obtain accurate interference measurements that inform subsequent transmission decisions, thereby maintaining overall system efficiency.
Data Source
AI summary
A technique for controlling a distortion for an interference measurement, IM, by controlling a power in a radio transmission of orthogonal frequency-division multiplexing, OFDM, symbols (408, 410) from a network node (100) to a radio device (120) is described. As to a method aspect of the technique, at least one IM symbol (410) out of the OFDM symbols (408, 410) is transmitted (202) from the network node (100) to the radio device (120). The at least one IM symbol (410) comprises zero power resource elements, ZP RES (412; 414), and zero or more non-zero power resource elements, NZP REs (418), wherein a set (412) of the ZP REs (412; 414) is allocated to the IM at the radio device (120), and wherein the power in subcarriers (402) outside of the set (412) and in each of the at least one IM symbol (410) is less than or equal to a power in the subcarriers (402) outside of the set (412) and in another symbol (408) out of the OFDM symbols (408, 410) other than the at least one IM symbol (410). At least one channel state information, CSI, report is received from the radio device (120), wherein the CSI report is indicative of a result of the IM based on the transmitted (202) at least one IM symbol (410).