CRS Muting Carrier Access Control via MIB Scrambling
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Solution Overview
Problem
Legacy user equipment (UEs) that do not support cell-specific reference signal (CRS) muting are unable to demodulate and decode communications on carriers using CRS muting, leading to interference and resource overhead issues in wireless communication networks.
Innovation Solution
A method and apparatus for determining whether a carrier uses CRS muting, and adjusting the scrambling sequence of master information blocks (MIB) and physical broadcast channels (PBCH) accordingly, as well as configuring symbols for primary and secondary synchronization signals (PSS/SSS), to prevent UEs that do not support CRS muting from accessing these carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If CRS muting is enabled on a carrier, then interference is reduced and resource overhead is decreased, but legacy UEs cannot demodulate and decode communications on that carrier
Solution Approach 1:
The base station performs preliminary actions by determining whether a carrier uses CRS muting before transmitting MIB/PBCH, and accordingly determines the appropriate scrambling sequence. This preliminary determination ensures that legacy UEs can be prevented from camping on carriers they cannot properly receive, while allowing CRS muting to be applied where supported. The scrambling sequence is selected in advance based on the CRS muting status, preventing demodulation failures before they occur.
2Adaptability or versatility
If legacy UEs are allowed to access carriers using CRS muting, then network coverage is maintained, but demodulation failures and interference occur
Solution Approach 1:
The MIB scrambling sequence acts as an intermediary mechanism that mediates between legacy UEs and carriers using CRS muting. By using different scrambling sequences for MIB/PBCH based on whether CRS muting is applied, the system enables legacy UEs to successfully decode MIB on non-muted carriers while preventing them from camping on muted carriers. This intermediary approach maintains network coverage for legacy devices while preventing them from accessing carriers they cannot properly receive, thereby avoiding interference and demodulation failures.
3Adaptability or versatility
If scrambling sequence is adjusted based on CRS muting status, then UE compatibility is improved, but system complexity increases
Solution Approach 1:
The invention changes the parameter of MIB/PBCH scrambling sequence based on the CRS muting status of the carrier. By adjusting this specific parameter (scrambling sequence initialization) according to whether CRS muting is applied, the system achieves improved UE compatibility without requiring fundamental changes to the overall system architecture. The base station simply selects between different scrambling sequence initialization values based on the CRS muting configuration, which is a straightforward parameter adjustment rather than a complex system redesign.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a first information element (IE) and a second IE, wherein the first IE indicates whether all UEs that do not support cell-specific reference signal (CRS) muting are barred from a carrier and the second IE indicates whether all UEs that support CRS muting are barred from the carrier; and selectively access the carrier based at least in part on at least one of the first IE or the second IE. In some aspects, a UE may determine whether the UE supports cell-specific reference signal (CRS) muting; and transmit, to a base station, a capability report that indicates whether the UE supports CRS muting. Numerous other aspects are provided.