Joint Communication and Sensing RACH Preamble Retransmission via Backscatter
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Solution Overview
Problem
Existing 5G technologies face challenges in managing frequency band convergence with radar 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 RACH preamble re-transmission interval, to facilitate backscatter measurement-based multiple random access channel (RACH) preamble transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate communication and sensing platforms are used, then functionality is provided, 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 radar sensing measurements. This merging eliminates the need for separate independent platforms, directly resolving the technical contradiction by providing joint capability while reducing complexity.
Solution Approach 2:
The reference signal in the patent is designed to perform multiple functions simultaneously. It serves as both a communication reference signal for channel estimation and a radar reference signal for sensing measurements. This multi-functionality allows a single system component to fulfill both communication and sensing roles, addressing the contradiction by providing versatility without increasing platform complexity.
2Measurement precision
If backscatter power measurement is performed to determine blockage, then sensing accuracy is improved, but measurement and control complexity increases
Solution Approach 1:
The same reference signal is used for both communication channel estimation and sensing measurements. The base station transmits a reference signal that enables the UE to perform both communication functions and backscatter power measurements for blockage detection using identical signal resources, thereby improving measurement precision without significantly increasing system complexity.
Solution Approach 2:
The UE autonomously measures the backscatter power of the received reference signal and independently determines whether blockage exists based on comparing measured power against threshold values. The UE also autonomously selects whether to transmit a RACH preamble or RAR message based on its blockage determination. This self-service approach improves measurement precision while minimizing additional complexity by leveraging existing UE capabilities.
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 efficient and cost-effective joint handling of communications and sensing by allowing the WTRU to adapt beamforming and retransmit RACH preambles based on backscatter power measurements, improving system performance and reducing complexity.
Implementation Method 1
measure a backscatter power of the transmitted RACH preamble
Implementation Method 2
transmit a RACH preamble in a RACH occasion corresponding to a preferred synchronization signal block (SSB) index, using an 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.