Beam-forming Vector Weight Selection in Combined Radio Cells
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Solution Overview
Problem
In combined radio cell deployments, transmitting the same signal from each network node can lead to suboptimal throughput due to random phase differences among antennas, resulting in signal cancellation and power wastage for some user equipment (UEs), which decreases achievable throughput.
Innovation Solution
The method involves creating and transmitting probing pilots multiplied by beam-forming vector weights, receiving channel quality feedback, ranking these weights, and selecting the optimal weight for data and control channel transmission to improve signal alignment and maximize throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same signal is transmitted from each network node in a combined radio cell deployment, then the implementation is simple and uniform, but random phase differences among antennas cause signal cancellation and decrease throughput
Solution Approach 1:
The patent applies parameter changes by introducing beam-forming vector weights that modify the phase and amplitude parameters of signals transmitted from different antennas. Instead of transmitting identical signals with random phases, the system multiplies probing pilots by specific beam-forming weights selected from a codebook, thereby controlling the phase relationships to prevent signal cancellation and maximize throughput.
2Productivity
If beam-forming vector weights are used to improve signal alignment, then throughput increases, but the complexity of selecting and managing multiple weights increases
Solution Approach 1:
The patent implements preliminary action by pre-defining a codebook of beam-forming weights before actual communication occurs. The system evaluates multiple pre-prepared weight options by transmitting probing pilots with different weights and selecting the optimal one based on channel quality feedback, thereby avoiding the need to compute and manage complex weight combinations in real-time.
Solution Approach 2:
The system employs feedback mechanisms where user equipment reports channel quality indicators (CQI) for different beam-forming weights. Based on this feedback, the network node selects the optimal beam-forming weight from the codebook, creating a closed-loop system that adapts to channel conditions while managing complexity through structured feedback rather than exhaustive optimization.
3Productivity
If multiple beam-forming weights are evaluated through probing pilots, then the optimal weight can be selected for maximum throughput, but the time and signaling overhead increase
Solution Approach 1:
The patent applies partial action by evaluating only a limited set of beam-forming weights from the codebook rather than exhaustively testing all possible weight combinations. The system transmits probing pilots with selected weights and stops evaluation once sufficient channel quality information is obtained, thereby achieving adequate throughput optimization without excessive time consumption.
Data Source
AI summary
The present disclosure relates to radio communication and, more particularly, to beam-forming in a combined radio cell deployment. In one example embodiment, the disclosure presents a method performed by a network node operating in a combined radio cell, wherein the method comprises creating a probing pilot (e.g., a F-CPICH) which is multiplied with a beam-forming vector weight; and transmitting a first radio signal to a UE, the first radio signal comprising the created probing pilot multiplied with the beam-forming vector weight.