White Paper: Planning for 802.11ac Adoption with Ekahau Site Survey™ 6.0
In the paper, Ekahau makes some of the very same points that I have made in prior posts about the need for careful channel planning with 802.11ac due to the likelihood co-channel interference at larger 80 MHz and 160 MHz channel widths by ensuring non-overlapping 40 MHz and 20 MHz primary channels.
Wide 80MHz and 160MHz channels improve throughput but only when full channel bandwidth is free from interfering transmissions. In dense network deployments, careful channel planning is critical to ensure interference-free operation. Channels cannot be selected arbitrarily but primary channels must always be selected so that access points within radio range can fall back to use lower non-overlapping channel for simultaneous transmissions. For example, APs on an 80MHz channel can fall back to use 40MHz or 20MHz channel bandwidths as described in Figure 1.
Here is Figure 1 from the guide:
ESS™ 6.0 also offers channel planning capabilities to help WLAN administrators ensure they provide non-overlapping channels to allow simultaneous transmissions.
For 802.11ac, the user can configure the utilized channel bandwidth as well as the allowed channels. The planning algorithm selects frequency channels using the selected bandwidth, including selection of the center channel as well as the primary channel. Channels are selected in such a way, that interference and channel overlap in the network is minimized. The primary channel selection algorithm is optimized for a mixed 802.11ac/802.11n client base and supports parallel non-overlapping 80MHz, 40MHz, and/or 20MHz bandwidth transmissions when full bandwidth is not available.Here is a screenshot of an automatic channel plan for 802.11ac 80 MHz channels derived by the tool:
|Ekahau Site Survey™ 6.0 Provides Automated 802.11ac Channel Planning|
One question that I still have, and hope to uncover once I get my hands on the tool, is if ESS™ 6.0 can automatically plan for non-overlapping 40 MHz channels while simultaneously assigning neighboring APs channels such that the likelihood of simultaneous 80 MHz transmissions are maximized? Here is my figure, depicting non-overlapping 40 MHz and 20 MHz primary channels while still allowing 80 MHz channel use on a best-effort basis:
|802.11ac Non-Overlapping 40 MHz and 20 MHz Channels|
I also really like how Ekahau Site Survey™ incorporates capacity planning into their site survey tool, rather than relying on RF coverage alone. This is a point that I focused on when writing the Aerohive High-Density Wi-Fi Design and Configuration Guide. Today's Wi-Fi networks are growing in size and client density, which requires adequate focus on capacity planning by understanding client and application requirements coupled with traditional RF coverage and channel planning.
The goal of network analysis is to understand network capacity. The ESS capacity estimation algorithm allows user to accurately estimate the capacity of the planned network with a different set of client devices and traffic patterns. ESS models the key parameters of 802.11ac including the MIMO configurations, channel bandwidths, new QAM256 modulation, and frame aggregation just to name few. To support analysis of your own device, ESS includes predefined templates of AP and client devices and allows estimation of network capacity with a user-configurable set of client devices and their applications. This allows estimation of how network capacity differs, for example, between first and second generation 802.11ac devices.
Ekahau will be hosting live webinars on April 15th and April 19th to cover 802.11ac and ESS 6.0™ features. I'm planning on attending to hear about how this tool can help WLAN administrators adequately prepare for 802.11ac and high-density networks.
I have been a user of Ekahau Site Survey™ 5.5, but admittedly I have only used it on rare occasions since I have not invested the time to learn it properly. I'll have to upgrade to version 6.0 and invest more time and effort (perhaps training?), since it appears to take the right approach to WLAN planning that other tools historically have not.
I have no formal affiliation with Ekahau and was not compensated in any fashion for writing this article.
Other posts you might be interested in:
802.11ac Gigabit Wi-Fi Series:
- The Impact of 802.11ac Gigabit Wi-Fi on Enterprise Networks
- 802.11ac Channel Planning
- Safely Using 80 MHz Channels with 802.11ac
- First Look - 802.11ac Gigabit Wi-Fi Speed