Serving Cell Availability Indicator for Wireless Data Transmission
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Solution Overview
Problem
The introduction of the Listen-Before-Talk (LBT) mechanism in LTE Licensed-Assisted Access (LAA) systems leads to interruptions in data transmission due to unavailability of transmission opportunities in unlicensed bands, affecting Hybrid Automatic Repeat Request (HARQ) performance and causing significant transmission delays and throughput losses.
Innovation Solution
A method where a device determines the availability of a scheduled serving cell before data communication and informs other devices, allowing data communication to be performed on either the scheduled serving cell or an available serving cell, ensuring continuous data transmission by switching to an alternative cell if the primary cell is unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If LBT mechanism is introduced in LTE LAA systems, then interference with other wireless systems is reduced, but data transmission is interrupted due to unavailability of transmission opportunities
Solution Approach 1:
The patent applies preliminary action by performing Clear Channel Assessment (CCA) checks before data transmission to determine channel availability in advance. This allows the system to detect potential transmission opportunities beforehand and prepare alternative serving cells, ensuring that data transmission can continue without interruption when the primary cell becomes unavailable due to LBT requirements.
Solution Approach 2:
The patent introduces an intermediary mechanism by using a serving cell availability indicator that communicates channel availability status between the base station and user equipment. This indicator acts as a mediator that coordinates transmission decisions across multiple serving cells, allowing the system to switch to alternative cells when the primary cell is unavailable while maintaining seamless data transmission.
2Object-affected harmful factors
If LBT mechanism is introduced in LTE LAA systems, then co-channel interference is alleviated, but transmission delays increase due to frequent interruptions
Solution Approach 1:
The patent ensures continuity of useful action by maintaining multiple serving cells (both licensed and unlicensed) that can alternatively carry data transmission. When the primary unlicensed serving cell becomes unavailable due to LBT requirements, the system seamlessly switches to an alternative serving cell, ensuring that data transmission continues without interruption and minimizing transmission delays.
Solution Approach 2:
The system performs preliminary checks on alternative serving cells to ensure their availability before the primary cell becomes unavailable. This advance preparation allows for immediate switching when needed, preventing transmission delays that would otherwise occur during cell reconfiguration.
3Adaptability or versatility
If LBT mechanism is introduced in LTE LAA systems, then spectrum sharing is enabled, but throughput loss increases due to retransmission delays
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple serving cells and performing availability checks in advance. This allows the system to maintain ready-to-use alternative transmission paths, ensuring that retransmissions can occur immediately on alternative cells without the delays that would normally accompany cell reconfiguration, thereby maintaining high throughput while enabling spectrum sharing.
Solution Approach 2:
The serving cell availability indicator acts as an intermediary that coordinates retransmission decisions across multiple serving cells. This mechanism ensures that retransmissions are efficiently directed to available cells without unnecessary delays, maintaining throughput performance while enabling flexible spectrum sharing through LBT.
Data Source
AI summary
The subject matter described herein relates to data communication in wireless communication systems. The device determines availability of scheduled serving cell before data communication and informs a device the determined availability of the scheduled serving cell. Depending upon the determined availability, the device is controlled to perform the data communication on the scheduled serving cell or another available serving cell. In this way, the unfinished data communication, for example, retransmission of a data block in an uplink or downlink HARQ process can be continued on an available serving cell, whereby avoiding large transmission delay and throughput loss in the wireless communication system.