Radio Frame-Based DMRS Sequences for NPUSCH Interference Randomization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In a TDD narrowband IoT system, the 3.75-kHz NPUSCH format 2 is limited to specific slot usage, leading to identical DMRS sequences across cells, which fails to ensure inter-cell interference randomization, affecting demodulation performance.
Innovation Solution
A communication method that generates DMRS sequences based on radio frame numbers, using pseudo-random sequences initialized with cell identifiers and frame numbers to vary sequence indexes, ensuring inter-cell interference randomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slot number is used to determine DMRS sequence, then inter-cell interference randomization is implemented, but in 3.75-kHz NPUSCH format 2 only specific slot numbers are available, causing identical sequences across all slots
Solution Approach 1:
The patent changes the parameter used for DMRS sequence determination from slot number to radio frame number. This parameter substitution resolves the contradiction because radio frame numbers continue to increment over time even when slot numbers repeat within the same radio frame, thereby maintaining sequence variation and inter-cell interference randomization capability across different slots.
2Device complexity
If the same slot number is used in all slots, then device complexity is reduced, but inter-cell interference randomization cannot be ensured
Solution Approach 1:
The patent substitutes the slot number parameter with radio frame number parameter in the sequence determination formula. This maintains simplicity in the determination process while ensuring that different radio frames produce different sequence indexes, thereby achieving inter-cell interference randomization without increasing device complexity.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A communication method and an apparatus are provided, to implement inter-cell interference randomization. The method includes: generating a demodulation reference signal based on a first parameter, where the first parameter includes a radio frame number of a radio frame for sending the demodulation reference signal; and sending the demodulation reference signal and a first channel, where the first channel is for carrying uplink control information, and the demodulation reference signal is a reference signal for demodulating the first channel.