RACH Preamble Retransmission Using JCS Backscatter Measurement
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Solution Overview
Problem
Existing 5G technologies face challenges in managing frequency band convergence with radar and mobile communication systems, leading to increased complexity and cost in separate communication and sensing platforms.
Innovation Solution
Implementing a wireless transmit/receive unit (WTRU) with a Joint Communications and Sensing (JCS) Reference Signal (RS) configuration, including a JCS backscatter power fraction and minimum random access channel (RACH) preamble re-transmission interval, to facilitate backscatter measurement and adaptive beam management for efficient communication and sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate communication and sensing platforms are used, then reliability of independent operations is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines communication and sensing functions into a single integrated platform. The base station transmits reference signals that serve dual purposes: enabling communication channel estimation and enabling sensing through backscatter measurements from target devices. This merging eliminates the need for separate independent platforms while maintaining operational reliability through unified resource management.
Solution Approach 2:
The reference signal transmission mechanism is designed to perform multiple functions simultaneously. The same transmitted signal enables both communication operations (channel estimation, data transmission) and sensing operations (backscatter detection, target characterization) without requiring separate dedicated signals, thus achieving multi-functionality on a single platform.
2Device complexity
If joint communication and sensing platform is used, then device complexity is reduced, but measurement precision of backscatter power deteriorates
Solution Approach 1:
The base station performs preliminary channel estimation using reference signals before conducting backscatter measurements. By first characterizing the direct communication channel and then using this knowledge to isolate and measure the backscatter component, the system prepares the measurement environment in advance, thereby improving backscatter power measurement precision despite the integrated platform constraints.
Solution Approach 2:
The system uses feedback from channel state information and received signal measurements to iteratively refine backscatter power estimates. The base station adjusts its processing based on measured channel conditions and received power levels, improving measurement accuracy through continuous feedback loops that compensate for the challenges of the integrated platform.
3Measurement precision
If backscatter power measurement is optimized, then sensing accuracy is improved, but re-transmission interval increases
Solution Approach 1:
The system performs partial backscatter measurements using only the necessary portion of transmitted reference signals required for adequate measurement precision. By selecting minimal sufficient measurement opportunities rather than exhaustive measurements, the system achieves adequate sensing accuracy while minimizing the time required, thus reducing re-transmission intervals.
Solution Approach 2:
The system implements periodic backscatter measurements at optimized intervals rather than continuous monitoring. By performing measurements periodically at strategically selected moments when channel conditions are favorable and using predictive algorithms to maintain accuracy between measurements, the system achieves sustained sensing accuracy while minimizing measurement overhead and re-transmission delays.
4Productivity
If minimum random access channel preamble re-transmission interval is reduced, then system productivity is improved, but reliability of power control deteriorates
Solution Approach 1:
The system performs preliminary power level assessments and channel condition evaluations before initiating random access preamble re-transmissions. By pre-characterizing the channel and estimating required power levels in advance, the system can quickly re-transmit with appropriate power settings, achieving both reduced re-transmission intervals and maintained power control reliability through advance preparation.
Solution Approach 2:
The system uses self-service mechanisms where the base station autonomously adjusts power control parameters based on real-time backscatter measurements and channel state information without requiring extensive external coordination. This autonomous adaptation enables rapid power adjustments that maintain reliability while reducing re-transmission intervals, as the system serves its own power control needs based on immediate feedback.
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
Enables cost-effective and low-complexity joint handling of communications and sensing by optimizing backscatter power measurement and beam management, enhancing system efficiency and reducing re-transmission intervals.
Implementation Method 1
measure backscatter power (PBS) using a receive beam corresponding to the initial transmit beam
Data Source
AI summary
Systems, devices and methods for a backscatter measurement based multiple RACH preamble transmissions are disclosed. A WTRU may receive a JCS-RS configuration comprising a minimum RACH preamble retransmission interval. The JCS-RS configuration may comprise a JCS backscatter power fraction (λ) of the WTRU transmit power (PTx). The WTRU may transmit a RACH preamble in a RACH occasion corresponding to a preferred SS/PBCH Index using an initial WTRU transmit beam, having an associated first RA-RNTI value. The backscatter power (PBS) may be measured using the WTRU receive beam corresponding to the WTRU transmit beam used for the RACH preamble transmission. On a condition that PBS>λPTX, the WTRU may retransmit the RACH preamble after a retransmission interval, on resources associated with a second RA-RNTI value. The WTRU may be configured for monitoring the PDCCH common search space with the first RA-RNTI and the second RA-RNTI, for respective RAR window intervals.