Narrowband UE Multi-Channel LBT Synchronization
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Solution Overview
Problem
Narrowband wireless communication devices in unlicensed or shared spectra face inefficiencies due to their inability to monitor multiple channels simultaneously, leading to underutilization of wideband mediums as they can only serve when their base station gains access to the monitored channel, resulting in missed channel occupancy indications.
Innovation Solution
Base stations synchronize channel occupancy indications with narrowband user equipment (UE) monitoring schedules, configuring UE to switch between channels during specific monitoring occasions, and repeating occupancy indication signals to ensure detection, thereby improving medium utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If narrowband UE monitors one channel at a time in a wide system band, then the UE can detect channel occupancy indications, but the wideband medium becomes underutilized when the BS gains access to channels the UE is not monitoring
Solution Approach 1:
The system divides the wide system band into multiple narrowband channels and segments the monitoring task across time. The UE monitors one narrowband channel at a time according to a configured monitoring occasion pattern, while the BS performs LBT on multiple channels and transmits occupancy indications on the monitored channel during the UE's active monitoring periods.
Solution Approach 2:
The BS performs LBT and determines channel occupancy in advance before the UE needs to monitor. The BS transmits occupancy indication signals on the monitored channel before the UE's monitoring occasion begins, ensuring the UE receives the information it needs without having to monitor all channels simultaneously.
Solution Approach 3:
The system implements periodic monitoring occasions where the UE alternates between monitoring different narrowband channels at predetermined time intervals. The BS repeats occupancy indication transmissions during these periodic monitoring occasions to ensure reliable detection despite the UE's limited simultaneous monitoring capability.
2Adaptability or versatility
If narrowband UE switches between channels to monitor multiple channels, then more channels can be monitored, but the probability of missing occupancy indications increases due to switching delays
Solution Approach 1:
The BS transmits occupancy indication signals on the monitored narrowband channel before the UE's monitoring occasion begins. This preliminary transmission ensures the UE detects the indication without needing to switch channels during the critical detection window, eliminating switching delays.
Solution Approach 2:
The system configures periodic monitoring occasions with sufficient duration and spacing to allow the UE to switch between narrowband channels reliably. The periodic repetition of occupancy indications across multiple monitoring occasions provides redundancy, ensuring detection even if a single occasion is missed during channel switching.
3Productivity
If the BS performs LBT on multiple channels simultaneously, then spectrum utilization improves, but narrowband UEs cannot monitor all channels and thus cannot be served on channels they are not monitoring
Solution Approach 1:
The system segments the wide system band into multiple narrowband channels and divides the monitoring burden by assigning specific monitoring occasions to specific channels. The UE only needs to monitor its assigned narrowband channel during its monitoring occasions, greatly simplifying operation while the BS maintains multi-channel LBT capability.
Solution Approach 2:
The monitored narrowband channel acts as an intermediary between the BS's multi-channel LBT operations and the UE's limited monitoring capability. The BS transmits occupancy indications on the narrowband channel, which mediates the information transfer from the wideband system to the narrowband UE.
Data Source
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AI summary
Wireless communications systems and methods related to communications with narrowband wireless communication devices over a wide frequency band are provided. A first wireless communication device transmits a first configuration indicating a first set of channel monitoring occasions for a first channel and a second set of channel monitoring occasions for a second channel. The first wireless communication device transmits, in the first channel based on at least a listen- before-talk (LBT) in the first channel, a first occupancy indication signal indicating a first transmission opportunity (TXOP) in the first channel. The first wireless communication device transmits, in the first channel based on the first configuration, a second occupancy indication signal associated with the first TXOP in the first channel during a channel monitoring occasion of the first set of channel monitoring occasions within the first TXOP.