Link Scheduling Algorithm for OFDMA Relay Networks
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Solution Overview
Problem
Current link scheduling algorithms in wireless communication networks, such as those using relay nodes in LTE-Advanced systems, often fail to optimize network throughput due to inadequate management of the backhaul sub-frame, leading to bottlenecks and inefficient resource allocation, where activating the backhaul link can prevent access links from functioning optimally, especially under dynamic conditions.
Innovation Solution
A link scheduling algorithm that makes decisions on a per-relay node basis, activating either the backhaul or access link based on which allows the highest data transmission, considering the queued data, radio channel conditions, and available resources, to maximize network throughput, suitable for both dynamic and semi-static scheduling approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backhaul link is activated for all relay nodes, then the DeNB can communicate with all relay nodes, but the access links cannot function optimally due to resource conflicts and interference
Solution Approach 1:
The patent applies dynamic link scheduling where the DeNB dynamically selects whether to activate backhaul or access links for each relay node based on real-time channel conditions and traffic demands. This dynamic adaptation allows the system to optimize throughput by switching between modes rather than being fixed, resolving the contradiction between reliable communication and high productivity.
Solution Approach 2:
The system changes operational parameters by adjusting the activation state of backhaul and access links based on channel quality indicators and traffic conditions. By varying these parameters dynamically, the system achieves both reliable communication when needed and high throughput when conditions permit, eliminating the trade-off.
2Productivity
If access and backhaul links are scheduled simultaneously, then resource utilization increases, but interference between links increases due to the relay duplexing problem
Solution Approach 1:
The patent implements periodic scheduling where access and backhaul links are activated in alternating time periods. The DeNB schedules backhaul sub-frames and access sub-frames in a periodic manner, allowing resource utilization to increase while controlling interference by ensuring that relay nodes do not simultaneously transmit and receive on the same frequency, thus resolving the relay duplexing problem.
3Device complexity
If link scheduling decisions are made semi-statically, then implementation complexity is reduced, but the system cannot adapt to dynamic channel conditions
Solution Approach 1:
The patent employs dynamic link scheduling where the DeNB makes real-time decisions about backhaul and access link activation based on current channel conditions and traffic demands. This dynamic approach allows the system to adapt to changing conditions while maintaining manageable complexity through structured decision-making protocols, eliminating the trade-off between simplicity and adaptability.
Data Source
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AI summary
A method (200) for scheduling link activations within a wireless communications network (100) is proposed. The wireless communication network includes at least one network cell (110), the at least one network cell comprising a base station (105) providing radio coverage over the network cell and at least one relay node (120) for putting into communication the base station with at least one corresponding user equipment (115) within the network cell. Said at least one relay node communicates with the user equipment over an access link and with the base station over a backhaul link. In the solution according to one or more embodiments of the present invention, the method includes estimating (205), for the at least one relay node, an access link capacity according to status information indicative of a status of the user equipment associated with the relay node, estimating (210) a backhaul link capacity of the at least one relay node according to the status information, and scheduling (215), for the at least one relay node, either a backhaul link activation or an access link activation such that either one of the backhaul link and the access link is activated, in a predetermined time interval, based on a comparison between the access capacity and the backhaul capacity.