Beam Selection and Compression for 5G Front-Haul Bandwidth Reduction
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Solution Overview
Problem
The increasing number of antennas in 5G and C-RAN systems leads to significant bandwidth requirements on the front-haul link, which is challenging to manage without incurring unacceptable delays or performance degradation, especially since traditional data compression methods are not effective due to the absence of statistical redundancy in frequency domain data.
Innovation Solution
A method that selects a subset of beams based on received energies, allowing only the transmission of data from these selected beams over the front-haul link, without requiring channel estimates or significant computational complexity, and employs data compression techniques that minimize quantization error based on beam energy, thereby reducing bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antennas is increased to improve spectral efficiency and energy efficiency, then system performance is improved, but bandwidth requirements on the front-haul link increase significantly
Solution Approach 1:
The patent segments the full set of antenna signals into multiple beams, then selects only a subset of these beams for transmission over the front-haul link. This segmentation approach reduces the bandwidth requirements while maintaining system performance by transmitting only the most significant beam components.
Solution Approach 2:
The patent extracts and transmits only the essential beam components that carry the most important information, discarding redundant data. This extraction process significantly reduces the bandwidth requirements on the front-haul link while preserving the critical signal information needed for system operation.
2Quantity of substance
If data compression is applied to reduce bandwidth requirements, then bandwidth is reduced, but traditional compression methods are ineffective due to absence of statistical redundancy in frequency domain data
Solution Approach 1:
The patent changes the parameter representation from traditional frequency domain data to beam-space data. This parameter transformation reveals statistical redundancy that is not apparent in the original frequency domain representation, enabling effective data compression to be applied.
Solution Approach 2:
The patent discards redundant information in the beam-space representation and recovers the essential signal components at the receiving end. This approach enables compression by eliminating unnecessary data while preserving the information needed for accurate signal reconstruction.
3Quantity of substance
If beamforming is used to reduce bandwidth requirements, then bandwidth is reduced, but maintaining guarantee of data transmission delay becomes challenging
Solution Approach 1:
The patent performs beam selection and data compression in advance before transmission over the front-haul link. This preliminary processing reduces the amount of data that needs to be transmitted, thereby reducing transmission delay while maintaining the guaranteed delay requirements.
Solution Approach 2:
The patent transmits only a partial set of beam components rather than all antenna signals. This partial transmission approach reduces bandwidth requirements and transmission delay by sending only the essential information needed for system operation.
4Reliability
If all beam data is transmitted to maintain performance, then system performance is maintained, but bandwidth requirements become unmanageable
Solution Approach 1:
The patent applies different processing treatments to different beam components. The most significant beam components are transmitted with higher fidelity, while less critical components are compressed or discarded. This local quality approach maintains system performance for critical signals while reducing overall bandwidth requirements.
Data Source
AI summary
Described are techniques for limiting bandwidth requirements for user equipment UE data sent on a front haul link between a remote radio head RRH and a baseband unit BBU. For a given UE a subset of a plurality of beams is selected based on received energies of the plurality of beams, and for the given UE only data from the selected subset of beams transmitting on a front haul link. Multiple techniques are detailed for how the subset is selected, including (when UE allocation information is available) averaged received beam energy, total received beam energy, maximum received beam energy and also (when UE allocation information is not available). For further bandwidth reduction a special data compression technique uses the received energies of each beam to select a minimum gain offset value after dividing the data into I and Q components.