Uplink Scheduling with Layer 1 State Feedback for VoIP
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Solution Overview
Problem
Semi-persistent scheduling in VoIP for 3GPP Long Term Evolution systems faces inefficiencies in handling silent periods, leading to significant uplink capacity loss due to the inability to reallocate resources during inactive states without explicit signaling, resulting in increased overhead and potential voice quality degradation.
Innovation Solution
Implementing layer 1 state feedback mechanisms to autonomously detect and signal state transitions from active to inactive states, allowing for resource re-allocation during inactive periods, thereby reducing unnecessary resource holding and improving capacity utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If semi-persistent scheduling is used for VoIP, then resource allocation is simplified and overhead is reduced, but uplink capacity is lost during silent periods due to inability to reallocate resources
Solution Approach 1:
The system enables self-service by allowing the network to automatically detect silence periods and trigger resource release without requiring explicit signaling from the wireless terminal. The network autonomously monitors the semi-persistent resource usage and initiates reallocation when silence is detected, eliminating the need for complex terminal-side resource management while improving capacity utilization.
Solution Approach 2:
The invention implements feedback mechanisms where the network monitors resource usage patterns and terminal activity states to dynamically adjust resource allocation. By observing whether the terminal is actively using the semi-persistent resource or in a silent state, the network receives feedback that triggers appropriate actions (maintain or release resource), thereby optimizing capacity utilization without increasing terminal complexity.
2Productivity
If resource-release signalling is sent through RACH during silence state, then resources are freed for other terminals, but overhead increases and access delays occur due to contention-based access
Solution Approach 1:
The invention extracts the resource release signaling function from the contention-based RACH mechanism and relocates it to a dedicated, non-contention-based signaling path. By separating this specific function from the general-purpose RACH access mechanism, the system eliminates access delays and contention issues while maintaining the ability to free resources efficiently during silence periods.
Solution Approach 2:
The network acts as an intermediary that mediates the resource release process by autonomously detecting silence states and initiating resource release without requiring terminal-side RACH signaling. This intermediary role eliminates the need for contention-based access while ensuring resources are promptly released, thereby improving both efficiency and reducing delays.
3Productivity
If explicit resource request is sent through RACH for talk-spurt reestablishment, then resources are allocated for transmission, but overhead increases and voice quality degrades due to access delays
Solution Approach 1:
The system performs preliminary action by pre-configuring semi-persistent resources for VoIP terminals before actual voice transmission begins. When a talk-spurt occurs, the terminal can immediately use the pre-allocated resource without needing to send resource requests, thereby eliminating access delays and ensuring timely voice transmission while reducing signaling overhead.
Solution Approach 2:
The invention implements dynamic resource allocation where semi-persistent resources are automatically activated and deactivated based on real-time voice activity detection. The system dynamically transitions between resource allocation states (allocated vs. released) without requiring explicit requests, thereby maintaining fast response to voice traffic while optimizing resource utilization during silence periods.
Data Source
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AI summary
System and methods for signalling transitions between talk-spurt state (24, 30, 50, 74, 80, 100) and silence state (52, 102) for wireless terminals 10-1 having semi-persistently allocated uplink resources are employed. A layer 1/2 indication 40, 56, 90, 106 of the state transitions may be transmitted using a resource that is specifically allocated for that purpose. Alternatively, ACK/NACK signalling 126 may be employed. Layer 1 indications may be employed for both state transition types. Alternatively, in-band MAC layer signalling 84, 86, 104 may be used to signal state transition from talk-spurt state to silence, or the network may deduce this state transition on its own. A different uplink wireless transition resource is allocated for the talk-spurt state vs. the silence state.