Group-Based Random Access for Machine-Type Communications

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Solution Overview

Problem

The existing LTE system faces challenges in managing a high number of machine-type communications, leading to insufficient PRACH resources due to contention-based random access methods, which result in inefficient use of bandwidth and increased resource requirements.

Innovation Solution

A method where UEs in a group send a preamble over a shared time-frequency resource, allowing the eNB to allocate TC-RNTI and UL grants based on group IDs or pre-set rules, enabling efficient resource allocation and reducing the need for multiple PRACH resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contention-based random access is used for each UE individually, then each UE can access the network independently, but PRACH resources become insufficient when handling tens of thousands of UEs

Engineering Contradiction:

Improveaccess reliabilityVSAvoidPRACH resource quantity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Multiple UEs are grouped together and share a common PRACH resource for preamble transmission. The eNB receives preambles from grouped UEs on the same time-frequency resource, reducing the total number of PRACH resources needed while maintaining access reliability through group-based handling

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single PRACH resource serves multiple UEs simultaneously for random access purposes. The shared resource performs the function of supporting access for the entire UE group, making the PRACH resource multi-functional rather than dedicated to individual UEs

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If more PRACH resources are allocated to handle increased UE access density, then access capacity increases, but bandwidth efficiency decreases

Engineering Contradiction:

Improveaccess capacityVSAvoidbandwidth efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

Multiple UEs share a single PRACH resource, increasing access capacity without proportionally increasing resource allocation. This merging approach maintains bandwidth efficiency by avoiding the need to allocate separate resources for each UE while still handling high access density

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If individual UEs perform random access separately, then access control is precise, but resource overhead increases significantly

Engineering Contradiction:

Improveaccess control precisionVSAvoidresource management complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

UEs are organized into groups for shared PRACH access, reducing resource management complexity. The eNB manages resources at the group level rather than individual UE level, simplifying resource allocation and reducing overhead while maintaining control through group-based mechanisms

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3316651B1Random access method and corresponding device

Publication Date: 2020.01.29 ZTE CORP

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AI summary

A random access method comprises: transmitting, by a firstuser equipment (UE) in a UE group, and according to a time-frequency resource, a preamble to an evolved node B (eNB); and monitoring, by a second UE in the UE group and/or the first UE, for a random access response (RAR) corresponding to the preamble transmitted by the eNB, wherein the first UE is at least one UE in the UE group, and the second UE is all or a part of the UEs in the UE group.