MTC UE Spectrum Access via Base Station CCA
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently utilizing shared radio frequency spectrum for machine type communication (MTC) devices, particularly in performing clear channel assessments (CCAs) over narrowband regions to accommodate bundled transmissions, which can lead to interference and reduced coverage for MTC UEs.
Innovation Solution
A method is introduced where a base station performs a channel clear assessment (CCA) over a wideband region, transmitting a wideband preamble to reserve the spectrum for a period that includes the duration of bundled transmissions, followed by a narrowband preamble to reserve specific narrowband regions, allowing MTC UEs to communicate without performing a CCA, thus enhancing coverage and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MTC UEs perform CCA operations on narrowband regions in shared radio frequency spectrum, then spectrum access capability is improved, but coverage is reduced and interference increases
Solution Approach 1:
The patent segments the spectrum access process into two distinct parts: a wideband CCA performed by the base station over the entire SRFS band, and narrowband preambles transmitted in specific narrowband regions. This segmentation allows the base station to perform a single wideband assessment while providing targeted narrowband access for MTC UEs, thereby improving coverage without requiring each UE to perform separate CCA operations on every narrowband region.
Solution Approach 2:
The base station acts as an intermediary that performs the wideband CCA operation on behalf of multiple MTC UEs. Instead of each UE independently performing CCA, the base station conducts the assessment and then transmits narrowband preambles to indicate available narrowband regions. This intermediary approach reduces interference and improves coverage by centralizing the CCA function.
2Object-affected harmful factors
If MTC UEs perform CCA operations on narrowband regions, then interference reduction is achieved, but device complexity and operation difficulty increase
Solution Approach 1:
The patent implements a self-service mechanism where the base station automatically performs wideband CCA operations and transmits narrowband preambles to indicate available regions. MTC UEs simply need to detect these preambles and access the indicated narrowband regions without performing their own CCA operations. This self-service approach at the base station level reduces interference while keeping UE operations simple and straightforward.
Solution Approach 2:
The base station performs preliminary CCA actions before MTC UEs attempt to access the spectrum. By conducting the wideband assessment in advance and transmitting narrowband preambles to pre-indicate available regions, the base station eliminates the need for UEs to perform complex CCA operations, thereby reducing interference while maintaining ease of operation.
3Productivity
If base station performs wideband CCA and transmits preambles to reserve spectrum, then spectrum reservation efficiency is improved, but use of energy increases
Solution Approach 1:
The patent applies local quality by transmitting narrowband preambles only in specific narrowband regions where spectrum is available, rather than broadcasting across the entire wideband spectrum. This localized approach allows the base station to perform efficient spectrum reservation by targeting only the necessary frequency regions, thereby improving reservation efficiency while minimizing energy consumption compared to wideband transmissions.
Data Source
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AI summary
Aspects of the present disclosure provide techniques utilizing shared radio frequency spectrum (SRFS) for certain devices, such as machine type communication(s) (MTC) user equipments (UEs) and evolved or enhanced MTC (eMTC) UEs. An exemplary method, performed, for example, by a base station (BS), includes performing a channel clear assessment (CCA) for at least a portion of the SRFS including one or more narrowband regions, and communicating with at least one MTC UE, after performing the CCA, on at least one of the narrowband regions. A second exemplary method, performed, for example, by a MTC UE, generally includes receiving, from a BS, an assignment of resources in a narrowband region of the SRFS band for the MTC UE to use for communicating with the BS, and communicating with the BS on the narrowband region without performing a CCA for the narrowband region.