Front-Haul Controller Dynamic Bit-Rate Adjustment
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Solution Overview
Problem
Current radio access network (RAN) architectures, particularly in cloud-RAN (C-RAN) setups, face inefficiencies in front-haul capacity utilization due to constant bit-rate signals being transmitted regardless of user equipment (UE) load, leading to unnecessary bandwidth usage and latency constraints.
Innovation Solution
Implementing a frequency domain I/Q split in the C-RAN architecture, coupled with a front-haul controller that utilizes statistical multiplexing and variable bit-rate network links, such as FlexE, to dynamically adjust front-haul capacity based on UE load and optimize bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant bit-rate signals are transmitted in C-RAN architecture, then reliable communication is ensured, but front-haul bandwidth is wasted when UE load is low
Solution Approach 1:
The patent implements dynamic bit-rate adjustment in the front-haul link by using variable bit-rate network links (such as FlexE) that can adapt their capacity based on real-time UE load conditions. The front-haul controller monitors spectrum occupancy and dynamically provisions capacity, allowing the system to transition from static constant bit-rate transmission to dynamic variable bit-rate transmission that matches actual traffic demands.
Solution Approach 2:
The patent changes the bit-rate parameter of the front-haul link from a fixed constant value to a variable value that adjusts according to UE load. By monitoring spectrum occupancy and UE density, the system modifies the bit-rate parameter in real-time, enabling efficient bandwidth utilization while maintaining communication reliability through adaptive capacity provisioning.
2Loss of energy
If frequency domain I/Q split is implemented, then front-haul bandwidth is reduced, but queueing delay increases
Solution Approach 1:
The patent applies dynamic capacity allocation to compensate for the increased queueing delay introduced by frequency domain I/Q split. The front-haul controller monitors traffic conditions and dynamically adjusts front-haul capacity provisioning, ensuring that sufficient bandwidth is allocated during high-load periods to maintain low latency while still achieving overall bandwidth efficiency through the frequency domain split architecture.
Solution Approach 2:
The patent implements feedback mechanisms where the front-haul controller continuously monitors traffic conditions, queueing delays, and spectrum occupancy. Based on this feedback, the controller dynamically adjusts capacity provisioning and bit-rate allocation to balance the trade-off between bandwidth efficiency and latency performance, ensuring that queueing delay remains acceptable even with frequency domain I/Q split.
3Reliability
If front-haul capacity is scaled linearly with network parameters, then communication quality is maintained, but bandwidth consumption increases
Solution Approach 1:
The patent changes the scaling relationship from linear to adaptive by implementing dynamic bit-rate adjustment based on actual UE load and spectrum occupancy. Instead of scaling front-haul capacity linearly with network parameters such as number of antenna ports, sampling rate, or carriers, the system adjusts the bit-rate parameter dynamically to match actual traffic demands, maintaining communication quality while significantly reducing bandwidth consumption during low-load conditions.
Solution Approach 2:
The patent applies partial action by provisioning front-haul capacity only when needed, rather than maintaining full capacity continuously. The system scales capacity partially according to actual UE load, activating additional bandwidth resources only during high-demand periods while reducing or eliminating excess capacity during low-load periods, thereby avoiding linear scaling of bandwidth consumption.
Data Source
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AI summary
A front-haul controller for a network coupling a BBU and an RRH that exchanges RF analog signals with a supported UE. The network comprises a plurality of nodes coupled by variable bit-rate network communications links. The BBU exchanges packets of frequency-domain samples with the RRH along the network. The front-haul controller monitors information about wireless spectrum occupancy at the RRH and at least one spectrum occupancy threshold and varies a bit-rate of the network link in accordance therewith. The front-haul controller can proactively adjust the bit-rate and/or the threshold during periods associated with at least one event that may impact the spectrum occupancy. The network link can be a FlexE, SONET, DWDM, LAG and/or ECMP link.