CHAPTER 13: RF DESIGN & SITE SURVEY METHODOLOGY¶
13.1 WiFi 7 RF Design Principles¶
13.1.1 Design Philosophy: "Coverage First, Capacity Second"¶
Abhavtech WiFi 7 RF Design Goals:
Primary Objectives:
1. Coverage: 100% floor area with RSSI ≥-67 dBm (6 GHz)
2. Capacity: Support 4+ Gbps per client (executive floors)
3. Redundancy: Dual-AP coverage (any location served by 2+ APs)
4. MLO: Enable 5 GHz + 6 GHz simultaneous links
Secondary Objectives:
5. Minimize co-channel interference (320 MHz channels)
6. Future-proof: 20% capacity headroom for growth
7. Aesthetics: Conceal APs where possible (ceiling tiles, above-ceiling)
WiFi 7 vs WiFi 6 Design Differences:
| Design Aspect | WiFi 6 (Legacy) | WiFi 7 (Phase 5) | Impact |
|---|---|---|---|
| Primary Band | 5 GHz (80/160 MHz) | 6 GHz (320 MHz) | 2× spectrum, cleaner RF environment |
| AP Density | 1 AP per 2,000 sq ft | 1 AP per 1,333 sq ft | +50% APs (denser deployment) |
| Target RSSI | -70 dBm (5 GHz) | -67 dBm (6 GHz) | Higher signal required (6 GHz attenuation) |
| Channel Plan | DFS channels (5 GHz) | PSC channels (6 GHz) | Simpler, no DFS/radar detection |
| MLO Design | N/A (single link) | Dual-band (5+6 GHz) | Requires both bands operational |
13.1.2 6 GHz Specific Considerations¶
6 GHz Band Characteristics:
Advantages:
• Clean spectrum: No legacy WiFi 4/5/6 interference
• Wide channels: 320 MHz available (Ch 31, 63, 95, 127, 159, 191)
• Low power indoor (LPI): Simplifies deployment (no AFC required)
• PSC channels: No DFS/radar detection delays
Challenges:
• Higher attenuation: ~10% more path loss vs 5 GHz
• Client support: Requires WiFi 7 clients (Intel BE200, Qualcomm FastConnect 7800)
• Shorter range: Expect 15-20% reduced coverage radius vs 5 GHz
Design Implications:
• Denser AP deployment: 1 AP per 1,333 sq ft (vs 1 per 2,000 for WiFi 6)
• Higher transmit power: 17-23 dBm (max allowed for LPI indoor)
• 5 GHz backup: Essential for MLO (fallback when 6 GHz weak)
6 GHz Path Loss Calculation:
Free Space Path Loss (FSPL) Formula:
FSPL (dB) = 20 × log10(distance_m) + 20 × log10(frequency_MHz) + 32.44
Example (10 meters, 6 GHz = 6,000 MHz):
FSPL = 20 × log10(10) + 20 × log10(6000) + 32.44
= 20 × 1 + 20 × 3.778 + 32.44
= 20 + 75.56 + 32.44
= 128 dB
Comparison:
• 5 GHz (5,500 MHz) at 10m: 127 dB
• 6 GHz (6,000 MHz) at 10m: 128 dB
• Difference: +1 dB (6 GHz has ~10% more attenuation)
Practical Impact:
• 5 GHz coverage radius: 15 meters (target RSSI -70 dBm)
• 6 GHz coverage radius: 12 meters (target RSSI -67 dBm)
• AP spacing reduction: 20% denser deployment required
13.2 Site Survey Methodology¶
13.2.1 Pre-Deployment Survey (Predictive)¶
Predictive RF Modeling (Ekahau AI Pro):
Step 1: Import Floor Plans
• Source: CAD files from Facilities (AutoCAD .dwg format)
• Scale: Verify dimensions (measure known distance, e.g., corridor width)
• Buildings: Mumbai HQ (6 floors), Chennai (4 floors), London (2 floors)
Step 2: Define Attenuation Materials
Material Library:
• Drywall: 3 dB attenuation
• Glass (standard): 2 dB
• Glass (low-E coated): 6 dB (common in modern buildings)
• Concrete wall (6 inch): 8 dB
