User Equipment Coordination for Full-Duplex Crosstalk Cancellation
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Solution Overview
Problem
Existing wireless communication technologies face challenges in improving spectral efficiency and signal quality due to the interference between uplink and downlink transmissions, particularly in full-duplex communication where the transmitter output power can saturate the receiver's input circuitry, leading to challenges in decoding desired signals.
Innovation Solution
A user equipment-coordination set (UECS) is formed by multiple UEs that jointly receive downlink signals and transmit uplink signals, with a coordinating UE combining samples to cancel crosstalk and decode data, enhancing signal quality and power through geographic separation and coordinated processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex communication is implemented to improve spectral efficiency, then spectral efficiency is improved, but interference between uplink and downlink transmissions increases causing receiver saturation
Solution Approach 1:
The system segments the full-duplex communication into coordinated transmission and reception subsets. The coordinating UE divides the UECS into a first subset for joint downlink reception and a second subset for joint uplink transmission, allowing simultaneous operation while managing interference through structured organization of transmitting and receiving nodes
Solution Approach 2:
The system converts the harmful self-interference into a useful signal by having the coordinating UE receive both the desired downlink signal and the self-generated uplink interference, then uses signal processing to extract and cancel the interference component, transforming the harmful interference into a means for characterizing and removing it from the received signal
2Reliability
If transmitter output power is increased to improve signal quality, then signal quality is improved, but receiver input circuitry becomes saturated making decoding difficult
Solution Approach 1:
The coordinating UE acts as an intermediary that receives both the desired downlink signal and the self-interference from uplink transmission. It processes these combined signals to separate and cancel the interference component, effectively mediating between the high-power transmission and the sensitive reception without requiring separate physical paths
Solution Approach 2:
The system uses feedback from the received signal containing both desired signal and self-interference to characterize the interference channel. The coordinating UE uses this feedback information to construct and subtract an estimate of the self-interference from the received signal, enabling recovery of the desired downlink signal despite high transmit power
3Power
If multiple UEs are coordinated to jointly transmit and receive signals, then effective transmit and receive power are increased, but system complexity increases
Solution Approach 1:
The system merges the transmission capabilities of multiple UEs in the second subset to jointly transmit uplink signals, and merges the reception capabilities of multiple UEs in the first subset to jointly receive downlink signals. This combining provides diversity gain and increased effective power while the coordinating UE centralizes the complex signal processing functions
4Object-affected harmful factors
If geographic separation is used to reduce interference, then interference cancellation is improved, but device coordination and synchronization become more challenging
Solution Approach 1:
The system exploits the natural geographic separation and resulting different channel characteristics between UEs as a self-service mechanism. The channel differences that would normally complicate coordination actually provide the means for interference cancellation, as the self-interference experiences different propagation paths than the desired signals from the base station
Data Source
AI summary
Methods, devices, systems, and means for coordinating full-duplex communication are described in which a user equipment, UE, configured as a coordinating user equipment for a user equipment-coordination set, UECS, selects a first subset of UEs in the UECS to jointly receive downlink signals and selects a second subset of UEs in the UECS to jointly transmit uplink signals. The coordinating UE receives uplink data to transmit to the network entity and receives, from the first subset of UEs, demodulated and sampled downlink data that is received concurrently with joint-transmission of the uplink data. The coordinating UE combines the samples received from each UE in the first subset of UEs and jointly processes the combined samples to provide decoded data using the received uplink data to cancel crosstalk of uplink signals for the transmitted uplink data to downlink signals to the received downlink data.