Wideband eNB to Narrowband UE Channel Reservation in Unlicensed Spectrum
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently utilizing unlicensed radio frequency spectrum bands for data offloading due to interference from correlated signals and limited bandwidth in narrowband communications, particularly in NB-IoT and eMTC, which affects channel reservation accuracy.
Innovation Solution
Implementing a channel reserving signal sequence configured based on an antenna port identifier to reduce interference and improve detection capabilities in unlicensed spectrum, using techniques like CCA and eCCA to access contention-based shared radio frequency spectrum bands, and employing multiple antennas for enhanced communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wideband base station communicates with narrowband UEs in unlicensed spectrum, then data transmission capacity is enhanced, but channel reservation accuracy deteriorates due to interference from correlated signals
Solution Approach 1:
The patent applies local quality by configuring channel reserving signal sequences differently based on antenna port identifiers. Each antenna port uses a unique sequence configuration, allowing the system to distinguish between correlated signals from different antennas and maintain accurate channel reservation even in the presence of interference from wideband base stations.
2Device complexity
If narrowband UEs use limited bandwidth resources, then device complexity is reduced, but channel detection capability worsens due to interference in unlicensed spectrum
Solution Approach 1:
The patent introduces channel reserving signals as intermediaries between the base station and UEs. These signals, configured with antenna port-specific sequences, serve as mediators that enable reliable channel detection and reservation in unlicensed spectrum, allowing narrowband UEs to accurately detect channel availability despite limited bandwidth and the presence of interference.
3Productivity
If multiple antennas are employed for communication, then data transmission capacity increases, but harmful interference from correlated signals increases
Solution Approach 1:
The patent applies asymmetry by assigning unique channel reserving signal sequences to different antenna ports based on their identifiers. This asymmetric configuration ensures that even though multiple antennas transmit simultaneously to increase capacity, the correlated signals from different antennas can be distinguished and managed, reducing harmful interference through differentiated signal characteristics.
Data Source
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AI summary
A method and apparatus for wireless communication in the unlicensed spectrum between an eNB and UEs having different bandwidths, e.g., between a narrowband UE and a wideband eNB. A base station apparatus performs an LBT procedure at a beginning of frames and transmits a plurality of repetitions of a transmission. When the plurality of repetitions span multiple frames and the LBT procedure is not successful for a first frame, the base station drops or postpones at least one repetition in the first frame until a second frame when the LBT procedure is successful. A UE receives the plurality of repetitions and may combine a plurality of repetitions across multiple frames. The UE may determine whether the base station drops the at least one repetition in the first frame or postpones the at least one repetition in the first frame until a second frame.