• Metal door: 12 dB
• Elevator shaft: 20+ dB (RF blackout)
Floor-Specific Notes:
• Mumbai Floor 6 (Executive): Glass-walled offices (6 dB low-E glass)
• Chennai Floor 2 (Open plan): Minimal walls (mostly drywall cubes)
Step 3: Place APs (Predictive Model)
AP Type: Cisco Catalyst 9178I-BE (WiFi 7, 4×4:4 MIMO)
Transmit Power: 17 dBm (6 GHz), 20 dBm (5 GHz)
Antenna Pattern: Omnidirectional (ceiling-mounted)
Placement Strategy:
• Start with grid: 1 AP per 1,333 sq ft (36.5 × 36.5 feet spacing)
• Adjust for obstacles: Move APs to avoid elevator shafts, stairwells
• Executive offices: 1 AP per 2 offices (glass walls = high attenuation)
• Open plan: Grid pattern, avoid conference room overlap
Step 4: Run Simulation
Target Metrics:
• RSSI: ≥-67 dBm (6 GHz) for 95% of floor area
• SNR: ≥25 dB for 4096-QAM modulation
• Channel Overlap: <10% co-channel (320 MHz channels)
Simulation Output (Mumbai Floor 6):
• Total APs: 15 APs (20,000 sq ft / 1,333 = 15)
• Coverage: 97% of floor area ≥-67 dBm ✓
• Capacity: 15 APs × 25 clients/AP = 375 client capacity
• Dead zones: 3% (elevator cores, metal server closets)
Step 5: Generate AP Placement Map
• Export: PDF with AP locations (numbered: MUM-F6-AP01 through MUM-F6-AP15)
• Include: Mounting height (9 feet, drop ceiling tiles)
• Power: Mark PoE+ ports (30W per AP, identify switch uplinks)
• Ethernet: 10 Gbps fiber or multi-gig copper (2.5/5/10G)
Predictive Survey Deliverables:
1. AP Placement Map (PDF)
• Floor plan with 15 AP locations marked
• AP naming: MUM-F6-AP01, MUM-F6-AP02, etc.
• Power requirements: PoE+ (30W × 15 = 450W total)
2. Coverage Heatmap (RSSI)
• Color-coded: Green (≥-60 dBm), Yellow (-60 to -70), Red (<-70)
• Mumbai Floor 6: 97% green/yellow ✓
3. Capacity Analysis
• Peak client density: 80 executives + 20 guests = 100 clients
• AP load: 100 clients / 15 APs = 6.7 clients/AP (comfortable)
• Throughput: 6.7 × 4 Gbps = 26.8 Gbps per AP (within capacity)
4. Channel Plan
• Ch 31 (320 MHz): APs 1, 4, 7, 10, 13
• Ch 63 (320 MHz): APs 2, 5, 8, 11, 14
• Ch 95 (320 MHz): APs 3, 6, 9, 12, 15
• 5-channel reuse pattern (minimize co-channel interference)
5. Bill of Materials (BOM)
• 15× Cisco Catalyst 9178I-BE (WiFi 7 APs)
• 2× Catalyst 9300-48UXM (PoE+ switch, mGig ports)
• 15× Ceiling mount brackets
• 15× Cat6A cables (pre-terminated, 50 ft)
13.2.2 Post-Deployment Survey (Validation)¶
Validation Survey (Ekahau Sidekick 2 + Ekahau Survey App):
Objective: Verify predictive model accuracy, identify coverage gaps
Survey Equipment:
• Ekahau Sidekick 2: WiFi spectrum analyzer + packet capture
• Laptop: WiFi 7-capable (Intel BE200 adapter)
• SSID: Corp-Secure-7 (WPA3-Enterprise, live production)
Survey Procedure:
Step 1: Passive Survey (RF Environment)
• Walk entire floor at 2 mph pace
• Ekahau records: RSSI, channel utilization, AP visibility
• Duration: 45-60 minutes per floor (20,000 sq ft)
Step 2: Active Survey (Client Perspective)
• Connect to Corp-Secure-7 SSID
• Ekahau records: Throughput, latency, packet loss
• Perform: iPerf3 tests at 10 sample points (validate 4+ Gbps)
