Green Phase WLAN Transmission Mode for OFDMA Compatibility
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Solution Overview
Problem
The existing WLAN protocol lacks a perfect formal specification for integrating orthogonal frequency division multiple access (OFDMA) and uplink multiple user multiple-input multiple-output (MU-MIMO) technologies, leading to compatibility issues between next generation and existing WLAN systems, which restricts the improvement of network performance.
Innovation Solution
The method involves transmitting Clear To Send frames to enable stations to set network allocation vectors (NAV) and enter a 'Green Phase' for efficient communication, allowing the access point to communicate with multiple stations within a Green Phase period, ensuring backward compatibility and enabling the introduction of new technologies like OFDMA and MU-MIMO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CTS-to-self or RTS/CTS mechanism is used to ensure backward compatibility, then compatibility between existing and next generation WLAN systems is maintained, but only one station can access and transmit data at a time, preventing use of OFDMA and UL MU-MIMO technologies
Solution Approach 1:
The patent implements dynamic transmission mode switching between traditional single-user and Green Phase multi-user modes. The AP can dynamically select which stations to communicate with during Green Phase based on channel conditions and traffic requirements, enabling flexible use of OFDMA and UL MU-MIMO while maintaining backward compatibility with legacy stations that continue to use traditional CTS-to-self mechanism.
2Adaptability or versatility
If traditional CTS-to-self mechanism is used, then legacy stations can identify and respond to control frames, but two additional control frames need to be exchanged before each data transmission, reducing transmission efficiency
Solution Approach 1:
The patent extracts the compatibility assurance function from the traditional RTS/CTS handshake sequence and implements it selectively only for legacy stations. During Green Phase, the AP sends CTS frames only to stations that need to maintain backward compatibility, while new stations can directly transmit data without the additional handshake overhead, thereby reducing time loss for transmissions that don't require legacy compatibility.
3Productivity
If OFDMA and UL MU-MIMO technologies are introduced in next generation WLAN protocol, then network performance can be improved, but compatibility with existing WLAN system becomes problematic
Solution Approach 1:
The patent introduces Green Phase as an intermediary time period that mediates between legacy and next generation WLAN operations. During Green Phase, the AP can utilize OFDMA and UL MU-MIMO technologies to communicate with multiple new-generation stations simultaneously, while legacy stations continue to operate using traditional mechanisms. The Green Phase acts as a buffer that allows coexistence of both technologies without conflict.
Data Source
AI summary
Embodiments of the present invention provide a method and an apparatus for establishing a transmission mode, which relates to the field of network technologies, ensure backward compatibilities of an existing WLAN system and a next generation WLAN system, realize introduction of a new technology in the next generation WLAN protocol during data transmission, and improve network performance. The method includes: transmitting, by an access point AP, a first Clear To Send frame to a first station STA, to enable the first STA to set duration of a network allocation vector NAV of the first STA and remain in a silent state when the AP communicates with a second STA; transmitting the first Clear To Send frame to the second STA, to enable the second STA to process a Green Phase operation; and communicating with the second STA in a Green Phase period. The present invention is applied in data transmission.