Wireless Device Rate Control via HARQ Feedback
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Solution Overview
Problem
Existing wireless communication systems face challenges in achieving high-following rate control due to limitations in existing algorithms like ARF and RBAR, particularly in varying wireless environments and the inability of some devices to report transmission rates effectively.
Innovation Solution
The proposed solution involves using Hybrid Automatic Repeat Request (HARQ) with incremental redundancy, where a destination device reports data rates through existing control frames by modifying the 'Duration' field in CTS/NACK and CTS/ACK frames, allowing for dynamic modulation and coding rate adjustments based on signal quality, enabling efficient retransmissions and initial transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARF algorithm is used to select transmission rate based on past successful/unsuccessful transmissions, then the system can adapt to transmission outcomes, but the response time is slow when wireless environment changes because a long time is required to select the maximum rate
Solution Approach 1:
The destination device performs preliminary rate determination by calculating the optimal transmission rate based on received signal quality (SNR) before actual data transmission occurs. This preliminary rate information is then communicated to the source device, enabling the source to transmit at the pre-determined optimal rate without needing to wait for multiple trial transmissions and feedback loops.
2Reliability
If RBAR algorithm is used where destination device determines transmission rate based on SNR and reports it via control frame, then the rate control follows signal quality, but existing wireless communication devices may be incapable of transmitting or identifying such control frames
Solution Approach 1:
The invention makes the destination device capable of performing multiple functions: it both receives data and determines optimal transmission rates based on SNR measurements. This multi-functionality allows the destination to act as a rate control authority while using standard control frames that can be universally understood and implemented by existing wireless devices, thereby achieving both advanced rate control and broad compatibility.
Solution Approach 2:
The destination device continuously monitors received signal quality (SNR) and provides feedback to the source device about the optimal transmission rate. This feedback mechanism enables dynamic rate adaptation where the source device can adjust its transmission rate based on real-time channel conditions as reported by the destination, ensuring reliable communication while maintaining compatibility with standard protocols.
3Adaptability or versatility
If existing control frames are used without modification to report transmission rates, then compatibility is maintained, but the capability to report dynamic rate information is insufficient
Solution Approach 1:
The invention changes the interpretation or usage parameters of existing control frames to enable rate information reporting. Specifically, it modifies how control frames are utilized at the destination device to convey transmission rate recommendations, allowing standard frames to carry additional functional meaning without changing their fundamental structure, thus maintaining compatibility while enabling new capabilities.
Data Source
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Figure 2A~2B
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AI summary
A wireless communication device includes an estimator (26), a communication parameter determination unit (27), and a report unit (28). The estimator estimates a quality of a received signal that is transmitted from a source device. The communication parameter determination unit determines a communication parameter for a next communication transaction based on an evaluation value that indicates a result of subtracting a second value from a first value, the first value being determined based on a coding rate and a data length of a data signal received from the source device, the second value being determined based on the data length, a modulation scheme and a quality of the data signal. The report unit reports the communication parameter to the source device.