NB-IoT Reserved Resource Granularity for Better Channel Estimation
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently coexisting and improving channel estimation for narrowband Internet of things (NB-IoT) and new radio (NR) communications, particularly due to subframe-level resource reservations that degrade performance in low signal-to-noise ratio regimes.
Innovation Solution
Implementing finer granularity resource reservations, such as symbol-level or slot-level reservations, to allow NB-IoT and LTE-MTC transmissions in only a portion of a subframe, and determining whether narrowband reference signals (NRSs) or demodulation reference signals (DMRSs) are dropped based on reserved resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If subframe-level resource reservations are used for NB-IoT and NR coexistence, then resource allocation simplicity is maintained, but channel estimation performance degrades in low signal-to-noise ratio regimes
Solution Approach 1:
The patent segments the subframe-level resource reservation into finer granularity levels (symbol-level or slot-level reservations). This segmentation allows NB-IoT and NR transmissions to occur in specific portions of a subframe rather than requiring entire subframe reservations, thereby maintaining resource allocation simplicity while preserving channel estimation performance by allowing reference signals to be placed in non-reserved portions.
2Measurement precision
If finer granularity resource reservations are implemented, then channel estimation performance improves, but resource allocation complexity increases
Solution Approach 1:
The patent extracts the reference signal resources from the reserved resources, determining whether NRSs or DMRSs are dropped based on the reserved resource configuration. This extraction approach allows the system to implement finer granularity reservations for NB-IoT/LTE-MTC transmissions while explicitly managing reference signal placement to maintain channel estimation accuracy without proportionally increasing overall system complexity.
3Productivity
If reference signals are placed in reserved resources, then resource usage efficiency increases, but channel estimation degradation occurs
Solution Approach 1:
The patent implements dynamic determination of reference signal placement based on the reserved resource configuration. The system dynamically decides whether NRSs or DMRSs are dropped and adjusts reference signal positioning accordingly, allowing flexible adaptation to different reservation patterns while maintaining both resource usage efficiency and channel estimation reliability.
Data Source
AI summary
Techniques for narrowband transmissions with finer granularity of reserved resources. A method that may be performed by a user equipment (UE) includes receiving a configuration indicating first resource elements (REs) reserved from being used for narrowband Internet of things (NB-IoT) transmissions in a subframe; determining second REs, in the subframe, for narrowband reference signals (NRSs), based on the configuration; and processing the NRSs on the second REs in the subframe.