Random Access Channel Grouping for PRACH Collision Control
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Solution Overview
Problem
The increasing number of communication devices, particularly in Massive Machine-Type Communications (mMTC), leads to PRACH congestion, where multiple devices attempting random access to a base station using the same preamble result in collisions, hindering efficient connection establishment, especially exacerbated in non-terrestrial networks like satellite communication.
Innovation Solution
A communication control apparatus that identifies multiple random access channels, groups devices into distinct access groups, and restricts transmission to specific channels based on device identification and frame timing, reducing collisions by limiting access to designated channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple communication devices transmit random access information over the same random access channel, then the random access channel utilization is improved, but the collision rate between devices increases
Solution Approach 1:
The patent segments communication devices into different random access groups based on their identifiers, and assigns each group to specific random access channels. This segmentation prevents devices from randomly accessing any channel, thereby reducing collisions while maintaining channel utilization. The base station configures multiple random access channels and devices select channels based on their group membership rather than random selection.
2Reliability
If communication devices wait for the next PRACH opportunity after collision, then the random access procedure reliability is maintained, but the access delay increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring multiple random access channels and pre-grouping devices before random access occurs. The base station provides configuration information including channel assignments and group identifiers to devices in advance. This allows devices to immediately select their designated channel without waiting or retrying, eliminating access delay while maintaining reliability through structured channel assignment.
3Productivity
If the number of random access channels is increased to reduce congestion, then the system capacity is improved, but the device complexity for channel selection increases
Solution Approach 1:
The patent implements self-service by enabling devices to autonomously determine their assigned random access channel based on their identifier and the configuration information received from the base station. Devices calculate their group membership and select their designated channel without complex centralized coordination or additional signaling. This self-service mechanism maintains low device complexity while supporting increased system capacity through multiple channels.
Data Source
AI summary
A communication control apparatus has: a random access channel identification unit that identifies a plurality of random access channels over which a communication device can transmit random access information to a base station, a communication device grouping unit that groups each communication device into a plurality of random access groups that are associated with different portions of the plurality of random access channels, and a random access information transmission restriction unit that restricts the transmission of random access information, for a communication device grouped into each random access group, over the random access channels not associated with each random access group.