Random Access Control via Preamble Segmentation and Time Offsets
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Solution Overview
Problem
In mobile communication networks, the increasing number of devices leads to network overload, causing increased failure probabilities and access delays, particularly for M2M devices, which degrade the performance of H2H devices due to shared random access channel (RACH) resources and inadequate dynamic control mechanisms.
Innovation Solution
A random access method and device that uses an access time distributing scheme, preamble allocation based on priority, and access class barring (ACB) information to dynamically allocate RACH resources, preventing collisions and maintaining H2H device performance by generating random numbers for access and comparing them with frame information to determine appropriate preamble transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If all devices share the same RACH preambles for random access, then resource utilization is simplified, but collision probability increases and access success rate deteriorates under network congestion
Solution Approach 1:
The patent segments the 64 RACH preambles into two distinct groups: 32 preambles for H2H devices and 32 preambles for M2M devices. This segmentation prevents M2M devices from colliding with H2H devices during random access, ensuring that H2H devices maintain high access success probabilities while M2M devices can access the network with reduced contention.
Solution Approach 2:
The patent applies different quality characteristics to different device types by allocating specific preamble ranges based on device category. H2H devices are assigned preambles with higher priority and better access characteristics, while M2M devices use separate preambles with adjusted timing and resource characteristics, allowing each device type to operate with optimized local properties.
2Adaptability or versatility
If the number of M2M devices increases to support more applications, then network coverage and functionality improve, but network overload occurs and H2H device performance deteriorates
Solution Approach 1:
The patent segments RACH resources in the time domain by introducing different ra-PreamblesEqualsOffset values for H2H and M2M devices. This time-domain segmentation distributes M2M access attempts across different time offsets, preventing them from simultaneously contending with H2H devices and thereby maintaining H2H device performance while supporting large numbers of M2M devices.
Solution Approach 2:
The patent dynamically adjusts the random access parameters for M2M devices based on network conditions and device priorities. By configuring different preamble offsets, power levels, and timing advances for M2M devices, the system dynamically manages the massive number of M2M connections without degrading H2H device performance.
3Device complexity
If random access parameters are fixed for all devices, then system complexity is reduced, but access delay time increases and quality of service cannot be differentiated
Solution Approach 1:
The patent applies differentiated random access parameters to different device types and priority levels. High-priority devices receive smaller preamble offsets and preferential treatment, resulting in shorter access delays, while low-priority devices use larger offsets. This local quality differentiation maintains manageable system complexity while achieving differentiated quality of service and reduced delays for critical applications.
Data Source
AI summary
Disclosed is a random access method and device. A terminal generates a random number for a random access, and compares the random number and a setting value. When the random number is included in the setting value, the terminal transmits a preamble for a random access to a base station and attempts a random access.