D2D Resource Allocation Collision Avoidance in Cellular Systems
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Solution Overview
Problem
In communication systems supporting device-to-device (D2D) schemes, collisions occur between random access transmissions and D2D transmissions due to shared radio resources, leading to interference and inefficiencies in resource allocation.
Innovation Solution
The method involves detecting resource configuration information for both random access and D2D transmissions, determining if D2D resources overlap with random access resources, and adjusting resource usage to avoid collisions by configuring non-overlapping resources for each transmission type, employing guard bands, power control, and prioritizing transmissions to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D transmission and random access transmission share the same radio resources, then resource utilization is improved, but collision between transmissions occurs leading to interference
Solution Approach 1:
The patent segments the radio resources by introducing separate resource pools: one pool for random access transmissions (PRACH resources) and another pool for D2D transmissions. This segmentation prevents collisions by ensuring that random access preambles and D2D signals do not contend for the same time-frequency resources, thereby maintaining both high resource utilization and transmission reliability.
Solution Approach 2:
The patent applies local quality by configuring different resource allocation parameters for different transmission types. Specifically, it sets distinct subframe configurations, frequency offsets, and resource element patterns for random access versus D2D transmissions, allowing each transmission type to have optimized local resource characteristics that prevent interference while maximizing overall system capacity.
2Productivity
If D2D resources are allocated on UL frequency, then radio spectrum efficiency is improved, but collision with UE to BS transmission occurs
Solution Approach 1:
The patent resolves the conflict by introducing an additional dimension of resource differentiation through cyclic shifts and frequency offsets. Even though D2D and UL transmissions share the same uplink frequency band, the patent assigns different cyclic shift values and frequency offset parameters to D2D resource elements, creating orthogonal signal spaces that prevent mutual interference while maintaining spectrum efficiency.
3Adaptability or versatility
If random access and D2D transmissions use overlapping resources, then resource flexibility is improved, but collision avoidance becomes difficult
Solution Approach 1:
The patent implements preliminary action by pre-configuring non-overlapping resource pools for random access and D2D transmissions through higher-layer signaling (system information blocks). The network pre-allocates specific subframes, frequency resources, and resource element patterns for each transmission type, eliminating the need for complex real-time collision detection and resolution mechanisms, thereby reducing device complexity while maintaining resource flexibility.
Data Source
AI summary
A method for avoiding a collision between a device to device (D2D) transmission and a random access transmission by a user equipment (UE) in a communication system supporting a D2D scheme is provided. The method includes detecting resource configuration information related to a random access transmission and resource configuration information related to a D2D transmission, determining a result on whether a resource in which a D2D resource which corresponds to the resource configuration information related to the D2D transmission is included includes a random access resource which corresponds to the resource configuration information related to the random access transmission, and avoiding using the resource or the random access resource for the D2D transmission based on the determined result.