Carrier Wi-Fi is now Wi-Fi CERTIFIED Vantage™
The recent announcement by the Wi-Fi Alliance of the new certification designation, Wi-Fi CERTIFIED Vantage™, is a significant step for the industry. It is the culmination of years of collaboration within the Wi-Fi ecosystem and the result of incorporating industry established Carrier Wi-Fi requirements into industry certified Wi-Fi devices.
Wi-Fi Vantage devices will provide improved performance to users in managed Wi-Fi networks and make it easier to maintain quality connections in high usage environments including stadiums, airports, offices, campuses and home networks. Wi-Fi Vantage leverages current technologies that include Wi-Fi Alliance-certified Wi-Fi ac and Passpoint and will use subsequent releases to build upon using upcoming technologies and features. Ultimately, this accomplishment provides a mechanism for Wi-Fi operators to harden their networks to evolve from ‘best effort’ networks to operator-managed networks that will approach the reliability and functionality of mobile networks.
CableLabs is pleased to be part of the process to build this framework for Wi-Fi Vantage with Wi-Fi industry partners. We look forward to continued success in building upon the framework to benefit cable and mobile operators, the vendor community and, most importantly, consumers.
Collaboration Brings New Capabilities
Establishing solutions to the largest challenges faced by Wi-Fi operators, including cable operators, in the form of industry certifications has been the focus of CableLabs and many industry organizations. Some of the significant challenges collectively include: sticky client, secure and seamless access and connection, device provisioning, fast AP to AP handoffs in a secure SSID environment, load balancing across bands, and RF performance characterization for APs and clients.
Wi-Fi Vantage certified devices will be capable of resolving several of these challenges such as improved secure on-boarding of new clients, better customer experience when moving on a secure network, automatic discovery and attachment to roaming partner networks per operator driven network selection policy, and fast transitions across APs on secured networks to ensure subscribers receive the best performance available in the area.
Key Features of the First Release of Wi-Fi Vantage™
Wi-Fi Vantage is the technology suite operators will employ to deliver an exceptional user experience and help create the Wi-Fi preferred generation. More specifically, Wi-Fi Vantage delivers superior performance on global networks without intervention or effort from subscribers. Wi-Fi users are up and running on reliable networks with their favorite applications anywhere they roam simply by powering on their device. Wi-Fi Vantage will be the preferred service of a new generation of wireless data users by employing a number of superior service benefits including:
- Performance: Wi-Fi Vantage addresses the problem of inconsistent performance of Wi-Fi networks. Wi-Fi Vantage employs 802.11ac for the fastest throughput available on Wi-Fi technologies. Multi-band operations at 2.4 GHz, 5.0 GHz and future unlicensed bands ensure that all available spectrum is employed to deliver a superior subscriber experience.
- Device Provisioning and Operator Policy: Wi-Fi Vantage devices and provisioning systems support a single, standard interface for operators to provision and maintain user subscriptions, secure SSID profiles and network selection policy.
- Guest Network and Online Sign Up: Operators can provision and enforce policy for guest access on Wi-Fi Vantage networks and allow visitors to access guest networks without requiring visitors to sign up each time they enter a network. Operators can dynamically establish new user accounts, and create policy and customized accounts (ie. 1-day, 30-days, etc).
- Roaming: Wi-Fi Vantage will make pervasive, ubiquitous wireless connectivity a reality for users in major cities around the world.
Improving the Wi-Fi Experience
Cable operators are deploying millions of Access Points (APs) with public Service Set Identifiers, (SSID)s in their networks and linking their networks together into roaming consortiums in order to meet accelerating wireless data service demand. Wi-Fi Vantage brings the scale required to support roaming onto hundreds of roaming partner networks throughout the world with a single subscription. Wi-Fi operators can share their networks without having to provide and manage subscriptions separately. Wi-Fi devices automatically discover and attach to roaming partner networks per operator driven network selection policy.
Roaming starts at home and extends its reach to local, domestic and international networks. Cable operators and others are deploying public SSIDs in residential and small business APs to provide extensive Wi-Fi coverage for their subscribers. Wi-Fi Vantage provides network selection intelligence to help subscribers move onto their private networks while at home, and then roam onto neighborhood networks via public SSIDs on residential gateways. This roaming then extends to large operator managed outdoor metro networks, and finally, to Wi-Fi networks across nations and continents. Wi-Fi users will see their operators providing them with an integrated, extensive global Wi-Fi service.
Wi-Fi Vantage technologies provide a number of superior service elements for operators including performance, policy and provisioning and roaming. By delivering this exceptional user experience, Wi-Fi Vantage will be the preferred service of a new generation of wireless data users.
Mark Poletti is Director of Wireless Technologies at CableLabs.
