Multi-Stage Signaling for Emergency Network Access
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Solution Overview
Problem
Emergency and public safety-related calls in wireless communication systems, such as those based on IEEE 802.16 or WiMAX, often experience delays due to the network's inability to identify these calls promptly during the ranging process, leading to inefficient resource allocation and potential congestion.
Innovation Solution
Implementing a multi-stage signaling approach where a shared indicator code is used to quickly notify the network of emergency access, allowing for immediate resource provisioning and prioritization, and using a shared spreading channel code followed by a different code for establishing a private link, enabling faster communication without waiting for authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If ranging codes are partitioned into emergency and non-emergency groups to enable early identification of emergency calls, then emergency call identification speed is improved, but system performance deteriorates when signaling floods the system due to insufficient codes in the emergency group
Solution Approach 1:
The patent segments the ranging code usage into two distinct phases: a contention phase using partitioned emergency and non-emergency code groups for rapid emergency identification, and a non-contention phase using a separate indicator code for continued emergency signaling. This segmentation allows the system to handle emergency calls efficiently without overwhelming the emergency code group, thereby resolving the contradiction between fast emergency identification and system performance under signaling flood conditions.
2Reliability
If the network waits for authentication to complete before provisioning resources, then security is maintained, but emergency call latency increases
Solution Approach 1:
The patent implements preliminary action by allowing the network to provision resources and begin emergency call handling based on early detection of emergency indicator codes during the ranging process, before authentication is complete. The system performs resource allocation in advance based on the indicator code detection, then completes authentication subsequently, thereby maintaining security while reducing emergency call latency.
3Device complexity
If a single code is used for all access types, then code management is simplified, but emergency calls cannot be identified promptly during the ranging process
Solution Approach 1:
The patent applies local quality by assigning different code characteristics to different access phases: partitioned emergency and non-emergency code groups are used specifically during the contention phase for rapid emergency detection, while a separate indicator code is used in the non-contention phase. This localized differentiation of code properties enables prompt emergency identification without requiring complex code management across the entire system.
Data Source
AI summary
Various embodiments are described for improving network access through multi-stage signaling. Logic flow diagram 10 in FIG. 1 depicts functionality performed by a wireless communication system in accordance with multiple embodiments of the present invention. A network node configures (12) a shared indicator code for indicating an emergency and/or a group call access occurring in that sector. Thus, when an MS performs an emergency access, it transmits (13) an access signal on both the shared indicator code and on a randomly selected code. This more quickly notifies the network that there is at least one MS in the sector. Once aware that such an access is occurring in that sector, the network may (14) provision additional access resources, estimate the number of MSs transmitting based on the received power on that indicator code, start backing off non-emergency traffic, and/or begin transmitting communication without waiting for authentication to complete.