CSI-RS Sequence Generation and Mapping for LTE-A Channel Measurement
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Solution Overview
Problem
The existing LTE-A system lacks a method for generating and mapping Channel State Information Reference Signal (CSI-RS) sequences, which are crucial for channel measurement and feedback to the eNB, affecting frequency spectrum utilization and throughput.
Innovation Solution
A method is introduced to generate a pseudo-random sequence, perform QPSK modulation, and map the resulting CSI-RS sequence to a time-frequency location, using specific initial values and parameters such as time slot index, OFDM symbol index, cell ID, and CP length to ensure proper distribution and interference randomization across CSI-RS antenna ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sparse CSI-RS distribution is used to reduce pilot overhead, then resource utilization improves, but channel measurement accuracy deteriorates
Solution Approach 1:
The patent changes parameters including pseudo-random sequence initialization values based on antenna port indices, time slot indices, and cell IDs to generate different CSI-RS sequences for different antenna ports and cells. This parameter variation enables effective channel measurement with sparse pilot distribution by ensuring orthogonal and interference-free reference signals across multiple antennas and cells.
2Measurement precision
If multiple CSI-RS antenna ports are multiplexed using CDM, then channel measurement capability improves, but sequence generation complexity increases
Solution Approach 1:
The patent segments the CSI-RS sequence generation process by assigning different initialization parameters to different antenna ports. Each antenna port uses a unique combination of parameters (antenna port index, time slot index, cell ID) to generate its sequence, enabling orthogonal multiplexing through Code Division Multiple Access (CDM) while maintaining manageable generation complexity through systematic parameter assignment.
3Adaptability or versatility
If CSI-RS sequences are generated for maximum system bandwidth, then future scalability improves, but current resource consumption increases
Solution Approach 1:
The patent implements dynamic bandwidth adaptation by generating CSI-RS sequences based on the actual configured bandwidth rather than fixed maximum bandwidth. The sequence length and resource element allocation are dynamically adjusted according to the active bandwidth configuration, allowing the system to scale efficiently from small to large bandwidths without wasting resources on unused frequency resources.
Data Source
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AI summary
The present invention provides a method and device for generating and mapping a Channel State Information Reference Signal (CSI-RS) sequence, and the method includes: generating a pseudo-random sequence according to a pseudo-random sequence initial value, performing a Quadrature Phase-Shift Keying (QPSK) modulation on the pseudo-random sequence, and obtaining a first CSI-RS sequence according to maximum bandwidth of system; and cutting the first CSI-RS sequence according to the actual bandwidth of the system, obtaining a second CSI-RS sequence, and mapping the second CSI-RS sequence to a time frequency location of a CSI-RS antenna port. The CSI-RS reference signal sequence can be generated or obtained respectively at the UE terminal and eNB terminal in accordance with the stated methods for generating and mapping the reference sequence according to known parameters by the present invention, so that the calculated CSI-RS sequence can be utilized to measure the channel at the UE terminal.