Preamble Control for Unlicensed Spectrum Offloading
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Solution Overview
Problem
Current communication systems face challenges in efficiently utilizing unlicensed frequency bands for offloading traffic from licensed spectra due to differences in communication resources and interference from other systems, leading to inaccurate pathloss measurements and inefficient resource usage.
Innovation Solution
A control mechanism using preamble transmission commands and signals is implemented to determine the coverage and pathloss on unlicensed spectra, allowing communication network control elements to accurately assess and manage traffic offloading by triggering preamble signals on specific unlicensed bands and calculating UL pathloss values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traffic offloading to unlicensed spectra is implemented, then spectrum efficiency is improved, but measurement precision deteriorates due to inaccurate pathloss measurements
Solution Approach 1:
A preamble signal is introduced as an intermediary reference signal transmitted on the unlicensed spectrum. This preamble signal serves as a mediator that enables the network device to measure reference signal received power (RSRP) and calculate pathloss accurately on the unlicensed spectrum, resolving the measurement precision issue while maintaining traffic offloading benefits
Solution Approach 2:
The network device performs preliminary actions by first transmitting a preamble transmission command on the licensed spectrum, then transmitting the preamble signal on the unlicensed spectrum before actual traffic offloading. This preliminary measurement phase allows accurate pathloss determination to be established beforehand, ensuring both measurement accuracy and efficient traffic offloading
2Productivity
If unlicensed spectrum is used for traffic offloading, then spectrum efficiency is improved, but reliability deteriorates due to interference from other systems
Solution Approach 1:
The network device measures the reference signal received power of the preamble signal transmitted on the unlicensed spectrum and calculates the pathloss based on this feedback. This feedback mechanism allows the system to assess channel conditions and adjust transmissions accordingly, improving communication reliability while maintaining the spectrum efficiency benefits of unlicensed band usage
3Measurement precision
If preamble transmission command is sent on licensed spectrum, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The network device utilizes existing multi-functional capabilities to handle both licensed and unlicensed spectrum communications. The same device components that handle licensed spectrum control signals are also used to transmit preamble commands and measure unlicensed spectrum signals, achieving accurate measurements without significantly increasing device complexity through resource sharing and multi-functionality
Data Source
AI summary
There is provided a mechanism for controlling communications conducted via different frequency bands or communication spectrums. When a communication via a first communication path, for example an unlicensed or white space communication spectrum, is to be established, e.g. for offloading traffic from a second communication path, for example a licensed cellular communication spectrum, a preamble transmission command is generated and transmitted from a communication network control element, such as an eNB, via the second communication path to a communication element, such as a UE. By means of the preamble transmission command, the transmission of a preamble signal by the receiving communication element on the first communication path with predetermined communication resources is triggered. Based on a receipt or non-receipt of the preamble signal via the first communication path, the communication network control element is able to determine that the communication element can establish a connection on the first communication path, for example the unlicensed or white space communication spectrum.