Communications Device Signal Detection for Unlicensed Spectrum Interference Avoidance
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Solution Overview
Problem
Fourth generation mobile telecommunications networks face limitations in network capacity and geographical coverage, particularly in high-load situations, due to limited licensed frequency spectrum, and the use of unlicensed spectrum for LTE systems is proposed to supplement capacity but requires efficient interference management with existing systems like WiFi.
Innovation Solution
A communications device equipped with a transmitter, receiver, and controller that detects signals across a second wireless access interface, such as IEEE 802.11, and reports properties to a network element, enabling remote signal detection and positioning of a third wireless access interface to avoid interference, thereby identifying unoccupied frequencies for increased capacity without disrupting existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unlicensed spectrum is used to supplement licensed spectrum for increasing network capacity, then network capacity is improved, but interference with other wireless systems increases
Solution Approach 1:
The communications device performs signal detection on the second wireless access interface (e.g., WiFi) before the LTE system establishes transmission on unlicensed spectrum. The device detects existing signals, reports properties to the network element, which then positions the third wireless access interface to avoid detected signals in time and frequency domains, preventing interference before it occurs
Solution Approach 2:
The communications device acts as an intermediary between the LTE network element and the existing wireless systems. It detects signals from other systems (WiFi, etc.), reports their properties to the LTE network, enabling the LTE system to adapt its transmission to avoid interference while still utilizing unlicensed spectrum for capacity enhancement
2Measurement precision
If the network element directly detects signals on unlicensed spectrum, then interference detection accuracy is improved, but coverage area is reduced due to limited detection range
Solution Approach 1:
The communications device within the LTE coverage area performs self-service signal detection on the unlicensed spectrum. It autonomously detects signals from other wireless systems, analyzes their properties, and reports findings to the network element, enabling the network to make informed decisions about spectrum usage without requiring the network element to directly detect signals beyond its range
3Productivity
If LTE system transmits on unlicensed spectrum without sensing, then network capacity increases, but harmful interference to other systems is generated
Solution Approach 1:
The communications device provides feedback about detected signals on the unlicensed spectrum to the network element. This feedback includes properties of detected signals that enable the network element to position the third wireless access interface appropriately in time and frequency domains, ensuring LTE transmissions do not generate harmful interference while still achieving capacity enhancement
Data Source
AI summary
A communications device comprising a transmitter, a receiver and a controller operable to transmit and to receive signals representing data to and from a network element across a first wireless access interface, the first wireless access interface being provided by the network element and access to resources of the first wireless access interface being controlled by the network element. The controller is configured to control the receiver to perform detection of signals transmitted across a second wireless access interface, and to control the transmitter to transmit a reporting message to the network element across the first wireless access interface, the reporting message including an indication of one or more properties of signals that have been detected across the second wireless access interface.