DRX Cycle Offset for LTE Bluetooth Coexistence Interference
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Solution Overview
Problem
Coexistence interference between collocated radios such as 3GPP LTE and Bluetooth transceivers in wireless devices reduces data throughput due to simultaneous operation, with existing solutions like frequency division multiplexing and power reduction not fully addressing the issue.
Innovation Solution
Implementing a discontinuous reception (DRX) mechanism with extended long DRX cycle values of 2 ms, 5 ms, and 8 ms to coordinate the transmission and reception patterns of 3GPP LTE and Bluetooth transceivers, ensuring they do not interfere with each other by scheduling the Bluetooth transceiver to transmit when the LTE transceiver is not receiving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency division multiplexing is used to separate LTE and Bluetooth frequencies, then coexistence interference is reduced, but device complexity and signal processing requirements increase
Solution Approach 1:
The patent segments the time domain into distinct DRX cycles for LTE and Bluetooth operations. By dividing time into non-overlapping reception and transmission periods for different radio technologies, the system avoids frequency separation while maintaining isolation between technologies, thus reducing device complexity compared to frequency division multiplexing
Solution Approach 2:
The patent implements periodic DRX (Discontinuous Reception) cycles for LTE and periodic transmission cycles for Bluetooth. These periodic actions are synchronized so that LTE reception periods do not overlap with Bluetooth transmission periods, eliminating coexistence interference through time-based periodic scheduling rather than frequency separation
2Object-affected harmful factors
If power reduction is applied to reduce interference, then coexistence interference is reduced, but data throughput and communication effectiveness deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-scheduling DRX cycles and transmission periods before interference occurs. The eNodeB configures LTE DRX parameters and the device schedules Bluetooth transmissions in advance to avoid overlapping with LTE reception periods, eliminating the need for reactive power reduction and maintaining full power operation for both technologies
Solution Approach 2:
The patent implements dynamic time-domain scheduling where DRX cycle lengths, offsets, and transmission periods are adjustable based on traffic conditions and interference patterns. This dynamic adaptation allows the system to optimize throughput by extending active periods when interference-free operation is possible while maintaining interference avoidance, rather than applying static power reduction
3Productivity
If time domain multiplexing with DRX is implemented, then coexistence interference is reduced and data throughput is improved, but device complexity increases due to coordination requirements
Solution Approach 1:
The patent makes the DRX mechanism universal by applying it to multiple radio technologies (LTE, Bluetooth, Wi-Fi) through a unified time-domain scheduling framework. The same DRX cycle configuration and coordination principles work across different technologies, simplifying the coordination complexity compared to implementing separate scheduling mechanisms for each radio type
Solution Approach 2:
The patent introduces the DRX cycle as an intermediary scheduling mechanism that mediates between LTE and Bluetooth operations. The eNodeB acts as an external intermediary by configuring DRX parameters, while internal coordination mechanisms serve as intermediaries to synchronize Bluetooth transmissions with LTE DRX patterns, reducing direct coordination complexity between radios
Data Source
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Figure 3A~3B
AI summary
Technology for reducing coexistence interference in a multi-radio device is disclosed. One method comprises applying discontinuous reception (DRX) to a user equipment (UE) having a plurality of radio transceivers. The DRX can include a long DRX cycle for the UE. One of a 2 milliseconds (ms), 5 ms, and 8 ms cycle start offset period may be provided for the long DRX cycle to reduce coexistence interference between the plurality of radio transceivers in the UE. The cycle start offset period is selected to provide at least one Hybrid Automatic Repeat Request (HARQ) process reservation pattern to reduce the coexistence interference between the plurality of radio transceivers in the UE.