MU-RTS CTS Scrambling for Wireless Overhead Reduction
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Solution Overview
Problem
In wireless networking, especially in high-density scenarios, existing technologies face inefficiencies in MU-MIMO and OFDMA communications due to high overhead from sounding operations and inadequate protection mechanisms, which impact throughput and power utilization.
Innovation Solution
A method involving a wireless device that receives a Multi-User Request-To-Send (MU-RTS) frame, descrambles the data using a first scrambling sequence, and generates a Clear-To-Send (CTS) frame using a second scrambling sequence, where the CTS frame includes data scrambled with the same sequence as the MU-RTS frame, ensuring efficient RF combining and channel utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional protection mechanisms (RTS/CTS) are used in MU transmissions, then channel protection is provided, but overhead increases and throughput decreases
Solution Approach 1:
The patent merges multiple CTS frames from different stations into a single RF-combined CTS transmission. Instead of each station transmitting separate CTS frames that would interfere with each other, the access point RF-combines the CTS responses from multiple stations into one unified transmission, reducing overhead while maintaining protection functionality.
Solution Approach 2:
The access point acts as an intermediary that collects CTS frames from multiple stations and RF-combines them before retransmitting. This intermediary process allows the system to maintain individual station protection needs while achieving efficient combined transmission that reduces overall overhead.
2Reliability
If multiple stations transmit CTS frames simultaneously, then channel reservation is achieved, but signal interference occurs
Solution Approach 1:
The patent converts the potentially harmful signal interference from multiple simultaneous CTS transmissions into a beneficial RF-combined signal. By using RF combining technology, the system takes the multiple transmitted signals that would normally interfere with each other and combines them constructively into a single strong signal that improves reliability.
3Reliability
If scrambling sequences are used for RF combining, then all transmissions must use the same sequence, but this limits flexibility
Solution Approach 1:
The patent implements a universal scrambling sequence approach where all stations use the same scrambling sequence for their CTS frames. This universal sequence enables efficient RF combining while the system maintains adaptability through the access point's ability to select appropriate sequences based on the specific transmission context and requirements.
Data Source
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AI summary
A wireless device receives a Multi-User Request-To-Send (MU-RTS) frame, descrambles first scrambled data in the MU-RTS frame using a first scrambling sequence, generates second scrambled data using a second scrambling sequence, and transmits a Clear-to-Send (CTS) frame including the second scrambled data in response to receiving the MU-RTS frame. The second scrambling sequence is an N-bit left cyclic shift of the first scrambling sequence. Another wireless device generates first scrambled data using a first scrambling sequence and transmits an MU-RTS frame including the first scrambled data. The wireless device receives a CTS frame transmitted in response to the MU-RTS frame, and descrambles second scrambled data in the CTS frame using a second scrambling sequence. The second scrambling sequence is an N-bit left cyclic shift of the first scrambling sequence. In either device, N may be 7, and lengths of the first and second scrambling sequences may be 127 bits.