Dynamic Pilot Signal Transmission for MIMO Interference Reduction
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Solution Overview
Problem
In MIMO systems, transmitting pilot signals over additional antennas can cause significant interference to traditional terminals, affecting their performance, and existing pilot design methods do not adequately address this issue while ensuring the performance of advanced MIMO terminals.
Innovation Solution
A method where pilot signals CPICH1 and CPICH2 are transmitted over the first and second antennas, with additional pilot signals CPICHk1 and CPICHk2 transmitted over other antennas only when specific MIMO terminals are scheduled, using different code channels and adjusting power based on terminal categories to minimize interference and optimize channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot signals are transmitted over additional antennas (3rd and 4th antennas) in a 4 Branch MIMO system, then channel estimation performance for advanced MIMO terminals is improved, but interference to traditional terminals increases significantly
Solution Approach 1:
The patent applies local quality by differentiating pilot signal transmission strategies for different terminal types. Traditional terminals receive pilot signals only from the first two antennas, while 4 Branch MIMO terminals receive additional pilot signals from the third and fourth antennas. This localized differentiation allows advanced terminals to achieve better channel estimation without degrading traditional terminal performance.
Solution Approach 2:
The patent segments the pilot signal transmission into two distinct parts: CPICH signals transmitted from the first two antennas for traditional terminals, and additional pilot signals transmitted from the third and fourth antennas for 4 Branch MIMO terminals. This segmentation enables independent optimization of transmission parameters for each terminal category, resolving the interference issue.
2Measurement precision
If pilot signal power is increased to ensure performance of 4 Branch MIMO terminals, then channel estimation accuracy improves, but interference to traditional terminals worsens
Solution Approach 1:
The patent implements local quality by assigning different power levels to different pilot signal groups. The CPICH signals from the first two antennas use a power level optimized for traditional terminals, while the additional pilot signals from the third and fourth antennas use power levels optimized for 4 Branch MIMO terminals. This localized power optimization achieves high accuracy for advanced terminals without causing excessive interference to traditional terminals.
Data Source
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AI summary
Embodiments of the present invention disclose a pilot signal transmission method, a channel estimation method, an apparatus, and a system, where the method includes: transmitting a pilot signal 1 CPICH1 over a first antenna, and transmitting a pilot signal 2 CPICH2 over a second antenna; transmitting a pilot signal CPICHk1 over a k1th antenna; and when it is determined that a terminal of a first category in the MIMO system is scheduled, transmitting a pilot signal CPICHk2 over the k1th antenna. Interference caused by a pilot signal to a traditional terminal is better reduced, performance of the traditional terminal is ensured while the terminal of the first category properly works in the MIMO system, and power consumption for transmitting a pilot frequency is effectively reduced.