HERE - WLAN Pros

Ultra‐High Density WLAN Design & Deployment
Chuck Lukaszewski, CWNE #112, ACMP, AWMP
CONFIDENTIAL © Copyright 2010‐2014. Aruba Networks, Inc. All rights reserved
Agenda
• Key Concepts & Terminology for Ultra-HD WLANs
• Understanding WiFi Channel Capacity
• Configuration Best Practices
• Case Study #1 – Indoor Arena Picocell (AA Center)
• Case Study #2 – Outdoor Football Picocell (Levi’s Stadium)
Aruba Validated Reference Designs
•
•
•
Aruba is the thought leader in our
industry. We produce a library of
Validated Reference Designs
The High Density (HD) WLANs VRD
covers ultra high capacity spaces such
as auditoriums, arenas, stadiums and
convention centers
The recommendations have been field
proven at dozens of customers
VRDs are free to download from Aruba
Design Guides web page:
http://www.arubanetworks.com/VRD
Aruba High-Density
Wireless Networks for
Auditoriums
Solution Guide
•
Key Concepts & Terminology for Ultra‐High Density WLANs
CONFIDENTIAL © Copyright 2011. Aruba Networks, Inc. All rights reserved
Stadium WLAN Quoting Process
Associated User Capacity
• What is max occupancy of the coverage area?
• What percentage must be able to associate?
• What percentage on 2.4GHz and 5GHz?
Active User Capacity
• How large is the uplink pipe?
• What applications will run over the air?
AP Layout
• Ceiling, wall or floor mounting?
• Concealed or in user space?
Infrastructure Dimensioning
• Is HA required?
• Wired pipe dimensioning
• Network service dimensioning
ROM Quote
• Funded or not?
• Serious or not?
Understanding Associated User Capacity
• Associated user capacity means the number of devices
that the HD WiFi network can “carry”.
=
• To add association capacity, all we have to do is add APs
=
Understanding Active User Capacity
• Active user capacity is the number of lanes on the road - (or
out of the parking lot after the game)!
• For usage targets up to 20%, “stacking” APs on the same
channel will block on uplink pipe before channel capacity.
36 40 44 48 149 153 157 161 165
2.4GHz
5GHz
1 6 11
Estimating Stadium AP Counts (Pre-Survey)
» Take the stated occupancy and divide by 300. This is the estimated
number of access points for the primary access area
-
Example (typical):
» 6,000 capacity @ 1 device/person = 20 APs
» 18,000 capacity @ 1 device/person = 60 APs
» 75,000 capacity @ 1 device/person = 250 APs
» Add the concourse, office and locker room secondary areas at 1 AP
/ 4,000 square feet average
-
Typically this results in around double the “bowl” APs for the total
Example (typical)
» 6,000 capacity = 20 APs for the bowl + 28 APs for other areas = 48 total
» 18,000 capacity = 100 APs total
» 75,000 capacity = 400 APs total
Coverage Strategies for High Density Areas
Overhead coverage is a good choice
when uniform signal is desired
everywhere in the target area
Wall installations are most often seen
where ceiling or under-floor access is
not possible or too expensive.
Under-floor or on-floor mounting –
also known as a “picocell” design –
uses very small cells to maximize
reuse.
“Under-Seat” Installation
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10
#airheadsconf
“Under Concrete” Installation
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11
#airheadsconf
Under Concrete Example
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12
#airheadsconf
Overhead Installation Example
“Hybrid” Installation
Multiple Installation Strategies can be used in a single deployment
Understanding WiFi Channel Capacity
CONFIDENTIAL © Copyright 2011. Aruba Networks, Inc. All rights reserved
Measured 20MHz Channel Capacity
Capacity Planning – 2SS Laptop
iPad4 Teardown
1 antenna
• Murata 339S0171 Broadcom BCM4334 WiFi Module
18
Antenna
iPhone 5 Teardown
• All iPhones and all iPads are 1x1:1 devices with 1
antenna chain
ONLY 1 Antenna!!!
iPhone 5
WiFi Radio
http://www.ifixit.com/Teardown/iPhone+5+Teardown/10525/3
Galaxy S4 Teardown
• BCM4335 5G WiFi MAC/baseband/radio
• Skyworks SKY85303-11 2.4G Bluetooth 256QAM??
