Cross-Band Random Access for 5G Spectrum Sharing
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Solution Overview
Problem
Current wireless communication systems face interference and communication inefficiencies due to the need for multiple network operating entities to contend for shared radio frequency spectrum, leading to increased signaling overhead and latency, especially in 5G networks with diverse deployments and services.
Innovation Solution
A method and apparatus for a user equipment (UE) to search for system information signals in both low-band and high-band spectra, transmit random access requests, receive responses, and resolve contention across different spectra, enabling joint low-band and high-band operation to optimize access and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple network operating entities contend for shared radio frequency spectrum, then spectrum utilization is achieved, but interference increases and communication efficiency decreases
Solution Approach 1:
The patent segments the random access procedure into two distinct phases operating on different frequency bands: initial access messages (Msg1-Msg3) are transmitted on one band while response messages (Msg2-Msg4) are transmitted on another band. This segmentation allows different network entities to operate on different bands simultaneously, reducing interference while maintaining spectrum utilization.
Solution Approach 2:
The patent introduces a frequency band dimension to the random access communication by enabling cross-band message exchange. Instead of all messages traveling on the same frequency band, the system transitions messages between bands (e.g., transmitting on low-band, receiving response on high-band), adding a spectral dimension to reduce contention and interference.
2Object-affected harmful factors
If joint low-band and high-band operation is implemented, then interference is reduced, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure cross-band random access parameters through system information broadcasting before the actual random access procedure begins. The UE receives and stores configuration information indicating which bands to use for transmitting and receiving random access messages, eliminating the need for real-time band selection decisions and reducing device complexity during execution.
3Loss of time
If cross-band random access message exchange is used, then latency is reduced, but signaling overhead increases
Solution Approach 1:
The patent merges the random access configuration information for both low-band and high-band operations into a single system information broadcast. The configuration includes parameters for both bands (e.g.,rach-ConfigCommonLow, rach-ConfigCommonHigh), allowing the UE to obtain all necessary cross-band random access parameters in one signaling event rather than multiple separate configurations.
Data Source
AI summary
A joint low-band and high-band operation is disclosed for use in new radio (NR) shared spectrum (NR-SS) networks. In such networks, uplink and downlink communications may occur over separate bands, selected based on performance or quality characteristics. A user equipment (UE) may search each of one or both of a low-band spectrum and a high-band spectrum for system information signal that includes both a low-band random access configuration and a high-band random access configuration. The UE transmits a random access request on one of the bands and receives the random access response from one or more cells on the other band. The UE continues the random access procedure, transmitting the uplink message based on the random access response on the first band to a selected cell. The UE would then receive the contention resolution message from the selected cell on the second band.