Collocated Bluetooth and LTE Radio Interference Mitigation
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Solution Overview
Problem
The simultaneous operation of Bluetooth radios with Orthogonal Frequency Division Multiple Access (OFDMA) radios in wireless devices leads to interference, reducing data throughput and effectiveness of both types of radios due to power differences and timing collisions.
Innovation Solution
A prediction algorithm is implemented to synchronize Bluetooth packet transmissions with 3GPP LTE radio subframes, using mechanisms like frame synchronization, delaying Bluetooth transmissions during LTE transmit periods, and ceasing transmissions during LTE receive subframes to avoid interference, along with a repeating Tx/Rx pattern that aligns with LTE TDD configurations to minimize co-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Bluetooth radio operates simultaneously with 4G radio at higher power, then Bluetooth communication can be maintained, but substantial interference occurs in WiFi and Bluetooth radios reducing their effectiveness
Solution Approach 1:
The patent segments the time domain into distinct transmission and reception periods for both 4G and Bluetooth radios. By dividing the operation into non-overlapping time slots (4G transmission periods and Bluetooth transmission periods), the system allows high-power 4G operation without interfering with Bluetooth communication, as they operate in separate time segments rather than simultaneously
Solution Approach 2:
The patent implements periodic action by establishing repeating patterns of 4G transmission periods and Bluetooth transmission periods. The system alternates between these modes in a cyclic fashion, with each radio transmitting during its designated periodic intervals and remaining silent during the other radio's transmission periods, thereby avoiding interference while maintaining both communication functions
2Reliability
If WiFi and Bluetooth radios operate at lower power, then interference from 4G radio is reduced, but their communication effectiveness is still reduced due to timing collisions
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing Bluetooth transmission timing with 4G radio subframe boundaries before actual communication occurs. The system establishes predetermined time slots for Bluetooth transmission that are calculated in advance to fall within 4G receive periods, ensuring that Bluetooth packets are transmitted at optimal times without experiencing timing collisions or interference
Solution Approach 2:
The patent implements dynamics by allowing the system to adaptively adjust Bluetooth transmission timing based on the current 4G radio state. The Bluetooth radio dynamically selects transmission opportunities based on real-time detection of 4G transmission/reception periods, optimizing its transmission schedule to maximize communication effectiveness while avoiding interference
3Object-affected harmful factors
If Bluetooth transmissions are delayed or ceased during LTE transmit periods, then interference is reduced, but data throughput and power efficiency are impacted
Solution Approach 1:
The patent converts the harmful effect of 4G high-power transmission into a beneficial scheduling constraint. By treating 4G transmission periods as designated 'quiet zones' for Bluetooth, the system transforms potential interference into a structured time-division framework where both radios can operate effectively. The harm of 4G power is converted into a scheduling advantage that organizes Bluetooth transmissions around these high-power periods
Data Source
AI summary
Technology for reducing interference in collocated radios is disclosed. One method comprises logging transmit/receive information from a Bluetooth radio and an OFDMA radio for a repeating Tx/Rx pattern. Data collisions between the radios are identified. A persistent reservation is requested in the OFDMA radio for collisions in the repeating Tx/Rx pattern. A repeating Bluetooth Tx/Rx pattern is derived from the logged data and the collision data. Bluetooth radio communication is accomplished using the Bluetooth Tx/Rx pattern.