Trigger Frame Spatial Stream Allocation in UL OFDMA
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Solution Overview
Problem
Current communication networks, particularly in wireless communication, face challenges in efficiently coordinating uplink transmissions between access points and stations, as existing standards like IEEE 802.11ax lack clear mechanisms for efficiently selecting between SU-MIMO and MU-MIMO channels and indicating stream allocations within trigger frames.
Innovation Solution
The proposed solution involves a mechanism for an access point to generate and transmit trigger frames with a standardized format that includes a constant-sized Spatial Stream (SS) allocation field, allowing efficient selection between SU-MIMO and MU-MIMO channels, and indicating stream numbers and sequences, eliminating the need for additional bits to distinguish between channel types by using the Resource Unit allocation field to determine scheduling types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable-length SS allocation fields are used to indicate different numbers of spatial streams for different users, then the flexibility in indicating stream allocations is improved, but the frame format complexity and processing overhead increase
Solution Approach 1:
The patent applies homogeneity by making all SS allocation fields in the trigger frame have the same fixed length. This ensures that every user entry occupies a consistent number of bits, simplifying the frame structure and making it easier to process. The fixed-length approach eliminates the need for variable-length encoding logic while still providing sufficient range to indicate different numbers of spatial streams through the standardized field format.
2Loss of information
If additional bits are added to trigger frames to distinguish between SU-MIMO and MU-MIMO channel types, then the clarity in channel type identification is improved, but the frame size and transmission overhead increase
Solution Approach 1:
The patent applies universality by designing the SS allocation field to serve multiple functions simultaneously. The same fixed-length field not only indicates the number of spatial streams but also implicitly conveys the channel type (SU-MIMO or MU-MIMO) through its value range and context. This multi-functional approach eliminates the need for separate identification bits while maintaining clear channel type distinction.
Solution Approach 2:
The patent merges the channel type identification function with the spatial stream allocation indication. By encoding both pieces of information in the same SS allocation field, the patent reduces the total frame size while ensuring that receivers can correctly interpret both the channel type and stream allocation from a single unified field.
3Measurement precision
If trigger frames use inconsistent field formats for different user types, then the specificity in addressing different scheduling types is improved, but the processing complexity at STAs increases
Solution Approach 1:
The patent applies homogeneity by standardizing the SS allocation field format across all user types in the trigger frame. Every user entry uses the same fixed-length field structure, which significantly simplifies STA processing. Stations can uniformly parse and interpret all SS allocation fields without needing to handle different formats or perform complex format detection, thereby reducing processing complexity while maintaining the ability to distinguish between SU-MIMO and MU-MIMO scheduling types.
Data Source
AI summary
A method for establishing an uplink transmission. A recipient station receives a trigger frame. The trigger frame including at least one per user info field. Each of the at least one per user info field comprising at least a user identifier field identifying a STA to be allocated a resource unit, a resource unit allocation field for allocating a resource unit for the identified STA, and a spatial stream allocation field identifying a number of streams to be allocated for the identified STA. The recipient STA evaluating an order of the at least one per user info fields to determine a sequence of the allocated streams that matches the order of the at least one per user info fields. The recipient STA comparing the values from each of the resource unit allocation fields and grouping corresponding at least one per user info fields with matching values to identify members of a set STAs allocated to MU-MIMO. In some aspects, the spatial stream allocation field of the per user info fields comprises three bits.