Adaptive LLR Quantization for Split RAN Fronthaul Bandwidth
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Solution Overview
Problem
The high data rates required for transmitting soft bits (LLR) between demodulation and decoding devices in split RAN architectures, particularly in option 7.3, exceed the capacity of communication buses, leading to potential signal degradation and inefficiencies in fronthaul networks.
Innovation Solution
Adapting a quantization table based on channel decoding error rates to optimize the data rate required for soft bit transmission, using methods that dynamically adjust the quantization table according to the signal's BLER, either through pre-calculated tables or real-time learning, to minimize decoding errors and reduce bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft bits (LLR) are transmitted with high precision between demodulation and decoding devices in split RAN architectures, then decoding performance is improved, but data transmission bandwidth requirements exceed communication bus capacity
Solution Approach 1:
The patent applies dynamic quantization by adjusting the number of bits used to represent LLR values based on channel conditions and signal characteristics. Instead of using a fixed high-precision representation, the system dynamically adapts the quantization level to maintain decoding performance while reducing bandwidth consumption when full precision is not necessary.
Solution Approach 2:
The patent changes the parameter of LLR precision by applying quantization tables that map continuous LLR values to discrete representations with varying bit depths. This parameter transformation allows the system to transmit softened bit information with reduced bandwidth requirements while preserving sufficient information for reliable decoding through optimized quantization schemes.
2Quantity of substance
If quantization is applied to reduce soft bit data rate, then bandwidth requirements are reduced, but decoding error rate increases
Solution Approach 1:
The patent applies preliminary quantization at the demodulation stage before transmitting soft bits to the decoding device. By pre-quantizing the LLR values using optimized quantization tables, the system prepares the data in a compressed format that reduces bandwidth requirements while maintaining the essential information needed for accurate decoding, thus preventing error rate increase despite reduced precision.
Solution Approach 2:
The system uses feedback mechanisms to adapt the quantization process based on channel conditions and observed decoding performance. By monitoring the relationship between quantization level and decoding error rate, the system can adjust quantization parameters to maintain reliability while maximizing bandwidth efficiency, ensuring that quantization does not degrade performance below acceptable thresholds.
Data Source
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AI summary
The invention relates to a method and a device for adapting a quantisation table of data representative of a radio signal received by a radio antenna of a mobile network, comprising: - obtaining a piece of information representative of a channel decoding error rate for a decoded quantised demodulated signal resulting from demodulation of the radio signal received by the antenna, the demodulated radio signal having been quantised by the quantisation table, and the quantised demodulated radio signal having been channel-decoded, - adapting the quantisation table when the channel decoding error rate is greater than a determined threshold, - transmitting a piece of information representative of the adaptation of the quantisation table to a channel decoding device or to a demodulation device.