Base Station Fronthaul Scaling for Lower 5G Sample Compression Bit Rate
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Solution Overview
Problem
Current sample compression methods in 5G RANs are inefficient due to high variability of signals within a PRB, leading to excessive bit usage for quantization noise and unnecessary repetition of carrier scaling factors.
Innovation Solution
Implementing a two-level block scaling factor system, where a wide block scaling factor covers many samples and a narrow block scaling factor covers fewer samples, with the narrow block scaling factor updated more frequently, and applying the same scaling factor across multiple antennas to reduce bit rate over the fronthaul interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single scaling factor is used for all samples in a PRB, then device complexity is reduced, but measurement precision deteriorates due to high signal variability within a PRB
Solution Approach 1:
The patent divides the scaling factor application into two segments: a wide block scaling factor applied to the entire PRB and narrow block scaling factors applied to individual samples or small groups of samples. This segmentation allows the system to maintain low complexity for the overall scaling while achieving high precision for individual sample quantization, directly resolving the contradiction between complexity and precision.
2Measurement precision
If carrier scaling factors are repeated for every sample, then signal accuracy is maintained, but bit rate increases unnecessarily
Solution Approach 1:
The patent merges the carrier scaling factor into the wide block scaling factor that applies to the entire PRB or large blocks of samples. By combining these scaling operations, the system eliminates the need to transmit separate scaling factors for every sample, thereby maintaining signal accuracy while significantly reducing the bit rate required for transmission.
Solution Approach 2:
The patent applies local quality by using narrow block scaling factors only where needed (for individual samples or small groups) while using the wide block scaling factor for the majority of samples. This selective application of different scaling granularities optimizes the balance between accuracy and bit rate, avoiding unnecessary repetition of scaling factors.
3Measurement precision
If different scaling factors are applied to each antenna, then signal processing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements universality by using the same wide block scaling factor across multiple antennas, allowing a single scaling factor to serve multiple antennas simultaneously. This reduces the number of scaling factors that need to be managed and transmitted, while narrow block scaling factors can still be applied individually to each antenna when needed, balancing precision requirements with complexity reduction.
Data Source
AI summary
One embodiment of the disclosure provides a method performed by a first component part of a base station. The first component part comprises one of a central unit and a radio unit. The base station further comprises a second component part, which comprises the other of the central unit and the radio unit. The method comprises: receiving a user data stream to be transmitted to the second component part, the user data stream comprising a plurality of data samples which are for transmission by the base station over an air interface, or which have been received by the base station over the air interface; applying first and second scaling factors to the data samples to generate a scaled user data stream, wherein the first scaling factor is updateable every first plurality of data samples, wherein the second scaling factor is updateable every second plurality of data samples, and wherein the second plurality of data samples is less than the first plurality of data samples; and transmitting the scaled user data stream and an indication of the first and second scaling factors to the second component part.