Uplink Reference Signal Rate Control for 5G Mobility
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Solution Overview
Problem
In dense cell deployments of 5G wireless communications networks, the conventional downlink reference signal measurement-based handover procedure is inefficient, leading to high signalling overhead and interference due to increased TRP density and misalignment of downlink transmissions, which affects mobility management and channel orthogonality.
Innovation Solution
The approach involves the terminal device periodically transmitting Uplink Reference Signals (URS) to allow the network to select the appropriate TRP for communication, with the transmission rate adjusted based on the device's speed and channel conditions, and Downlink Time Adjustment commands to synchronize downlink transmissions and maintain orthogonality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downlink reference signal measurement-based handover procedure is used in dense cell deployments, then mobility management can be performed, but signalling overhead and interference increase due to increased TRP density and frequent handovers
Solution Approach 1:
The patent inverts the conventional handover approach by switching from downlink measurement-based handover (UE measures downlink signals) to uplink measurement-based handover (network measures uplink signals from UE). This inversion reduces signalling overhead because the UE does not need to continuously measure and report downlink reference signals for every TRP, instead the network actively measures uplink signals to determine optimal TRP selection.
Solution Approach 2:
The patent introduces Synchronization Signal Blocks (SSBs) as intermediaries that carry both synchronization information and measurement references. The SSBs enable the network to perform uplink measurements while providing a structured framework for handover decisions, reducing the need for separate reference signal measurements and reports.
2Reliability
If downlink reference signal measurement-based handover procedure is used in dense cell deployments, then mobility management can be performed, but handover frequency and interruptions increase
Solution Approach 1:
The patent implements preliminary actions by having the network continuously measure uplink signals from the UE and pre-evaluate TRP candidates before handover is triggered. This allows the network to prepare handover decisions in advance, reducing the actual handover execution time and minimizing interruptions to the UE connection.
Solution Approach 2:
The patent establishes a feedback mechanism where the network continuously monitors uplink signal quality from the UE to different TRPs and provides feedback through SSBs and other control channels. This continuous feedback enables smoother handover transitions by keeping the UE connected to the optimal TRP without frequent disconnections and reconnections.
3Productivity
If TRP density is increased to support more devices, then network capacity increases, but channel orthogonality deteriorates due to downlink transmission misalignment
Solution Approach 1:
The patent applies dynamics by making the uplink transmission timing adjustable and adaptable to each UE's specific conditions. The network can dynamically configure the timing of uplink transmissions (e.g., PUCCH, PUSCH, SRS) to maintain orthogonality even as TRP density changes. This dynamic timing adjustment prevents persistent interference patterns that would occur with fixed timing in dense deployments.
Solution Approach 2:
The patent changes key parameters including uplink transmission timing, frequency resources, and sequence initialization values based on TRP identification and network conditions. By adjusting these parameters dynamically, the system maintains channel orthogonality across different TRPs even when TRP density increases, preventing interference and maintaining signal quality.
Data Source
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AI summary
A terminal device comprising telecommunications transceiver circuitry configured to transmit data to and receive data from a communication node in a telecommunications network and controller circuitry configured to control the transceiver circuitry is described. The controller circuitry is configured to: determine the speed of movement of the terminal device; and control the transceiver circuitry to transmit an uplink reference signal that allows the communication node to determine the channel quality between the communication node and the terminal device, wherein the rate of transmission of the uplink reference signal is determined by the speed of movement of the terminal device.