Network Node Guard Period Allocation for D2D Sidelink
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Solution Overview
Problem
In TDD cellular networks, guard periods (GPs) are often too large due to propagation delays, leading to wastage of resources as they are unused, which affects the efficiency of Device-to-Device (D2D) operations.
Innovation Solution
A method where a network node (NN) determines the number of guard period (GP) symbols within a switching time resource for D2D operation based on propagation delay criteria, reusing these symbols for Sidelink (SL) communication to optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guard period symbols are configured to be large to account for propagation delay, then the reliability of uplink transmission is improved, but the productivity of the system deteriorates due to resource wastage
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the number of guard period symbols based on propagation delay measurements. The network node determines the actual propagation delay between UE and network, and configures the GP symbols accordingly. This allows the system to use only the necessary number of guard symbols, avoiding resource wastage while ensuring reliable uplink transmission. The parameter (number of GP symbols) is changed from a fixed large value to a dynamically optimized value.
Solution Approach 2:
The patent implements dynamics by making the guard period configuration adaptive rather than static. The network node continuously monitors propagation delay conditions and adjusts the number of GP symbols in real-time. This dynamic adjustment allows the system to respond to changing network conditions, optimizing resource usage while maintaining transmission reliability under varying propagation delays.
2Stability of the object's composition
If the same TDD pattern is used in all cells with large guard period, then the stability of downlink-to-uplink switching is improved, but the loss of time for D2D operations increases
Solution Approach 1:
The patent applies local quality by allowing different TDD configurations in different cells based on local propagation delay conditions. Instead of using a uniform TDD pattern across all cells, each cell can be configured with appropriate guard period duration according to its specific propagation characteristics. This enables optimized D2D operation time in each cell while maintaining stable DL-to-UL switching where needed.
Solution Approach 2:
The patent implements segmentation by dividing the network into different cell regions with different TDD configurations. Cells with large propagation delays can have longer guard periods, while cells with smaller propagation delays can use shorter guard periods or even eliminate them in favor of D2D operations. This segmented approach allows simultaneous optimization of switching stability and D2D operation time across different network regions.
Data Source
AI summary
A method performed by a Network Node (NN) for handling Device to Device (D2D) operation between a first D2D User Equipment (UE) and a second D2D UE in a radio communications network is provided. The NN obtains data related to propagation delay in one or more cells served by the NN. The propagation delay is related to any one or more out of: the first D2D UE, the second D2D UE, other D2D UEs, and cellular UEs. The NN then determines whether or not to configure a number of Guard Period (GP) symbols within a switching time resource, as Sidelink (SL) radio resources for the D2D operation. The determining is based on one or more criteria applied to the obtained data related to the propagation delay.