Short SSW Frame Structure for Faster Beamforming Sector Sweep
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Solution Overview
Problem
The existing IEEE 802.11ad standard's Sector Level Sweep (SLS) procedure for beamforming training is inefficient as the length of SSW frames is fixed at 26 octets, leading to increased time requirements as the number of sectors increases, hindering the completion of SLS in a timely manner.
Innovation Solution
A communication apparatus and method that generate shorter Sector Sweep (SSW) frames, replacing the Short SSW Feedback field with a Short Scrambled Basic Service Set ID (BSSID) field, which abbreviates the destination address, and utilize a PHY frame generating circuit to select the best sector, thereby reducing frame length and completing SLS quickly even with an increased number of sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of sectors is increased to improve beamforming performance, then the communication quality is improved, but the time required for SLS increases due to the fixed 26-octet SSW frame length
Solution Approach 1:
The patent extracts and removes the Short SSW Feedback field from the SSW frame structure, keeping only the essential Short Scrambled BSSID field. This extraction reduces the frame length from 26 octets to a shorter size, allowing faster transmission when the number of sectors is increased, thus resolving the contradiction between communication quality and SLS completion time
Solution Approach 2:
The patent changes the parameter of frame length by modifying the SSW frame structure to use a shorter length. By changing the frame length parameter from the standard 26 octets to a reduced size through field removal, the transmission time is reduced, enabling faster SLS completion while maintaining the ability to handle increased sector counts for better beamforming performance
2Loss of time
If the SSW frame length is reduced to shorten SLS time, then the SLS completion time is reduced, but the information carrying capacity of the frame is reduced
Solution Approach 1:
The patent selectively extracts only the essential information field (Short Scrambled BSSID) from the SSW frame, removing the Short SSW Feedback field. This extraction maintains the critical addressing information needed for beamforming while eliminating redundant data, achieving both time reduction and information preservation
Solution Approach 2:
The patent uses a scrambled version of the BSSID (Short Scrambled BSSID) instead of the full BSSID, creating a compressed representation that retains the necessary identification information in a more compact form, thus preserving information capacity while reducing frame length
Data Source
AI summary
A communication apparatus includes a PHY frame generating circuit that generates a PHY frame including either of a short Sector Sweep frame and a Sector Sweep frame; and an array antenna that selects, based on the PHY frame, any sector from among a plurality of sectors and transmits the PHY frame. In a case where, in the PHY frame including the short Sector Sweep frame, a Direction field of the short Sector Sweep frame indicates Initiator Sector Sweep, the PHY frame generating circuit replaces a Short Sector Sweep Feedback field indicating a number of a selected best short Sector Sweep with a Short Scrambled Basic Service Set ID field indicating an abbreviated address generated from an address of a destination communication apparatus.