Step 3: Spectrum Analysis (Interference Detection)
• Scan 6 GHz band (5,925-7,125 MHz)
• Identify: Non-WiFi interference (rare in 6 GHz, but check)
• Check: Co-channel interference (same-channel APs overlapping)
Survey Metrics (Target vs Actual):
• RSSI ≥-67 dBm coverage: Target 95%, Actual 97% ✓
• Throughput ≥4 Gbps: Target 90%, Actual 94% ✓
• Latency <10ms: Target 95%, Actual 98% ✓
• Channel utilization: Target <50%, Actual 35% ✓
Survey Deliverables:
1. Heatmap (RSSI, actual): Overlay on floor plan
2. Throughput heatmap: Show Gbps per location
3. Issue List: Document 3 dead zones (elevator cores)
4. Recommendation: Add 2 APs in corners (MUM-F6-AP16, AP17)
Post-Survey Optimization:
Issue 1: Dead Zone in SE Corner (Elevator Core)
• Predictive Model: RSSI -72 dBm (marginal)
• Actual Survey: RSSI -78 dBm (unacceptable)
• Root Cause: Elevator shaft (metal) blocks RF more than predicted
• Solution: Add MUM-F6-AP16 (SE corner, 10 ft from elevator)
• Validation: Re-survey SE corner → RSSI improved to -62 dBm ✓
Issue 2: High Channel Utilization on Ch 31 (3 APs overlapping)
• Predictive Model: Ch 31 utilization 40%
• Actual Survey: Ch 31 utilization 65% (degraded performance)
• Root Cause: APs 1, 4, 7 all on Ch 31, overlapping coverage
• Solution: Change AP-04 from Ch 31 → Ch 127 (new channel)
• Validation: Ch 31 utilization reduced to 42% ✓
Issue 3: Slow Throughput in Conference Room (MUM-F6-CONF-01)
• Expected: 4.5 Gbps
• Actual: 2.8 Gbps (38% slower)
• Root Cause: AppleTV (WiFi 6) in room causing co-channel contention
• Solution: Move AppleTV to 5 GHz only (disable 6 GHz radio)
• Validation: Throughput improved to 4.3 Gbps ✓
13.3 AP Placement Guidelines¶
13.3.1 Density Calculations¶
AP Density Formula (Coverage-Based):
AP Count = Floor Area (sq ft) / Coverage Area per AP (sq ft)
Coverage Area per AP (6 GHz, RSSI -67 dBm):
• Radius: 12 meters = 39.4 feet
• Area: π × (39.4)² = 4,877 sq ft
Adjusted for Overlap (20% redundancy):
• Effective Area: 4,877 × 0.8 = 3,900 sq ft
Conservative Design (Abhavtech):
• Target: 1 AP per 1,333 sq ft (more aggressive, higher density)
• Reason: Executive floors require premium performance (>4 Gbps)
Example: Mumbai Floor 6 (20,000 sq ft)
AP Count = 20,000 / 1,333 = 15 APs ✓
AP Density Formula (Capacity-Based):
AP Count = Peak Client Count / Clients per AP
Clients per AP (WiFi 7, 4×4:4 MIMO):
• Recommended: 25 clients/AP (CWAP standard)
• Abhavtech Conservative: 15 clients/AP (premium performance)
Example: Mumbai Floor 6
• Peak Clients: 80 executives + 20 guests = 100 clients
• AP Count: 100 / 15 = 6.7 APs ≈ 7 APs minimum
Comparison:
• Coverage-based: 15 APs (more APs)
• Capacity-based: 7 APs (fewer APs)
• Chosen: 15 APs (coverage-driven design, capacity is bonus)
13.3.2 Mounting Guidelines¶
AP Installation Best Practices:
Mounting Height:
• Standard: 9 feet above floor (drop ceiling tiles)
• High ceiling: 12-15 feet (warehouse, atrium) - use directional antennas
• Low ceiling: 8 feet minimum (residential-style offices)
Orientation:
• Ceiling-mount: Omnidirectional pattern (360° coverage)
• Wall-mount: Directional (rare, use for corridors only)
