MCS Index Determination for PUSCH Uplink Efficiency
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Solution Overview
Problem
In LTE systems, the existing methods for determining the Modulation and Coding Scheme (MCS) index for Physical Uplink Shared Channel (PUSCH) are inadequate as they do not accurately account for the difference in bandwidth between the Sounding Reference Signal (SRS) and PUSCH, leading to inappropriate MCS selection and reduced uplink transmission efficiency, especially at the cell edge where transmission power is restricted.
Innovation Solution
A method and device that compute a second Signal to Interference plus Noise Ratio (SINR) for PUSCH based on the first SINR measured from the SRS, considering the power difference between SRS and PUSCH, to precisely determine the MCS index and the number of Physical Resource Blocks (PRBs) for accurate PUSCH scheduling, ensuring the MCS index matches the actual SINR of the PUSCH channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the MCS index is determined based on SRS measurement SINR, then the MCS determination process is simple, but the MCS index does not match the actual PUSCH channel conditions leading to transmission errors
Solution Approach 1:
The patent replaces the direct SRS-based MCS determination method with a new calculation approach that uses SRS SINR as a baseline and applies power difference compensation. Instead of directly using SRS measurement results, the system substitutes in a corrected SINR value that accounts for the power relationship between SRS and PUSCH, thereby improving accuracy while maintaining computational simplicity.
2Reliability
If the transmission power of a single PRB is increased to improve SINR, then the received power increases, but the total transmission power exceeds the maximum power limit
Solution Approach 1:
The patent changes the SINR parameter calculation by introducing a power difference compensation term. Instead of using the raw SRS SINR measurement, the system calculates a corrected SINR that incorporates the difference between SRS power configuration and actual PUSCH power allocation. This parameter transformation allows accurate MCS selection without requiring excessive transmission power.
3Productivity
If 96 PRBs are scheduled for a UE at cell edge, then the data transmission capacity is maximized, but the received power per PRB becomes too low for correct decoding
Solution Approach 1:
The patent performs preliminary SINR calculation and MCS determination before final PRB allocation. By calculating the required SINR based on power headroom and SRS measurements in advance, the system can determine the maximum number of PRBs that can be allocated while maintaining acceptable SINR levels. This preliminary action prevents allocating too many PRBs that would result in insufficient power per PRB for reliable decoding.
Data Source
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AI summary
Disclosed in embodiments of the present invention are an MCS index determination method and base station equipment. The method comprises: calculating, by a base station equipment and according to a first SINR obtained by measuring an SRS signal at time k0, a second SINR of PUSCH signal; determining, by the base station equipment and according to the second SINR, a first MCS index; and calculating, by the base station equipment and according to the first MCS index and data volume actually required to be transmitted by a user, an actually scheduled PRB amount, and a second MCS index actually used. In an embodiment of the present invention, an MCS index of PUSCH matches actual SINR of a PUSCH channel to effectively ensure receiving performance of the PUSCH, thereby increasing an uplink transmission efficiency of an LTE system, and particularly increasing an uplink transmission efficiency of a user near a cell edge, so as to ensure PUSCH transmission performance of a user near the cell edge or having a large path loss, and facilitate an increase in an uplink service rate of the edge user.