Wireless Broadcast Collision Avoidance via Time Reservation
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Solution Overview
Problem
Current wireless communication technologies, such as IEEE 802.11, fail to effectively prevent frame collisions during broadcast and multicast transmissions in wireless networks, leading to reduced Quality of Service due to overlapping BSSs and intra-BSS collisions.
Innovation Solution
A protocol is introduced where an Access Point (AP) reserves broadcast transmission time and conveys this reservation to its associated stations and neighboring APs, using beacon or action frames, to prevent frame collisions by setting network allocation vectors to restrict transmissions during reserved times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DCF/EDCA or PCF/HCCA methods are used for controlling AP transmissions, then transmission rights are distributed among STAs, but frame collisions still occur during broadcast and multicast transmissions
Solution Approach 1:
The patent applies preliminary action by having the AP reserve a specific time period for broadcast/multicast transmissions before actual transmissions occur. This reservation is communicated to all STAs via beacon or action frames, allowing STAs to set their network allocation vectors to prevent transmissions during the reserved time, thereby avoiding collisions before they can happen.
2Productivity
If AP broadcasts frames to all associated STAs simultaneously, then broadcast coverage is maximized, but collisions occur with simultaneous STA transmissions
Solution Approach 1:
The patent implements preliminary action by establishing a reserved time period for AP broadcast/multicast transmissions before the actual transmissions take place. This reservation is communicated to all STAs in advance through beacon or action frames, enabling them to set their network allocation vectors to defer transmissions until the reserved period expires, thus preventing collisions while maintaining broadcast efficiency.
3Productivity
If overlapping BSSs transmit simultaneously to maximize resource utilization, then network capacity increases, but inter-BSS frame collisions occur
Solution Approach 1:
The patent applies preliminary action by having each AP reserve a specific time period for broadcast/multicast transmissions and communicate this reservation to neighboring APs. This allows overlapping BSSs to coordinate their transmissions in advance, with neighboring APs adjusting their network allocation vectors to avoid transmitting during reserved periods, thereby preventing inter-BSS collisions while maintaining high network capacity.
Solution Approach 2:
The patent implements feedback by having APs communicate their reserved broadcast transmission times to neighboring APs through beacon or action frames. This feedback mechanism allows neighboring APs to adjust their transmission schedules accordingly, creating a coordinated system where overlapping BSSs can operate at high capacity without causing inter-BSS collisions.
4Reliability
If random backoff is used for transmission timing, then collision probability is reduced, but transmission delay increases
Solution Approach 1:
The patent applies preliminary action by establishing predetermined reserved time periods for broadcast/multicast transmissions through coordination between APs and STAs. This eliminates the need for random backoff during these reserved periods, as all parties know in advance when transmissions will occur, thereby reducing both collision probability and transmission delay compared to random backoff mechanisms.
Data Source
AI summary
A protocol for collision avoidance in inter and intra basic service set broadcast/multicast communication in a wireless network is disclosed. An access point reserves a broadcast transmission time and conveys that reservation to each of its associated stations. Using a beacon or an action frame, the transmission reservation time is sent to all stations and other neighboring access points within range of the primary access point. Upon receiving the broadcast transmission time reservation, each station associated with the reserving access point and any neighboring access points set their network allocation vector thus preventing frame transmission or reception during the now reserved transmission time.