• Avoid: Mounting behind metal objects (ceiling plenums, HVAC ducts)
Clearance:
• Horizontal: 6 inches from walls, light fixtures
• Vertical: 12 inches from HVAC vents (airflow disrupts cooling)
• Avoid: Directly above heat sources (servers, copy machines)
Aesthetics:
• Preferred: Conceal in ceiling tiles (white AP blends with tiles)
• Alternative: Above-ceiling mount (plenum-rated, visible only from below)
• Executive Floors: Coordinate with facilities (match office aesthetics)
Cabling:
• Cat6A required: Supports 10 Gbps (WiFi 7 AP uplinks)
• Length: <90 meters (295 feet) from switch
• Labeling: Clear labels (AP name + port number on switch)
Mumbai Floor 6 AP Mounting Example:
AP: MUM-F6-AP01
Location: North Wing, Grid E7 (see floor plan)
Mounting:
• Height: 9 feet (drop ceiling tile #E7-12)
• Tile Type: 2×2 ft Armstrong suspended ceiling
• Bracket: Cisco AIR-AP-T-RAIL-R (T-bar rail mount)
• Cable: Cat6A, 40 ft run to IDF-6N (closet)
Power:
• PoE+: 30W (802.3at)
• Switch: Catalyst 9300-48UXM, Port Gi1/0/1
• Backup Power: UPS in IDF-6N (2-hour runtime)
Ethernet:
• Uplink: 10 Gbps (mGig auto-negotiation)
• VLAN: Management VLAN 100 (AP management)
• Trunking: 802.1Q trunk (all corporate VLANs)
Validation:
• Post-install RSSI: -58 dBm at 10m (excellent) ✓
• Channel: 31 (320 MHz, 6 GHz)
• Clients: 8 executives (healthy load)
13.4 Channel Planning (6 GHz)¶
13.4.1 6 GHz Channel Allocation¶
6 GHz Spectrum Overview:
Total Spectrum: 5,925-7,125 MHz (1,200 MHz)
320 MHz Channels (WiFi 7):
• Channel 31: 5,955-6,275 MHz (center: 6,115 MHz)
• Channel 63: 6,275-6,595 MHz (center: 6,435 MHz)
• Channel 95: 6,595-6,915 MHz (center: 6,755 MHz)
• Channel 127: 6,915-7,235 MHz (center: 7,075 MHz) [partial, upper band]
• Channel 159: 7,115-7,435 MHz [not available in most regions]
• Channel 191: 7,235-7,555 MHz [not available in most regions]
Available Channels (India, US):
• Non-overlapping: 3 channels (Ch 31, 63, 95)
• Overlapping: Ch 127 (use with caution, overlaps Ch 95)
PSC (Preferred Scanning Channel):
• Definition: Channels clients scan first (faster discovery)
• PSC List: 5, 21, 37, 53, 69, 85, 101, 117, 133, 149, 165, 181, 197
• WiFi 7 (320 MHz): Use Ch 31, 63, 95 (all contain PSC channels)
Channel Plan (Mumbai HQ Floor 6):
Channel Assignment Strategy:
• Pattern: 3-channel reuse (Ch 31, 63, 95)
• Avoid: Adjacent APs on same channel (co-channel interference)
• Goal: Maximize spatial separation for same-channel APs
Floor 6 AP Channel Assignments (15 APs):
Ch 31 (320 MHz): 5 APs
• MUM-F6-AP01 (North Wing, NW corner)
• MUM-F6-AP04 (North Wing, center)
• MUM-F6-AP07 (Center Wing, W side)
• MUM-F6-AP10 (South Wing, center)
• MUM-F6-AP13 (South Wing, SE corner)
Ch 63 (320 MHz): 5 APs
• MUM-F6-AP02 (North Wing, NE corner)
• MUM-F6-AP05 (North Wing, E side)
• MUM-F6-AP08 (Center Wing, center)
• MUM-F6-AP11 (South Wing, W side)
• MUM-F6-AP14 (South Wing, SW corner)
Ch 95 (320 MHz): 5 APs
• MUM-F6-AP03 (North Wing, center-E)
• MUM-F6-AP06 (Center Wing, E side)
• MUM-F6-AP09 (Center Wing, center-W)
• MUM-F6-AP12 (South Wing, E side)
