Group-Addressed ATIMs Reduce Awake Window Duration
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Solution Overview
Problem
In directional multi-gigabit wireless networks, the Awake Window (AW) is limited by substantial signaling overhead due to individual unicast announcement traffic indication message (ATIM) transmissions by the access point (AP), leading to increased power consumption and reduced power savings as devices remain awake for longer durations.
Innovation Solution
The AP transmits group-addressed ATIMs using reduced interframe spaces (RIFS) between directional beamformed links, reducing the number of ATIM frames and duration of the AW, and employing DMG control mode modulation and coding schemes for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual unicast ATIM transmissions are used by the AP, then each device can be individually addressed, but signaling overhead increases and power savings are reduced
Solution Approach 1:
The patent merges multiple individual unicast ATIM transmissions into a single group-addressed ATIM transmission. The AP transmits one ATIM frame addressed to a group of STAs simultaneously, eliminating the need for separate transmissions to each STA. This combining approach reduces signaling overhead and allows STAs to enter sleep mode sooner, improving power savings while maintaining reliable delivery to all intended recipients.
2Reliability
If multiple unicast ATIM frames are transmitted to different STAs, then all STAs can be notified, but the Awake Window duration increases
Solution Approach 1:
The patent combines multiple ATIM frame transmissions into a single group-addressed transmission. Instead of sending separate ATIM frames to each STA which would extend the AW duration, one ATIM frame is sent to a group containing all target STAs. This allows all STAs to be notified simultaneously, enabling them to transition to sleep mode at the same time and thus reducing the overall AW duration.
Solution Approach 2:
The patent introduces group addressing as a new dimension for ATIM frame delivery. Rather than using traditional unicast addressing in a sequential time dimension, the invention uses group addressing to deliver messages to multiple STAs simultaneously across the network spatial dimension, thereby compressing the time dimension and reducing AW duration.
3Reliability
If group-addressed ATIMs are transmitted with standard interframe spaces, then reliability is maintained, but signaling overhead and AW duration are not optimized
Solution Approach 1:
The patent changes the interframe space parameter from standard SIFS to reduced RIFS for group-addressed ATIM transmissions. By modifying this timing parameter, the system achieves more efficient channel access and reduced overhead. The RIFS value is specifically optimized for group-addressed frames, allowing tighter packing of transmissions and improved power management efficiency while maintaining reliability through the DMG control mode.
Data Source
AI summary
Devices and methods of for wireless communication in a directional multi-gigabit (DMG) band are generally described. A device can detect a starting point of an awake window (AW). The device can encode a first announcement traffic indication message (ATIM) for directional transmission, after no more than a point coordination function (PCF) interframe space (PIFS) subsequent to the starting point, over a first beamformed link to a first station (STA). The device can encode a second ATIM for directional transmission subsequent to directional transmission of the first ATIM, within the AW and in a different direction than the directional transmission of the first ATIM, over a second beamformed link to a second STA. Other devices, systems and methods are also described.