Cross-Cell D2D Resource Allocation via Base Station Coordination
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Solution Overview
Problem
In wireless communication systems, device-to-device (D2D) communication across different cells faces interference issues when using grant-less resources, affecting communication efficiency and reliability.
Innovation Solution
Base stations of neighboring cells coordinate to allocate grant-free uplink (GUL) resources for D2D connections, enabling efficient resource management and interference mitigation through synchronized sounding reference signal (SRS) measurements and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D connections use grant-less resources for communication, then communication efficiency is improved, but interference between D2D connections and between D2D and uplink/downlink connections increases
Solution Approach 1:
The system performs preliminary actions by having UEs transmit Sounding Reference Signals (SRS) before actual D2D data transmission. These SRS transmissions are used to measure channel conditions and predict potential interference, allowing the network to proactively allocate resources and configure parameters that prevent interference issues before they occur during actual communication.
Solution Approach 2:
The system implements feedback mechanisms where UEs report Channel State Information (CSI) based on SRS measurements to the network. This feedback loop allows the network to continuously monitor channel conditions and adjust resource allocation, power control parameters, and interference coordination strategies to maintain efficient D2D communication while minimizing interference.
2Reliability
If base stations coordinate to allocate GUL resources for D2D connections, then interference is reduced, but device complexity increases
Solution Approach 1:
The network introduces an intermediary coordination mechanism where a serving base station acts as a mediator for D2D resource allocation. Instead of direct complex coordination between all neighboring base stations, the serving base station receives SRS measurements from UEs, determines appropriate GUL resource allocation, and manages the coordination with neighboring cells through standardized interfaces, thereby reducing overall system complexity while maintaining reliable interference management.
3Measurement precision
If SRS measurements are used for channel assessment, then resource allocation accuracy is improved, but measurement time and signaling overhead increase
Solution Approach 1:
The system makes Sounding Reference Signals (SRS) multi-functional by using them for both uplink channel quality assessment and D2D channel measurement purposes. This universal approach allows the same SRS transmissions to serve multiple functions: evaluating uplink conditions for grant-less transmissions and simultaneously assessing D2D channel quality for cross-cell D2D resource allocation, thereby reducing the need for separate dedicated measurement signals and minimizing time overhead.
Data Source
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AI summary
Base stations of neighbor cells can coordinate with each other in allocating grant-free uplink (GUL) resources for a device-to-device (D2D) connection or channel between user equipments (UEs) across the neighbor cells. The base stations coordinate to determine a condition conducive to D2D communication between the UEs. If the condition exists, the base stations coordinate to allocate network resources for D2D communication between the UEs, and establish a D2D connection between the UEs using the allocated network resources for D2D communication.