MU-MIMO Frame Transmission Alignment via Slot-Based Timing
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Solution Overview
Problem
In wireless local area networks (WLAN) supporting multi-user multiple input multiple output (MU-MIMO), maintaining synchronization between frames transmitted to multiple stations is challenging, leading to inefficiencies in radio resource usage and increased complexity, which limits throughput and increases implementation costs.
Innovation Solution
The method involves aligning the transmission start times of frames to each other and adjusting frame lengths by padding null data, using a slotted reduced inter-frame space (RIFS) set to a multiple of the orthogonal frequency division multiplex (OFDM) symbol duration, and employing an aggregate MAC protocol data unit (A-MPDU) format with null bits to indicate null data, ensuring synchronized multiple frame transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frames are transmitted to multiple STAs simultaneously in MU-MIMO system, then throughput is improved, but synchronization between frames is lost and complexity increases
Solution Approach 1:
The patent applies periodic action by using slot-based transmission timing where frames are transmitted at regular intervals defined by slot boundaries. The slot structure creates periodic transmission opportunities that maintain synchronization across multiple STAs while enabling simultaneous transmissions, thus resolving the contradiction between improved throughput and synchronization complexity.
Solution Approach 2:
The patent changes the timing parameter by introducing slot-based alignment where frame transmission start times are adjusted to specific slot boundaries. This parameter change enables synchronized transmissions across multiple STAs, maintaining system coordination while supporting MU-MIMO throughput improvements.
2Stability of the object's composition
If frame lengths are adjusted by padding null data, then synchronization is maintained, but overhead increases
Solution Approach 1:
The patent applies partial action by selectively padding only those frames that require length adjustment to match slot boundaries, rather than padding all frames uniformly. This approach maintains synchronization where needed while minimizing unnecessary overhead, resolving the contradiction between synchronization stability and overhead reduction.
3Productivity
If multiple frames are transmitted consecutively to each STA, then data rate is improved, but radio resource utilization efficiency decreases
Solution Approach 1:
The patent applies continuity of useful action by ensuring that multiple frames transmitted to different STAs are time-aligned to the same slot boundaries. This continuous, synchronized transmission approach maximizes radio resource utilization efficiency while maintaining high data rates, as resources are used efficiently without gaps or misalignment between transmissions.
Data Source
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AI summary
A method of transmitting multiple frames in a wireless local area network (WLAN) system supporting multi user-multiple input multiple output (MU-MIMO) is provided. The method comprises transmitting a first frame and a second frame consecutively to a first station (STA) and transmitting a third frame and a fourth frame consecutively to a second STA, wherein a transmission start time of the first frame and a transmission start time of the third frame are aligned to each other, and wherein a transmission start time of the second frame and a transmission start time of the fourth frame are aligned to each other.