• MUM-F6-AP15 (South Wing, S wall)
Spatial Reuse:
• Same-channel APs separated by ≥30 meters (minimize overlap)
• Example: AP01 (Ch 31, NW) and AP04 (Ch 31, center) are 40m apart ✓
Co-Channel Overlap:
• Target: <10% (client rarely sees 2 APs on same channel with RSSI >-70 dBm)
• Actual: 8% (Ekahau simulation) ✓
13.4.2 Dynamic Channel Assignment (RRM)¶
DNAC RRM (Radio Resource Management):
RRM Overview:
• Purpose: Automatically adjust AP channels/power to optimize RF
• Trigger: Every 10 minutes (default), or on-demand via DNAC
• Algorithm: AI-based (DNAC AI Network Analytics)
RRM Inputs (Telemetry):
• Channel utilization (% airtime used)
• Client count per AP
• Interference (non-WiFi sources)
• Neighbor AP RSSI (detect overlapping coverage)
• Throughput per client
RRM Actions:
1. Channel Change: Move AP from congested channel to cleaner channel
Example: AP04 on Ch 31 (65% utilization) → Ch 127 (25% utilization)
2. Transmit Power Adjustment: Reduce power if too many clients from one AP
Example: AP08 power 20 dBm → 17 dBm (reduce cell size)
3. Load Balancing: Steer clients from busy AP to idle AP
Example: AP01 has 25 clients, AP02 has 5 clients → Move 10 clients to AP02
RRM Configuration (DNAC):
DNAC → Provision → Wireless → Advanced
• Dynamic Channel Assignment (DCA): Enabled ✓
• DCA Interval: 10 minutes (default)
• DCA Sensitivity: Medium (balance stability vs optimization)
• Transmit Power Control (TPC): Enabled ✓
• TPC Threshold: -70 dBm (target RSSI for cell edge)
• Load Balancing: Enabled (move clients if AP >20 clients)
RRM Best Practices:
• Monitor RRM changes in DNAC logs (detect frequent channel flapping)
• Disable RRM during large events (conference, all-hands meeting)
• Use "RRM Hold" for critical APs (e.g., auditorium AP stays on Ch 31)
13.5 Capacity Planning¶
13.5.1 Throughput Budgeting¶
Per-Client Throughput Calculation:
Client: Executive Laptop (WiFi 7, Intel BE200, 2×2:2 MIMO)
PHY Rate (Physical Layer):
• 6 GHz, 320 MHz, 4096-QAM, 2×2 MIMO, MLO
• PHY Rate: 5,764 Mbps (from 802.11be spec)
MAC Efficiency (Medium Access Control Overhead):
• Ideal: 100% (no overhead)
• Realistic: 70% (OFDMA, frame overhead, retransmissions)
• Effective Throughput: 5,764 × 0.70 = 4,035 Mbps ≈ 4 Gbps ✓
Application Layer Throughput (TCP/IP):
• TCP Overhead: ~5% (headers, acknowledgments)
• Application Throughput: 4,035 × 0.95 = 3,833 Mbps ≈ 3.8 Gbps
• Measured (iPerf3): 3.6-4.2 Gbps (matches calculation) ✓
Shared Medium (Multiple Clients):
• 1 Client: 4 Gbps (full AP capacity available)
• 5 Clients: 4 Gbps / 5 = 800 Mbps per client (contention)
• 15 Clients: 4 Gbps / 15 = 267 Mbps per client (saturated)
Recommendation:
• Max 15 clients per AP (maintain >250 Mbps per client minimum)
• Preferred: 10 clients per AP (maintain >400 Mbps per client)
Aggregate Floor Throughput:
Floor: Mumbai Floor 6 (15 APs)
Peak Throughput (All APs):
• 15 APs × 4 Gbps = 60 Gbps aggregate ✓
• Client Count: 100 clients (80 executives + 20 guests)
• Per-Client Average: 60 Gbps / 100 = 600 Mbps per client (comfortable)
Fabric Uplink Validation:
• AP Uplink: 10 Gbps (mGig, Cat6A)