Multiple Access Point Architectures and Wi-Fi Whole Home Coverage
As mentioned in a previous blog post on AP Coordination by my colleague Neeharika Allanki, homes sizes are growing and the number of client devices in a home network are increasing exponentially. There is a need for not only consistent performance in terms of throughput and connectivity, but also Wi-Fi coverage throughout the home. Consumers often need more than one Wi-Fi Access Point (AP) in the home network to provide that coverage.
Many houses in the world do not have existing wires that can be used to network these APs together, and so one of the easiest and most cost effective ways to provide whole home Wi-Fi coverage is by using Wi-Fi itself to connect together the APs in the home. The technologies available today that can do this are Mesh APs (MAPs), Repeaters or Extenders.
Wireless repeaters and extenders have been around for years due to consumers seeing the need to expand Wi-Fi coverage in their homes. While some form of wireless mesh networking has been around for more than ten years, until recently there were not products designed for the home that used mesh to connect multiple APs. In the past year, there has been a dizzying array of product announcements and introductions for home Wi-Fi coverage, with many of them using mesh networking.
Mesh Access points (MAPs) are quickly gaining traction in home networks mainly due to ease of installation (even over Repeaters/Extenders) and the promise of high throughput with whole home coverage. A mesh AP network can be defined as a self-healing, self-forming, and self-optimizing network of MAPs. Each MAP can communicate with others using smart routing protocols and thereby choose an optimal path in order to relay the data from one point to another.
As mentioned before in our AP Coordination blog, client steering (moving Wi-Fi clients to the best AP in each location) and band steering (moving and keeping Wi-Fi clients on the best band: 2.4 GHz or 5 GHz) are very important in any multi-AP solution, such as mesh or an AP + repeaters/extenders network. This is needed to ensure that each mobile client stays connected to the best AP for its current location. Without client steering, Wi-Fi clients may show connectivity to Wi-Fi, but throughput may suffer tremendously. This often shows up as the dreaded “Buffering…” message when streaming a video or a slow progress bar when loading a web page. In a fully wireless multiple AP solution, client steering and band steering is even more critical due to the throughput and latency penalty when traffic is repeated over Wi-Fi from one AP to another. As MAPs communicate with each other to form the mesh network, they implement some form of AP Coordination, and it is usually proprietary in nature.
CableLabs recently tested mesh networking solutions and AP + repeater solutions consisting of 3 APs in a 5000+ sq. ft. test house. We performed throughput, jitter, latency and coverage testing at more than twenty locations in and around the house. We found that we were able to run two streaming videos, at HD bitrates (~20Mbps), to video clients in the home while also delivering over 50Mbps to our test client. Both mesh and AP + repeater solutions were able to handle this video throughput, as well as deliver over 50Mbps throughput throughout the house and even to some areas 20’ outside the house. This is excellent news for consumers whose access to the Internet is wireless and who want that access everywhere in their homes.
CableLabs is working with vendors to define a standardized AP Coordination Protocol that would allow all APs in a home network to share information to allow them to make client steering decisions, along with other network maintenance tasks.
Solutions for Whole Home Wi-Fi Coverage
For the majority of homeowners, a single Wi-Fi Access Point (AP) is enough to provide whole home coverage with reliable performance. However, there are homes where a single AP provides insufficient coverage or has unreliable performance in certain areas of the home. For example, as the size of the house increases (> 3000 square feet), the number of locations in the house with poor signal strength (RSSI at -80 dBm or lower) increases. Since Wi-Fi supports adaptive modulation, the performance and quality of the link between the AP and client decreases as the path loss between the AP and client increases.
Wi-Fi performance can be affected by a number of factors, including the construction material of the home, and interference from other Wi-Fi networks using either the same, adjacent, or alternate channels. Similarly, non-Wi-Fi sources such as 5 GHz cordless phones, baby monitors and microwaves can have an impact on the performance as well. Furthermore, location of the AP in the customer’s home can make a big difference in the Wi-Fi signal coverage and performance. Comcast has an excellent blog, “10 Ways You Might Be Killing Your Home Wi-Fi Signal” that provide guidelines on where not to place your Wi-Fi AP.
Even with the optimal placement of the AP, if there are locations in the home with no or poor Wi-Fi signal, we recommend the use of multiple APs.
For a multiple-AP solution, consumers have a number of options. Ultimately, it comes down to how the multiple APs in the home are connected to each other. These options can be subdivided into two solutions, wireless-only and hybrid:
- Wireless-only solutions make use of the wireless link to connect the APs to each other. This includes products such as repeaters, extenders, and mesh networks.
- Hybrid solutions make use of wires to connect the multiple APs. Examples products include MoCA-to-Wi-Fi, Powerline-to-Wi-Fi, and Ethernet-to-Wi-Fi extender.
