AIoT Random Access with Adaptive ID Size for Low-Power Contention
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Solution Overview
Problem
Existing IoT devices face challenges with power consumption during random access procedures, especially in ambient energy harvesting scenarios, as the 4-step random access process is too expensive and existing cellular devices cannot efficiently handle contention resolution without significant power consumption.
Innovation Solution
A wireless transmit/receive unit (WTRU) determines the size of the ID for MSG1 transmission based on the number of devices to be paged and previous random access procedures, adjusting the random ID size to optimize power consumption and reduce contention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 4-step random access procedure is used, then contention resolution is achieved, but power consumption becomes too high for energy harvesting devices
Solution Approach 1:
The patent extracts and removes the MSG3 and MSG4 steps from the traditional 4-step random access procedure, retaining only MSG1 and MSG2. This extraction eliminates the need for contention resolution through MSG4, allowing energy harvesting devices to complete random access with significantly lower power consumption while maintaining sufficient reliability through MSG2-based resolution.
Solution Approach 2:
The patent applies partial action by implementing only the necessary portion of the random access procedure (MSG1 and MSG2) rather than the complete 4-step process. This partial implementation provides sufficient functionality for device identification and basic contention resolution without the excessive power consumption of the full procedure.
2Device complexity
If a fixed random ID size is used, then device complexity is reduced, but power consumption cannot be optimized for different device counts
Solution Approach 1:
The patent implements dynamics by making the random ID size adjustable rather than fixed. The network can dynamically configure the ID size based on the number of active devices, allowing optimization of power consumption. When fewer devices are present, a smaller ID size reduces transmission power requirements, while larger ID sizes provide sufficient uniqueness when more devices are active.
Solution Approach 2:
The patent applies parameter changes by varying the random ID size parameter according to the number of devices. The network configures different ID sizes (e.g., 8 bits for up to 256 devices, 16 bits for up to 65536 devices) based on the actual device count, optimizing the balance between uniqueness guarantees and power consumption for each deployment scenario.
3Reliability
If larger random ID size is used, then contention probability is reduced, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by adapting the random ID size parameter to the specific deployment scenario. The network determines the appropriate ID size based on the number of active devices and configures it accordingly. This ensures that sufficient ID space is allocated to avoid contention when needed, while avoiding unnecessary power consumption when fewer devices are present and smaller IDs suffice.
Data Source
AI summary
Methods and devices are disclosed contention resolution of Ambient Internet of Things (AIoT) devices. In one example, a wireless transmit receive unit (WTRU) receives, from a network, configuration information including a threshold number of devices to be queried, at least a first random ID size and a second random ID size. The WTRU selects a random ID size for an RA procedure based on a number of devices expected to respond to a query and a number of configured query occasions, and sends a paging message to one or more devices to be queried, indicating the selected random ID size. The WTRU may then receive, from the one or more devices, a first message including a device-selected random ID corresponding to the indication of the selected random ID size. The WTRU may further determine whether to increase the random ID size for a next configured query occasion.