GMSK Modulation with Negative Index for MTC Coexistence

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Solution Overview

Problem

Existing wireless communication systems, particularly GSM, face challenges in supporting new types of devices like Machine Type of Communication (MTC) without disrupting legacy device operations, as they were not developed with these new requirements in mind, and existing systems need cost-efficient modifications to coexist with MTC devices without affecting conventional traffic and performance.

Innovation Solution

Implementing GMSK modulation with a negative modulation index selected based on the type of wireless device, allowing two types of devices to coexist by ensuring legacy devices cannot interpret new signals, thus enabling the reuse of existing systems with minimal modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If GMSK modulation with negative modulation index is applied to support new MTC devices, then the system can accommodate new device types with reduced interference, but legacy devices may have difficulty interpreting the new signals

Engineering Contradiction:

Improvesupport for new device typesVSAvoidsignal interpretation by legacy devices

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies different modulation indices (positive for legacy devices, negative for MTC devices) to different signal streams based on the target device type. This local differentiation allows the system to optimize for specific device categories while maintaining compatibility across the network through selective application of modulation parameters.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The core invention changes the modulation index parameter from its traditional positive value to a negative value for MTC device communications. This parameter inversion creates distinct signal characteristics that enable new device types to be supported while legacy devices continue to operate with their expected positive modulation index signals, thus resolving the contradiction between adaptability and ease of operation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If existing GSM systems are modified to support MTC devices, then new device requirements can be met, but system complexity and modification costs increase

Engineering Contradiction:

Improvesupport for MTC devicesVSAvoidsystem modification requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent enables the existing GMSK modulation framework to serve multiple device types (legacy and MTC) by introducing a simple sign change in the modulation index. This universal approach allows a single modulation scheme to handle diverse device requirements without creating entirely separate systems, thereby minimizing modification complexity while maximizing adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of fundamentally redesigning the modulation system to accommodate MTC devices, the patent inverts the traditional approach by using the negative modulation index as the distinguishing feature for new devices. This inversion leverages the existing positive modulation index infrastructure while adding minimal complexity through a simple parameter sign change, thus meeting new requirements without substantial system overhaul.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If GMSK modulation with negative modulation index is used, then coexistence of legacy and new devices is enabled, but the modulation scheme deviates from traditional GSM standards

Engineering Contradiction:

Improvedevice coexistence capabilityVSAvoidcompliance with existing standards

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces dynamic selection of modulation index signs based on the target device type. The system adaptively chooses between positive modulation index for legacy devices and negative modulation index for MTC devices, allowing seamless coexistence while maintaining standard compliance for each device category. This dynamic parameter selection resolves the contradiction between enabling new device types and maintaining reliability according to existing standards.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3183855B1Radio network node, wireless device and methods thereof using GMSK modulation applying negative modulation index

Publication Date: 2019.10.30 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

A radio network node (110) comprised,and a wireless device (121) configured to be operative, in a wireless communication system(100).The radio network node (110) obtains (701; 801; 901; 1401) downlink data and converts(702; 802-805; 902-905;1402) it to a baseband signal. The conversion comprises Gaussian Minimum Shift Keying(GMSK)modulation of the downlink data. The modulation applies a negative modulation index selected based on a type of wireless device (121) that is a target for the downlink data. A radio signal is provided based on the baseband signal and sent to, and received by, the wireless device (121) that provides user data based on the radio signal.