Emergency Call Prioritization via Reduced Backoff Parameters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In contention-based random access procedures, emergency calls face significant latency due to increased collision risks when multiple devices compete for network resources, leading to prolonged delays in establishing connections.
Innovation Solution
Emergency calls are prioritized by reducing the backoff time between access attempts and increasing the maximum number of preamble transmissions, with the backoff parameter value initially set to a lower value for emergency calls, which gradually increases based on failed attempts until it reaches the regular value, thereby reducing latency and improving emergency call establishment time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If emergency calls use standard contention-based random access procedures with regular backoff parameters, then network resource allocation follows uniform distribution principles, but access latency becomes excessively long due to collision risks when multiple devices compete for resources
Solution Approach 1:
The patent changes the backoff parameter values dynamically based on call type. For emergency calls, it sets the backoff parameter to a minimum value (e.g., 0 or a small predefined value), whereas non-emergency calls use standard uniform distribution backoff parameters. This parameter change reduces the waiting time before retransmission attempts for emergency calls, directly addressing the access latency issue while maintaining acceptable collision risk levels through increased transmission attempts.
Solution Approach 2:
The patent implements dynamic adjustment of backoff parameters and maximum preamble transmission limits based on the nature of the call. Emergency calls are assigned differentiated parameters (lower backoff values, higher maximum transmissions) compared to regular calls. This dynamic differentiation allows the system to adapt resource access behavior to urgency levels, resolving the contradiction between fast access and collision avoidance for critical communications.
2Speed
If the backoff parameter value is reduced for emergency calls to decrease latency, then access speed improves, but collision probability increases when multiple devices attempt access simultaneously
Solution Approach 1:
The system dynamically adjusts the backoff parameter based on call type classification. For emergency calls, it sets the backoff parameter to a minimum value to maximize access speed, accepting higher collision probability as a necessary trade-off. For non-emergency calls, standard backoff parameters are used to maintain lower collision rates. This dynamic approach resolves the contradiction by allowing high-speed access when critically needed while maintaining stability during normal operations.
Solution Approach 2:
The patent changes key parameters (backoff value and maximum preamble transmissions) based on emergency call detection. By setting backoff to minimum values and increasing maximum transmission attempts for emergency calls, the system prioritizes access speed over collision avoidance when necessary, while regular calls maintain balanced parameters. This parameter adaptation resolves the speed-collision trade-off contextually.
3Reliability
If multiple access attempts are made with standard backoff timing, then collision risk is distributed uniformly, but emergency call establishment time becomes unacceptably long
Solution Approach 1:
The patent implements differentiated parameter sets for emergency versus non-emergency calls. For emergency calls, it sets backoff parameters to minimum values and increases maximum preamble transmission limits, creating a non-uniform access pattern that prioritizes speed. This parameter change allows emergency calls to make multiple rapid attempts rather than waiting through standard backoff intervals, directly reducing call establishment time while maintaining reasonable collision distribution through the increased number of attempts.
Solution Approach 2:
The system dynamically modifies access behavior based on call type detection. When an emergency call is identified, the system switches to an aggressive access mode with reduced backoff timing and increased transmission attempts. This dynamic adaptation resolves the contradiction by allowing emergency calls to break from uniform distribution patterns and establish connections rapidly, while non-emergency calls continue to follow uniform distribution for stable network operation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A mobile device implemented method includes receiving a request at the mobile device from a user to make an emergency call over a network, attempting to place the emergency call via the mobile device, detecting a failure of random access attempt procedure for the emergency call by the mobile device, using a reduced back off parameter value as compared to a back off parameter value for a non-emergency call, and re-attempting the random access procedure for the emergency call via the mobile device as a function of the reduced back off parameter value.