VoIP Call Admission Control via Packet Delay Metrics
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Solution Overview
Problem
Existing wireless network scheduling algorithms fail to adequately address the voice quality and delay-sensitive needs of VoIP users, leading to increased packet delay and decreased perceived voice quality as the network load increases, without an effective mechanism to regulate access and maintain quality of service (QoS).
Innovation Solution
A call admission and call control method that determines packet delay metrics by generating time stamps for data packets and acknowledgments, filters these metrics to produce average sector delay metrics, and uses these metrics to block access or force-drop users when thresholds are exceeded, thereby managing network resources and maintaining QoS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of users is increased to improve network utilization, then productivity is improved, but packet delay increases and voice quality deteriorates
Solution Approach 1:
The system performs preliminary actions by measuring packet delay before admitting new calls. The network element continuously monitors delay metrics and uses these measurements to predict whether admitting additional users would cause unacceptable delay increases, thereby preventing quality degradation before it occurs.
Solution Approach 2:
The system implements feedback by continuously measuring packet delay, comparing it against thresholds, and using this information to dynamically control call admission decisions. This closed-loop feedback mechanism ensures that network utilization is optimized while maintaining acceptable voice quality levels.
2Reliability
If call admission control is implemented to maintain voice quality, then voice quality is improved, but network access is restricted
Solution Approach 1:
The system changes parameters by establishing delay thresholds that differentiate between acceptable and unacceptable delay conditions. By monitoring whether measured delay exceeds these parameters, the system makes objective admission control decisions that maintain voice quality while allowing access when conditions permit.
3Reliability
If existing scheduling algorithms are used to optimize for voice traffic, then voice traffic handling is improved, but delay sensitivity requirements are not adequately met
Solution Approach 1:
The system performs preliminary delay measurements and assessments before admitting voice calls. By evaluating current network delay conditions in advance, the system ensures that voice traffic is only admitted when delay requirements can be met, rather than relying solely on scheduling algorithms to handle delay issues after admission.
Data Source
AI summary
A method and apparatus for providing wireless data packet call regulation and call access for wireless Voice over Internet Protocol (VoIP) communications in a wireless network. A first and second time stamp is generated upon the reception and successful transmission of a data packet. A packet delay is determined based upon the first and second time stamps. At least one average delay metric is used to determine whether to provide new call access based on the at least one average delay metric. Another aspect of the present invention is to block a class of users based, in part, on the average sector delay for each user subscriber class. If the average sector delay is greater than that allowed for a class of users, users of that class are denied access. A delay quality of service (QoS) block metric is used to determine if an individual user should be force dropped.