• 15 APs → 2 Fabric Edge Switches (C9300)
• Per Switch: 7-8 APs × 10 Gbps = 70-80 Gbps potential
• Switch Uplink to Core: 40 Gbps (4× 10G ports, port-channel)
• Utilization: 60 Gbps / 40 Gbps = 150% oversubscription (acceptable burst)
Result: Floor 6 has sufficient WiFi + fabric capacity ✓
13.5.2 Client Density Planning¶
Executive Floor (Mumbai Floor 6):
User Types:
• 80 Executives (C-suite, VPs, Directors)
• 20 Guests (visitors, contractors)
• Total: 100 concurrent clients (peak, 10 AM - 2 PM)
Client Distribution:
• Private Offices: 60 executives (1-2 per office)
• Open Collaboration Area: 20 executives + 20 guests
• Conference Rooms: 5 executives (video calls)
AP Loading (15 APs):
• Average: 100 clients / 15 APs = 6.7 clients per AP ✓ (comfortable)
• Peak AP (Collaboration Area): MUM-F6-AP08 = 18 clients (acceptable)
• Minimum AP (Private Office Wing): MUM-F6-AP03 = 3 clients
Hotspot Analysis:
• Collaboration Area (3 APs: AP07, AP08, AP09): 40 clients
• Load per AP: 40 / 3 = 13.3 clients per AP (healthy)
• Throughput: 4 Gbps / 13.3 = 300 Mbps per client (acceptable)
Growth Planning (20% headroom):
• Current: 100 clients
• Future (3 years): 120 clients (+20%)
• Future Load: 120 / 15 = 8 clients per AP (still comfortable)
• Result: No additional APs needed for 3-year growth ✓
13.6 Interference Management¶
13.6.1 Co-Channel Interference Mitigation¶
6 GHz Advantage: Clean Spectrum
Traditional 5 GHz Problems (Pre-Phase 5):
• Legacy WiFi 4/5/6 interference (neighboring buildings)
• Radar detection (DFS channels, causes channel changes)
• Microwave ovens, Bluetooth, Zigbee (2.4 GHz bleed-over)
6 GHz Benefits:
• No legacy WiFi interference (WiFi 7-only band)
• No DFS/radar (PSC channels always available)
• No 2.4 GHz devices (separate spectrum)
Abhavtech 6 GHz Spectrum Scan (Ekahau):
• Non-WiFi Interference: 0% (clean spectrum) ✓
• Neighboring Networks: 0 APs detected (clean building)
• Co-Channel (Abhavtech APs): 8% overlap (acceptable)
Result: 6 GHz provides interference-free environment ✓
Co-Channel Mitigation Strategies:
Strategy 1: Channel Reuse Pattern
• Use 3 non-overlapping channels (Ch 31, 63, 95)
• Spatially separate same-channel APs by ≥30m
• Result: <10% co-channel overlap ✓
Strategy 2: OFDMA (Orthogonal Frequency Division Multiple Access)
• WiFi 7 feature: Allocate different sub-carriers to different clients
• Benefit: Multiple clients on same channel, minimal interference
• Abhavtech: Enabled by default on all WiFi 7 APs ✓
Strategy 3: Multi-RU (Resource Unit Allocation)
• WiFi 7 enhancement: Allocate non-contiguous RUs to single client
• Benefit: Avoid interference on specific sub-carriers
• Example: Client gets RU 1-4, 9-12 (skip RU 5-8 if interference)
Strategy 4: RRM Dynamic Channel Assignment
• DNAC RRM detects high channel utilization
• Auto-moves AP to cleaner channel (e.g., Ch 31 → Ch 127)
• Abhavtech: RRM enabled, 10-minute interval ✓
Strategy 5: Transmit Power Reduction
• Lower AP power = smaller cell size = less overlap
• DNAC TPC (Transmit Power Control): Auto-adjusts power
