Coexistence Predictor for Bluetooth and WiMAX Interference
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Solution Overview
Problem
The coexistence of Bluetooth and Orthogonal Frequency Division Multiple Access (OFDMA) radios on the same device at the same frequency band is challenging due to internal interference, with packet losses as high as 25% on the downlink and 38% on the uplink, primarily because synchronization of their clocks is not preferred and there is limited flexibility in delaying one technology's transmission relative to the other's reception.
Innovation Solution
A method and apparatus that use a co-existence predictor to determine when to shut down the Bluetooth transmitter based on an estimated Media Access Protocol (MAP) signal, allowing the OFDMA receiver to maintain synchronization by predicting future MAP symbol timing and controlling the Bluetooth transmitter to avoid interference during expected MAP message receipt, using techniques like Fast Fourier Transform and delay-locked loop for signal analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Bluetooth and OFDMA radios operate simultaneously on the same frequency band, then device functionality and spectral efficiency are improved, but internal interference and packet loss increase
Solution Approach 1:
The system performs preliminary action by predicting future MAP symbol timing and proactively shutting down the Bluetooth transmitter before interference occurs. The co-existence predictor analyzes current and historical MAP symbols to determine when OFDMA reception is expected, allowing the Bluetooth transmitter to be silenced in advance, preventing packet loss before it happens.
Solution Approach 2:
The system implements feedback by continuously monitoring historical MAP symbol patterns and using this information to adjust Bluetooth transmission timing. The co-existence predictor processes received MAP symbols to identify patterns, feeds this information back into the decision logic, and uses it to dynamically control Bluetooth transmitter operation, creating a closed-loop interference avoidance mechanism.
2Adaptability or versatility
If clock synchronization is avoided between Bluetooth and OFDMA radios, then communication independence and interference randomness are improved, but coordination flexibility and packet reception reliability deteriorate
Solution Approach 1:
The system compensates for the lack of clock synchronization by performing preliminary analysis of MAP symbol timing patterns. The co-existence predictor examines historical MAP symbols to forecast future reception times, allowing the Bluetooth transmitter to be shut down proactively without requiring synchronized clocks between the two radio systems.
Solution Approach 2:
The system introduces an intermediary mechanism - the co-existence predictor - that mediates between the asynchronous Bluetooth and OFDMA systems. This predictor analyzes MAP symbol patterns and generates shutdown decisions for the Bluetooth transmitter, serving as a coordination layer that enables reliable operation without direct clock synchronization.
3Productivity
If Bluetooth transmitter operates continuously, then transmission reliability and data throughput are improved, but internal interference with OFDMA receiver increases
Solution Approach 1:
The system implements periodic action by rhythmically shutting down and restarting the Bluetooth transmitter based on predicted OFDMA reception timing. The co-existence predictor continuously monitors MAP symbol patterns to determine optimal shutdown intervals, creating a periodic transmission pattern that avoids interference during critical OFDMA reception windows while maintaining throughput during acceptable periods.
Solution Approach 2:
The system performs preliminary action by predicting when OFDMA reception will occur and shutting down the Bluetooth transmitter in advance. The co-existence predictor analyzes historical MAP symbols to forecast future reception times, allowing the Bluetooth transmitter to be silenced before interference would occur, thereby protecting OFDMA reception while maintaining Bluetooth transmission opportunities.
Data Source
AI summary
A method for coexistence of an orthogonal frequency division multiple access (OFDMA) receiver (117) such as a WiMAX receiver with a synchronous frame-based transmitter (115) such as a Bluetooth transmitter within a mobile station (110) receives an estimated media access protocol (MAP′) signal indicating when a MAP message is expected to be received by the OFDMA receiver (117) and uses it at a Bluetooth shutdown signal (190) at least when a MAP message is expected to be received. The MAP′ signal can be taken directly from the ODFMA transceiver (117) or it may be produced through analysis of a receiver-enable (RXE) signal that includes not only MAP symbols but also downlink data symbols. The RXE signal can be analyzed using interrupt-and-timer, Fast Fourier Transform, covariance, and/or delay-locked loop techniques to extract historical MAP symbol information and generate expected MAP symbol information. Shutting down a Bluetooth transmitter during expected MAP message receipt permits the OFDMA receiver to maintain synchronicity with an access point while not requiring the Bluetooth transmitter to shut down every time the OFDMA receiver expects to receive an OFDMA symbol.