Dual-Pipelined Modulation for Millimeter Wave WLAN Spectral Efficiency
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Solution Overview
Problem
Current WLAN systems, particularly in 802.11ah, face limitations in spectral efficiency due to the primary channel being restricted by the smallest bandwidth supported by all stations, leading to inefficient carrier sensing and NAV settings.
Innovation Solution
The proposed solution involves dual-pipelined modulation and a redesigned OFDM PPDU format for millimeter wave transmission, allowing for more reliable Control PHY transmission and improved spectral efficiency by utilizing different constellation mappings and data communication resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the primary channel bandwidth is limited by the smallest bandwidth supported by all stations, then backward compatibility is maintained, but spectral efficiency deteriorates
Solution Approach 1:
The patent segments the channel into control field portions and data field portions, allowing different bandwidth allocations for control information and data transmission. The control field can be transmitted on a narrower bandwidth compatible with all stations, while data transmission can utilize wider bandwidth channels for improved spectral efficiency.
Solution Approach 2:
The patent introduces frequency dimension by allowing control frames to be transmitted on a primary channel with bandwidth suitable for all stations, while data transmission occurs on secondary channels or bonded channels with wider bandwidth. This dimensional separation resolves the contradiction between compatibility and efficiency.
2Productivity
If dual-pipelined modulation with different constellation mappings is used, then spectral efficiency improves, but device complexity increases
Solution Approach 1:
The patent employs dynamic constellation mapping where the modulation scheme can be adapted based on channel conditions and station capabilities. Different constellation mappings are used dynamically in different time-frequency resources, allowing the system to optimize spectral efficiency while managing complexity through selective application.
Solution Approach 2:
The patent changes modulation parameters (constellation mapping, order) based on transmission requirements. By varying these parameters across different control field portions and data field portions, the system achieves improved spectral efficiency without requiring maximum complexity throughout the entire transmission.
3Productivity
If millimeter wave transmission with redesigned OFDM PPDU format is implemented, then throughput increases, but reliability in low SNR ranges may deteriorate
Solution Approach 1:
The patent incorporates robust control field design with repeated fields and error protection mechanisms before data transmission. The control frames contain necessary information for synchronization and channel access that are transmitted with higher reliability保障措施, cushioning against potential failures in low SNR conditions before attempting high-throughput data transmission.
Solution Approach 2:
The patent uses control frames as intermediaries between legacy stations and millimeter wave transmissions. These control frames carry essential information in a format that ensures reliability in low SNR conditions, mediating between the high-throughput requirements of mmWave and the reliability needs of challenging channel conditions.
Data Source
AI summary
Modulating millimeter waves may be embodied via a plurality of means. In at least one embodiment of the process disclosed herein, the process includes receiving, at a transmitter, a set of bits. The process also includes generating at least two complex-valued symbols based on the set of bits using a pipelined modulation at least in part by (i) mapping the set of bits to a first symbol using a first constellation mapping and (ii) mapping the set of bits to a second symbol using a second constellation mapping. The process also includes selecting a first data communication resource in a first single carrier channel for the first symbol and selecting a second data communication resource in a second single carrier channel for the second symbol. The process also includes transmitting, via the transmitter, the first and second symbols using the respective selected data communication resources.