Relative Uplink Channel Estimation via Round-Trip Signaling
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Solution Overview
Problem
Conventional uplink channel estimation methods require significant signaling, making them inefficient for determining the uplink precoder in communications networks, especially in scenarios where downlink channel estimation is not feasible.
Innovation Solution
A method for terminal devices to estimate the relative uplink channel using only round-trip channel estimates, eliminating the need for downlink channel estimation and reducing signaling overhead, by transmitting reference signals from multiple antennas and receiving their forwarded representations to calculate the relative uplink channel and subsequently determine the precoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional uplink channel estimation methods are used, then downlink channel knowledge can be obtained, but signaling overhead increases significantly
Solution Approach 1:
The invention extracts only the necessary uplink channel information from round-trip channel measurements, eliminating the need for complete downlink channel estimation and associated signaling. By focusing solely on the uplink channel relation H_UL2/H_UL1, the method removes unnecessary signaling overhead while maintaining estimation accuracy.
Solution Approach 2:
The round-trip channel measurement serves multiple purposes: it provides both downlink channel information and uplink channel information simultaneously. This multi-functionality eliminates the need for separate downlink channel estimation procedures, thereby reducing signaling overhead while maintaining comprehensive channel knowledge.
2Reliability
If downlink channel estimation is performed, then complete channel state information is obtained, but system complexity increases
Solution Approach 1:
The method extracts only the essential uplink channel relation from round-trip measurements, removing the complexity of complete downlink channel estimation. By calculating only H_UL2/H_UL1 from the round-trip channel, the system achieves sufficient information for precoder determination with reduced procedural complexity.
Solution Approach 2:
Instead of estimating the downlink channel and then deriving uplink information, the invention inverts the approach by directly extracting uplink channel relations from round-trip measurements. This reversal simplifies the estimation procedure by working backwards from the available measurements to the required information.
3Ease of operation
If full round-trip and downlink channel estimation is performed, then accurate uplink precoder can be determined, but signaling requirements increase
Solution Approach 1:
The invention extracts only the necessary uplink channel relation H_UL2/H_UL1 from round-trip measurements, eliminating the need for separate downlink channel estimation signaling. This selective extraction maintains precoder determination accuracy while significantly reducing signaling overhead.
Solution Approach 2:
The round-trip channel measurement is used universally to provide both the reference for uplink channel estimation and the basis for precoder determination. This multi-functional use of a single measurement set eliminates redundant signaling procedures while maintaining complete information for accurate precoder design.
Data Source
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AI summary
There is provided mechanisms for relative uplink channel estimation. A method is performed by a terminal device. The method comprises transmitting reference signals from at least two antennas on respective uplink channels towards a network node. The method comprises receiving a forwarded representation of each of the reference signals from the network node. The method comprises estimating a relation between the uplink channels towards the network node for the at least two antennas using the reference signals and the received forwarded representations of the reference signals, thereby estimating the relative uplink channel, towards the network node, between the at least two antennas.