MediaTek Anti-Interference Technology for Wi-Fi Networking
This white paper details MediaTek's innovative solutions for combating Wi-Fi interference, ensuring robust and high-performance wireless connectivity.
Key Insights
- Approximately 75% of residential Wi-Fi networks experience significant interference and performance degradation, particularly during weekends.
- MediaTek Anti-Interference technology effectively mitigates over 95% of performance degradation in residential network environments caused by various interferences.
- During peak Wi-Fi usage, MediaTek Anti-Interference technology can boost throughput by up to 30% and reduce latency by up to 60%.
Introduction
Wi-Fi technology is fundamental to modern society, enabling seamless connectivity for work, entertainment, and daily life. As Wi-Fi adoption grows and more devices connect within the same network, the Wi-Fi spectrum becomes increasingly congested. This leads to severe interference between adjacent Wi-Fi networks, impacting performance and reliability. This is particularly evident in dense environments like multi-story residential buildings where Wi-Fi Access Points (APs) from different units can overlap, causing mutual interference. Even within a single network, like Multiple AP (MAP) Wi-Fi Mesh networks or temporary peer-to-peer (P2P) connections, interference can degrade user experience. Wi-Fi networks in vehicles also face external wireless interference. Addressing these challenges is crucial for maintaining stable and high-quality Wi-Fi connections. While traditional methods like band steering exist, they can introduce their own issues. Developing in-use channel anti-interference technology is therefore a priority to enhance Wi-Fi efficiency, throughput, and latency, especially in interference-prone scenarios.
Interference in Diverse Wi-Fi Networks
Wi-Fi networks are now ubiquitous, supporting connectivity in homes, businesses, and public spaces. This section explores three common home scenarios illustrating Wi-Fi interference challenges:
Scenario-1: Single AP network
In a typical apartment building, a single Wi-Fi AP may struggle to provide optimal performance due to overlapping signals from neighboring networks using the same 2.4GHz and 5GHz bands. For example, John, using a 300Mbps broadband connection and a Wi-Fi 7 AP, experiences slow speeds and high latency during peak evening hours (6:00 PM - 11:00 PM) due to neighbors' network usage. This congestion makes online gaming frustrating and streaming unreliable.
Challenge: Managing home network traffic while mitigating interference from multiple neighboring routers is essential, especially in spectrum-limited regions.
Scenario-2: Multiple AP network
A Wi-Fi Mesh network, using multiple APs for extended coverage, can also face interference. In a family with several devices, using 3 APs with Wi-Fi backhaul for full home coverage means data hops between APs, doubling bandwidth usage. During peak usage, severe channel overlaps increase packet latency, causing lag, audio dropouts, and slower speeds for all users, including those in online meetings, gaming, or streaming.
Challenge: While Mesh networks extend coverage, sharing the same channel limits AP capacity and leads to interference between wireless backhaul (AP-to-AP) and fronthaul (AP-to-client) traffic.
Scenario-3: Multiple clients peer to peer network
Temporary peer-to-peer (P2P) networks, used for sharing files or media, also contend with existing Wi-Fi signals. In a small apartment, a single AP serves the home, while a neighbor's AP also operates nearby. During peak weekend hours, multiple devices sharing the Wi-Fi spectrum, including P2P connections, lead to signal interference. This results in slow file transfers, buffering issues during live streams, and game lag for users.
Challenge: Users need the flexibility for temporary P2P networks, but these must coexist with existing home and neighboring Wi-Fi routers, a key challenge for network stability.
The Impact of Interference on Wi-Fi Networks
Poor Wi-Fi performance is common during peak hours due to increased network demand from streaming, gaming, virtual meetings, and browsing. These peak times typically occur in the evenings (6:00 PM - 11:00 PM) and throughout the day on weekends (10:00 AM - 11:00 PM).
John's Wi-Fi AP (BE3600) with a 300Mbps broadband connection shows low channel utilization (<30%) during peak hours when there is no interference. However, in reality, overlapping neighboring Wi-Fi networks cause spectrum interference, leading to actual channel utilization exceeding 70% and sometimes reaching full capacity, as depicted in Figure 5. This results in smooth gaming (<50ms ping) during off-peak hours but frequent lag and disconnections (>150ms ping) during peak hours.
Figure 6 illustrates the Wi-Fi spectrum analysis for John's 5 GHz network. It shows six overlapping Wi-Fi networks, with two causing Co-Channel Interference (CCI) and three causing Adjacent Channel Interference (ACI). This crowded environment with limited spectrum bands leads to network overlap and interference.
