Wireless Device Request Timing During Cell Outage
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Solution Overview
Problem
Current wireless communication systems face challenges in managing simultaneous requests for location updates and call reestablishments when a cell outage occurs, leading to network congestion and potential call rejections, especially in scenarios with a large number of devices.
Innovation Solution
Implementing a method where wireless devices determine a random time delay for transmitting requests to a target cell based on the cause of the radio connection loss, using information about cell outages and network conditions to reduce the burden on neighboring cells during cell outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If all wireless devices transmit requests simultaneously to target cells after a cell outage, then the location update and call reestablishment procedures can be completed quickly, but network congestion and call rejections increase significantly
Solution Approach 1:
The patent implements a mechanism where wireless devices apply periodic backoff intervals before transmitting location update or call reestablishment requests to target cells. The network broadcasts outage information that triggers devices to wait for a predetermined number of radio frames (e.g., 10 frames) before initiating requests. This periodic delay spreads out the request transmissions over time, preventing simultaneous bursts that cause network congestion while still allowing all devices to eventually complete their procedures.
2Reliability
If wireless devices apply random time delay before transmitting requests, then the number of simultaneous requests to target cells is reduced, but the total time for completing location updates and call reestablishments increases
Solution Approach 1:
The patent employs dynamic adjustment of backoff parameters based on network conditions. The network can broadcast different outage durations or backoff interval lengths depending on the severity and expected duration of the cell outage. Devices dynamically adapt their waiting periods based on the broadcast information, allowing the system to optimize between quick recovery (shorter delays) and congestion avoidance (longer delays) based on real-time network state.
Solution Approach 2:
The patent changes the temporal parameter of request transmission by introducing configurable backoff intervals measured in radio frames. Instead of immediate transmission, devices modify their transmission timing parameter based on the broadcast outage information. The network can adjust parameters such as the number of frames to wait (e.g., 10 frames) or the length of the backoff period, thereby controlling the rate at which devices resume normal operations and reducing the surge of simultaneous requests.
Data Source
AI summary
A method for operating a wireless device during a radio connection loss. The method includes establishing that the cause of the radio connection loss corresponds to an outage of a radio cell hosting the wireless device and determining, based at least on the established cause, a policy of applying a random time delay when transmitting a request to a radio network node in a target radio cell. A method for operating a radio network node in a first radio cell is also provided. The method includes obtaining information specifying that an outage of a second radio cell has occurred and broadcasting the obtained information together with information identifying the second radio cell to enable wireless devices hosted by the second radio cell to select a policy for transmitting a request to a radio network node in said first radio cell based on the broadcasted information.