• Example: AP08 power reduced 20 dBm → 17 dBm (reduce overlap with AP07)
13.6.2 Adjacent Channel Interference¶
320 MHz Challenge: Limited Non-Overlapping Channels
Problem:
• Only 3 non-overlapping 320 MHz channels (Ch 31, 63, 95)
• 15 APs on Floor 6 → 5 APs per channel (channel reuse required)
Adjacent Channel Interference (ACI):
• Definition: Interference from adjacent frequency channels
• 320 MHz: Minimal ACI (channels well-separated: 320 MHz apart)
• Example: Ch 31 (5,955-6,275 MHz) vs Ch 63 (6,275-6,595 MHz)
→ 0 MHz overlap (perfect separation) ✓
Practical Impact:
• Adjacent channel interference: <1% (negligible)
• Co-channel interference: 8% (managed via spatial reuse)
• Total interference: ~9% (acceptable, target <10%) ✓
Fallback Strategy (If Interference Detected):
• Reduce channel width: 320 MHz → 160 MHz
• Benefit: 6 non-overlapping channels (Ch 5, 21, 37, 53, 69, 85)
• Trade-off: 50% throughput reduction (4 Gbps → 2 Gbps)
• Abhavtech Decision: Maintain 320 MHz (interference not an issue) ✓
13.7 Validation Testing¶
13.7.1 Coverage Validation¶
Post-Deployment Coverage Test:
Test Procedure:
• Tool: Ekahau Sidekick 2 + Ekahau Survey App
• Walk: Entire floor at 2 mph (simulate user movement)
• Record: RSSI, SNR, AP association (every 1 second)
• Duration: 60 minutes (Mumbai Floor 6, 20,000 sq ft)
Target Metrics:
• RSSI ≥-67 dBm: 95% of floor area
• SNR ≥25 dB: 90% of floor area (required for 4096-QAM)
• Dual AP Coverage: 80% (redundancy, any location sees 2+ APs)
Actual Results (Mumbai Floor 6):
• RSSI ≥-67 dBm: 97% ✓ (exceeded target)
• RSSI ≥-60 dBm: 78% (excellent coverage)
• SNR ≥25 dB: 93% ✓
• Dual AP Coverage: 85% ✓
Coverage Gaps Identified:
1. Elevator Core (SW corner): RSSI -78 dBm (unacceptable)
→ Remediation: Add MUM-F6-AP16 (new AP, 10 ft from elevator)
2. Metal Server Closet (IDF-6S): RSSI -85 dBm (RF blackout)
→ Remediation: Accept (no WiFi needed in server closet)
3. Conference Room MUM-F6-CONF-03 (back wall): RSSI -71 dBm (marginal)
→ Remediation: Relocate AP12 5 feet closer to conference room
Post-Remediation Re-Survey:
• RSSI ≥-67 dBm: 99% ✓ (after adding AP16 + moving AP12)
• Coverage Gaps: <1% (elevator core, server closet only)
13.7.2 Throughput Validation¶
iPerf3 Throughput Test (Sample Points):
Test Setup:
• Client: Dell Latitude 7450 (WiFi 7, Intel BE200)
• Server: iPerf3 server on fabric network (10.252.80.10)
• Protocol: TCP (downstream, 60-second test)
• Sample Points: 10 locations across Floor 6
Sample Point Results:
Location 1: North Wing Office (near AP01)
• RSSI: -58 dBm (excellent)
• PHY Rate: 5,764 Mbps (MLO, 320 MHz)
• iPerf3: 4.5 Gbps ✓ (target: >4 Gbps)
Location 2: Collaboration Area (between AP07 and AP08)
• RSSI: -65 dBm (good)
• PHY Rate: 5,764 Mbps
• iPerf3: 4.2 Gbps ✓
Location 3: Conference Room CONF-01 (near AP05)
• RSSI: -62 dBm (excellent)
• PHY Rate: 5,764 Mbps
• iPerf3: 4.4 Gbps ✓
Location 4: Private Office (far from AP, -68 dBm)
• RSSI: -68 dBm (marginal)
• PHY Rate: 4,324 Mbps (lower modulation, 1024-QAM)
• iPerf3: 3.8 Gbps ⚠️ (below target, acceptable)
Location 5: SW Corner (AP16 coverage, post-remediation)
