Wireless Multicast Delivery via Contention-Free Periods
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Solution Overview
Problem
Current wireless communication networks face inefficiencies in delivering multicast and broadcast packets, leading to increased power consumption, unreliable data transfer, and delayed packet delivery due to interruptions from unicast transmissions and high packet error rates, particularly in IEEE 802.11 standards.
Innovation Solution
Implementing a contention-free period (CFP) during beacon transmissions to ensure uninterrupted delivery of multicast and broadcast packets, using quality of service (QoS) control fields for prioritization, and employing negative acknowledgments (NACK) for reliable voice packet retransmission, along with prioritization of inbound traffic and queue management to optimize power usage and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stations stay awake to receive multicast and broadcast packets after DTIM, then reliable packet delivery is achieved, but power consumption increases
Solution Approach 1:
The system performs preliminary actions by sending confirmations before the scheduled multicast/broadcast packet delivery. Stations receive these confirmations in advance and can determine whether to stay awake or enter sleep mode, eliminating the need to remain awake for the entire packet delivery period while ensuring reliable reception of critical packets.
2Use of energy by moving object
If multicast and broadcast packets are delivered after DTIM, then stations can enter low power mode, but delivery is interrupted by inbound unicast transmissions causing delays
Solution Approach 1:
The system implements feedback mechanisms where the access point sends confirmations to stations indicating whether multicast/broadcast packets will be delivered. This feedback allows stations to make informed decisions about power mode transitions without being forced to stay awake for extended periods, reducing both power consumption and delivery delays.
3Reliability
If stations must stay awake until all multicast/broadcast packets are delivered, then no packets are lost, but spectral efficiency decreases due to extended awake time
Solution Approach 1:
By sending confirmations in advance that indicate packet delivery status, the system enables stations to make early decisions about when to wake up and when to sleep. This preliminary information allows the network to optimize spectral efficiency by reducing the duration stations must remain awake, while still ensuring complete packet delivery through coordinated wake-up schedules.
Data Source
AI summary
Methods for delivery of multicast packets in a wireless communication system are disclosed. The methods comprise transmitting a contention free period initiation signal from an access point to the station, transmitting broadcast packets from the access point to the station, transmitting multicast packets from the access point to the station and holding the multicast packets in storage after the transmission, transmitting a contention free period end signal from the access point to the station, determining if a negative acknowledgement message has been received, retransmitting the multicast packets in response to receiving a negative acknowledgment message, and eliminating the multicast packets at a next beacon interval.