Multi-Band Signal Combining to Reduce RRU Ports and PIM
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Solution Overview
Problem
Current radio remote units (RRUs) supporting multiple frequency bands face challenges in avoiding passive intermodulation (PIM) issues while also efficiently reducing the number of antenna ports used.
Innovation Solution
A signal processing apparatus comprising power amplification and filtering modules, along with a combiner unit, separates and combines signals from different frequency bands based on preset conditions, allowing for effective PIM avoidance and reduced port usage by sending combined signals through fewer ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antenna ports are used to support multiple frequency bands, then the RRU can transmit signals belonging to multiple frequency bands, but the quantity of antenna ports increases
Solution Approach 1:
The patent combines signals from different frequency bands through a combiner unit before transmission. Multiple frequency band signals are merged into a single combined signal that can be transmitted through one antenna port, reducing the total quantity of ports required while maintaining support for multiple frequency bands
2Quantity of substance
If signals from different frequency bands are combined, then the quantity of antenna ports is reduced, but passive intermodulation (PIM) problems occur
Solution Approach 1:
The patent applies preliminary filtering to each frequency band signal before combination. Filter units remove unwanted frequency components and intermodulation products from each signal path before the signals are combined, preventing PIM problems from occurring in the first place rather than dealing with them after combination
3Ease of manufacture
If frequency band combinations are coupled with port assignments, then power amplifier development is simplified, but the system cannot flexibly adapt to different frequency band combinations
Solution Approach 1:
The patent creates a universal signal processing architecture where the combiner unit can handle any combination of frequency bands through a standardized interface. The filter units are designed to be configurable for different frequency ranges, allowing the same hardware structure to adapt to various frequency band combinations without requiring dedicated power amplifiers for each specific combination
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
The solution effectively reduces the number of antenna ports required while preventing PIM issues, enabling timely communication and simplifying the development of power amplifiers by decoupling frequency band combinations from port assignments.
Implementation Method 1
The first power amplifier is configured to: perform power amplification on a received first signal, to obtain a second signal
Implementation Method 2
The first filter unit is configured to: receive the second signal sent by the first power amplifier, and filter the second signal, to obtain a first sub-signal belonging to the first frequency band and a second sub-signal belonging to the second frequency band
Implementation Method 3
The combiner unit is configured to: combine the first sub-signal and i (1≤i≤n, and i is an integer) sub-signals in the n sub-signals based on a preset condition, to obtain a first combined signal
Data Source
AI summary
Example access network devices are described. One example access network device includes a signal processing apparatus. The signal processing apparatus includes a first power amplifier, a second power amplifier, a first filter, a second filter, and a combiner. The first filter filters a second signal obtained by the first power amplifier, to obtain a first sub-signal belonging to a first frequency band and a second sub-signal belonging to a second frequency band. The second filter filters a fourth signal obtained by the second power amplifier, to obtain n sub-signals including at least a third sub-signal belonging to a third frequency band. The combiner combines the first sub-signal and i sub-signals in the n sub-signals based on a preset condition, to obtain a first combined signal. The communication module sends the first combined signal by using a first port, and sends the second sub-signal by using a second port.