Narrowband IoT Resource Allocation via Subcarrier Granularity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing LTE system faces challenges in resource allocation for NB-IoT equipment, which requires narrower band support due to limited usable bandwidth, leading to inefficiencies in communication, particularly with the existing PRB-based resource allocation units.
Innovation Solution
The proposed solution involves a user terminal and radio base station configuration that allows for resource allocation by a frequency unit smaller than the existing LTE system's PRB, using a narrow band (e.g., 180 kHz) with variable frequency positions, enabling efficient communication through frequency hopping and scheduling, and optimizing subframe sets for control and data channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PRB-based resource allocation is used in LTE system, then resource allocation follows standard LTE procedures, but resource usage efficiency deteriorates for NB-IoT equipment with narrow bandwidth
Solution Approach 1:
The patent changes the fundamental parameter of resource allocation granularity from PRB (Physical Resource Block) to subcarrier level. This allows NB-IoT equipment to allocate resources according to actual bandwidth needs rather than being constrained by fixed PRB sizes, thereby improving both bandwidth adaptability and resource usage efficiency.
Solution Approach 2:
The patent segments the PRB into smaller subcarrier units for resource allocation. By dividing the traditional atomic resource unit (PRB) into finer subcarrier segments, the system can allocate exactly the amount of bandwidth needed by NB-IoT devices, reducing wasted resources while maintaining compatibility with LTE infrastructure.
2Area of stationary object
If narrow band (180 kHz) is used for NB-IoT equipment, then bandwidth requirement is satisfied, but resource allocation flexibility is limited
Solution Approach 1:
The patent introduces dynamic resource allocation within the narrow band by enabling flexible subcarrier assignment. Instead of fixed PRB allocation, the system can dynamically adjust which subcarriers are allocated to different NB-IoT devices within the 180 kHz band, providing adaptability while satisfying the narrow bandwidth constraint.
Solution Approach 2:
The patent adds flexibility by introducing frequency hopping across multiple subframe sets. This creates a time-frequency dimension where resources can be allocated not only within the narrow band but also across different time slots, effectively increasing resource allocation versatility without expanding bandwidth.
3Productivity
If multiple pieces of data are scheduled in the same subframe set, then resource usage efficiency improves, but scheduling complexity increases
Solution Approach 1:
The patent segments the subframe set into multiple independent subcarrier groups that can be allocated to different data transmissions. This segmentation allows multiple pieces of data to be scheduled simultaneously within the same subframe set by assigning different subcarrier segments to different data flows, improving resource efficiency while managing complexity through structured division.
Solution Approach 2:
The patent creates a universal subcarrier allocation mechanism that can handle multiple data types and traffic patterns within the same subframe set. The same resource allocation framework supports different NB-IoT devices, different data priorities, and different modulation schemes, reducing the need for separate scheduling mechanisms and thereby managing complexity.
4Reliability
If frequency hopping is implemented for NB-IoT, then coverage and robustness are improved, but system complexity increases
Solution Approach 1:
The patent implements periodic frequency hopping where NB-IoT transmissions switch between different subcarrier frequencies at regular intervals defined by subframe sets. This periodic structure provides robustness against fading and interference while maintaining predictable timing patterns that simplify implementation compared to aperiodic frequency selection.
Solution Approach 2:
The patent performs preliminary configuration of frequency hopping patterns through higher-layer signaling before actual data transmission. By pre-defining the frequency hopping sequence and parameters, the system reduces real-time processing complexity while maintaining the robustness benefits of frequency diversity.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
To appropriately perform communication even when resource allocation is controlled by a frequency unit (for example, a subcarrier unit) that is smaller than a resource allocation unit of an existing LTE system, the present invention provides a user terminal having: a reception unit that receives downlink control information on a downlink control channel included in a given duration in a given bandwidth; and a control unit that controls uplink data transmission based on the downlink control information. The control unit controls start timing of the uplink data transmission with reference to a last subframe in which the downlink control channel is transmitted in the given duration