D2D Relay Probability Control for Urban Non-LOS Shadowing
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Solution Overview
Problem
In wireless communication systems, half-duplex communication in D2D (device-to-device) UE environments faces challenges with shadowing and blocking, particularly in urban non-line of sight (LOS) environments, where traditional methods fail to effectively form diverse link paths and minimize these issues.
Innovation Solution
A method where D2D UE determines whether to relay a message based on a received relay probability, forming various link paths to minimize shadowing or blocking by controlling the uplink channel transmit power and utilizing a decode-and-forward scheme for cooperative communication among UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If D2D UE performs half-duplex communication in urban non-LOS environment, then communication can be established, but shadowing and blocking occur reducing link reliability
Solution Approach 1:
The patent segments the communication path by introducing multiple relay UEs that forward messages between source and destination UEs. This creates multiple independent link segments, so that shadowing or blocking affecting one segment does not necessarily affect all communication paths, thereby improving overall link reliability in urban non-LOS environments.
Solution Approach 2:
The patent introduces relay UEs as intermediary nodes that receive and forward messages between D2D UEs. These intermediaries create alternative transmission paths, reducing the direct impact of shadowing and blocking between source and destination, thus enhancing communication reliability in challenging urban environments.
2Adaptability or versatility
If D2D UE transmits messages directly without relaying, then transmission simplicity is maintained, but link diversity is insufficient in non-LOS environments
Solution Approach 1:
The patent implements self-service by having each D2D UE autonomously determine whether to act as a relay based on locally available information such as relay probability and message type, without requiring complex centralized control. This self-making decision reduces overall system complexity while still achieving link path diversity through distributed relay selection.
Solution Approach 2:
The patent applies partial action by implementing relay functionality selectively rather than universally. UEs determine whether to relay based on specific conditions (relay probability, message type, channel state), performing relaying only when beneficial. This partial implementation achieves sufficient link diversity without the complexity of full mesh relaying among all UEs.
3Reliability
If relay probability is increased to form more link paths, then shadowing and blocking are reduced, but half-duplex communication efficiency decreases
Solution Approach 1:
The patent implements dynamic relay probability adjustment where UEs adapt their relay behavior based on current channel conditions, message type, and network state. This dynamic approach allows the system to optimize between reliability and efficiency in real-time, increasing relay probability when needed for reliability while maintaining higher direct transmission probability when efficiency is prioritized, rather than using a static high relay probability.
Solution Approach 2:
The patent changes the parameter of relay probability dynamically based on message type (e.g., control messages vs. data messages) and channel conditions. By adjusting this parameter selectively rather than maintaining a constantly high value, the system achieves improved communication reliability for critical messages while preserving communication efficiency for less critical transmissions, resolving the trade-off between reliability and productivity.
Data Source
AI summary
A method of performing D2D (device-to-device) relay communication, which is performed by a user equipment (UE) in a wireless communication system according to various embodiments, and an apparatus are disclosed in the present invention. The method includes the steps of receiving information on a relay probability corresponding to a probability for performing relaying, receiving a message to be relayed, determining whether to perform relaying on the received message based on the information on the relay probability, and if it is determined to perform relaying, transmitting the message.