Contention-Free Random-Access Preamble in Paging Process

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Solution Overview

Problem

In cellular wireless networks, access contention occurs when multiple UEs randomly select the same preamble for access requests, leading to potential access failures and unnecessary re-paging, which consumes limited paging channel resources.

Innovation Solution

A base station includes a contention-free random-access preamble in the paging message to UEs, allowing them to engage in contention-free random access, thereby avoiding access contention and reducing the need for re-paging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple UEs randomly select preambles for access requests, then the access process is simple and flexible, but access contention occurs leading to access failures and re-paging

Engineering Contradiction:

Improveaccess success rateVSAvoidpaging process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The base station performs preliminary action by assigning dedicated preambles to specific UEs before the random access process. When the base station needs to page a UE, it includes a dedicated preamble in the paging message, which the UE can use to initiate random access without contention. This preliminary assignment eliminates the need for random selection and potential conflicts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by providing different types of preambles for different purposes: dedicated preambles for specific UEs that need reliable access (such as those being paged), and random preambles for general access. This localized differentiation ensures that UEs requiring guaranteed access receive dedicated resources while maintaining overall system efficiency.

Inventive Principle:

Principle #3Local quality

2Reliability

If dedicated preambles are assigned to UEs for paging response, then access contention is avoided, but paging channel resources are consumed

Engineering Contradiction:

Improveaccess contention avoidanceVSAvoidpaging channel resource consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The base station applies partial action by assigning dedicated preambles only to those UEs that are being paged and require reliable access, rather than allocating dedicated preambles to all UEs. This selective assignment minimizes resource consumption while ensuring contention-free access for the specific UEs that need it.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If random preambles are used for access requests, then resource allocation is efficient, but access failures occur due to preamble collision

Engineering Contradiction:

Improveresource allocation efficiencyVSAvoidaccess reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The base station performs preliminary action by pre-assigning dedicated preambles to UEs that are about to be paged. This preliminary assignment ensures that when these UEs respond to paging messages, they use unique preambles that have been reserved for them, eliminating collision possibilities while maintaining efficient resource utilization.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9942412B1Use of contention-free random-access preamble in paging process

Publication Date: 2018.04.10 SPRINT SPECTRUM LLC

AI summary

Disclosed is a method and system to help ensure contention-free response to a paging message. As disclosed, when a base station transmits a paging message for receipt by a UE, the base station includes in the paging message a contention-free random-access preamble useable by the UE to engage in contention-free random access in response to the paging message. The UE thus receives the paging message and responsively engages in a contention-free random access process with the base station, to establish a radio-link-layer connection between the UE and the base station.