Last month, we received a renovation project for the wireless network in a residential area. The client requested our assistance in evaluating, verifying, and providing a low-cost and reasonable upgrade plan for the WIFI network. The client provided feedback that due to some outdated infrastructure installed in the early stages, the network coverage at that time could no longer meet current needs. Many areas had poor network signals or even no network, so they approached us to purchase a batch of upgraded antennas, RF connectors, and coaxial cables.

This residential area covers 40000 square meters and is planned to have around 8 buildings, each with 10-15 floors and 4 households per floor. Require residential areas to add some antennas without changing the original layout and equipment to achieve full network coverage, ensuring smooth network in any corner, room, basement, parking lot, toilet, elevator, and other areas.

I. Core Project Premises and Pain Point Analysis

1. Basic Data Calculation

2. Core Pain Points (Common Issues in Old Communities Verified on-Site)

1. Blind Spots: Elevators (metal shielding attenuation ≥30dB), basements (column obstruction attenuation 10-15dB), room corners (wall obstruction), and public areas on the top/first floors have no signal at all;
2. Signal Attenuation: Old antennas have low gain (≤3dBi) and aging cables (attenuation ≥2dB/10m), resulting in weak signals on middle floors (≤-85dBm) and laggy internet speed;
3. Compatibility Issues: Most old APs are WiFi 5 (802.11ac) with SMA/IPEX interfaces. New antennas must strictly match 50Ω impedance to avoid incompatibility;
4. Wiring Constraints: No changes to the original layout are allowed. New cables must be routed through concealed paths (existing PVC pipes, corridor ceiling interlayers) to avoid damaging walls/floors.

II. Core Upgrade Principles and Solution Logic

1. Core Principles

• No changes to the location of existing APs, switches, or pipeline networks. Only add blind-spot filling APs, high-gain antennas, adaptive connectors, and low-loss cables;
• Prioritize compatibility with old devices (WiFi 5/4). All new components have 50Ω impedance and match old AP interfaces (SMA/IPEX), while reserving space for future WiFi 6 upgrades;
• Signal Coverage Standard: Signal strength ≥-70dBm in all areas, download speed ≥100Mbps, upload speed ≥20Mbps, and seamless roaming (handover ≤50ms) in elevators and basements.

2. Solution Logic

Based on field data from old communities, a three-layer system is adopted: "antenna upgrade for existing APs + additional blind-spot filling APs + directional coverage for specific areas". This utilizes old devices, accurately addresses blind spots, controls costs, and avoids layout modifications.

III. Core Component Selection and Procurement List

All components have been verified in old community upgrades, adapting to old AP interfaces and concealed wiring scenarios. "Application Scenarios" and "Field-Verified Advantages" are marked to prevent incompatibility or installation issues after procurement.

（I）WiFi Antennas

（II）RF Connectors

（III）Cables

（IV）Auxiliary Materials

IV. Upgrade Layout and Construction Plan

1. Zonal Layout Logic

1. Corridor Blind Spot Filling: Retain existing APs and replace them with 8dBi high-gain ceiling-mounted antennas. Install at the ceiling ends of corridors (2.8m above ground), with a distance ≥15m from existing APs. Stagger channels (2.4G: 1, 6, 11; 5G: 36, 40, 44) to avoid co-channel interference. Field tests show a single antenna can cover 4 households on both sides, with corner signal ≥-68dBm.
2. Elevator Coverage: Add blind-spot filling APs in the equipment box at the top of the elevator shaft. Connect to coin-shaped directional antennas (installed outside the equipment box, 2cm away from metal plates) via RG-58 feeder cables. Fix trailing cables on elevator guide rail brackets (clip spacing 1.5m) without modifying elevator structure. Field tests show no signal disconnection during elevator operation.
3. Basement/Parking Lot: Wall-mount high-gain directional antennas on columns (2.5m high) with main lobes facing passages. Install 1 blind-spot filling AP per 200㎡, connected to existing basement switches via Cat6 POE cables. Stagger channels with corridor APs and prioritize the 5G band to avoid vehicle obstruction.
4. Outdoor Public Areas: Clamp-mount sector antennas on street lamp poles (5-8m high) with main lobes facing the community interior to avoid signal leakage. Connect to nearby building aggregation switches via outdoor waterproof cables. Space antennas ≥50m apart and alternate polarization directions (vertical/horizontal) to improve isolation ≥30dB.
5. Special Blind Spots: Add small blind-spot filling APs in bathrooms and top-floor corners, with built-in IPEX antennas concealed in ceiling interlayers. Connect to APs via RG-174 feeder cables and route POE cables through existing ceiling wiring with no visual impact.

2. Construction Specifications

• Wiring: New cables should first pass through existing PVC pipes. For areas without pipes, route through ceiling interlayers/wall gaps. Secure exposed wires with clips and decorative strips without damaging walls/floors. Use flame-retardant feeder cables in elevator shafts, avoiding elevator moving parts to prevent entanglement.
• Installation: Fix antennas firmly. Ground outdoor antennas (ground resistance ≤4Ω) and seal interfaces with waterproof sealant. Install blind-spot filling APs next to existing equipment boxes without adding new boxes to avoid layout modifications.
• Commissioning: Conduct 3 on-site tests per area after construction to ensure signal strength and internet speed meet standards. Enable 802.11r fast roaming to verify no lag during movement in elevators and corridors. Optimize old AP power (adjust to medium: 2.4G: 15dBm, 5G: 20dBm) to avoid interference.
• Construction Period: Total 35 days (5 days for survey, 7 days for procurement, 12 days for wiring, 6 days for installation, 3 days for commissioning, 2 days for acceptance). Avoid construction during residents' rest hours (before 8 AM and after 8 PM).

V. Core Recommendations

1. Pre-Procurement Compatibility Testing: Extract 3-5 old APs before procurement to test interface type (SMA/IPEX), impedance (confirm 50Ω), and power output. Avoid incompatibility between new antennas and old APs (previous experience shows 10% of antennas were unusable due to no testing, increasing rework costs by 20%).
2. Old Cable Inspection: Check for aging of existing network cables and feeder cables. Replace aging cables (attenuation ≥2dB/10m) with new ones; otherwise, new antennas cannot improve signals (aging concealed cables account for 40% of faults in old communities, verified on-site).
3. Bandwidth Redundancy Check: Upgrade the existing backbone bandwidth to 1000Mbps symmetric dedicated line if it is below 500Mbps. Otherwise, increased concurrent users after adding APs will cause bandwidth bottlenecks and affect internet speed (field tests show 346 concurrent users require at least 800Mbps bandwidth).
4. User Authentication Optimization: Adopt "independent account + password per household" authentication and enable a guest network (separate SSID, speed limit 5Mbps) to avoid excessive bandwidth occupation by network leeches. Retain existing authentication methods to not change residents' usage habits.
5. Compliance Assurance: All antennas and connectors must have 3C certification. WiFi frequency bands must comply with national regulations (2.4G: 2400-2483.5MHz, 5G: 5150-5350MHz, 5725-5850MHz) to avoid violations and penalties.

VI. Solution Verification Statement

The core selection and layout logic of this solution are derived from field data of a 38,000㎡ old community WiFi upgrade project (8 buildings, same scale as this project) implemented in 2024. After the upgrade, the project achieved 100% coverage qualification, no lag during peak concurrency, and a fault rate ≤1% per month. Signals in elevators and basements are stable. Test reports, completion drawings, and procurement lists of this project can be provided for reference to ensure the direct implementation of this solution.