LTE WLAN Coexistence via Interference-Aware Subframe Suspension
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Solution Overview
Problem
Concurrent operation of multiple wireless communication technologies within a device, such as 3GPP LTE and WLAN, often results in interference due to overlapping frequency bands, leading to disrupted transmissions and reduced throughput.
Innovation Solution
A communication device is configured with a first network interface for cellular protocols and a second for WLAN protocols, using interference mitigation techniques where the device suspends LTE operations during subframes of poor channel quality to enable WLAN operations, thereby minimizing interference and optimizing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple wireless communication technologies (LTE and WLAN) operate concurrently in the same device, then communication capabilities and versatility are improved, but interference between systems occurs and reliability deteriorates
Solution Approach 1:
The patent segments the time domain by dividing radio frames into subframes and further into slots. It identifies specific slots (e.g., slots 1 and 5 in a 10ms frame) as high-interference slots where WLAN transmissions from nearby devices cause significant degradation. The LTE system then avoids scheduling transmissions during these identified high-interference slots, effectively segmenting the transmission timeline to prevent interference while maintaining concurrent operation of both LTE and WLAN technologies.
2Productivity
If LTE transmissions are scheduled during high-interference slots, then productivity is improved, but interference from WLAN causes loss of information and reduced reliability
Solution Approach 1:
The patent implements preliminary action by having the UE perform measurements and identify high-interference slots in advance before actual data transmission occurs. The device measures reference signals (CRS, CSI-RS, or RS for channel measurement) during initial access and connection setup phases to predict which slots will experience WLAN interference. Based on these preliminary measurements, the network configures the UE with a pattern of high-interference slots, allowing the UE to proactively avoid transmitting or receiving data during these problematic slots, thereby preventing information loss before it occurs.
3Reliability
If the device suspends LTE operations during identified high-interference slots, then reliability of WLAN reception is improved, but productivity of LTE transmission is reduced
Solution Approach 1:
The patent applies local quality by treating different time slots differently based on their interference characteristics. Instead of uniformly suspending LTE operations across all time slots, the system identifies specific slots (local regions in the time domain) where WLAN interference occurs and applies suspension only to those particular slots. The LTE system continues normal operations during non-high-interference slots, maintaining high throughput where conditions permit. This localized approach ensures that WLAN reception reliability is improved during problematic slots while minimizing the impact on overall LTE productivity.
Data Source
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AI summary
In a method of operating a communication device that includes at least (i) a first network interface configured to operate according to a first communication protocol and (ii) a second network interface configured to operate according to a second communication protocol, the first communication interface is operated according to the first communication protocol. The first communication protocol defines a periodically repeating set of time intervals. One or more time intervals, from the set of time intervals, that meet a selection criteria are determined. The selection criteria is based on level of interference experienced by the first network interface. During the determined one or more time intervals, operation of the first network interface according to the first communication protocol is suspended, and operation of the second network interface according to the second communication protocol is enabled.