Wireless Channel Separation for Collision Reduction
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Solution Overview
Problem
The IEEE 802.11 CSMA/CA protocol leads to frequent collisions and low channel utilization in wireless communications, especially as the number of stations and access points increases, due to heavy dependence on a primary 20 MHz channel.
Innovation Solution
A method and apparatus that separate control and data transmission on different channels, using a common control channel for control information and data channels for data transmission, with transmission allocation frames indicating specific data channels and time periods, allowing for efficient allocation and utilization of channels beyond the primary 20 MHz band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If CSMA/CA protocol is used for distributed channel access, then channel access is simple and decentralized, but collisions occur frequently leading to severe performance degradation
Solution Approach 1:
The patent segments the channel access mechanism into two distinct modes: distributed mode (CSMA/CA for simple access) and centralized mode (scheduler-based for collision-free access). The access point can switch between these modes based on network conditions, allowing the system to leverage the simplicity of distributed access when needed while avoiding collisions through centralized scheduling when necessary.
Solution Approach 2:
The patent introduces a scheduler as an intermediary component between stations and the channel. The scheduler receives transmission requests from stations and mediates channel access by assigning time slots and selecting optimal channels, thereby eliminating collisions while maintaining the benefits of distributed operation through centralized coordination.
2Device complexity
If primary channel is used for management, control and data frame transmission, then control functions are simple, but secondary channels cannot be used even when idle leading to low channel utilization
Solution Approach 1:
The patent segments channel functions by separating management/control frames from data frames. Management and control frames continue to use the primary channel for simplicity, while data frames are transmitted on data channels (including secondary channels) as indicated by transmission allocation frames. This segmentation enables parallel utilization of multiple channels for different purposes.
Solution Approach 2:
The patent adds a dimensional separation between control channel and data channel operations. By introducing transmission allocation frames that carry channel indication information, the system creates an additional layer of control that enables data transmission on multiple channels simultaneously without interfering with primary channel control functions.
3Reliability
If 20 MHz primary channel is occupied for control transmission, then control signals are reliably transmitted, but heavy dependence on primary channel occurs in large-band transmission scenarios
Solution Approach 1:
The patent introduces transmission allocation frames as intermediaries that carry channel indication information. These frames act as mediators between the primary channel control functions and the data channel transmission, allowing the system to maintain reliable control signaling on the primary channel while flexibly utilizing multiple data channels for actual data transmission.
Solution Approach 2:
The patent implements dynamic channel selection for data transmission. Instead of being fixed to the primary channel, the system dynamically selects from multiple available data channels based on transmission requirements, channel conditions, and allocation decisions made by the access point, thereby enhancing adaptability while maintaining control reliability.
Data Source
AI summary
Embodiments of this application provide a wireless communications method and apparatus. The wireless communications method in this application includes: A first access point sends, over a common control channel, a first transmission allocation frame to a station, where the first transmission allocation frame is used to indicate the station to communicate with the first access point in a first time period over a first data channel; and the station communicates with the first access point in the first time period over the first data channel.