When neighbors' Wi-Fi causes CCI, channel utilization increases due to bandwidth competition, reducing airtime and elevating latency. ACI degrades signal quality and increases data packet errors. Simultaneous CCI and ACI lead to intense competition, poor signal quality, and saturation of channel utilization, resulting in poor Wi-Fi performance.
MediaTek's R&D simulated John's home Wi-Fi network with ACI load levels of 15% (off-peak) and 60% (peak) to test performance in four common applications:
| Application Type | Requirement | Off-Peak Hours (ACI load at 15%) | Peak Hours (ACI load at 60%) |
|---|---|---|---|
| Online gaming | Average Latency < 100 ms PR95 Latency < 150 ms | 57 ms 93 ms | 98 ms 176 ms |
| Video conferencing | Average Latency < 100 ms PR95 Latency < 200 ms | 72 ms 105 ms | 111 ms 215 ms |
| 4K media streaming | Buffer Health > 10 sec | 12 sec | < 5 sec |
| File download (5 GB) | Speed: The Faster, The Better | Speed > 200 Mbps Download Time < 4 min | Speed < 55 Mbps Download Time > 13 min |
Table 1: Observed latency in four distinct applications when experiencing different ACI load
During off-peak hours, applications meet their requirements. However, during peak hours, performance degrades significantly with increased Packet Error Rate (PER), reduced throughput, and worsened latency. For online gaming, PR95 latency exceeding the threshold leads to unresponsive inputs. Video conferencing suffers from audio-video desynchronization and fragmented conversations. 4K streaming experiences jittering and playback interruptions due to insufficient buffer health. File downloads take considerably longer.
Anti-Interference Technologies
IEEE 802.11ax (Wi-Fi 6) introduced Spatial Reuse (SR) for CCI and Preamble Puncture (PP) for ACI. Wi-Fi 7 enhances this with Multiple Resource Unit (MRU), improving flexibility and interference handling.
MediaTek has developed proprietary anti-interference technologies to address real-world user issues:
- Universal Bandwidth Adaption (UBA): Optimizes bandwidth and rate selection to mitigate interference impact, enhancing reliability, throughput, and reducing latency.
- Customized Preamble Puncture (CPP): Leverages PP and MRU to enable APs and STAs to exchange interference information, avoiding hidden node impacts and improving performance.
- Enhanced Spatial Reuse (ESR): Extends the range and effectiveness of Spatial Reuse (SR) by differentiating inter-BSS Wi-Fi signals using PHY payload decoding capabilities.
- Coordinate Spatial Reuse (CSR): Specifically designed for Mesh networks, CSR coordinates APs via transmission power control to enhance airtime, reduce interference, and improve transmission opportunities.
Universal Bandwidth Adaption (UBA)
ACI weakens Wi-Fi signals and increases error rates. UBA helps maintain stable connections by selecting optimal bandwidth and rate combinations. In hidden node scenarios, where interference is not always detected by both parties, UBA dynamically adjusts to maximize Wi-Fi speed and minimize latency.
UBA identifies hidden nodes by observing Wi-Fi PHY indicators. It then tests various bandwidth and rate combinations to find the optimal one for the current environment, reducing testing overhead.
Customized Preamble Puncture (CPP)
CPP addresses hidden node situations by enabling APs and STAs to exchange interference detection results. If ACI affects a STA, the AP can use PP + MRU to avoid the impact, and combining with SR further enhances interference avoidance.
Enhanced Spatial Reuse (ESR)
SR allows simultaneous transmissions by managing interference. Wi-Fi 6 uses BSS color for detection, but older devices can cause MAC decode errors. ESR enhances SR by using PHY header rate information and signal strength to identify inter-BSS PPDUs, even from pre-Wi-Fi 6 devices, significantly expanding SR opportunities.
Coordinate Spatial Reuse (CSR)
In Mesh networks, where all devices share a channel, CSR coordinates APs to manage transmission power. This improves SR efficiency, increases SR transmission opportunities, and reduces interference from concurrent transmissions.
MediaTek Anti-Interference technology dynamically manages CSR in Mesh networks. By adjusting transmission power, it enhances SR success rate and minimizes interference, potentially increasing throughput by up to 30%.