• RSSI: -64 dBm (good)
• PHY Rate: 5,764 Mbps
• iPerf3: 4.3 Gbps ✓
Summary (10 Sample Points):
• Mean Throughput: 4.15 Gbps ✓
• Min Throughput: 3.6 Gbps (Location 8, far corner)
• Max Throughput: 4.6 Gbps (Location 1, near AP)
• Success Rate: 90% meet >4 Gbps target ✓
Action Items:
• Location 8 (3.6 Gbps): Add AP17 to improve coverage
• All other locations: No action needed (meet targets) ✓
13.8 RF Design Summary¶
13.8.1 Design Validation Checklist¶
Mumbai Floor 6 RF Design Sign-Off:
☑ Coverage Requirements:
✓ RSSI ≥-67 dBm: 99% of floor area (target: 95%)
✓ SNR ≥25 dB: 93% of floor area (target: 90%)
✓ Dual AP coverage: 85% (target: 80%)
☑ Capacity Requirements:
✓ Throughput >4 Gbps: 90% of sample points (target: 85%)
✓ Client density: 6.7 clients/AP average (target: <15)
✓ Aggregate throughput: 60 Gbps (15 APs × 4 Gbps)
☑ Interference Management:
✓ Co-channel overlap: 8% (target: <10%)
✓ Non-WiFi interference: 0% (6 GHz clean spectrum)
✓ Channel plan: 3-channel reuse (Ch 31, 63, 95)
☑ Redundancy:
✓ AP count: 15 APs (1 per 1,333 sq ft)
✓ Dual AP coverage: 85% of floor area
✓ MLO enabled: 100% of APs (5 GHz + 6 GHz)
☑ Aesthetics:
✓ Ceiling-mount: 100% (concealed in drop ceiling)
✓ Cabling: Hidden above ceiling (no visible cables)
✓ AP color: White (matches ceiling tiles)
☑ Future-Proofing:
✓ Capacity headroom: 20% (100 → 120 clients supported)
✓ Uplink capacity: 10 Gbps per AP (sufficient for 3-5 years)
✓ Modular design: Easy to add APs if needed
Overall Assessment: ✅ PASS - RF Design Meets All Requirements
Sign-Off: Network Architect, Facilities Manager, IT Director
Date: Week 8 (End of Pilot Phase)
13.8.2 Lessons Learned & Best Practices¶
Key Insights from Phase 5A Pilot:
1. Predictive Surveys Are Accurate (±5% RSSI)
• Ekahau predictive model: 97% coverage
• Actual validation survey: 97% coverage
• Lesson: Trust predictive tools, validate post-deployment
2. 6 GHz Requires 20% Denser Deployment
• WiFi 6 (5 GHz): 1 AP per 2,000 sq ft
• WiFi 7 (6 GHz): 1 AP per 1,333 sq ft
• Lesson: Budget for 50% more APs when migrating to 6 GHz
3. Glass Walls Attenuate 6 GHz Significantly
• Standard glass: 2 dB
• Low-E coated glass: 6 dB (common in modern buildings)
• Lesson: Survey glass-walled areas carefully, may need extra APs
4. MLO Is Essential for Reliability
• 6 GHz-only: 15% of locations have marginal RSSI (<-70 dBm)
• MLO (5+6 GHz): 99% of locations covered (5 GHz fallback)
• Lesson: Always enable MLO, don't rely on 6 GHz alone
5. 320 MHz Channels Deliver Promised Performance
• Theoretical: 4+ Gbps (per WiFi 7 spec)
• Actual: 4.15 Gbps average (iPerf3 testing)
• Lesson: WiFi 7 marketing claims are realistic ✓
6. RRM Should Be Enabled (But Monitored)
• RRM optimized channels automatically (Ch 31 → Ch 127)
• Improved throughput 15% (reduced co-channel interference)
• Lesson: Trust DNAC AI, but review RRM logs weekly
7. User Satisfaction Correlates with RSSI >-65 dBm
• RSSI >-65 dBm: 95% user satisfaction
• RSSI -65 to -70 dBm: 85% user satisfaction
• RSSI <-70 dBm: 60% user satisfaction (complaints)
• Lesson: Target RSSI >-65 dBm for premium experience