LTE-NR Coexistence via MBSFN Subframe Interruption
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Solution Overview
Problem
In environments where Long Term Evolution (LTE) and New Radio Access Technology (NR) coexist, NR signals interfere with LTE reference signals due to their periodic transmission, causing orthogonality issues and potential interference with LTE data signals.
Innovation Solution
A communication device that controls the base station of the LTE system to interrupt the periodic transmission of reference signals for a predetermined period, allowing NR communication to occur without interfering with LTE signals by shifting to a mode where the reference signal is not transmitted, such as an MBSFN subframe, and allocating alternative radio resources for NR user data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NR predetermined signals are transmitted periodically according to specification, then NR communication can be established, but interference occurs with LTE reference signals
Solution Approach 1:
The patent implements periodic interruption of LTE reference signal transmission to align with periodic NR signal transmission. The base station periodically switches to MBSFN subframes at specific timings when NR synchronization signals or physical random access channels are transmitted, creating a periodic pattern that allows NR signals to be transmitted without continuous interference to LTE reference signals.
Solution Approach 2:
The patent extracts the reference signal transmission from the continuous periodic pattern by removing reference signals during specific subframes (MBSFN subframes) when NR predetermined signals are transmitted. This extraction creates interference-free windows for NR signals while maintaining LTE reference signal transmission during other subframes.
2Object-affected harmful factors
If NR signals are transmitted short in time direction (wide in frequency direction) at shifted timings, then interference with reference signals is prevented, but orthogonality with OFDM signals is compromised
Solution Approach 1:
The patent dynamically adjusts the transmission mode by switching between different subframe types (MBSFN and non-MBSFN) based on the timing of NR predetermined signals. This dynamic switching allows the system to adapt to different NR signal transmission requirements while maintaining orthogonality with OFDM signals through proper resource allocation and timing synchronization.
3Reliability
If LTE reference signal transmission is continuously maintained, then LTE communication reliability is preserved, but NR signal transmission is interfered with
Solution Approach 1:
The patent implements periodic interruption of LTE reference signal transmission to align with periodic NR signal transmission. The base station periodically switches to MBSFN subframes at specific timings when NR synchronization signals or physical random access channels are transmitted, creating a periodic pattern that allows NR signals to be transmitted without continuous interference to LTE reference signals.
Solution Approach 2:
The patent changes the transmission parameter of reference signals by switching the subframe type from non-MBSFN to MBSFN at specific timings. This parameter change (subframe type switching) allows the system to control reference signal transmission dynamically, creating windows where reference signals are not transmitted to avoid interfering with NR predetermined signals.
Data Source
AI summary
A communication device, which is capable of performing communication via a second wireless communication system that is different from a first wireless communication system, in a frequency band that is used by the first wireless communication system, the first wireless communication system periodically transmitting a reference signal, transmits, to a base station device of the first wireless communication system, information for operating the base station device in a mode in which the periodical transmission of the reference signal is interrupted for a predetermined period, and performs communication involving a predetermined signal of the second wireless communication system while the base station device of the first wireless communication system is operating in the mode.