TTI-Bundle Scheduling via Single Control Message
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Solution Overview
Problem
Current LTE systems face challenges in efficiently scheduling multiple Transmission Time Interval (TTI)-bundle transmissions, leading to high signaling overhead and difficulty in simultaneously achieving good coverage and high capacity for VoLTE services, especially at the cell edge where UEs experience limited power and deep signal fading.
Innovation Solution
A method is introduced to schedule multiple TTI-bundle transmissions using a single control message by employing a new parameter, TTI-Bundle Scheduling Number (TBSN), within the Downlink Control Information format 0 (DCIO) or DCI format 4, which allows for the indication of the number of TTI-bundles, reducing the need for multiple scheduling grants and minimizing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate control messages are sent to schedule multiple TTI-bundle transmissions, then resource allocation flexibility is improved, but signaling overhead increases
Solution Approach 1:
The patent combines multiple separate control messages into a single control message that schedules multiple TTI-bundle transmissions. The downlink control information (DCI) is enhanced to include a bundle size indicator field that specifies the number of TTI-bundles, allowing one control message to allocate resources for multiple bundled transmissions simultaneously, thereby reducing signaling overhead while maintaining allocation flexibility
Solution Approach 2:
The control message structure is designed to serve multiple functions: it not only schedules individual TTI-bundle transmissions but also indicates the bundle size through the added field. This multi-functional design allows the same control message to convey both resource allocation details and bundling configuration, eliminating the need for separate signaling for bundle size indication
2Reliability
If TTI bundling is used to improve coverage at cell edge, then decoding success rate is improved, but transmission delay increases
Solution Approach 1:
The patent introduces dynamic control of TTI-bundle size through a bundle size indicator field in the DCI. The network can dynamically adjust the number of TTI-bundles scheduled based on current channel conditions, UE location, and traffic requirements. This dynamic adjustment allows the system to optimize between coverage enhancement and delay reduction by adapting the bundle size in real-time rather than using fixed bundling configurations
3Manufacturing precision
If multiple control messages are used for scheduling, then precise resource allocation is improved, but network capacity is reduced
Solution Approach 1:
By merging multiple control messages into a single enhanced DCI structure, the patent reduces the number of control channel elements (CCEs) required for scheduling. The single control message includes resource allocation fields that can specify resources for multiple TTI-bundles, thereby preserving precise resource allocation capabilities while reducing control channel overhead and increasing available resources for data transmission, thus improving overall network capacity
Data Source
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AI summary
A method for transmitting data by a user equipment (UE) over a plurality of Transmission Time Interval, TTI, bundles in a communication network is provided. The method comprises: receiving a single control message indicating a uplink scheduling grant for data transmissions; determining a number of TTI-bundles, scheduled for the data transmissions of the UE in accordance with the received control message; and sending the data to the communication network, using the determined number of TTI-bundles. A user equipment for implementing the method is also provided.