Prioritized Access Backoff Control in Wireless Systems
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Solution Overview
Problem
In wireless communication systems, particularly in LTE, the existing backoff mechanisms can lead to blocking of important access trials due to congestion, as they apply backoff parameters uniformly across all access types, including prioritized accesses, which may result in delayed or failed connections for emergency or high-priority communications.
Innovation Solution
A method where user equipment (UE) identifies prioritized accesses and determines whether to apply or ignore received backoff parameters based on specific access types, such as emergency or high-priority access, voice/video services, and VoLTE, allowing for customized backoff strategies to prevent blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backoff parameters are applied uniformly to all access types, then system congestion is reduced, but prioritized access (emergency/high-priority) is blocked or delayed
Solution Approach 1:
The patent applies different backoff behaviors to different access types. Prioritized access (emergency, high-priority) ignores backoff parameters and transmits immediately, while non-prioritized access applies standard backoff. This local differentiation ensures reliable access for critical traffic without completely sacrificing system throughput.
Solution Approach 2:
The patent segments the random access procedure into two distinct paths: one for prioritized access that bypasses backoff, and another for non-prioritized access that follows standard backoff. This segmentation is implemented through access type identification and selective backoff application, resolving the contradiction between reliability and productivity.
2Reliability
If backoff is applied to all random access attempts, then collision probability is reduced, but access delay increases for emergency calls
Solution Approach 1:
The patent implements local quality by applying different time characteristics to different access types. Emergency and high-priority access attempts have zero or reduced delay (ignoring backoff), while other access types experience standard backoff delays. This ensures emergency calls connect quickly without significantly impacting overall system performance.
3Device complexity
If uniform backoff is used for all UEs, then backoff mechanism is simple to implement, but prioritized access cannot guarantee timely connection
Solution Approach 1:
The patent maintains relative simplicity by using a flag-based identification system (e.g., establishment cause indicators) to distinguish prioritized from non-prioritized access. The UE simply checks the flag and applies different backoff behavior accordingly, avoiding complex decision algorithms while still guaranteeing timely connection for emergency calls.
Data Source
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AI summary
A method and apparatus for performing backoff in a wireless communication system is provided. A user equipment (UE) identifies a prioritized access, receives a backoff parameter from a network, and determines whether or not to apply the received backoff parameter according to the prioritized access. The prioritized access corresponds to one of emergency access, high priority access, control element/information in media access control (MAC), radio link control (RLC) or packet data convergence protocol (PDCP), data radio bearer (DRB) for voice/video service, signaling radio bearer (SRB) 0, SRB 1, SRB 2, multimedia telephony service (MMTEL)-voice, MMTEL-video, and voice over long-term evolution (VoLTE).