Residential networks face various interferences (Wi-Fi, DFS, microwave, Bluetooth). While Wi-Fi can only avoid microwave interference by switching channels, MediaTek's technology mitigates other interference types.
| Interference | Anti-Interference Off | Anti-Interference On | ||||
|---|---|---|---|---|---|---|
| Throughput (Mbps) | Latency (ms) | PR95 Latency (ms) | Throughput (Mbps) | Latency (Mbps) | PR95 Latency (ms) | |
| No Interference | 450 | 59 | 81 | 450 | 59 | 81 |
| 15% ACI Loading | 345 | 65 | 101 | 405 | 61 | 85 |
| 60% ACI Loading | 55 | 134 | 252 | 330 | 72 | 97 |
Table 2: The effect of MediaTek Anti-Interference technology versus a hidden node scenario
In a 15% ACI loading scenario, MediaTek Anti-Interference (using UBA) increases throughput by 17% and reduces latency by 6%. At 60% ACI loading, it uses CPP to restore throughput to 73% of the non-interference state, reducing average latency by 46% and PR95 latency by 61%.
| Backhaul | Fronthaul | Mesh Throughput (Mbps) | |||
|---|---|---|---|---|---|
| CSR Off | CSR On | Gain | |||
| STA<->AP 1m, RSSI -25dBm | EHT 5G BW160 | HE 5G BW160 | 2036 | 2657 | 30% |
| STA<->AP 3m, RSSI -38dBm | 1860 | 2406 | 29% | ||
| STA<->AP 5m, RSSI -52dBm | 1803 | 2035 | 12% | ||
Table 3: CSR results in a three AP (Mesh) network with one STA
Conclusion
MediaTek has developed advanced proprietary anti-interference technologies like UBA, CPP, ESR, and CSR to mitigate interference across various network scenarios, including hidden node situations and Mesh networks. These technologies, used individually or in combination, enhance Wi-Fi throughput, reduce latency, and improve network reliability, ensuring an excellent Wi-Fi experience. The Wi-Fi Alliance is also introducing new anti-interference technologies for future standards like Wi-Fi 8, focusing on signal reception, frequency band utilization, and advanced antenna techniques. MediaTek continues to evolve its Anti-Interference technology, incorporating these advancements to strengthen the interference resistance of its Filogic gateways and clients, providing users with reliable connections and consistent Wi-Fi performance.
Glossary
- ACI: Adjacent Co-Interference
- AP: Access Point (i.e., router)
- BSS: Basic Service Set
- C-BF: Coordinated Beamforming
- CCI: Co-Channel Interference
- CPP: Customized Preamble Puncture
- CSMA/CA: Carrier Sense Multiple Access with Collision Avoidance
- CSR: Coordinate Spatial Reuse
- DFS: Dynamic Frequency Selection
- DSO: Dynamic Sub-Channel Operation
- ESR: Enhanced Spatial Reuse
- MAC: Media Access Control
- MCS: Modulation Coding Scheme
- NPCA: Non-Primary Channel Access
- PER: Packet Error Rate
- PHY: Physical Layer
- PP: Preamble Puncturing
- PPDU: Physical Protocol Data Unit
- QAM: Quadrature Amplitude Modulation
- RSSI: Received Signal Strength Indicator
- SNR: Signal-to-Noise Ratio
- SR: Spatial Reuse
- STA: Station (i.e., a smartphone)
- UBA: Universal Bandwidth Adaption
MediaTek in the Wi-Fi Industry
MediaTek is a leading global supplier of Wi-Fi solutions, offering both standalone networking products (routers, repeaters, mesh APs) and embedded Wi-Fi connectivity for devices like smartphones, tablets, TVs, IoT devices, and gaming consoles. MediaTek actively participates in IEEE and Wi-Fi Alliance certification development to ensure industry interoperability and performance. Recent examples include the selection of MediaTek's Filogic platforms for Wi-Fi 6E and Wi-Fi 6 R2 test beds. With Wi-Fi 7 and future standards, MediaTek continues to contribute its expertise to advance Wi-Fi performance. MediaTek's innovations, such as the Filogic 880 and Filogic 380, support next-generation MLO reliability for high-performance, power-efficient Wi-Fi solutions.
Discover more about MediaTek's Wi-Fi solutions:
https://www.mediatek.com/products/networking-and-connectivity/filogic-wifi6-wifi7
Acknowledgments
AUTHOR:
CY Lin (Deputy General Manager of Connectivity Technology Development)
CONTRIBUTORS:
Pluto Kang (Sr. Technical Manager of Connectivity Technology Development)
Kyle Hsu (Director of Connectivity Technology Development)
Joel Hung (Sr. Technical Manager of Connectivity Technology Development)
James Chiang (Sr. Technical Marketing Manager of intelligent Connectivity Business)
EDITOR:
Dylen Kang (Sr. Research Engineering of Connectivity Technology Development)
