C-RNTI Extension Identifier for Dense User Identification

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Solution Overview

Problem

The existing cellular communications system, particularly in LTE networks, faces limitations with the 16-bit Cell Radio Network Temporary Identifier (C-RNTI) in supporting a high density of users, such as in M2M applications, where a single cell may need to accommodate over 100,000 users, exceeding the capacity of conventional RNTIs.

Innovation Solution

The method involves allocating a combination of a C-RNTI and an extension identifier to user equipment (UE), where the extension identifier is used to enhance identification and communication, allowing the UE to communicate with the network by verifying the consistency of the C-RNTI and extension identifier in downlink control information (DCI), thereby expanding network capacity to accommodate more users.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a 16-bit C-RNTI is used to identify user equipment, then the system maintains simplicity in identifier management, but the network capacity is limited to a maximum of 65536 users per cell

Engineering Contradiction:
Improvenetwork capacityVSAvoididentifier structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The identifier system is segmented into two parts: a 16-bit C-RNTI and a 16-bit extension identifier. The C-RNTI maintains backward compatibility with existing systems, while the extension identifier provides additional capacity. This segmentation allows the system to support over 100,000 users without completely redesigning the identifier structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution adds another dimension to the identifier space by introducing the extension identifier. Instead of increasing the bit length of the original C-RNTI, the patent creates a two-dimensional identifier system where the combination of C-RNTI and extension identifier provides the expanded capacity needed for M2M applications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the extension identifier is always included in DCI transmission, then UE identification accuracy is improved, but downlink control information overhead increases

Engineering Contradiction:
ImproveUE identification accuracyVSAvoidcontrol information overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The extension identifier is not always transmitted in every DCI message. Instead, it is selectively included only when needed for disambiguation. The base station determines whether the C-RNTI alone is sufficient for identifying the target UE, and only adds the extension identifier when multiple UEs share the same C-RNTI or when additional identification is required.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent dynamically changes the parameter of identifier inclusion in DCI based on network conditions and UE context. When a C-RNTI is uniquely assigned to one UE, the DCI contains only the C-RNTI. When multiple UEs share a C-RNTI or ambiguity exists, the extension identifier parameter is added to the DCI to ensure accurate identification.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2986039B1Downlink information sending and receiving methods, base station, and user equipment
Publication Date: 2020.02.19 HUAWEI TECH CO LTD
  • EP2986039B1 patent drawingFigure 1~2
  • EP2986039B1 patent drawingFigure 3~6

AI summary

The present invention relates to a downlink information sending method and receiving method, a base station, and user equipment. The sending method includes: allocating a cell radio network temporary identifier C-RNTI and an extension identifier to first user equipment UE, where a combination of the extension identifier and the C-RNTI is used to identify the first UE; notifying the first UE of the C-RNTI and the extension identifier; scrambling downlink control information DCI of the first UE by using the C-RNTI; and sending the scrambled DCI, where the scrambled DCI carries the C-RNTI and the extension identifier, so that the first UE communicates with a network according to the DCI when determining that the notified C-RNTI and the C-RNTI in the scrambled DCI are the same and the notified extension identifier and the extension identifier carried in the DCI are the same; or sending a Medium Access Control control element MAC CE and the scrambled DCI, where the MAC CE carries the extension identifier, so that the first UE communicates with a network according to the DCI when determining that the notified C-RNTI and the C-RNTI in the scrambled DCI are the same and the notified extension identifier and the extension identifier carried in the MAC CE are the same. UE is identified by using a combination of a C-RNTI and an extension identifier, to achieve an objective of distinguishing the UE. Compared with the prior art in which UE is distinguished by using a C-RNTI, more UEs can be distinguished, and a problem that an existing C-RNTI cannot satisfy a requirement for distinguishing UEs of highly dense users is resolved. Therefore, a problem that C-RNTIs in a cellular communications system are insufficient is resolved, so that a capacity of a wireless communications network can be expanded to accommodate more users.