NR Random Access Using Beam-Specific Synchronization
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Solution Overview
Problem
The severe path loss and non-line-of-sight losses in millimeter wave systems, such as diffraction, penetration, and oxygen absorption, limit the coverage area and reliability of 5G New Radio (NR) communications, particularly in diverse deployment scenarios.
Innovation Solution
A method and system for determining beam reciprocity in wireless transmit/receive units (WTRUs) by using downlink beams for synchronization, TRP TX/RX beam correspondence information, and selecting appropriate WTRU TX beams for data transmission, based on NR-PBCH reception and resources, to enhance beamforming and random access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If millimeter wave frequencies are used to increase data rate and spectrum efficiency, then higher data rate and spectrum efficiency are achieved, but severe path loss and non-line-of-sight losses occur
Solution Approach 1:
The patent segments the random access procedure into beam-specific steps, where the WTRU determines TRP TX/RX beam correspondence information separately for each downlink beam, allowing targeted beam selection that overcomes path loss by focusing energy in specific directions
Solution Approach 2:
The patent changes the parameter of beam correspondence information determination by using de-masking of NR-PBCH CRC mask, NR-PBCH resources, NR-PBCH payload, or SIB to derive beam-specific parameters that enable reliable communication despite millimeter wave propagation challenges
2Area of stationary object
If beamforming is implemented to overcome path loss, then coverage area is extended, but device complexity increases due to beam management procedures
Solution Approach 1:
The patent makes the downlink beam serve multiple functions: it is used for synchronization, for determining TRP TX/RX beam correspondence information, and for selecting uplink transmit beams, thereby extending coverage without proportionally increasing complexity through a single unified beam management approach
Solution Approach 2:
The patent performs preliminary determination of beam correspondence information using downlink beam measurements before actual uplink transmission, allowing the WTRU to pre-select appropriate transmit beams and reduce complexity during the actual data transmission phase
Data Source
AI summary
A wireless transmit/receive unit (WTRU) may receive, from a base station, a synchronization signal/physical broadcast channel (SS/PBCH) block transmission. The WTRU may transmit using a physical random access channel (PRACH) resource. Further, the PRACH resource may be determined based on an SS/PBCH block index. Also, the SS/PBCH block index may be determined based on information associated with the SS/PBCH block transmission. In a further example, the information associated with the PBCH block may be derived from a demodulation reference signal (DMRS) sequence. In another example, the DMRS sequence may be a PBCH DMRS sequence. Also, the information associated with the PBCH block may be derived from PBCH payload bits. Further, the SS/PBCH block index may be associated with a beam. In addition, SS/PBCH transmissions of different beams may be transmitted at different times. Further, the PRACH resource may include a preamble resource, a time resource and a frequency resource.