In our previous blog, we presented field test results to show the difference between wireless-only architectures through the use of Wi-Fi Repeater and Extenders. In this blog, we will address Hybrid solutions using commonly available in-home coaxial cables and compare their performance with wireless-only solutions. While a consumer has many variables to consider before choosing a solution (e.g., complexity, availability of wiring, cost), this article will focus on comparing data rate with respect to SNR.
Performance Comparison of Hybrid versus Wireless-only Solutions
For the analysis, we used the Wi-Fi network configuration described in Table 1.
|Wi-Fi Client:||One client with 2x2:2 MIMO and 802.11ac|
|Wi-Fi Channel Bandwidth:||80 MHz channel for both fronthaul and backhaul|
|AP, Repeater and Extender:||4x4:4 MIMO, 802.11ac|
|Link between AP and Wi-Fi Repeater:||Modulation Coding Scheme (MCS) 3 with 4 Spatial Streams|
|Link between AP and Wi-Fi Extender:||MCS 3 with 4 Spatial Streams|
|Link between AP and MoCA to Wi-Fi extender:||MoCA2.0 (bonded)|
|Airtime fairness:||Repeater supports airtime fairness for the link between the AP/repeater and the AP/client|
These are example configurations and were selected to demonstrate the difference between solutions. It is important to note that for all configurations (Wi-Fi repeater, Wi-Fi Extender and MoCA to Wi-Fi Extender) analyzed in this article, the fronthaul link between the AP and client, and extender and client is the same (i.e., 4x4 extender/repeater and 2x2 client).
In the following graph (Figure 1), we provide a theoretical comparison of data rate versus Signal to Noise Ratio (SNR) for the hybrid and wireless-only solutions. While the X-axis shows the SNR (measured at the client) for the AP, extender, and repeater, the Y-axis shows the Data Rate. The SNR first deteriorates as the client moves away from the AP (blue star) and then improves as the client moves closer to the extender (red star). Finally the SNR deteriorates again as the client moves away from the extender (red star). For our analysis we assume an interference free environment.
In this analysis, we also assumed that each extender is placed in the same location (highlighted with a red star on the chart) with respect the AP. The location of the main AP is reflected with a blue star on the chart.
Figure 1. Hybrid and Wireless-only Solution Comparison
The blue line shows the data rate with respect to SNR that the client can achieve while it is connected to the AP. Similarly, the red, brown and green lines show the data rate with respect to SNR that the client can achieve while it is connected to the Wi-Fi repeater, Wi-Fi extender and MoCA to Wi-Fi extender respectively. In our analysis we assumed that the client and network are intelligent and can steer the client from the AP to Wi-Fi repeater, Wi-Fi Extender and MoCA to Wi-Fi Extender at the points where red, brown and green lines intersects with the blue line.
As shown in Table-1, the same repeater/extender and client configurations were used for both the wireless-only and hybrid solutions; specifically, 4X4 Repeater/Extender and 2X2 client with 80 MHz channel. Therefore, as expected, the range improvement (i.e., the increase in coverage area) is about the same for both wireless-only and hybrid solutions. This is illustrated in Figure-1, where the red, brown, and green lines eventually converge as the client moves away from the AP.
The difference in data rate performance is primarily due to the difference in the performance of the backhaul link between the AP and the extender. In Figure 1, we observe that the wired backhaul link outperforms the wireless backhaul link due to the higher backhaul data rate that can be achieved by a MoCA 2.0 bonded channel relative to a 5.8 GHz Wi-Fi backhaul in that location. Given the location of the Wi-Fi Extender with respect to the AP, the wireless backhaul link supports a maximum data rate of ~518 Mbps while the MoCA2.0 (bonded) link can support data rates as high as 800 Mbps.
As we see in Figure 1, the contour for MoCA 2.0 (bonded) to Wi-Fi extender looks different than the lines for other systems. The reason is that the performance of the MoCA 2.0 (bonded) to Wi-Fi extender is limited by the capacity of the fronthaul link between the extender and client. On the other hand, the performance of Wi-Fi Repeater and Extender, when the client is in close range, is limited by the capacity of the backhaul link between the AP and Repeater and AP and Extender.
Figure 2 shows the details of Wi-Fi Repeater (Conf#A) and Extender (Conf#B) configurations that we used for our analysis.
Figure 2: Wi-Fi Repeater and Extender Configuration used for Analysis
What did we learn?
Although wireless-only solutions are highly convenient, the hybrid wireless solutions using MoCA2.0 (bonded) or 1000Base-T for backhaul offer much better data rate performance. In the absence of structured wiring in the home, wireless-only networks (i.e. using Wi-Fi repeaters or extenders) can be an efficient and convenient near-term solution to extend coverage and enhance data rate performance.
-- Authored by Vikas Sarawat