Unlicensed Carrier Aggregation for Reliable LTE Coexistence
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Solution Overview
Problem
Deploying a mobile radio access technology system primarily designed for licensed spectrum bands in unlicensed spectrum bands poses technical challenges due to the lack of centralized control and potential interference from other technologies, requiring modified approaches for efficient and reliable coexistence.
Innovation Solution
A method and apparatus for a wireless telecommunications system that involves receiving and transmitting data using a secondary component carrier on unlicensed radio resources by indicating and allocating configuration settings and transmission resources, allowing for carrier aggregation between licensed and unlicensed frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mobile radio access technology system designed for licensed spectrum bands is deployed in unlicensed spectrum bands, then the use of unlicensed radio resources is enhanced, but interference from other technologies and lack of centralized control causes unreliable communication
Solution Approach 1:
The patent introduces a gateway as an intermediary component that bridges the licensed and unlicensed spectrum domains. The gateway performs spectrum sensing to detect available unlicensed resources, coordinates resource allocation between different technologies, and manages interference mitigation. This intermediary enables reliable LTE communication in unlicensed bands by providing centralized control and coordination that would otherwise be absent in the unlicensed spectrum environment.
2Quantity of substance
If unlicensed spectrum is shared among different technologies without centralized control, then spectrum availability increases, but unpredictable interference occurs
Solution Approach 1:
The system performs preliminary spectrum sensing and channel assessment before allocating unlicensed spectrum resources to LTE transmissions. The gateway proactively identifies available frequency bands and time slots by detecting the presence of other technologies such as Wi-Fi. This preliminary action allows the system to pre-coordinate resource usage and implement interference avoidance strategies before actual data transmission begins, thereby maintaining both high spectrum utilization and low interference levels.
3Productivity
If LTE technology operates in unlicensed bands with best effort basis, then spectrum utilization improves, but guaranteed spectrum resources are lost
Solution Approach 1:
The patent implements a feedback mechanism where the gateway continuously monitors the quality of unlicensed spectrum resources and adjusts resource allocation dynamically. Channel quality indicators from LTE transmissions in unlicensed bands are fed back to the gateway, which then modifies spectrum sensing parameters, resource block allocations, and power control settings to maintain optimal performance. This closed-loop feedback system ensures that while operating on a best-effort basis in unlicensed bands, the system can adapt to maintain reliable communication when resources are available.
Data Source
AI summary
Although not part of the telecommunications system 400 itself, also shown in FIG. 4 are some other devices which are operable to wirelessly communicate with one another and which are operating within the radio environment of the telecommunications system 400. In particular, there is a pair of wireless access devices 416 communicating with one another via radio link 418 operating in accordance with a Wi-Fi standard and a pair of Bluetooth devices 420 communicating with one another via radio link 422 operating in accordance with a Bluetooth standard. These other devices represent a potential source of radio interference for the telecommunications system 400. It will be appreciated that in practice there will typically be many more such devices operating in the radio environment of the wireless telecommunications system 400, and only two pairs of devices 416, 420 are shown in FIG. 4 for simplicity.