Distributed MIMO Frame Formats for Synchronized Joint Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in successfully receiving and decoding transmissions by a single access point, particularly in MIMO configurations, due to synchronization and alignment issues between master and slave access points.
Innovation Solution
A method and system for joint transmission by a group of distributed access points, involving a master access point transmitting information to a slave access point, estimating synchronization, and coordinating a joint null data packet transmission to enable successful reception and decoding by a station device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If joint transmission is implemented by multiple distributed access points, then data throughput and reliability are improved, but synchronization and alignment issues between master and slave access points cause reception and decoding failures
Solution Approach 1:
The patent applies preliminary action by implementing a sounding sequence before the actual joint transmission. During this sounding phase, the master access point transmits training fields that allow slave access points to estimate synchronization parameters (carrier frequency offset, sampling frequency offset, timing offset) in advance. This preliminary synchronization estimation enables the slave access points to adjust their transmission timing and frequency before participating in the joint null data packet transmission, thereby resolving the synchronization issues that would otherwise cause reception failures.
Solution Approach 2:
The patent implements feedback mechanisms where the master access point receives channel state information from station devices and uses this feedback to coordinate the joint transmission. The sounding sequence provides feedback about channel conditions, and the master access point uses this information to schedule and coordinate transmissions from multiple access points, ensuring proper synchronization and alignment while maintaining reliable reception.
2Manufacturing precision
If synchronization information is estimated during the joint transmission setup, then alignment between access points is improved, but additional time periods and coordination overhead are required
Solution Approach 1:
The patent merges the synchronization estimation process with the existing sounding sequence infrastructure. Instead of implementing a separate synchronization protocol, the patent combines synchronization parameter estimation into the training field transmission phase of the sounding sequence. This allows synchronization information to be obtained during the same time period when channel sounding is performed, thereby reducing additional time overhead while achieving the necessary synchronization alignment for joint transmission.
Data Source
AI summary
Disclosed herein are related to systems and methods for a multiple-input multiple-output (MIMO) communication. In one aspect, during a first time period, a master access point transmits, to a slave access point, information for a joint transmission by the master access point and the slave access point. In one aspect, the slave access point estimates synchronization information for the joint transmission, according to the information for the joint transmission. In one aspect, during a second time period after the first time period, the master access point transmits a portion of a null data packet to a station device. In one aspect, during the second time period, the slave access point transmits the portion of the null data packet to the station device, based on the synchronization information for the joint transmission. In one aspect, the station device determines steering information for the MIMO communication, according to the null data packet.