LTE UE Relay Interference Management via Licensed-Unlicensed Spectrum Coordination
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Solution Overview
Problem
Wireless communication networks face interference issues when using Long Term Evolution (LTE) user equipment (UE) relays operating in unlicensed spectrums, as they may interfere with or be interfered by non-cooperating devices such as WiFi and other LTE devices from different operators.
Innovation Solution
Implementing techniques for LTE UE relays that involve synchronizing devices and managing duplexing modes to minimize interference, including determining unlicensed access link duplexing, channel usage, and managing interference through coordinated multipoint techniques and advanced receiver capabilities to cancel interfering signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE UE relays operate in unlicensed spectrum to extend coverage and improve network capacity, then network coverage and capacity are improved, but interference from and to non-cooperating devices (WiFi, other LTE operators) increases
Solution Approach 1:
The patent applies preliminary action through listen-before-talk (LBT) procedures and advance synchronization mechanisms. Devices perform channel sensing and clearance checks before transmitting in unlicensed spectrum, and relay nodes are pre-synchronized with donor eNBs to coordinate their operations. This prevents interference proactively rather than reacting to it after occurrence.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting transmission parameters such as power levels, timing advances, and frequency selections based on channel conditions and interference measurements. Relay nodes modify their operating parameters to adapt to the unlicensed spectrum environment and minimize interference with non-cooperating devices.
2Area of stationary object
If multiple relay nodes operate in unlicensed spectrum simultaneously, then network coverage is extended, but interference between relay nodes increases
Solution Approach 1:
The patent implements feedback mechanisms where relay nodes continuously monitor channel conditions, interference levels, and transmission quality. This feedback information is reported to donor eNBs, which then adjust scheduling decisions, power allocations, and resource assignments to minimize inter-relay interference while maintaining extended coverage.
Solution Approach 2:
The patent applies segmentation by dividing the unlicensed spectrum resources among multiple relay nodes through time-division and frequency-division multiplexing. Different relay nodes are assigned different time slots, frequency resources, or spatial beams, allowing simultaneous operation while reducing mutual interference.
3Productivity
If LTE UE relays use unlicensed access link to improve spectral efficiency, then data throughput increases, but complexity of interference management increases
Solution Approach 1:
The patent uses donor eNBs as intermediaries that centralize interference management functions. Rather than requiring complex distributed interference coordination between relay nodes, the donor eNB acts as a mediator that receives interference reports, makes scheduling decisions, and coordinates resource allocation across multiple relays, simplifying the overall system complexity.
Solution Approach 2:
The patent applies multi-functionality by designing relay nodes that can operate in both licensed and unlicensed spectrum, supporting multiple duplexing modes (FDD, TDD, half-duplex), and providing both relay and direct communication capabilities. This universal design reduces complexity by consolidating multiple functions into unified protocols and procedures.
Data Source
AI summary
Certain aspects of the present disclosure provide methods and apparatus for employing relaying devices, such as Long Term Evolution (LTE) user equipment (UE) relays, having a licensed wireless or wired backhaul link and an unlicensed access link. One method generally includes receiving, at a first device, data from a first apparatus via a first carrier frequency in a licensed spectrum, wherein the first device comprises a relaying device, and relaying the data to a second apparatus via a second carrier frequency in an unlicensed spectrum. In this manner, wireless communication systems with relaying devices may achieve better spectral efficiency in unlicensed access links.