Reducing PAPR in 802.11be U-SIG Disregard Bits
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Solution Overview
Problem
The existing wireless communication systems, particularly in the 802.11be protocol, face challenges in reducing the peak to average power ratio (PAPR) of physical layer protocol data units (PPDUs), which affects the performance of both multi-user (MU) and trigger-based (TB) PPDUs due to the high PAPR caused by the disregard bits being set to '1' in the universal signal (U-SIG) field.
Innovation Solution
A method and apparatus are introduced to modify the disregard bits sequence in the U-SIG field by setting values to sequences with '0' bits, changing the validate bit, relocating the bits, or replacing them with cyclic redundancy check (CRC) bits, to reduce the PAPR. Specific sequences and modifications are provided for different bandwidths and PPDU types, such as MU and TB PPDUs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the disregard bits in the U-SIG field are set to '1' as per the 802.11be protocol specification, then the protocol compliance is maintained, but the peak to average power ratio (PAPR) increases causing transmission performance degradation
Solution Approach 1:
The patent changes the parameter values of disregard bits from all '1's to specific sequences containing '0' bits. By modifying the bit sequences to predefined patterns (e.g., '00101' for 20 MHz bandwidth, '01001' for 40 MHz bandwidth), the PAPR is reduced while maintaining protocol functionality, as receivers can still process these modified sequences correctly.
Solution Approach 2:
The patent applies different disregard bits sequences to different bandwidth configurations and PPDU types. Each bandwidth (20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz) has specifically optimized bit sequences, and different sequences are applied to MU-PPDU and TB-PPDU types, achieving local optimization for each scenario.
2Reliability
If the disregard bits are copied from the trigger-based frame in TB PPDU, then the validation mechanism is maintained, but the PAPR problem persists affecting both MU PPDU and TB PPDU performance
Solution Approach 1:
The patent modifies the disregard bits sequences for TB-PPDU by setting specific bit patterns instead of copying all '1' sequences from trigger-based frames. The validation mechanism is preserved through careful selection of bit patterns that maintain detectability while reducing PAPR, using sequences like '010010' for 20 MHz TB-PPDU.
3Device complexity
If the disregard bits are set to all '1' values to simplify the transmission, then the device complexity is reduced, but the power amplifier backoff increases reducing efficiency
Solution Approach 1:
The patent introduces specific non-random bit sequences for disregard bits instead of using all '1' values. This maintains a level of simplicity in implementation while significantly reducing PAPR, thereby reducing power amplifier backoff and improving energy efficiency. The sequences are predefined and easy to implement.
4Productivity
If the disregard bits sequence is modified to reduce PAPR, then the transmission efficiency is improved, but the compatibility with existing receivers may be affected
Solution Approach 1:
The patent uses carefully selected bit sequences that maintain compatibility with existing receivers. The modified sequences preserve the structural properties that receivers expect in the U-SIG field, allowing them to correctly identify and process the packets while benefiting from reduced PAPR.
Solution Approach 2:
The patent converts the potential harm of modified bit sequences (which could cause compatibility issues) into a benefit by selecting sequences that simultaneously reduce PAPR and maintain receiver compatibility. The specific patterns chosen serve dual purposes: lowering power requirements and ensuring correct reception.
Data Source
AI summary
This application relates to the field of communications technologies, in particularly related to wireless fidelity (WIFI) technologies, and provides a method and apparatus for reducing peak to average power ratio (PAPR) for transmitting a physical layer protocol data units (PPDUs). The method can be used for both an access point (AP) and a station (STA). The method comprises: operating on a first disregard bits sequence to obtain a second disregard bits sequence, wherein the first disregard bits sequence is with all bits set to ‘1’, and transmitting the PPDU, wherein the PPDU comprises the second disregard bits sequence.