VoIP Downlink Packet Scheduling with Delay Threshold Drop
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Solution Overview
Problem
Conventional mobile communication Base Station systems face inefficiencies in wireless VoIP service due to high radio channel costs and low throughput, leading to frequent instantaneous bottlenecks and delayed packet transmission, which affects Quality of Service (QoS) and results in packet loss.
Innovation Solution
A downlink packet scheduling method that calculates transmission delay time by determining network and queuing delays, and decides whether to drop packets based on a predefined threshold to ensure timely delivery, using a packet drop module within the BS system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional BS system carries all received VoIP packets to ensure complete transmission, then packet loss is minimized, but transmission delay increases and QoS deteriorates due to buffer overflow and instantaneous bottlenecks
Solution Approach 1:
The patent applies partial action by selectively transmitting only those packets that meet the delay threshold requirement, rather than transmitting all packets. The packet drop module determines whether to transmit each packet based on calculated transmission delay, allowing the system to sacrifice some packets (controlled loss) to maintain timing requirements for the packets that are transmitted, thereby resolving the contradiction between complete delivery and timely delivery
Solution Approach 2:
The conventional approach inverts the normal logic by attempting to transmit all packets regardless of delay. This patent inverts the approach by deliberately dropping packets that exceed the delay threshold, making delay compliance the primary criterion rather than complete packet delivery. This inversion resolves the contradiction by prioritizing QoS timing requirements over absolute packet delivery
2Productivity
If statistical multiplex scheme is used to request oversubscription above link capacity, then radio resource utilization improves, but instantaneous bottlenecks occur frequently within the BS
Solution Approach 1:
The patent implements feedback through the packet drop module that continuously monitors transmission delay and compares it against a threshold. This feedback mechanism allows the system to dynamically adjust packet transmission decisions based on current delay conditions, preventing buffer overflow and bottlenecks while maintaining high radio resource utilization through statistical multiplexing
Solution Approach 2:
The system performs preliminary calculation of transmission delay for each packet before transmission decisions are made. By calculating delay upfront and comparing against the threshold before committing to transmission, the system prevents bottlenecks from occurring rather than reacting to them, maintaining both high utilization and system stability
3Reliability
If packets are buffered to system buffer when transmission is delayed, then packet loss is avoided, but buffer capacity is exceeded and subsequent packets are dropped
Solution Approach 1:
Rather than buffering all delayed packets (excessive action), the system applies partial action by selectively dropping packets that would exceed acceptable delay thresholds. This prevents buffer overflow while maintaining delivery completeness for packets within acceptable delay ranges, resolving the contradiction between avoiding packet loss and managing buffer capacity
Data Source
AI summary
A VoIP downlink packet scheduling apparatus and method in a mobile communication Base Station (BS) system are provided. The downlink packet scheduling apparatus includes a packet queue for storing a downlink packet when the downlink packet is received; a downlink scheduler for selecting a packet stored to the packet queue under a certain condition and scheduling a corresponding packet according to whether a packet drop module determines to drop the selected packet; and the packet drop module calculates a transmission delay time of the packet, determines whether the transmission delay time of the packet meets a threshold, and determines whether to drop or transmit the corresponding packet according to whether the threshold is satisfied.