Edgewater Wireless July 2015 Solving High Density WiFi Does High Throughput 802.11ac hold up in high density applications? The answer might surprise you. While everyone is trying to design networks using high-throughput 802.11ac & 802.11n, Edgewater Wireless is reengineering the WiFi world using multi-channel technology Why 802.11ac & 802.11n doesn t work for high density networks Historically, WiFi technology has largely been driven by home or small business (SOHO) markets. These SOHO WiFi applications, where higher bandwidth requirements, generated by in-home applications, have been the main driver and, as a result, the IEEE specifications for 802.11, have been written to improve these home environments. Equipment manufacturers, service providers and building owners and managers are challenged to respond to the data demand and impact on the network with the ever increasing number of devices connected to the network. Based on a detailed analysis of high throughput 802.11n and 802.11ac performance capabilities and specifications for applications in High-Client Density environments, Edgewater Wireless can deliver far greater Quality of Service (QoS) through the deployment of concurrent, multichannel access points in the network. Calling Out AC MIMO SISO Channel Combining the use of multiple spatial streams is only effective in very short range applications (such as homes) The primary end users devices in high-density environment are SISO and as a result offer only one spatial stream (40, 80, 160 MHz) is only effective at very short ranges additionally, there is an adjacent channel availability problem Beamforming Transmit beamforming is not effective in high client density environments Network operators need to plan and optimize their environments for capacity and managing a high density of users.
Challenges in 40 MHz Channel Bandwidth by Channel Combining in 802.11n for High Density Networks An 802.11 OFDM PHY channel is normally 20 MHz wide. However, the 802.11n PHY specification allows a channel (the primary) channel to be combined with an adjacent secondary channel to form a 40 MHz wide channel, if the adjacent channel isn t being used. By FCC rules, where conducted power levels to the antenna are regulated, if the bandwidth (B) is doubled, then the signal (S) to noise (N) ratio is cut in half, because the S (power per Hz) is divided by two but the N (noise per Hz) remains constant. Now, because S decreases in inverse proportion to the square of the distance (1/r2) between the AP and the client STA, to achieve means that you ll have to move the client STA (0.707 1)/1= 29% closer to the AP to get the expected double channel capacity due to channel combining. Challenges in Beamforming in High Density Networks In the IEEE 802.11n specifications, there exists no standardized sounding and feedback protocols to support beamforming. A beamforming access point makes direction decisions without explicit feedback from STAs with which it is communicating. Further, government regulations limit the transmit power of beam formed transmitters according to the antenna gain such that EIRP is only moderately greater than that of an omnidirectional antenna. NOTE: beamforming antenna array elements are largely omnidirectional so beamforming can only occur in the azimuth (horizontal) plane. The benefit of beamforming is that it minimizes the probability of co-channel interference (CCI) between access points in low client density environments. NOTE: Beamforming will not be effective in a high density client environments as avoidance of CCI will become unattainable. The Proximity Challenge for 802.11ac in High Density Networks 256-QAM Optional PHY 256-QAM modulation reduces constellation spacing and thus, reduces the SNR and increasing errors. The implementation of 1/2, 2/3, 3/4 and 5/6 FEC will not overcome the reduced SNR. Lower SNR requires clients to be much closer to the access point, a few metres range at best, to have the same reliability in order to realize the increased formation rate. Aliquam scelerisque sagittis erat. 2
The Proximity Challenge for 802.11ac in High Density Networks cont d Optional 40, 80, 160 MHz Channel Bandwidth by Channel Bonding Mandatory 40 and 80 MHz channel bonding with an option for 160 MHz requires either noncontiguous 80+80 MHz or contiguous 160 MHz. Current government regulations allow only the same power regardless of bandwidth and as a result: Signal Power per Hz goes down while the Noise Power per Hz remains constant, reducing SNR. Lower SNR requires the client STAs to be much closer to the Access Point to have the same reliability in order to realize the increased information rate MIMO for up to Eight Spatial Streams The implementation of 802.11ac MIMO specifications require up to 8 antenna and government regulations allow only the same power regardless of the number of antenna. As a result: Signal Power per Hz for higher numbers of spatial streams goes down while Noise Power per Hz remains constant Lower SNR requires client STAs to be much closer to the AP to have the same reliability in order to realize increased information rate Downlink Multi-User MIMO (MU-MIMO) For Multi-user MIMO an access point aggregates data streams for one to four client STAs into a single MPDU. Client STAs reassemble the MPDUs they receive keeping only data meant fro them (and throwing away data not meant for them). As a result: Packet protocol overhead (packet header and inter-message gaps) is reduced thus increasing performance as it uses larger 64k MTU size The advantage of a MU-MIMO aggregation MPDU is each client STA can be sent data in separate MPDUs with larger payloads the actual throughput gain achieved is questionable as illustrated below: Send one MU-MIMO MPDU with an X = X1/4+X2/4+X3/4+X4/4 byte payload for four client STA1, STA2, STA3 and STA4 respectively so 4Å~(OH+X) = 4Å~(OH+ X1/4+X2/4+X3/4+X4/4) = 4Å~OH+X1+X2+X3+X4 3
