Secondary Cell Activation in Massive MIMO Systems
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Solution Overview
Problem
In massive MIMO systems, determining and exchanging downlink Tx beam and uplink Rx beam information for secondary cells is challenging when primary and secondary cells are served by different eNodeBs, complicating carrier aggregation and throughput enhancement in 5G networks.
Innovation Solution
The implementation of Beam Reference Signal Receiving Power (BRS-RP) measurement and Physical Random Access Channel (xPRACH) scanning to select the best Tx and Rx beams, along with the use of medium access control (MAC) elements for activating or deactivating secondary cells, enables efficient beam acquisition and management across multiple eNodeBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with primary and secondary cells served by different eNodeBs, then spectral efficiency and throughput are improved, but beam information exchange and cell management complexity increase
Solution Approach 1:
The patent introduces an intermediary mechanism where the primary cell serves as a mediator for beam information exchange. The UE first establishes beam information with the primary cell eNodeB, which then facilitates the exchange of beam information with the secondary cell eNodeB. This intermediary approach simplifies the overall complexity by providing a coordinated point of reference rather than requiring direct complex exchanges between all components.
Solution Approach 2:
The patent applies preliminary action by establishing beam information and cell configuration for the primary cell before attempting to add secondary cells. The UE and network prepare beam information, reference signals, and measurement configurations in advance through the primary cell relationship, which then serves as a foundation for efficiently managing secondary cell additions and beam exchanges.
2Measurement precision
If beam reference signal measurements and xPRACH scanning are performed for secondary cell activation, then beam selection accuracy is improved, but signaling overhead and activation time increase
Solution Approach 1:
The patent performs preliminary beam sweeping and reference signal transmission before actual secondary cell activation. The eNodeB transmits beam reference signals and the UE performs measurements in advance, preparing beam information that can be quickly utilized during activation. This preliminary preparation reduces the time required during the actual activation phase while maintaining measurement accuracy.
Solution Approach 2:
The patent implements a streamlined activation process where, once beam information is established through preliminary measurements, the actual activation proceeds rapidly by skipping unnecessary repeated measurement steps. The system rushes through the activation phase using pre-established beam information, reducing delays while maintaining the accuracy benefits of thorough initial measurements.
Data Source
AI summary
Embodiments of enabling a secondary cell in a massive MIMO system are generally described herein. An example apparatus of UE may include memory and processing circuitry to configure a MIMO transceiver to establish primary cell transmit and receive channels for communication with an eNodeB, and to receive a secondary cell addition signal that includes a preamble index for a secondary cell. The processing circuitry further configures the MIMO transceiver to receive beam reference signals (BRS), and select one of the BRS from the eNodeB as a secondary cell transmit channel for the secondary cell based on detected BRS receive power. The processing circuitry further configures the MIMO transceiver to provide information for the selected BRS, and provide xPRACH transmissions that include a transmit index to the eNodeB. The processing circuitry further configures the MIMO transceiver to receive selection of one of the xPRACH transmissions as a secondary cell receive channel.