Uplink Signal Combining Node Selection in Combined Cells
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Solution Overview
Problem
The operation of signal combining on uplink radio signals in combined cells served by multiple radio nodes in cellular networks is often imperfect, leading to frequent re-transmissions, increased interference, and potential connection loss due to poor channel estimation by some nodes.
Innovation Solution
A controlling node in the cellular network receives signal quality information from User Equipment (UE) on node-specific probing pilot signals and selects a subset of radio nodes with the best signal quality for signal combining, excluding nodes that would deteriorate the process, thereby improving signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If signal combining is performed on uplink radio signals received by multiple radio nodes, then the coverage and capacity of the combined cell is improved, but the signal combining operation becomes imperfect leading to frequent re-transmissions and increased interference
Solution Approach 1:
The patent changes the parameter of signal quality threshold to filter radio nodes. By evaluating signal quality metrics (such as RSRP, RSRQ, or SINR) and comparing against thresholds, the system dynamically adjusts which radio nodes participate in signal combining, thereby improving the reliability of the combining operation while maintaining coverage.
Solution Approach 2:
The patent extracts problematic radio nodes from the signal combining process. By identifying and excluding radio nodes that provide poor quality signals (below threshold), the system removes the harmful elements that cause imperfect combining, frequent re-transmissions, and increased interference, while retaining beneficial nodes.
2Device complexity
If all radio nodes in a combined cell participate in signal combining, then the network complexity is reduced, but nodes with poor channel estimation deteriorate the signal combining process
Solution Approach 1:
The patent applies local quality assessment to each radio node individually. Instead of treating all nodes uniformly, the system evaluates the signal quality locally at each node (or from UE measurements) and makes node-specific decisions about participation in signal combining. This allows high-quality nodes to contribute while isolating poor-quality nodes that generate harmful interference.
3Loss of information
If signal combining is performed without node selection, then the signaling overhead is reduced, but the UE is required to make frequent re-transmissions and increase transmit power
Solution Approach 1:
The patent performs preliminary evaluation of radio node signal quality before the actual signal combining operation. By assessing node quality in advance (using reference signals or pilot measurements) and pre-selecting suitable nodes, the system avoids subsequent failed combining attempts that would require re-transmissions and additional UE power consumption.
Data Source
AI summary
A method and controlling node (500) to control a signal combining operation performed on uplink radio signals transmitted from a User Equipment, UE, in a combined cell served by multiple radio nodes (502). Signal quality information (SQ) is received from the UE indicating a signal quality measured by the UE on a node-specific probing pilot signal (PS1-PS4) transmitted from each of the multiple radio nodes, and a subset (RN2-RN3) of the multiple radio nodes is selected based on the received channel quality information. The signal combining operation is then performing (204) on the uplink radio signals received by the selected subset of the multiple radio nodes. Thereby, the performance of the signal combining operation can be improved.