Transmission Parameter Grade Determination for Limited CSI Feedback
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Solution Overview
Problem
Current technologies lack a specific solution for determining transmission parameters in scenarios where Channel State Information (CSI) feedback is limited, particularly in LTE Release-13 for Machine Type Communication (MTC) and Device to Device (D2D) communication, affecting adaptive coding and modulation.
Innovation Solution
A method and apparatus for determining a transmission parameter grade based on a predetermined set and indication signaling, which includes Radio Resource Control (RRC) and Downlink Control Information (DCI), to optimize HARQ transmission parameters such as repeat count, code rate, time-frequency resources, and modulation scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional CSI feedback is used, then adaptive coding and modulation can be implemented, but in LTE Release-13 for MTC and D2D communication, the receiving end cannot perform CSI feedback due to power saving requirements or broadcast communication limitations
Solution Approach 1:
The patent implements feedback through soft HARQ ACK/NACK signals that carry embedded link information. The receiving end feeds back not just acknowledgment status but also transmission parameter grades (code rate, modulation scheme, SINR differences) within the ACK/NACK bits, enabling the sending end to adapt transmission parameters based on actual channel conditions without requiring traditional CSI feedback mechanisms
Solution Approach 2:
The patent uses soft HARQ ACK/NACK signals as an intermediary carrier to transport link information. Instead of directly transmitting CSI feedback, the system embeds transmission parameter grades within the ACK/NACK bits, allowing the receiving end to convey channel quality information indirectly while maintaining power saving requirements and simplifying the feedback mechanism
2Reliability
If soft HARQ with attached link information is implemented, then the sending end can obtain link information for adaptive adjustment, but the feedback bits need to be increased to carry additional information
Solution Approach 1:
The patent changes the parameter representation by using transmission parameter grades instead of absolute values. The receiving end determines a transmission parameter grade based on the difference between current and target SINR, and feeds back this graded information. This parameter transformation reduces the feedback overhead while maintaining the ability to perform accurate link adaptation
Solution Approach 2:
The patent applies partial action by selecting only the most critical transmission parameters (code rate, modulation scheme, SINR difference) to feed back within the ACK/NACK bits, rather than transmitting complete CSI reports. This partial feedback approach provides sufficient information for adaptive adjustment while minimizing the increase in feedback overhead
3Loss of time
If link information is determined in an appointment manner without signaling interaction, then sending and receiving ends can acquire link information simultaneously, but the receiving end cannot perform link information feedback
Solution Approach 1:
The patent resolves this contradiction by implementing feedback within the soft HARQ mechanism. The receiving end determines link information locally and feeds back transmission parameter grades within the ACK/NACK signals. This allows simultaneous determination of link information by both ends while maintaining the feedback capability, as the feedback is embedded in the existing HARQ protocol rather than requiring separate signaling interactions
Data Source
AI summary
A transmission parameter determination method and apparatus are provided. In the method, a second node determines a transmission parameter grade X1 based on a predetermined set and at least one of predetermined information and indication signaling.