Cisco Cisco Aironet 3500p Access Point Libro blanco
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RF Planning for Capacity
With stadium Wi-Fi designs, it is significantly more challenging to provide ubiquitous coverage and high capacity
throughout the venue than with typical enterprise or 3G offload sites (for example, coffee shops and bookstores)
because of the total number of Wi-Fi-enabled devices to be supported in stadiums and the high density of these
devices in a relatively small area. Large outdoor venues can approach 100,000 fans at capacity, and even indoor
venues such as arenas can accommodate 20,000 or more fans. Providing Wi-Fi coverage throughout the venue
can be challenging, but the greater challenge is to achieve reliable and high-speed network capacity throughout the
venue. Capacity planning starts with accommodating Wi-Fi busy periods (for example, TV timeouts and
intermissions) so that fans and other Wi-Fi network users rarely experience poor or unacceptable network access
conditions.
throughout the venue than with typical enterprise or 3G offload sites (for example, coffee shops and bookstores)
because of the total number of Wi-Fi-enabled devices to be supported in stadiums and the high density of these
devices in a relatively small area. Large outdoor venues can approach 100,000 fans at capacity, and even indoor
venues such as arenas can accommodate 20,000 or more fans. Providing Wi-Fi coverage throughout the venue
can be challenging, but the greater challenge is to achieve reliable and high-speed network capacity throughout the
venue. Capacity planning starts with accommodating Wi-Fi busy periods (for example, TV timeouts and
intermissions) so that fans and other Wi-Fi network users rarely experience poor or unacceptable network access
conditions.
The first step in capacity planning is determining the desired coverage per access point (AP). Assume for network
planning purposes that the goal is to offer each fan a network throughput of 500 kbps, which is enough for
comfortable web surfing or for viewing video formatted for mobile devices. Because many smartphones currently
only support the 802.11g standard, the maximum over-the-air data rate is 54 Mbps and the throughput, when
supporting only a single device, could exceed 20 Mbps. A stadium design must support many users per access
point, multiple networks, devices that must operate at lower data rates, and a mix of upstream and downstream
traffic, leading to a less aggressive real-world capacity target per access point on the order of 10 Mbps (Figure 2).
planning purposes that the goal is to offer each fan a network throughput of 500 kbps, which is enough for
comfortable web surfing or for viewing video formatted for mobile devices. Because many smartphones currently
only support the 802.11g standard, the maximum over-the-air data rate is 54 Mbps and the throughput, when
supporting only a single device, could exceed 20 Mbps. A stadium design must support many users per access
point, multiple networks, devices that must operate at lower data rates, and a mix of upstream and downstream
traffic, leading to a less aggressive real-world capacity target per access point on the order of 10 Mbps (Figure 2).
Figure 2. Planning for Stadium Capacity
Consider for example, a venue that seats 50,000 fans. Assuming 25 percent of the fans have Wi-Fi-enabled
handheld devices, up to 12,500 fans will be able to access the Wi-Fi network. Assuming further that during Wi-Fi
busy periods, 25 percent of the fans with Wi-Fi-enabled devices access the network, the access point coverage
should be limited to roughly 320 fans: (320 fans) x (25% with Wi-Fi) x (25% active Wi-Fi) x (500 kbps per fan) = 10
Mbps. Limiting an access point’s coverage to 320 seats or 320 fans in high-density concourse areas translates to
designing coverage cells that are tens of feet in diameter.
handheld devices, up to 12,500 fans will be able to access the Wi-Fi network. Assuming further that during Wi-Fi
busy periods, 25 percent of the fans with Wi-Fi-enabled devices access the network, the access point coverage
should be limited to roughly 320 fans: (320 fans) x (25% with Wi-Fi) x (25% active Wi-Fi) x (500 kbps per fan) = 10
Mbps. Limiting an access point’s coverage to 320 seats or 320 fans in high-density concourse areas translates to
designing coverage cells that are tens of feet in diameter.