Dynamic Priority Scheduling for VoIP Over WLAN and Bluetooth Interference
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Solution Overview
Problem
Interference between WLAN and Bluetooth signals in mobile terminals, particularly in voice over IP communications, due to their operation in the same 2.4 GHz ISM band, leads to packet loss and retransmissions, affecting speech integrity and network capacity.
Innovation Solution
Implementing a new mode of operation for the control block between WLAN and Bluetooth transceivers, prioritizing WLAN transmissions over Bluetooth, and utilizing the Extended Synchronous Connection-Oriented (eSCO) logical transport with retransmission windows to ensure successful retransmission of interrupted Bluetooth packets, without altering the existing standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WLAN and Bluetooth transceivers operate simultaneously in the 2.4 GHz ISM band, then both communication functions are available, but signal interference occurs causing packet loss and retransmissions
Solution Approach 1:
The patent implements dynamic priority assignment where WLAN transmissions are given higher priority during normal operation, but Bluetooth retransmissions receive elevated priority when packet loss is detected. The control block continuously adjusts transmission priorities based on real-time communication conditions, allowing the system to adapt between maintaining WLAN throughput and ensuring Bluetooth voice packet delivery reliability
Solution Approach 2:
The patent establishes eSCO links with pre-configured retransmission windows before voice communications begin. The control block is pre-programmed with the priority assignment rules and retransmission parameters, enabling immediate response to packet loss conditions without requiring real-time negotiation or configuration changes during active communication
2Productivity
If WLAN transmissions are prioritized over Bluetooth, then WLAN throughput is improved, but Bluetooth packet delivery may be interrupted
Solution Approach 1:
The patent implements a feedback mechanism where the control block monitors Bluetooth packet delivery success rates and automatically triggers retransmission procedures when losses are detected. The system uses acknowledgment packets and error detection codes to identify failed transmissions, then reallocates priority resources to ensure successful delivery, creating a closed-loop control system that balances WLAN throughput with Bluetooth reliability
Solution Approach 2:
The patent provisions retransmission windows and buffer resources in advance of potential packet losses. By pre-allocating time slots and control block resources for retransmissions, the system cushions against the impact of WLAN priority assignments on Bluetooth voice traffic, ensuring that even if initial packets are lost to WLAN interference, reliable delivery can be achieved through scheduled retransmissions
3Reliability
If Bluetooth retransmissions are allowed, then speech integrity is maintained, but network capacity and WLAN performance are reduced
Solution Approach 1:
The patent implements selective retransmission rather than universal retransmission of all Bluetooth packets. The control block identifies only those packets that are actually lost or corrupted through acknowledgment mechanisms, and retransmits only those specific packets. This partial action approach maintains speech integrity for affected packets while minimizing the overall impact on network capacity and WLAN performance compared to retransmitting all Bluetooth traffic
Data Source
AI summary
A system and method are disclosed for reducing interference in simultaneous wireless LAN (WLAN) and wireless personal area network (PAN) signal handling in mobile wireless terminals having both a WLAN and a PAN interface. The wireless terminal includes a first transceiver operating in the PAN network in a communications band and a first communications protocol transmitting first data units. The wireless terminal also includes a second transceiver operating in the WLAN network in substantially the same communications band and a second communications protocol transmitting second data units. The wireless terminal further includes a controller coupled to the first and second transceivers, assigning a higher transmission priority to the second data units than to the first data units when transmission of the second data units overlaps a first occurring transmission of the first data units, to abort transmission of the first occurring data unit. The controller assigns a higher transmission priority to the aborted first data unit than to the second data units when transmission of the second data units overlaps the retransmission of the aborted first data unit, to transmit the aborted first data unit.