Single antenna
20
How CCI Reduces WLAN Performance
• Any Wi-Fi device detecting an 802.11 frame on the air cannot
transmit/ receive until the frame has ended.
• If the transmit/receive stations are on the same channel and
can decode one another's frames, it is the case.
802.11 Preamble = Interference Radius
Can be decoded with
only 4dB of SNR!!
Interference Radius
20m
40m
80m
160m
Preamble
Continues
to
4 SNR
r
2r
-65dBm
25 SNR
4r
-71dBm
19 SNR
8r
-77dBm
13 SNR
and
>250m !!!!
-83dBm
7 SNR
• Cell Edge Radius(r1)
» This is what we usually call the “cell edge” of the AP
» It is the target data rate radius (e.g. -67dBm = MCS15 or 54Mbps)
• Interference Radius (r2)
» 802.11 preamble can be decoded (SNR >= 4dB)
Determine Available Channel Count
•
•
•
Channel bonding reduces
capacity in HD WLANs
20MHz channels should be
used in 2.4 and 5 GHz
bands
Available channel count
varies from country to
country.
» U.S. Channel Count is limited
to 9 without DFS
•
•
This limitation requires
sophisticated engineering in
LPV’s to re-use channels as
many time as possible
The goal is to use structural
components to improve APAP isolation
Understanding Total System Bandwidth
•
•
•
•
HD / UHD areas typically cannot achieve more than 1 spectrum reuse
Max single channel goodput is severely reduced (by about 75%) due
to high collision / contention rates
Total bandwidth = channel count * impaired per channel goodput
Adding APs reduces rather than increases total bandwidth
5GHz Devices (%)
2.4GHz Devices (%)
% Fans with Device
Devices per Fan
% Devices Concurrent Us
Channels (5GHz)
Per‐Channel BW (5GHz)
Channels (2.4GHz)
Per‐Channel BW (2.4GHz)
Attendance
Attendance
50%
50%
50%
1
50%
18 ==> USA allows 9 indoor non‐DFS channels ; 22 total indoor; and 18 outdoor channels
20 Mbps
3
15 Mbps
Concurrent
Devices
5GHz
1 Reuses
360 Mbps
2 Reuses
720 Mbps
3 Reuses
1,080 Mbps
4 Reuses ===> Effective channel reuses
1,440 Mbps ===> Gross effective capacity
Concurrent
Devices
2.4GHz
1 Reuses
45 Mbps
2 Reuses
90 Mbps
3 Reuses
135 Mbps
4 Reuses ===> Effective channel reuses
180 Mbps ===> Gross effective capacity
Understanding Maximum Per-User Bandwidth
• Dividing the total bandwidth on the last slide by the device
count gives best case, average per-device bandwidth
Attendance
1,000
10,000
20,000
50,000
75,000
100,000
Attendance
1,000
10,000
20,000
50,000
75,000
100,000
Concurrent
Devices
250
2,500
5,000
12,500
18,750
25,000
5GHz
1 Reuses
360 Mbps
1,440 Kbps
144 Kbps
72 Kbps
29 Kbps
19 Kbps
14 Kbps
2 Reuses
720 Mbps
2,880 Kbps
288 Kbps
144 Kbps
58 Kbps
38 Kbps
29 Kbps
3 Reuses
1,080 Mbps
4,320 Kbps
432 Kbps
216 Kbps
86 Kbps
58 Kbps
43 Kbps
4 Reuses
1,440 Mbps
5,760 Kbps
576 Kbps
288 Kbps
115 Kbps
77 Kbps
58 Kbps
Concurrent
Devices
250
2,500
5,000
12,500
18,750
25,000
2.4GHz
1 Reuses
45 Mbps
180 Kbps
18 Kbps
9 Kbps
4 Kbps
2 Kbps
2 Kbps
2 Reuses
90 Mbps
360 Kbps
36 Kbps
18 Kbps
7 Kbps
5 Kbps
4 Kbps
3 Reuses
135 Mbps
540 Kbps
54 Kbps
27 Kbps
11 Kbps
7 Kbps
5 Kbps
