Time-Multiplexed Broadcast Signal Transmission in Wireless Networks

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Solution Overview

Problem

In ultra-narrowband wireless communication systems, efficiently transmitting broadcast signals to terminals while minimizing the impact on uplink message collection and reducing electricity consumption for signal detection, especially in scenarios where terminals need to identify the correct frequency band without frequent measurements.

Innovation Solution

A method where a group of base stations synchronized in time transmit broadcast signals in the same frequency band, using time division multiplexing, allowing terminals to detect signals efficiently and reducing the number of base stations available for uplink message reception, thus minimizing the impact on message collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If base stations transmit broadcast signals simultaneously in the same frequency band, then signal detection is simplified and electricity consumption is reduced, but the number of base stations available for uplink message reception decreases

Engineering Contradiction:
Improveelectricity consumption for signal detectionVSAvoidnumber of base stations available for uplink message reception
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent implements time-division multiplexing where base stations transmit broadcast signals in periodic time slots rather than continuously. Each base station transmits broadcast signals during its assigned time slot and remains silent during other time slots, allowing it to receive uplink messages during those periods. This periodic transmission pattern reduces the average electricity consumption for signal detection while ensuring that each base station is available for uplink reception during its non-transmission periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent divides the operation of base stations into distinct functional segments: transmission segments (when broadcasting signals) and reception segments (when receiving uplink messages). By segmenting the time domain into separate slots for different functions, the system allows base stations to alternately perform broadcasting and uplink reception, thereby maintaining both functions with reduced resource conflicts.

Inventive Principle:
Principle #1Segmentation

2Reliability

If terminals perform frequent measurements to identify the most appropriate base station, then uplink message reception reliability is improved, but electricity consumption increases

Engineering Contradiction:
Improveuplink message reception reliabilityVSAvoidelectricity consumption for measurements
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements preliminary action by having base stations transmit their identifiers and synchronization information during the broadcast signal transmission in the downlink. Terminals can detect these broadcast signals and identify appropriate base stations in advance, before needing to send uplink messages. This preliminary identification eliminates the need for frequent measurements during uplink transmission periods, significantly reducing terminal electricity consumption while maintaining reliable connection to the most appropriate base station.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If base stations use half-duplex operation to reduce deployment cost, then manufacturing cost is reduced, but uplink messages may be missed during broadcast transmission

Engineering Contradiction:
Improvedeployment cost of access networkVSAvoiduplink message collection completeness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies periodic action through time-division multiplexing, where half-duplex base stations alternate between transmission mode (sending broadcast signals) and reception mode (collecting uplink messages). Each base station is configured to transmit broadcast signals during specific time slots and switch to reception mode during other time slots. This periodic switching allows inexpensive half-duplex base stations to maintain both broadcasting and uplink collection functions without missing messages, as the system schedules transmissions and receptions in non-overlapping time periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making base station functionality time-dependent. Base stations dynamically switch between transmission and reception states based on their assigned time slots in the time-division multiplexing scheme. This dynamic state switching allows half-duplex base stations to adapt their operational mode according to the current time slot, ensuring that they can both broadcast signals and collect uplink messages effectively despite hardware limitations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3281472B1Method for transmitting broadcast signals in a wireless communication system
Publication Date: 2020.02.19 SIGFOX
  • EP3281472B1 patent drawingFigure 1~3
  • EP3281472B1 patent drawingFigure 4~6

AI summary

The invention relates to a method (50) for the transmission of broadcast signals from a group of base stations (31) to terminals (20) of a wireless communication system (10), each base station comprising a coverage area. The coverage areas of the base stations of the group are distributed geographically such as to serve a geographical area. Since the broadcast signals are of limited duration and are transmitted in a frequency band used by all of the base stations of the group, the base stations (31) of the group are time-synchronised in relation to one another and the broadcast signals from the base stations (31) of the group are time-multiplexed. In addition, the wireless communication system (10) comprises multiple geographical regions, each including multiple groups of base stations (31), and the broadcast signals of different geographical regions are time-multiplexed.