LTE Advanced Reference Signal Grouping for Antenna Expansion
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Solution Overview
Problem
The existing communication systems face challenges in expanding antenna ports while maintaining compatibility with original systems and controlling system overhead, particularly in LTE communication systems where the addition of new antennas requires significant modifications and increased overhead.
Innovation Solution
The method involves grouping expanded transmitting antennas into pairs, with each group sending RSs as [a*s1, b*s1*ejw] in one period and [a*s2, −b*s2*ejw] in the next, where a and b are real numbers, allowing the original antennas' RSs to remain unchanged or undergo simple power adjustments, and the new antennas' RSs to match or differ by phase rotation, thereby reducing system modifications and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If simple expansion is used to add new antenna ports, then the number of transmitting antenna ports is increased, but the system overhead of RSs is increased and large modification is made on the original system
Solution Approach 1:
The patent merges the RS transmission of original and expanded antenna ports by having expanded antenna ports transmit RSs in the same time-frequency resources as original antenna ports. Specifically, in the first RS period, original antenna ports transmit RSs while expanded antenna ports transmit RSs with phase rotation, allowing both to share resources and avoiding overhead increase.
Solution Approach 2:
The patent uses periodic RS transmission with two distinct periods: a first RS period where original and expanded antenna ports transmit RSs simultaneously, and a second RS period where only original antenna ports transmit RSs. This periodic structure enables the system to benefit from expanded antennas while maintaining compatibility with original systems.
2Adaptability or versatility
If simple expansion is used to add new antenna ports, then the number of transmitting antenna ports is increased, but large modification is made on the original system
Solution Approach 1:
The patent applies local quality by differentiating the RS transmission behavior between original and expanded antenna ports. Original antenna ports transmit RSs using the original sequence, while expanded antenna ports transmit RSs with phase rotation. This localized differentiation allows the system to expand antenna ports without requiring widespread modification of the original system's RS design.
Solution Approach 2:
The patent changes the parameter of phase rotation for expanded antenna ports' RS transmissions. By introducing phase rotation as a distinguishing parameter rather than creating entirely new RS sequences, the system achieves antenna expansion with minimal modification to the original RS design, maintaining backward compatibility.
3Adaptability or versatility
If original system RSs are used for expanded antennas, then backward compatibility is maintained, but the gains from added antennas cannot be obtained
Solution Approach 1:
The patent introduces dynamic RS transmission patterns where the transmission behavior changes between different periods. In the first RS period, expanded antenna ports transmit RSs with phase rotation to enable gain extraction. In the second RS period, only original antenna ports transmit RSs to maintain compatibility. This dynamic approach allows the system to adapt between compatibility mode and performance mode.
Data Source
AI summary
A method, a device, and a system for sending reference signals (RSs) are provided, which are capable of least modifying an original system and controlling the system overhead of the RSs. The method includes: grouping expanded transmitting antennas, wherein each group includes two transmitting antenna ports; and in two adjacent RS periods 2T, the RSs sent through the two transmitting antenna ports of each group are [a*s1, b*s1*ejw] respectively in a first period T and [a*s2, −b*s2*ejw] respectively in a second period T. The method, the device, and the system for sending RSs are applicable in design of transmitting antennas of an LTE Advanced system.