Superposition Coding for Concurrent V2X Uplink and Sidelink Transmission
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Solution Overview
Problem
In Rel-16 Mode-1 V2X systems, separate resources are typically assigned for sidelink and uplink messages, which can lead to inefficient resource utilization due to separate transmission channels, especially when there is a high signal-to-noise ratio mismatch between uplink and sidelink communication channels.
Innovation Solution
Implementing superposition coding to concurrently transmit uplink and sidelink messages using a single broadcast transmission, where the base layer is encoded on the weaker link and the enhancement layer on the stronger link, allowing both the base station and user equipment to understand the base layer while only the base station receives both messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate resources are assigned for sidelink and uplink messages, then transmission reliability is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent combines sidelink and uplink messages into a single broadcast transmission using superposition coding. The UE transmits both message types simultaneously on the same time-frequency resources, with the sidelink message encoded at a lower power level and the uplink message at a higher power level, allowing the base station to decode both messages reliably while improving resource utilization efficiency.
Solution Approach 2:
The patent applies different encoding strategies to different parts of the transmission. The sidelink message is encoded with lower power and simpler modulation suitable for direct UE-to-UE communication, while the uplink message is encoded with higher power and more robust modulation for base station reception. This localized quality differentiation allows each message type to be optimized for its specific reception requirements.
2Measurement precision
If separate transmission channels are used for sidelink and uplink messages, then message delivery accuracy is improved, but spectral efficiency deteriorates
Solution Approach 1:
The patent merges sidelink and uplink transmissions into a single channel using superposition coding. By transmitting both messages simultaneously on the same spectral resources with different power levels, the system achieves high spectral efficiency while maintaining message delivery accuracy through appropriate power control and decoding strategies at the receiver.
Solution Approach 2:
The patent changes the power parameter differently for different message types within the same transmission. The sidelink message is transmitted at a lower power level (P_sidelink) while the uplink message is transmitted at a higher power level (P_uplink), where P_sidelink < P_uplink. This parameter differentiation allows the base station to decode the higher power uplink message while UE can decode the sidelink message by subtracting the known uplink signal.
3Use of energy by moving object
If a single broadcast transmission is used for both sidelink and uplink messages, then spectral efficiency is improved, but message decoding complexity increases
Solution Approach 1:
The patent simplifies the decoding process by applying local quality principles: the base station only needs to decode the uplink message at high power level, while UE only needs to decode the sidelink message at the lower power level after removing the uplink signal. This localized decoding approach reduces overall system complexity compared to requiring all receivers to decode all messages.
Solution Approach 2:
The patent segments the decoding process into two separate stages: first, the base station decodes the uplink message from the high power component; second, the UE decodes the sidelink message from the remaining lower power component after subtracting the decoded uplink signal. This segmentation of the decoding process reduces complexity by allowing each receiver to focus on decoding only its intended message.
Data Source
AI summary
Aspects of this disclosure relate to a user equipment (UE) for wireless communication within a network. The UE receives, from a radio access network (RAN) entity, one of an uplink indication or an uplink port identification associated with an uplink port. The uplink indication and the uplink port identification are associated with an uplink message. The UE also maps one of the uplink indication to a sidelink indication associated with a sidelink message or the uplink port identification to a sidelink port identification associated with a sidelink port and the sidelink message. The UE further superposition codes the uplink message and the sidelink message into a broadcast transmission based on one of (A) the uplink indication and the sidelink indication, or (B) the uplink port and the sidelink port. In addition, the UE transmits, to the RAN entity, the broadcast transmission.