Distributed RAN Gain Coordination for ADC Distortion Control
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Solution Overview
Problem
In mobile communications systems, especially in distributed radio access networks (RANs), the conversion of uplink radio frequency (RF) signals to digital signals can lead to distortion due to the limited dynamic range of analog-to-digital converters (ADCs), which affects communication quality and user experience.
Innovation Solution
A distributed RAN with a server apparatus and wireless transceiver nodes that employ variable gain amplifiers (VGAs) to adjust the power amplitude of uplink RF signals within the dynamic range of ADCs, and a coordinated amplifier gain optimization method where a common gain value is determined and applied across nodes to prevent distortion, using RF test signals and a control circuit to set effective gain values for VGAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If variable gain amplifiers are used to adjust signal amplitude to ADC dynamic range, then signal distortion is prevented, but device complexity increases
Solution Approach 1:
The system implements a feedback mechanism where the server apparatus receives information about the actual gain values applied by VGAs in distributed RAN nodes, compares them with target gain values, and sends correction commands to minimize the difference. This closed-loop feedback ensures signal quality while allowing the use of VGAs, thereby managing the complexity through intelligent control rather than hardware redesign.
Solution Approach 2:
The invention changes the operational parameters of VGAs dynamically based on received signal conditions. The server apparatus calculates optimal target gain values for each node based on measured signal characteristics and communicates these as parameter settings to the distributed nodes, allowing the system to adapt to varying conditions without increasing hardware complexity.
2Area of stationary object
If multiple distributed RAN nodes are deployed to improve coverage, then network coverage is enhanced, but coordination difficulty increases
Solution Approach 1:
The server apparatus performs multiple functions: it acts as a central coordinator for gain optimization, a signal quality monitor, a parameter calculator, and a command distributor. By consolidating these diverse functions into a single multi-functional server, the system manages the coordination of multiple distributed nodes without proportionally increasing overall system complexity.
Solution Approach 2:
The system enforces homogeneity by requiring all distributed RAN nodes to use the same VGA model with identical operational characteristics and to follow the same gain optimization protocol. This standardization simplifies coordination across geographically dispersed nodes, as the server apparatus deals with uniform devices rather than heterogeneous equipment.
3Manufacturing precision
If target gain values are calculated and communicated to distributed nodes, then signal distortion is reduced, but communication overhead increases
Solution Approach 1:
The system implements periodic gain optimization rather than continuous adjustment. The server apparatus calculates and communicates target gain values at specific intervals or when signal conditions change significantly, rather than continuously. This periodic action reduces communication overhead while maintaining signal quality within acceptable ranges between optimization cycles.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that uplink digital communications signals are processed without distortion, enhancing performance and user experience in the distributed RAN by maintaining signal quality across all nodes.
Implementation Method 1
a variable gain amplifier (VGA) to adjust the power amplitude of the uplink RF signal to the defined dynamic range of the ADC
Data Source
AI summary
A distributed radio access network (RAN) is provided. A selected wireless transceiver node(s) in a selected coverage cell receives a radio frequency (RF) test signal(s). The selected wireless transceiver node(s) determines an effective gain value based on a predefined characteristic of the RF test signal(s). The selected wireless transceiver node(s) communicates the effective gain value and other related parameters to a server apparatus in the distributed RAN. The server apparatus determines a common gain value for the selected wireless transceiver node(s) in the selected coverage cell based on the parameters. Accordingly, the selected wireless transceiver node(s) operates based on the common gain value. By determining a respective common gain value for each of the coverage cells in the distributed RAN, it may be possible for all the wireless transceiver nodes in the distributed RAN to communicate an uplink digital communications signal(s) without causing distortion in the uplink digital communications signal(s).