Why 802.11ac/n in Doesn t Perform in High-Client Density Environments The 802.11ac and 802.11n specifications, when applied to High-Client Density Environments, such as stadiums, campus and large enterprises, simply does not provide the Quality of Service required for proper long term service delivery. The Facts MIMO - the use of multiple spatial streams is only effective in very short range applications (such as homes or small businesses) The primary end users devices in high density environment are SISO and as a result offer the following: One Spatial Stream 40 MHz channel via combining 20MHz OFDM channel with adjacent 20MHz is only effective at short ranges and are exasperated by the Adjacent channel availability problem MU-MIMO throughput gains are of questionable net benefit Channel Combining (40, 80, 160 MHz) is only effective at very short ranges. Additionally, there is the adjacent channel availability problem Transmit beamforming is not effective in high client density environments Based on a detailed analysis of both the IEEE 802.11n and IEEE 802.11ac specifications, taken in light of applications in High-Client Density environments, Edgewater Wireless has determined a far greater quality of service can be gained through the deployment of concurrent, multichannel access points in the network. 4
Edgewater Wireless WiFi3 for High Density Networks Edgewater Wireless WiFi3 powered access points are designed to address the needs of carrier-class WiFi deployments indoor and outdoor. Our wideband, 802.11 WiFi3 radio architecture can deliver up to 50x greater performance over single-channel access points and offers a rich, carrier feature set that includes integrated, real-time spectral surveillance, right out of the box.. Each of our products integrate with one or more WiFi3 powered radios capable of supporting up to three concurrent channels simultaneously. Each channel supports four Virtual Access Points (VAPs) providing unbeatable flexibility for configuration. Each WiFi 3 integrated radio supports Edgewater Wireless Spectrum Surveillance Architecture (SSA ) with the ability to identify interferers and security threats. Independent transmit power control is supported on each channel and can be configured by the operator to optimize the network deployment. INTEGRATING WiFi3 INTO YOUR SOLUTION Edgewater Wireless WiFi3 technology is backed by our growing portfolio of over 20 patents. Through our rich patent portfolio we have created a depth of intellectual property (IP) that makes up our WiFi3 technology which is quickly being accepted as the solution for solving the congestion and data demand issues becoming more prevalent with high-density WiFi networks. Edgewater Wireless offers licensing and technology integration solutions to manufacturers of OEM equipment and products for the wireless and WiFi industry to leverage our extensive patent portfolio and technology. Edgewater Wireless Development Kit Edgewater s WiFi3 Development Kit provides OEMs, and innovators of all sizes, an all-in-one prototyping pack than includes Edgewater s latest multi-channel Wi-Fi technology combined with a license and support package. The development kit allows for easy integration and licensing of Edgewater s multi-channel technology into various high density products including Access Points, Small Cells, Distributed Antenna Systems and Networking Hardware. Technology Licensing & Partnerships Edgewater Wireless manages its licensing activities on the premise that the licensing of our intellectual property be based on a principled, professional, business-oriented approach that allows our partners and licensees and to discuss the applicable intellectual property and our available patents and come to an agreement as to its value as well as use in specific products or technology domains. Engaging with Edgewater Wireless To discuss the Edgewater Wireless Products, Development Kit, Technology Licensing or Partnerships, please contact us. 5
Discover WiFi3 From Edgewater Wireless About Edgewater Wireless Systems Inc.: Edgewater Wireless develops and commercializes leading edge technologies and intellectual property for the communications market. Edgewater Wireless delivers advanced product solutions designed to meet the highdensity, high quality of service (QoS) and high-reliability needs of service providers and their customers. Leveraging over twenty (20) patents, Edgewater s WiFi3 is redefining Wi-Fi technology with its wide-band, multi-channel radio and high-capacity Access Point solutions, and delivering next generation Wi-Fi, today. The best solution for High-Density Wi-Fi networks, Edgewater Wireless WiFi3 powered access point products enable innovative service providers to plan, build and deploy reliable, high-capacity services (like VoWiFI) for high-density wireless data demand in any environment. Do more with less! Fewer access points delivering high quality service at a lower overall deployment cost make our patented WiFi3 technology the right choice for your next high density Wi-Fi network. Explore the evolution of Wi-Fi at www.edgewaterwireless.com Edgewater Wireless Systems Inc. 50 Hines Road Ottawa, Ontario Canada +1 613 271 3710.