Wireless Data Transmission for Legacy Station Virtual Carrier Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Legacy stations in wireless networks cannot perform virtual carrier sensing when coexisting with high throughput stations, leading to inefficient data transmission due to their inability to interpret HT data, resulting in unfair media access and increased overhead in control frames.
Innovation Solution
The method involves transmitting legacy format data without an HT preamble, allowing legacy stations to perform virtual carrier sensing by using a legacy response frame structure that includes a Legacy Short Training Field, Legacy Long Training Field, and Legacy Signal Field, enabling them to participate in backoff procedures alongside HT stations, and transmitting short data in a legacy format to reduce overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If HT stations transmit data using HT format with HT preamble, then data transmission rate is improved, but legacy stations cannot interpret the data and cannot perform virtual carrier sensing
Solution Approach 1:
The patent segments the PPDU into two distinct parts: a legacy format portion (with legacy preamble and legacy signal field) that legacy stations can interpret, and an HT format portion (with HT preamble and HT signal field) that enables high throughput transmission. This segmentation allows HT stations to transmit at high rates while ensuring legacy stations can still access and understand the control information for carrier sensing.
Solution Approach 2:
The legacy format portion acts as an intermediary layer between the HT data transmission and legacy station requirements. It provides a bridge that allows legacy stations to interpret control frames and perform virtual carrier sensing without requiring them to understand the full HT format, thus enabling coexistence between HT and legacy stations.
2Reliability
If legacy stations use physical carrier sensing, then they can detect channel status, but media access becomes unfair compared to HT stations that use virtual carrier sensing
Solution Approach 1:
The patent creates a copy of the legacy PPDU format within the HT PPDU structure. By including a legacy format portion with legacy signal field that contains duration information, the system allows legacy stations to copy the virtual carrier sensing mechanism from HT stations, enabling them to access the medium efficiently without requiring full HT capability.
3Productivity
If HT stations transmit control frames at high rate, then transmission efficiency is improved, but overhead increases when legacy stations need to be supported
Solution Approach 1:
Instead of transmitting the complete HT format for all control frames (which would maximize efficiency but increase complexity and incompatibility), the patent applies partial action by including only the necessary legacy format portion in the control frames. This partial legacy format provides just enough information for legacy stations to function while minimizing the overall frame complexity and overhead.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and an apparatus are provided for enabling a legacy station to perform virtual carrier sensing when a plurality of stations with heterogeneous capabilities coexist in a wireless network. The method includes receiving first data compliant with a first protocol, and transmitting second data compliant with a second protocol, where the first protocol is downward compatible with the second protocol.