Cellular Control Channel Segmentation for Low-Bandwidth MTC Devices

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Solution Overview

Problem

Machine-type communication (MTC) devices face challenges in connecting to modern cellular communication systems like LTE due to higher bandwidth and processing requirements, which increase costs and power consumption, making it difficult for them to operate efficiently with limited bandwidth capabilities.

Innovation Solution

The method involves a network node that supports both full-bandwidth and limited-bandwidth devices by transmitting control channel information over different bandwidths at non-coinciding time intervals, allowing MTC devices to operate within a predefined bandwidth of 1.4 MHz, and providing system information to enable connection and data reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If LTE systems use full bandwidth control channels for all devices, then system capacity and communication speed are improved, but power consumption and cost increase for limited bandwidth devices

Engineering Contradiction:
Improvesystem capacityVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control channel transmission is segmented into two distinct channels: a first control channel spanning the full cell bandwidth for conventional UEs, and a second control channel occupying a reduced bandwidth for MTC devices. This segmentation allows each device type to receive control information through the appropriate channel width, enabling MTC devices to operate with lower bandwidth requirements while full-bandwidth devices continue to use the comprehensive control channel, thus resolving the contradiction between system capacity and power consumption.

Inventive Principle:
Principle #1Segmentation

2Speed

If LTE systems allocate full bandwidth resources, then data transmission rate is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedata transmission rateVSAvoiddevice complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

Different quality levels of control channel resources are allocated to different device types based on their specific needs. MTC devices receive control information through a reduced-bandwidth second control channel that matches their processing capabilities and cost constraints, while conventional UEs utilize the full-bandwidth first control channel for higher data transmission rates. This local quality differentiation resolves the contradiction by matching resource quality to device capability.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If MTC devices operate on reduced bandwidth, then power consumption and cost are reduced, but system resource utilization decreases

Engineering Contradiction:
Improvepower consumptionVSAvoidsystem resource utilization
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system employs time-domain multiplexing where the second control channel for MTC devices is transmitted in specific time intervals (e.g., certain subframes) that do not coincide with the first control channel transmissions. This periodic allocation of reduced-bandwidth resources to MTC devices allows them to conserve power while the system maintains high resource utilization by serving both MTC and conventional UEs in an interleaved manner across different time periods.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3570597B1Cellular communication system support for limited bandwidth communication devices
Publication Date: 2022.01.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3570597B1 patent drawingFigure 1
  • EP3570597B1 patent drawingFigure 2
  • EP3570597B1 patent drawingFigure 3

AI summary

A network node that serves a host cell in a cellular communication system transmits, at (a) first time interval(s), first control channel information on a control channel that extends over a first bandwidth of a radiofrequency spectrum. The first control channel communicates information necessary to enable a first type of communication device to receive data from the host cell. The first type of communication device can receive first bandwidth-wide signals. At (a) second time interval(s), second control channel information is transmitted on a second control channel of a first M-cell. The second control channel occupies a second bandwidth that is smaller than the first bandwidth. The second time interval(s) do(es) not coincide with any of the first time interval(s). A second type of communication device having reduced receive bandwidth capabilities compared to those of the first type of communication device is thereby made capable of being served by the node.