Grant-Free Uplink Resource Allocation for 5G mMTC
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Solution Overview
Problem
In the context of 5G massive machine-type communication (mMTC), the existing scheduling-based data transmission mechanisms in LTE systems result in significant signaling overhead and energy consumption, which poses challenges for battery life and resource allocation, especially when dealing with infrequent small data transmissions.
Innovation Solution
A data transmission method that allows terminal devices to obtain a grant-free resource by indicating mobility information to the network side device, enabling them to transmit data without requesting resource allocation, using either dedicated or universal grant-free resources, thereby reducing the need for signaling and optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a scheduling-based mechanism is used for uplink data transmission, then the network side device can allocate resources and ensure reliable transmission, but significant signaling overhead and energy consumption are caused
Solution Approach 1:
The terminal device autonomously selects and uses grant-free resources for uplink transmission without requiring network scheduling. The device independently determines resource allocation based on pre-configured parameters, eliminating the need for scheduling requests and resource allocation messages, thus reducing signaling overhead and energy consumption while maintaining transmission reliability through pre-allocated resources
2Productivity
If a scheduling-based mechanism is used for uplink data transmission, then resource allocation can be controlled, but transmission delay increases due to signaling processes
Solution Approach 1:
Grant-free resources are pre-configured and allocated to terminal devices before actual data transmission occurs. The network side device provides configuration information including resource pools and parameters in advance, allowing terminal devices to immediately transmit data using pre-allocated resources without waiting for scheduling decisions, thus eliminating signaling delay and improving transmission efficiency
3Reliability
If dedicated grant-free resources are allocated to each terminal device, then transmission reliability is improved, but the network side device cannot ensure allocation for all devices within service scope due to limited resources
Solution Approach 1:
The grant-free resources are divided into multiple resource pools, with each pool containing resources that can be shared by multiple terminal devices. The network side device configures multiple pools with different parameters, allowing terminal devices to select appropriate pools based on their service requirements. This segmentation enables scalable support for large numbers of devices while maintaining transmission reliability through diversified resource options
Solution Approach 2:
Multiple grant-free resource pools are configured to serve different service scenarios and terminal device types. Each pool can be universally accessed by any terminal device that meets the configuration criteria, allowing the system to adapt to varying service requirements (eURLA, eMTC, NB-IoT) while providing grant-free transmission capabilities across the entire service scope
4Adaptability or versatility
If universal grant-free resources are used, then more terminal devices can access the network, but the data message size increases due to included identifiers
Solution Approach 1:
The terminal device's identifier is extracted and embedded into the physical uplink shared channel (PUSCH) resources rather than being included as separate data in the message payload. The network side device identifies the transmitting device through resource detection and association with pre-configured device profiles, allowing universal grant-free resource access while keeping data message sizes minimal by removing redundant identifier fields
Data Source
AI summary
Embodiments of this application provide a data transmission method, a terminal device, and a network side device. The method may include receiving, by a terminal device, a first identifier (ID). The method may also include indicating, by the terminal device, mobility information of the terminal device to the first network side device. Furthermore, the method may include receiving, by the terminal device, target grant free information indicated by the first network side device, where the target grant free resource is a dedicated grant free resource or a universal grant free resource, data information sent by the terminal device to the first network side device using the dedicated grant free resource includes data sent by the terminal device, and data information sent by the terminal device to the first network side device using the universal grant free resource includes data sent by the terminal device and the first ID.