Random Access Preamble Prioritization for Handover Reliability
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Solution Overview
Problem
In wireless communication networks, devices in handover situations experience less favorable radio conditions, leading to increased drop rates and user dissatisfaction due to delayed random access responses in contention-based random access procedures, as existing methods do not differentiate or prioritize devices effectively.
Innovation Solution
The method involves broadcasting threshold values for wireless devices to select either a first or second preamble group, with dedicated signaling overriding broadcast values to prioritize devices in handover situations, allowing for differentiation and prioritization of preambles, thereby reducing handover drop rates and enhancing user satisfaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random access responses are scheduled based on received preamble power, then devices with stronger signals are served first, but devices in handover situations with less favorable radio conditions experience delayed service and connection drops
Solution Approach 1:
The patent changes the parameter used for prioritizing random access responses from received signal power to handover status indication. By detecting whether a preamble belongs to a handover device (through specific indication bits or reserved preamble indices), the system prioritizes handover devices regardless of their signal strength, thus resolving the contradiction between reliability and delay.
Solution Approach 2:
The patent segments the random access preamble space into different groups: handover preambles (with specific indications) and non-handover preambles. This segmentation allows the system to treat handover devices differently and prioritize them separately, ensuring that handover connections are maintained without being delayed by devices with stronger signals.
2Ease of operation
If all wireless devices use common preamble sequences, then the system is simple to operate, but contention resolution becomes complex and time-consuming
Solution Approach 1:
The patent segments the preamble sequences into dedicated handover preambles and common preambles. Handover devices use dedicated preambles that include specific indications, allowing the network to immediately identify and prioritize handover devices without complex contention resolution, thus reducing time loss while maintaining operational simplicity.
Solution Approach 2:
The patent introduces an intermediary indication mechanism within the preamble structure itself (using reserved indices or specific bit patterns) that allows handover devices to signal their status before actual data transmission. This intermediary signal enables the network to pre-prepare for handover prioritization, reducing subsequent contention resolution time.
Data Source
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AI summary
The present teachings relates to methods 10 performed in a network node 2 of a wireless communication network 1. The method 10 comprises: broadcasting 11 one or more threshold values enabling the wireless devices 4, 5 to determine fulfillment of one or more criteria f1, f2 for selecting a contention based random access preamble either from a first preamble group or from a second preamble group for use in a contention based random access procedure; transmitting 12 to a selected wireless device 4, 5 one or more threshold values using dedicated signaling, the one or more threshold values sent in the dedicated signaling overriding a corresponding broadcasted threshold value and being set so that the wireless device 4, 5 fulfills the criteria to select a preamble from the first preamble group, wherein the threshold values sent on the dedicated signaling differ from the broadcast threshold values; and prioritizing 13 preambles of the first preamble group over preambles of the second preamble group.