With the widespread adoption of 5G and IoT technologies, wireless network traffic is growing exponentially. Performance bottlenecks and interference issues have become core factors hindering user experience. This article analyzes performance indicators, identifies interference source characteristics, and combines technical measures such as channel optimization and power control. The effectiveness of the solution is verified through enterprise case studies, providing a practical path for wireless operations and maintenance in complex environments.

From home Wi-Fi to industrial WLANs, wireless networks have deeply penetrated production and daily life. According to IDC, the number of connected IoT devices worldwide will exceed 75 billion by 2025. This massive access will lead to channel congestion and increased interference, resulting in throughput in some scenarios reaching only 40% to 60% of the nominal value. Accurately identifying interference and formulating scientific optimization strategies are critical to ensuring network stability.

I. Analysis of Core Wireless Network Performance Indicators

Signal Strength and Signal-to-Noise Ratio (SNR)

Signal strength is measured in dBm. Ideal coverage should be maintained between -40dBm and -70dBm. Packet loss rates increase significantly below -85dBm. SNR reflects the useful signal-to-noise ratio. A value ≥25dB meets requirements such as high-definition video. Values below 15dB require antenna adjustment or AP additions.

Throughput and Bandwidth Utilization

Throughput is affected by channel width and modulation method. For example, while the theoretical single-stream rate of 802.11ax (Wi-Fi 6) is 1.2Gbps, the actual single-user rate typically remains between 300Mbps and 500Mbps due to interference and terminal compatibility. Channel bonding (20MHz → 40MHz) can increase bandwidth, but adjacent channel interference must be avoided.

Latency and Jitter

Industrial control and telemedicine require latency less than 10ms. Wireless network latency is composed of propagation delay (1μs/m), processing delay (AP/terminal forwarding time), and queuing delay (channel congestion). Jitter exceeding 5ms can cause voice stuttering and video tearing.

II. Classification and Characteristics of Wireless Network Interference Sources

Co-channel Interference: "Signal Collision" from Channel Overlap

The 2.4GHz band has only three non-overlapping channels (1, 6, and 11). When multiple APs share the same channel and have overlapping coverage, the "hidden node" problem can easily occur, causing terminal signals to be misinterpreted as noise and resulting in data retransmission. Although the 5GHz band has 24 non-overlapping channels (in China), high-density deployments (such as shopping malls and stadiums) still cause interference due to channel reuse.

Adjacent Channel Interference: "Edge Effect" of Spectrum Leakage

The wireless signal spectrum has a bell-shaped distribution. When the distance between adjacent channel APs is less than 10 meters, the edge of a strong signal can intrude into a weak signal channel. For example, if the AP power on channel 6 is too high, it can interfere with channels 5 and 7, increasing the demodulation error rate of weak-signal terminals by over 30%.

Non-wireless Interference: The "Invisible Obstacle" of the Electromagnetic Environment

Among electronic devices, microwave ovens (2.45GHz) generate broadband noise when operating, covering the entire 2.4GHz channel with an interference radius of up to 5 meters. Metal obstructions (such as elevator shafts and steel structures) cause signal attenuation of 80%-90%, creating blind spots. Even with high concurrency, Bluetooth and ZigBee devices can still conflict with WiFi.

III. Core Technologies and Practices for Performance Optimization

Dynamic Channel Planning: From "Fixed" to "Intelligent"

Traditional static configuration is easily affected by the environment. We recommend a three-step "Scan - Analyze - Assign" approach: Use Ekahau or AirMagnet to collect AP data and generate spectrum heatmaps. Prioritize channels with a high interference index (channel occupancy < 30%, SNR > 20dB), and avoid overlapping channels in the 2.4GHz band. Enable automatic switching for enterprise-class APs (such as Cisco DNA Center), scanning every 15 minutes and adjusting when thresholds are exceeded.

Fine-grained Power Control: Balancing Coverage and Interference

Following "coverage on demand": Indoor single AP power is set at 15dBm-20dBm in the 2.4GHz band and 18dBm-23dBm in the 5GHz band to avoid power differences exceeding 6dBm between adjacent APs. Outdoor directional antennas can be increased to 25dBm, but a field survey is required to define coverage boundaries. In multi-story buildings, power is maintained uniformly on all floors, with power reduced by 3dBm-5dBm between floors above and below to minimize vertical interference.

Topology Reconstruction: From "Single" to "Three-Dimensional"

High-density scenarios (conference rooms, classrooms) utilize a "micro-cell" network: deploy one 802.11ax OFDMA-capable AP for every 50-80 square meters, serving 30+ terminals. Enable load balancing, and when an AP exceeds 30 terminals or CPU utilization exceeds 70%, redirect new terminals to idle APs. Mesh nodes are used to fill blind spots in elevators and basements, and coverage is expanded through wired or 5GHz backhaul.

IV. Practical Interference Location and Elimination Case Studies

A 1,500-square-meter internet company office area, equipped with 12 802.11ac APs, reported video stuttering and file transfers below 10Mbps. Initial inspection revealed occupancy of 2.4GHz channel 6 of 85%. Location: Spectrum analysis revealed three strong interference signals on the 2.4GHz band, with peaks occurring every two minutes. On-site investigation revealed a sudden spike in interference when three microwave ovens were operating in the pantry, causing the SNR of surrounding APs to drop from 28dB to 12dB. Wireshark capture data showed a 25% retransmission rate for terminals near the pantry (normally less than 5%).
Optimization: 2.4GHz channels were switched to non-overlapping channels 1, 4, and 5GHz. 2.4GHz power of APs surrounding the pantry was reduced from 20dBm to 15dBm. Peak microwave usage was offset from meeting times, and shielding nets were installed.
Results: After one week, 2.4GHz utilization was less than 40%, and 5GHz utilization remained stable at 55%. Video lag was eliminated, file transfer speeds reached 50Mbps to 80Mbps, and employee satisfaction increased from 35% to 92%.