MU-MIMO Packet Signaling for Mixed BCC and LDPC WLAN Stations
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Solution Overview
Problem
Next-generation wireless local area network (WLAN) systems require a method to efficiently transmit and receive multiple input multiple output (MIMO) packets, particularly in multi-user (MU)-MIMO scenarios, where access points (APs) need to accommodate diverse capabilities among stations (STAs) for effective data transmission and reception.
Innovation Solution
The solution involves a physical layer convergence procedure (PLCP) protocol data unit (PPDU) transmission scheme that includes control information allowing STAs to interpret and decode data based on their supported encoding and modulation and coding schemes (MCS), with the AP providing group IDs and specific encoding scheme information for each STA, enabling MU-MIMO transmission to multiple STAs with different capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MU-MIMO transmission is implemented to transmit packets simultaneously to multiple STAs, then productivity is improved, but device complexity increases due to the need to manage different encoding schemes and MCS for each STA
Solution Approach 1:
The patent applies local quality by assigning different encoding schemes (BCC or LDPC) and MCS indices to different spatial streams targeted at specific STAs. The AP can selectively apply appropriate encoding schemes to each stream based on the capability of the target STA, thereby improving productivity through parallel transmissions while managing complexity through localized encoding decisions rather than system-wide uniformity
Solution Approach 2:
The patent segments the control information into separate fields: a common encoding scheme field applicable to all STAs, and per-STA MCS index fields. This segmentation allows the system to efficiently manage multiple encoding schemes by dividing the control structure into manageable parts, resolving the complexity issue while maintaining high productivity through organized information delivery
2Adaptability or versatility
If different encoding schemes are assigned to different STAs in MU-MIMO, then adaptability is improved, but loss of information increases due to the need for additional control information signaling
Solution Approach 1:
The patent merges the encoding scheme indication into the existing MCS index field structure by utilizing the least significant bits of the MCS index to encode the encoding scheme type (0 for BCC, 1 for LDPC). This merging approach allows the system to convey both the encoding scheme and modulation information in a unified field, improving adaptability to different STA capabilities while minimizing control information overhead by eliminating redundant signaling
3Ease of operation
If control information is optimized for SU-MIMO, then ease of operation is improved, but adaptability deteriorates when MU-MIMO transmission is required
Solution Approach 1:
The patent implements dynamics by making the interpretation of control information fields conditional based on the transmission mode. The receiving STA determines whether to interpret the MCS index field as containing both encoding scheme and modulation information (MU-MIMO mode) or as traditional MCS indexing (SU-MIMO mode) based on detection of MU-MIMO indication bits. This dynamic interpretation mechanism maintains ease of operation for legacy STAs while enabling adaptability for MU-MIMO transmissions
Solution Approach 2:
The patent creates universal control information fields that serve multiple functions: the MCS index field simultaneously indicates modulation scheme and encoding scheme type in MU-MIMO mode, while maintaining its traditional MCS indexing function in SU-MIMO mode. This multi-functionality allows the same control structure to support both transmission modes, improving adaptability without sacrificing the ease of operation established in legacy systems
Data Source
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AI summary
A method of transmitting a multiple input multiple output (MIMO) packet by a transmitter in a wireless local area network (WLAN) system is provided. The method includes: generating a MIMO packet including at least one spatial stream set transmitted respectively to at least one receiver, wherein each spatial stream set is encoded on the basis of one of two encoding schemes; transmitting first control information including a MIMO indicator and a first modulation and coding scheme (MCS) field, wherein the MIMO indicator indicates whether the MIMO packet is for single user (SU)-MIMO or multi user (MU)-MIMO, and the first MCS field indicates an MCS used for the MIMO packet if the MIMO packet is for SU-MIMO transmission, and indicates an encoding scheme applied for each of the spatial stream sets if the MIMO packet is for MU-MIMO transmission; and transmitting the MIMO packet to at least one receiver. The two encoding schemes are low-density parity check (LDPC) encoding scheme and binary convolution coding (BCC) encoding.