Access Point Trigger PPDU for Multi-User Channel Allocation
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Solution Overview
Problem
In wireless networks supporting Multi-User (MU) MIMO and MU Orthogonal Frequency Division Multiple Access (OFDMA) technologies, existing protocols often lead to inefficient channel capacity usage due to unnecessary backoff procedures and error recovery processes, especially in high-density scenarios with multiple simultaneous transmissions, which can result in packet transmission errors and reduced throughput.
Innovation Solution
The implementation of a method by an Access Point (AP) to allocate resources for Up-Link (UL) MU transmissions, where the AP transmits a Down-Link (DL) PHY Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) with trigger information across one or more 20 MHz channels, allowing stations to participate in UL MU transmissions using allocated resources, and includes an indication for random access in unallocated portions, optimizing resource allocation and reducing unnecessary backoff procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional backoff procedures and error recovery processes are used in MU MIMO and MU OFDMA transmissions, then protocol compatibility and reliability are maintained, but channel capacity utilization deteriorates due to unnecessary procedures reducing throughput
Solution Approach 1:
The patent extracts and removes unnecessary backoff procedures and error recovery processes from the MU MIMO and MU OFDMA transmission protocol. By taking out these redundant steps that do not contribute to actual data transmission, the system achieves higher channel capacity utilization and throughput while maintaining essential reliability mechanisms.
Solution Approach 2:
The patent inverts the traditional approach by having stations transmit acknowledgment frames immediately upon receiving data, rather than waiting for traditional error recovery procedures. This reversal of the acknowledgment timing and procedure eliminates unnecessary delays and backoff steps, improving channel efficiency while maintaining transmission reliability through the inverted acknowledgment mechanism.
2Ease of operation
If resource allocation for all portions of the channel is controlled by the AP, then transmission coordination is improved, but access flexibility deteriorates due to lack of random access capability
Solution Approach 1:
The patent segments the channel into two distinct types: allocated portions controlled by the AP for coordinated transmissions, and unallocated portions available for random access. This segmentation allows the system to simultaneously maintain AP-controlled coordination for scheduled transmissions while providing stations with flexible random access capability in unallocated portions, thus resolving the contradiction between coordination and flexibility.
Solution Approach 2:
The patent applies different access characteristics to different portions of the channel: allocated portions have strict AP-controlled coordination for reliable scheduled transmissions, while unallocated portions have open random access characteristics for flexible opportunistic transmissions. This local differentiation of access quality allows both coordinated operation and access flexibility to coexist in different parts of the same channel.
3Loss of time
If stations transmit acknowledgment frames immediately upon receiving data, then channel response time is improved, but collision probability increases in unallocated channel portions
Solution Approach 1:
The patent segments acknowledgment transmissions into two categories: those in allocated portions which are AP-coordinated and thus collision-free, and those in unallocated portions which may have collision risk. By segmenting the acknowledgment channel this way, the system achieves fast response times while isolating potential collisions to only the unallocated portions, protecting the overall acknowledgment mechanism from widespread collision issues.
Solution Approach 2:
The patent introduces the AP as an intermediary that coordinates transmissions in allocated portions, acting as a mediator that prevents collisions by controlling access timing and resource allocation. This intermediary role of the AP in allocated portions eliminates collisions for scheduled transmissions while allowing stations to attempt random access in unallocated portions, thus managing collision probability through the mediating coordination mechanism.
Data Source
AI summary
An Access Point (AP) performs a Multi-User (MU) transmission by allocating a plurality of resources of an Up-Link (UL) MU transmission to a first plurality of stations, and by transmitting, using one or more 20 MHz channels, a Down-Link (DL) PHY Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU). The DL PPDU includes trigger information. The trigger information solicits the first plurality of stations to participate in the UL MU transmission using the allocated resources. All of the allocated resources may be in the one or more 20 MHz channels of the DL PPDU. The allocated resources may include at least one resource in each of the one or more 20 MHz channels of the DL PPDU.