Uplink Resource Scheduling for Random Access Interference
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Solution Overview
Problem
In cellular communication systems, areas with uplink/downlink imbalances experience interference issues that hinder successful Random Access (RA) procedures, particularly in high-traffic or unfavorable radio conditions, where underlay nodes struggle to distinguish RA requests from uplink interference generated by macro nodes, leading to repeated failed attempts.
Innovation Solution
Determining and leaving specific uplink radio resources unscheduled in network nodes, allowing UEs in imbalanced areas to perform RA to neighboring nodes, thereby reducing interference and enabling successful RA attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink radio resources are scheduled in network nodes, then resource utilization and network capacity are improved, but interference to Random Access procedures in neighboring nodes increases
Solution Approach 1:
The uplink radio resources are segmented into different types: scheduled resources for normal uplink communication and unscheduled resources reserved for Random Access procedures. This segmentation allows the network to simultaneously support both regular traffic and Random Access without mutual interference, resolving the contradiction between resource utilization and RA performance.
Solution Approach 2:
Different quality characteristics are applied to different radio resources: scheduled resources optimize for data transmission efficiency, while unscheduled resources optimize for Random Access reliability. This local differentiation ensures that each resource type serves its specific function effectively, preventing scheduled resources from degrading RA performance.
2Object-generated harmful factors
If underlay nodes operate at lower reference signal powers, then interference to macro nodes is reduced, but uplink/downlink imbalance increases making RA detection difficult
Solution Approach 1:
The network proactively configures specific uplink radio resources as unscheduled before Random Access attempts occur. This preliminary action ensures that when UEs perform Random Access to underlay nodes, the designated resources remain free from macro node uplink interference, allowing reliable detection of RA preambles despite the power imbalance.
Solution Approach 2:
The unscheduled uplink radio resources act as an intermediary mechanism that mediates between the low-power underlay nodes and high-power macro nodes. By reserving these resources, the system creates a protected communication path for Random Access that is isolated from the interference generated by macro node uplink transmissions.
3Area of stationary object
If cell borders are based on downlink reference signal strengths, then downlink coverage is optimized, but uplink cell borders become misaligned causing interference
Solution Approach 1:
The resource allocation is segmented based on cell identity: resources in frequency range 1 are assigned to first cell nodes, while resources in frequency range 2 are assigned to second cell nodes. This segmentation ensures that even when downlink cell borders are optimized for coverage, uplink resources are properly distributed to prevent interference at cell boundaries.
Data Source
AI summary
Methods and nodes in a cellular communication system for supporting Random Access. A method in a first network node involves determining at least one uplink radio resource amongst a plurality of radio resources, and refraining from scheduling uplink communication in the at least one uplink radio resource, thus enabling a UE in an area with an uplink/downlink imbalance to perform Random Access to a neighbor second network node (B).