Downlink Transmission in Licensed Uplink Band
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Solution Overview
Problem
Operations in wireless communication networks that pair a downlink unlicensed band with an uplink licensed band are inefficient due to dependencies on listen-before-talk (LBT) failures in the downlink unlicensed band, leading to gated downlink transmissions and underutilization of the uplink licensed band.
Innovation Solution
Allocating a fraction of the uplink licensed band for low-duty cycle downlink communications, allowing the base station to opportunistically use the uplink licensed band for downlink transmissions upon LBT failures, and reducing interference by using a narrow center band and lowering transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If downlink transmissions are performed in unlicensed band using listen-before-talk mechanism, then spectrum sharing capability is improved, but transmission reliability deteriorates due to LBT failures
Solution Approach 1:
The patent introduces a licensed band as an intermediary channel to complement the unlicensed band. When LBT failures occur in the unlicensed band, the system can fall back to or supplement with transmissions in the licensed band, thereby maintaining transmission reliability while preserving spectrum sharing capabilities in the unlicensed band.
Solution Approach 2:
The system dynamically changes the transmission parameter (selected band) based on LBT outcomes. When LBT is successful in unlicensed band, transmissions occur there; when LBT fails, the system switches to licensed band transmissions, adapting the operational parameter to maintain reliability.
2Adaptability or versatility
If downlink transmissions are gated by LBT failures in unlicensed band, then spectrum access flexibility is improved, but network accessibility deteriorates
Solution Approach 1:
The patent ensures continuous network accessibility by establishing that either the unlicensed band or the licensed band must be available for downlink transmissions. This continuity mechanism prevents complete access denial when one band is unavailable or LBT fails, maintaining persistent network service.
Solution Approach 2:
The system prepares for LBT failures by having the licensed band ready as a backup option. This beforehand cushioning ensures that when unlicensed band access is blocked, the network can immediately switch to or supplement with licensed band transmissions, preventing accessibility interruptions.
3Productivity
If uplink licensed band is used for downlink transmissions, then resource utilization is improved, but interference levels increase
Solution Approach 1:
Instead of fully utilizing the uplink licensed band for downlink transmissions, the system employs partial action by using only a fraction of the band resources. This partial utilization approach improves resource utilization efficiency while keeping interference levels manageable, avoiding complete spectrum occupation that would cause excessive interference.
Data Source
AI summary
Wireless communications systems and methods related to operating in a network deployed in a downlink (DL) unlicensed band and an uplink (UL) licensed band are provided. A first wireless communication device communicates, with a second wireless communication device, a first downlink communication signal in a downlink unlicensed band of a network. The first wireless communication device communicates, with the second wireless communication device, a second downlink communication signal in an uplink licensed band of the network. The second downlink communication signal includes at least one of a synchronization signal block (SSB), system information, a random access response, a contention resolution message, paging information, a downlink feedback signal, or low-latency data.