NB-IoT Channel Quality Reporting for 16-QAM Modulation
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Solution Overview
Problem
Current narrowband Internet of Things (NB-IoT) channel quality reporting methods are insufficient for supporting 16-QAM modulation, as existing tables do not account for the increased data rates and power allocation changes, leading to inadequate selection of modulation and coding schemes (MCS) levels by the network, and lack of capability indication for 16-QAM modulation in user equipment (UE).
Innovation Solution
Extension of NB-IoT channel quality reporting to support 16-QAM modulation by defining a new table based on narrowband reference signal received power (NRSRP) and physical random access channel repetition levels, using a reserved bit in the downlink channel quality report (DCQR) MAC control element to indicate the selected table, allowing the UE to choose between legacy and new tables based on NRSRP or NPRACH configuration, and enabling semi-persistent scheduling for periodic reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing channel quality tables are used for NB-IoT devices, then backward compatibility is maintained, but the tables are insufficient for supporting 16-QAM modulation and increased data rates
Solution Approach 1:
The patent divides the channel quality reporting mechanism into multiple tables: existing tables for legacy QPSK modulation and new extended tables for 16-QAM modulation. This segmentation allows the system to maintain backward compatibility while supporting advanced modulation schemes with appropriate MCS selection for each modulation type.
Solution Approach 2:
The patent extends the existing channel quality tables by adding new dimensions or entries that accommodate 16-QAM modulation. The extended tables include additional rows or columns that map NRSRP values and repetition levels to MCS indices suitable for 16-QAM, effectively adding a new dimension to the original table structure.
2Productivity
If a new channel quality table is defined for 16-QAM, then support for increased data rates is improved, but device complexity increases
Solution Approach 1:
The patent pre-defines multiple channel quality tables (both existing and extended) with pre-calculated MCS mappings for different modulation schemes. The UE and network element are configured with these tables in advance, eliminating the need for complex real-time calculations and reducing runtime complexity despite the additional table management.
Solution Approach 2:
The extended channel quality tables are designed to serve multiple purposes: they support both legacy QPSK modulation (through original entries) and advanced 16-QAM modulation (through extended entries). This multi-functionality reduces the need for completely separate table structures, thereby limiting the increase in device complexity.
3Adaptability or versatility
If the UE selects between legacy and new tables based on NRSRP, then adaptability to different channel conditions is improved, but the selection process becomes more complex
Solution Approach 1:
The patent uses NRSRP (Narrowband Reference Signal Received Power) as a key parameter to drive table selection. By changing the NRSRP threshold values and mapping them to specific tables, the system automates the selection process. The UE compares measured NRSRP against predefined thresholds to determine whether to use legacy or extended tables, making the complex selection process more manageable through parameter-based decision rules.
4Adaptability or versatility
If existing DCQR MAC control element structure is used, then backward compatibility is maintained, but there is no capability indication for 16-QAM modulation
Solution Approach 1:
The patent extends the DCQR MAC control element by adding a new dimension or field that indicates 16-QAM capability. This could be an additional bit or field in the MAC CE structure that signals whether the UE supports 16-QAM modulation, allowing capability information to be transmitted without disrupting the existing DCQR reporting mechanism.
Solution Approach 2:
The patent introduces an intermediary indicator field in the DCQR MAC control element that mediates between the legacy structure and the new 16-QAM capability requirement. This intermediary field acts as a bridge, allowing the existing MAC CE format to coexist with new capability indication requirements by embedding the capability signal within or alongside the traditional DCQR information.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for downlink channel quality report for narrowband Internet of things user equipment. The method may include determining one or more of a physical random access channel repetition level or a reference signal received power. The method may also include selecting a channel quality table to use based on one or more of the physical random access channel repetition level or the reference signal received power. The method may further include determining a downlink channel quality report by using the selected channel quality table. In addition, the method may include transmitting the downlink channel quality report to the network element.