IEEE 802.11 Time-Based Admission Control for QoS Bandwidth Allocation
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Solution Overview
Problem
Current IEEE 802.11 networks lack effective admission control mechanisms for quality of service (QoS) that can accurately allocate and monitor bandwidth, especially in wireless environments with high packet error rates, and are inadequate for power-saving devices and time-based polling techniques.
Innovation Solution
A time-based admission control method that converts data rate and burst size into equivalent time measurements, allowing for periodic stream admission control by calculating the time equivalent to requested bandwidth, monitoring channel conditions, and modifying bandwidth allocations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If token bucket mechanism is used for bandwidth management, then bandwidth allocation is simplified, but it cannot accurately account for packet error rates and channel conditions in wireless networks
Solution Approach 1:
The patent changes the fundamental parameter from bytes per second (token bucket) to time-based measurements (TXOP duration). This allows the system to directly account for packet error rates and channel conditions by measuring actual transmission time rather than assuming ideal byte-based bandwidth, thereby improving reliability while maintaining manageable complexity through time-centric accounting.
2Reliability
If over-reservation of bandwidth is implemented to account for channel errors, then transmission reliability is improved, but network efficiency and available bandwidth are reduced
Solution Approach 1:
The patent implements feedback mechanisms where the access point monitors actual packet transmission success and uses this information to adjust TXOP allocations. This allows the system to account for channel errors dynamically rather than using fixed over-reservation, improving reliability through adaptive feedback while maintaining network efficiency by allocating bandwidth based on actual channel conditions rather than pessimistic assumptions.
3Device complexity
If time-based polling techniques are used for bandwidth allocation, then admission control is simplified, but they fail to consider hybrid coordinator negotiation and power saving device requirements
Solution Approach 1:
The patent makes the time-based polling mechanism universal by integrating it with hybrid coordinator negotiation protocols and power saving device requirements. The same TXOP allocation framework serves multiple device types and operational modes, allowing the access point to negotiate time allocations that work for both power-saving and always-on devices while maintaining simplified admission control through consistent time-based accounting.
4Ease of operation
If TSPEC is used for bandwidth specification, then QoS requirements are defined, but it provides no means for objectively verifying bandwidth allocation or specifying upper bound on channel occupancy
Solution Approach 1:
The patent introduces TXOP (transmission opportunity) duration as an intermediary measurement that bridges QoS specifications and actual bandwidth allocation. Instead of directly verifying complex bandwidth parameters, the system uses time-based TXOP duration as a measurable intermediary that objectively verifies allocation compliance and provides a concrete upper bound on channel occupancy, making both specification and verification more precise and operationally simple.
Data Source
AI summary
A system and method are provided for periodic stream admission control in an IEEE 802.11 network. The method comprises: at an access point (AP), receiving a transmit specification, including a requested bandwidth, from a quality of service station (QSTA); computing Ttemp, the time equivalent to the requested bandwidth; computing Tall, the time already allocated; and, computing Tres, the total time available. IfTtemp+Tall<Tres, then the QSTA is admitted. If Ttemp+Tall>Tres, the QSTA is not admitted. Some aspects of the method further comprise: monitoring the bandwidth of the admitted QSTA. In another aspect, the method: determines the bandwidth required by the admitted QSTA; and, modifies the bandwidth of the admitted QSTA in response to the determined QSTA requirements. In one aspect, the method: monitors channel conditions; and, modifies the bandwidth of the admitted QSTA in response to the channel conditions.