Wireless Communication Integrated Circuit Multiplexing Acknowledgement Responses
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Solution Overview
Problem
In wireless local area networks (WLANs) using the CSMA/CA protocol, the overhead from acknowledging data transmission in downlink multiuser MIMO systems increases with the number of terminals, hindering high throughput due to sequential acknowledgement responses from wireless terminals.
Innovation Solution
A wireless communication integrated circuit that multiplexes and transmits multiple frames, allowing simultaneous acknowledgement responses from wireless terminals using orthogonal preamble patterns, enabling the access point to correctly separate and estimate uplink propagation channel responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless terminals transmit acknowledgement responses sequentially in turns, then each terminal can be acknowledged properly, but the overhead increases with the number of terminals and throughput is hindered
Solution Approach 1:
Multiple acknowledgement responses from different wireless terminals are merged into a single multiplexed signal transmitted simultaneously. The access point receives and separates these acknowledgements using orthogonal preamble patterns, eliminating the need for sequential transmission and reducing overhead while maintaining reliability.
Solution Approach 2:
The system transitions from time-division sequential acknowledgement to spatial-division simultaneous acknowledgement by introducing orthogonal preamble patterns as a new dimension. This allows multiple terminals to transmit acknowledgements at the same time on the same frequency resources, separated by orthogonal codes rather than time slots.
2Productivity
If multiple wireless terminals transmit acknowledgement responses simultaneously, then overhead is reduced and throughput is improved, but signal separation and estimation become more difficult
Solution Approach 1:
Each wireless terminal is assigned a unique orthogonal preamble pattern, giving local distinction to each terminal's signal. This allows the access point to differentiate and separate individual acknowledgements from the multiplexed signal based on their unique orthogonal characteristics.
Solution Approach 2:
The system changes the parameter of preamble patterns from identical to orthogonal. By using orthogonal preamble patterns with different spatial or temporal characteristics, the access point can separately estimate uplink propagation channel responses for each terminal even when signals are transmitted simultaneously.
3Device complexity
If sequential acknowledgement responses are used, then signal separation is simple, but the time required for acknowledging data frames increases
Solution Approach 1:
Orthogonal preamble patterns are assigned to each wireless terminal in advance, before the actual data transmission and acknowledgement phase. This preliminary assignment enables the access point to separately estimate channel responses and decode multiple simultaneous acknowledgements without increasing processing complexity during the critical acknowledgement phase.
Data Source
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AI summary
The present embodiment provides a wireless terminal which can exchange an acknowledgment response efficiently. A wireless communication integrated circuit according to an embodiment includes a baseband integrated circuit. The circuit is configured to multiplex and transmit a plurality of first frames via an RF integrated circuit and receive, via the RF integrated circuit, a plurality of second frames that represent acknowledgement responses to the plurality of first frames and are multiplexed and transmitted. The base band integrated circuit sets first information necessary for transmission of the plurality of second frames in the plurality of first frames. The baseband integrated circuit is configured to separate the plurality of second frames based on the first information.