NB-IoT CINR Estimation via DL-RSRP and Path Loss
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Solution Overview
Problem
NB-IoT UE devices face challenges in accurately estimating and reporting carrier to interference plus noise ratio (CINR) during random access procedures, especially on non-anchor carriers, due to unpredictable radio conditions and the unavailability of narrowband reference signals, leading to stale or inaccurate measurements.
Innovation Solution
The method involves receiving a random access response with signals via multiple physical channels, estimating CINR based on these signals, and sending the CINR and connection request to the base station, allowing for accurate reporting without requiring CINR estimation in idle mode and reducing power consumption and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NB-IoT UE performs measurements on anchor carrier during random access procedure, then measurement reporting can be established, but the measurements become stale or outdated and do not reflect the actual channel conditions on non-anchor carriers
Solution Approach 1:
The patent applies preliminary action by having the UE estimate CINR on the non-anchor carrier before initiating the random access procedure. This preliminary CINR estimation is performed using the downlink reference signal received power (DL-RSRP) and downlink path loss information available prior to random access. By performing this measurement in advance, the UE ensures that accurate and timely channel quality information is available when needed for uplink transmission power control, eliminating the delay and inaccuracy associated with post-random-access measurements.
2Measurement precision
If NB-IoT UE performs accurate CINR estimation on non-anchor carriers, then channel quality assessment improves, but the complexity of the measurement and reporting process increases
Solution Approach 1:
The patent uses DL-RSRP as an intermediary parameter to facilitate CINR estimation on non-anchor carriers. Instead of directly measuring CINR which would require complex reference signal processing and interference measurement, the UE leverages the already-available DL-RSRP measurement combined with downlink path loss information to derive the CINR. This intermediary approach simplifies the measurement process while maintaining accuracy, as DL-RSRP is already part of the standard NB-IoT measurement set and the path loss can be calculated from existing uplink-downlink synchronization information.
Solution Approach 2:
The patent applies self-service by enabling the UE to autonomously perform CINR estimation using its own existing measurements (DL-RSRP) and calculated parameters (path loss). The UE independently derives the CINR value without requiring additional network assistance, configuration, or complex measurement procedures. This self-service approach reduces system complexity while providing accurate channel quality information for random access optimization.
3Reliability
If NB-IoT UE performs measurements in idle mode, then channel conditions can be assessed, but power consumption increases
Solution Approach 1:
The patent applies partial action by having the UE perform only the necessary CINR estimation at the specific moment when it needs to initiate a random access procedure, rather than continuously monitoring channel conditions in idle mode. The UE leverages existing DL-RSRP measurements and path loss calculations that are already maintained for other purposes, performing the CINR derivation only when required for uplink transmission planning. This selective, on-demand approach provides accurate channel quality assessment without the continuous power consumption associated with persistent idle mode measurements.
Data Source
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AI summary
An aspect of the present disclosure includes methods, systems, and computer-readable media for receiving, at the UE, a random access response including a first signal via a first physical channel and a second signal via a second physical channel from a base station (BS), generating a connection request based on the random access response, estimating a carrier to interference plus noise ratio (CINR) of a random-access channel based on at least one the first signal or the second signal, and sending a message including the CINR and the connection request to the BS in response to the random access response.