RF Retuning in LTE TDD for MTC Data Transmission
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Solution Overview
Problem
Current data transmission methods for Machine-Type Communications (MTC) in LTE networks face challenges with transmission mistakes due to longer retuning times, especially in low-end MTC devices operating on GSM/GPRS networks, which increases network maintenance costs and complexity.
Innovation Solution
A method and apparatus for wireless communication systems that perform radio frequency (RF) retuning from a first narrowband to a second narrowband during Time Division Duplex (TDD) mode, allowing for efficient Physical Uplink Shared Channel (PUSCH) transmission by utilizing a predetermined frequency hopping pattern and optimizing the number of symbols for retuning, thereby reducing transmission errors and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF retuning is performed from first narrowband to second narrowband during TDD mode, then frequency diversity is achieved and transmission efficiency is improved, but transmission mistakes occur when retuning time is longer than available time
Solution Approach 1:
The patent performs RF retuning in advance during the special subframe before the actual uplink data transmission begins. By completing the frequency switch beforehand in the special subframe (which contains downlink pilot timeslots and guard periods), the system ensures that the retuning is done before the uplink transmission starts, avoiding interference between retuning and data transmission processes
Solution Approach 2:
The patent divides the TDD frame structure into distinct segments: special subframes dedicated for RF retuning, downlink subframes, and uplink subframes. This segmentation allows the retuning operation to be isolated in specific time slots (special subframes) without interfering with data transmission in other subframes, thereby resolving the conflict between retuning time requirements and transmission accuracy
2Adaptability or versatility
If more MTC UEs are deployed in GSM/GPRS networks, then low-end MTC applications are supported, but network maintenance cost and complexity increase
Solution Approach 1:
The patent enables MTC UEs to operate in LTE networks using TDD frame structures with universal applicability. By designing a retuning method that works within the LTE TDD framework, the system allows MTC devices to be migrated from GSM/GPRS to LTE networks while maintaining support for low-end applications, thereby reducing reliance on legacy networks and simplifying overall network maintenance
3Device complexity
If reduced UE bandwidth of 1.4MHz is used for MTC UEs, then device complexity is reduced, but frequency hopping and RF retuning become more challenging
Solution Approach 1:
The patent operates within the 1.4MHz reduced bandwidth by utilizing the time dimension effectively. By performing RF retuning during special subframes (which contain guard periods and pilot timeslots) rather than during data transmission subframes, the system accommodates the retuning operation within the constrained frequency bandwidth without requiring additional frequency resources, thus maintaining ease of operation despite bandwidth limitations
Data Source
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AI summary
Embodiments of the present disclosure relate to data transmission in a wireless communication system. In an embodiment of the present disclosure, there are provided a method and apparatus of data transmission in a wireless communication system. The method comprises receiving information on assigned resources for the data transmission; and determining resources for respective data retransmissions based on the information on the assigned resources for the data transmission and a predetermined frequency hopping pattern. Particularly, a plurality of symbols are used to perform a radio frequency (RF) retuning and a time duration of the plurality of symbols is at least equal to a time interval required by the RF retuning. With embodiments of the present disclosure, there is provided a new solution for data transmission in which the RF retuning can be performed in a plurality of symbols, which might obtain the frequency diversity and at the same time can reduce transmission mistakes and improve the transmission efficiency.