PRACH Power Config for LTE-NR Spectrum Sharing
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently sharing spectrum between 3GPP LTE and new radio access technology (NR) due to limitations in beamforming methods, particularly in cost-effectiveness and frequency selective beaming, which restricts the simultaneous transmission of multiple beam directions across different frequency bands.
Innovation Solution
A method and apparatus for spectrum sharing between LTE and NR, enabling the transmission of physical random access channels (PRACH) using distinct power configurations for NR and LTE bands, allowing for flexible PRACH configurations to optimize beamforming and spectrum utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transceiver unit (TXRU) is provided for each antenna element to enable independent beamforming, then beamforming gain and coverage are improved, but cost effectiveness deteriorates
Solution Approach 1:
The patent segments the beamforming function into two separate parts: digital beamforming at a reduced number of TXRUs and analog beamforming at the antenna elements. This segmentation allows the system to achieve high beamforming gain through analog processing at each antenna element while avoiding the high cost of providing a TXRU at every element, thus resolving the contradiction between reliability and cost effectiveness.
Solution Approach 2:
The patent introduces a new dimension of analog phase shifters at the antenna element level, working in conjunction with digital TXRUs. This dimensional addition enables fine-grained phase control at each antenna element, achieving high beamforming gain without requiring full digital processing at every element, thereby improving reliability while controlling costs.
2Ease of manufacture
If analog beamforming is used to reduce cost, then cost effectiveness is improved, but frequency selective beaming capability deteriorates
Solution Approach 1:
The patent divides the beamforming processing into digital and analog segments. The digital TXRUs handle frequency-selective beamforming calculations and control, while the analog phase shifters at antenna elements execute the phase adjustments. This segmentation enables frequency selective beaming capability to be maintained through digital processing while using cost-effective analog hardware at the antenna level.
Solution Approach 2:
The patent introduces digital signal processing as an intermediary between the control system and the analog antenna elements. This digital intermediary calculates frequency-selective beamforming weights and controls the analog phase shifters, thereby enabling frequency selective beaming capability while using cost-effective analog hardware, resolving the contradiction between cost effectiveness and adaptability.
3Productivity
If spectrum sharing between LTE and NR is implemented, then spectral efficiency is improved, but system complexity deteriorates
Solution Approach 1:
The patent segments the PRACH configuration into separate configurations for LTE and NR bands. Each band has its own PRACH parameters, power settings, and resource allocations. This segmentation allows the system to manage spectrum sharing by handling each band independently, reducing the complexity of coordinating multiple technologies while improving spectral efficiency through unified spectrum utilization.
Solution Approach 2:
The patent implements dynamic PRACH power configuration where the UE can select appropriate PRACH power levels based on the target band (LTE or NR). This dynamic adaptation allows the system to efficiently share spectrum between LTE and NR by adjusting transmission parameters in real-time, improving spectral efficiency while managing system complexity through flexible, condition-based configuration.
Data Source
AI summary
A method and apparatus for transmitting a physical random access channel (PRACH) in a wireless communication system is provided. A user equipment (UE) receives multiple PRACH configurations which include a first PRACH configuration for new radio access technology (NR) downlink/uplink (DL/UL) carrier in a NR band and a second PRACH configuration for a supplemental UL carrier in a long-term evolution (LTE) band, and transmits at least one of a first PRACH for accessing the NR DL/UL carrier in the NL band by using a first PRACH power based on the first PRACH configuration, or a second PRACH for accessing the supplemental UL carrier in the LTE band by using a second PRACH power based on the second PRACH configuration. The first PRACH configuration and the second PRACH configuration include different PRACH power configurations.