Distributed WLAN AP Response Framing for SIFS Timing
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Solution Overview
Problem
In wireless local area networks (WLANs), the complexity of data transmission algorithms and the use of a distributed architecture with remotely separated baseband and radio frequency units can result in delays, preventing the access point (AP) from replying with a response frame within the required short interframe space (SIFS) after receiving a medium access control (MAC) protocol data unit (MPDU).
Innovation Solution
A method where a radio frequency processing device and a baseband processing device, remotely separated by a wired medium, communicate using broadband signals to enable immediate generation of a response frame field by the radio frequency processing device, reducing the need for complex processing by the baseband device, thus allowing the AP to reply within one SIFS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the baseband processing device generates and transmits the response frame using the wired medium, then the response frame can be sent accurately, but the processing delay increases and the SIFS requirement cannot be met
Solution Approach 1:
The patent divides the response frame into two parts: the target field (which requires immediate transmission) and the remaining fields (which can be processed later by the baseband device). The radio frequency processing device transmits the target field immediately upon receiving the target signal, while the baseband processing device transmits the remaining fields through the wired medium. This segmentation allows the time-critical portion to be sent without delay while the non-critical portion undergoes normal processing.
Solution Approach 2:
The patent extracts the target field from the complete response frame and handles it separately through the air interface. By taking out this critical component and transmitting it immediately via the radio frequency processing device, the system eliminates the wired medium transmission delay for the most time-sensitive part of the response frame, thereby meeting the SIFS requirement.
2Reliability
If the baseband processing device processes the response frame, then the processing is accurate and complete, but the complexity and time consumption increase
Solution Approach 1:
The patent segments the response frame processing into two parts: the target field is processed and transmitted immediately by the radio frequency processing device, while the remaining fields are processed by the baseband processing device through the wired medium. This division reduces the processing burden on the baseband device and allows the time-critical target field to be handled without complex baseband processing delays.
3Adaptability or versatility
If the AP uses a distributed architecture with remotely separated baseband and radio frequency units, then the system is more flexible and scalable, but additional remote transmission delay is introduced
Solution Approach 1:
The patent segments the response transmission path into two parallel channels: a direct air interface path for the target field and a wired medium path for the remaining fields. This segmentation allows the time-critical target field to bypass the remote wired transmission and be sent immediately through the air interface, eliminating the remote transmission delay for the most urgent data while maintaining the benefits of distributed architecture.
Solution Approach 2:
The radio frequency processing device acts as an intermediary that receives the target signal from the baseband processing device and immediately transmits the target field through the air interface without waiting for wired medium transmission. This intermediary function bridges the gap between the distributed baseband unit and the air interface, enabling immediate response transmission despite the physical separation.
Data Source
AI summary
A method for replying with a response frame, an apparatus, and an AP system. A radio frequency processing device receives a PPDU sent by an STA. The radio frequency processing device sends, to a baseband processing device by using a wired medium, a frame obtained based on the PPDU. The radio frequency processing device and the baseband processing device are remotely separated. In response to a target signal that is received by using the wired medium and that is from the baseband processing device, the radio frequency processing device generates a target field, and sends the target field to an air interface. The target field at least includes a first field of a response frame of the PPDU. The target signal is used to instruct the radio frequency processing device to immediately respond to the PPDU.