Subframe Staggering for Relay Backhaul Capacity
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Solution Overview
Problem
Existing wireless communication networks face limitations in efficiently supporting relay operations due to the half-duplex nature of relays, which restricts flexible resource allocation and leads to bottlenecks in backhaul capacity and interference management.
Innovation Solution
Subframe staggering is introduced, where the subframes of different relays are offset from each other, allowing for more flexible backhaul/access partitioning, improved resource utilization, and enhanced interference management by enabling relays to discover neighbors and adjust their transmission patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If relays use half-duplex operation with fixed backhaul/access partitioning, then implementation complexity is reduced, but resource utilization efficiency deteriorates and backhaul capacity is limited
Solution Approach 1:
The patent applies dynamics by making the backhaul subframe configuration flexible and adaptable rather than fixed. The eNodeB can dynamically assign different backhaul subframe patterns to different relays based on traffic conditions and network requirements, allowing the system to optimize resource utilization while maintaining half-duplex operation. This resolves the contradiction by enabling high backhaul capacity through dynamic configuration without increasing relay implementation complexity.
Solution Approach 2:
The patent changes the parameter of subframe configuration from fixed to variable. By allowing different relays to have different backhaul subframe assignments and by enabling the eNodeB to modify these assignments dynamically, the system achieves improved resource utilization and backhaul capacity. This parameter change approach maintains simple half-duplex relay operation while overcoming the capacity limitations of fixed partitioning.
2Ease of operation
If all relays use the same backhaul subframes, then coordination is simplified, but resource wastage increases and interference management becomes difficult
Solution Approach 1:
The patent applies local quality by allowing different relays to have different backhaul subframe configurations tailored to their specific needs and locations. Instead of uniform coordination, each relay can be assigned backhaul subframes that optimize its performance while minimizing interference with others. This resolves the contradiction by enabling efficient resource utilization through localized optimization without requiring complex coordination mechanisms.
Solution Approach 2:
The patent segments the backhaul subframe resources differently for different relays rather than using a unified allocation scheme. By dividing and assigning specific subframes to specific relays based on their individual requirements, the system reduces resource wastage and improves interference management. This segmentation approach maintains operational simplicity at the eNodeB while achieving efficient resource utilization across the network.
3Productivity
If relays transmit during all subframes, then access link capacity is maximized, but backhaul reception is impaired due to half-duplex constraints
Solution Approach 1:
The patent applies dynamics by enabling flexible switching between access and backhaul modes for different relays at different times. The eNodeB can dynamically adjust which relays are in access mode versus backhaul mode based on current network conditions, allowing the system to maximize access link capacity when needed while ensuring reliable backhaul reception. This dynamic approach resolves the contradiction by adapting relay operations to real-time requirements rather than using fixed transmission patterns.
Solution Approach 2:
The patent employs periodic action through structured backhaul subframe assignments where relays periodically switch between access and backhaul operations. By organizing relay operations into periodic patterns with designated backhaul subframes, the system ensures reliable backhaul reception while maintaining high access link capacity during access subframes. This periodic structure resolves the contradiction by creating predictable, manageable transmission patterns that satisfy both requirements.
Data Source
AI summary
Techniques for supporting relay communication with subframe staggering are described. For subframe staggering, subframes of different relays are staggered from one another, which can increase the number of potential backhaul subframes. In one design, a first relay determines its access subframes and backhaul subframes, which correspond to different non-overlapping subsets of the subframes of the first relay. The first relay communicates with at least one UE during the access subframes and communicates with a base station during the backhaul subframes. The subframes of the first relay are offset from the subframes of a second relay communicating with the base station. In one design, the access subframes of the first relay includes all subframes with either even or odd indices, which can support data transmission with HARQ. In one design, at least one access subframe corresponds to at least one reserved subframe having reduced transmit power from the base station.