4 Reuses
180 Mbps
720 Kbps
72 Kbps
36 Kbps
14 Kbps
10 Kbps
7 Kbps
Configuration Best Practices
CONFIDENTIAL © Copyright 2011. Aruba Networks, Inc. All rights reserved
LPV Configuration – SSID Profile
SSID Profile
Command(s)
Valid Range
Reason
a‐basic‐rates 24
Any valid rate
Set lowest BC+MC rate to 24
a‐tx‐rates 18 24 36 48 54
“
Allow 1 lower rate than BC+MC to facilitate roaming to next AP
g‐basic‐rates 11 24
“
11Mbps only to avoid device interop
problems
g‐tx‐rates 18 24 36 48 54
“
Allow 1 lower rate for roaming; do not allow 11b rates
a‐beacon‐rate 24
g‐beacon‐rate 24
“
“
Use high beacon rate to reduce airtime overhead
mcast‐rate‐opt
on / off
Force MC rates higher
max‐clients 250
1 – 255 (64)
Override low default value for LPVs
max retries 24
max‐tx‐fail 20
Platform specific
Force client disconnection in controller after too many errors (prevent BAR storms)
local‐probe‐req‐thresh 25
on / off
Only respond to probes from nearby clients
wmm
on / of
Enable WMM
LPV Configuration – Other Profiles
Traffic Mgmt
HT‐SSID
Virtual AP
Command
Valid Range
Reason
band‐steering
on / off
Use classic band steering & disable client‐
match in ARM profile (CM neighbor table limit 32  inadequate for LPV)
steering‐mode prefer‐5
force‐5 / prefer‐
5 / balance
Band steering should put every possible client on 5GHz, but “finicky” clients should be allowed back
deny‐inter‐user‐traffic
on / off
Prevent peer‐to‐peer communication
broadcast‐filter all
arp / all
Filter all BC+MC traffic (unless running MC video)
no 80‐MHz‐enable
no 40‐MHz‐enable
on / off
Only 20MHz channels should be used in HD/UHD areas
temporal‐diversity
on / off
Provides enhanced backoff for retries in high‐
contention periods
shaping‐policy fair‐access
fair‐access
preferred‐access
default‐access
ATF is vital to prevent older, slower clients from starving newer, faster clients. DFS Channels
• Four major device types – IOS, Android, Windows,
MacOS
» IOS, Windows, MacOS all support DFS reliably
» Android support is minimal and inconsistent across make/model
from same manufacturer
» However, all 11ac-capable devices should support DFS including
Android (e.g. Galaxy S4, Note 3)
• Assume at least 2 APs on every channel.
» Reduces risk for non-DFS capable devices. May connect at
lower SNR to nearest non-DFS AP.
Case Study – Levi’s Stadium
San Francisco 49ers
CONFIDENTIAL © Copyright 2011. Aruba Networks, Inc. All rights reserved
Coverage Strategy – Concentric Rings
Bowl
Concourses
Perimeter
Lower Bowl Seating
286 cells
Underseat Picocell Installation Concept
34
Enclosure Installations
Conduit, Cores & Termination to Enclosure
103
Concourse & Perimeter Coverage
IDF
L3C-104
L3P-104
106
L3C-105
L3P-105
110
L3C-106
119
L3P-106
L3C-107
L3C-108
L3P-107
L3C-110
L3P-108
L3C-113
L3P-109
L3P-112
300 Concourse
Sector A
~200’
37
Main Level Concourse Installation Concept
Concourse & Perimeter AP Enclosure Types
39
Example Suite AP Installation

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