ALLION USA INTERNET SERVICE PROVIDER WIRELESS GATEWAY COMPETITIVE ANALYSIS

Transcription

1 ALLION USA INTERNET SERVICE PROVIDER WIRELESS GATEWAY COMPETITIVE ANALYSIS Date: 4/25/2013 Rev 1.0 Visit our Web Site at: 1

2 Introduction Internet Service Providers (ISP) have a number of factors to consider when deploying wireless gateways with their service, and those decisions on gateway selection can have a major impact on the end user experience especially as homes become more wirelessly connected (i.e. TVs, gaming consoles, media servers, computing devices, etc.). Both performance and coverage delivered throughout the home should be key considerations when ISPs evaluate the capabilities of the gateways they offer. As the widely deployed 2.4GHz band becomes increasingly congested, the ability to leverage the 5GHz band also becomes an important consideration. Allion s competitive analysis evaluated both the performance and coverage of the gateways currently available from Comcast, Verizon, and AT&T. It highlights how ISPs decisions on including the following Wi-Fi technologies impact performance: n vs. Legacy (802.11bg) protocols MIMO vs. SISO antenna configuration(s) Dual-band capability (2.4GHz vs. 5GHz) The performance analysis is accomplished by conducting lab measurements of each gateway s throughput rate over the connection range of the test station / gateway connection. This was accomplished by performing a Rate vs. Range test. The second area of interest (coverage) was analyzed by measuring the gateway signal coverage and throughput performance throughout an area. This was accomplished by performing an Over- The-Air (OTA) RSSI Heat Map test and an OTA Throughput test. 2

3 Wireless Gateway s Tested The Allion Internet Service Provider Wireless Gateway Competitive Analysis summarizes a study conducted by Allion USA, LLC of the potential strengths and weaknesses of the following residential gateways available from three major Internet service providers*: Comcast / Cisco 3x3 ABGN XB3 with software version: dpc3939-p20-18-v303r acmcst.bin Verizon / Actiontec 2x2 BGN MI424WR Rev. I with software version Verizon / Actiontec 2x2 BGN M1424WR Rev. G with software version AT&T / 2-Wire 1x1 BG 2701HG-B with software version The following reference station was used collecting measurements: MacBook Pro (Mac OS 10.8) with the Broadcom BCM4322 Wi-Fi chipset The Comcast/Cisco device is newly available from Comcast. The devices attributable to Verizon and AT&T are standard residential gateway devices distributed by those companies with their service offerings. Conclusion This study shows that deltas in peak performance and potential coverage between gateways can be directly attributed to a combination of technology and hardware selection. As a result the gateway evaluated from Comcast, combining the advanced Wi-Fi technology of n, the latest hardware incorporating multiple antennae (3x3 MIMO), and dual band capability, will not only perform better than the gateway evaluated from AT&T which uses only legacy Wi-Fi technology, but also will perform better than the similarly spec d n Verizon gateways that use only a 2x2 MIMO configuration. Comcast provides the only wireless gateway that operates in both 2.4GHz and 5GHz bands. As discussed in more detail below, the testing evidenced that the Comcast gateway offered approximately 150 Mbps of throughput as compared to approximately 88 Mbps of throughput for the two Verizon gateways tested and approximately 25 Mbps for the AT&T device. Both the Comcast and Verizon devices evidenced significantly better connection ranges than AT&T s standard wireless gateway. As customers subscribe to higher speed services (e.g., 100 Mbps or higher) and utilize more wireless devices in the home, there will be an increased need for more advanced wireless gateway technology. * This study is geared towards wireless gateways available from ISPs to their customers, and therefore does not include off the shelf wireless gateways 3

4 Rate vs. Range This test simulated the effect of moving a wireless gateway from within very close proximity of the connected station to outside of the connectivity range of the gateway / station effectively measuring the ability of the gateway to negotiate an optimal modulation with a client under a given signal condition. Throughput performance is base-lined by collecting throughput measurements based on the changing RF conditions (channel fading) by performing a throughput speed test at each attenuation level incrementally increasing the attenuation between the station and wireless gateway. The goal of this test was twofold: 1. To determine the baseline peak throughput performance of a connected station as the signal is gradually faded out. 2. To understand the connection range of the tested wireless gateway device. Typically, rate vs. range tests are run in a completely conductive (cabled-only) environment where the gateway s antenna sub-system is by-passed via a cabled solution. This methodology is inadequate when system integrators (ISPs) want to make these same types of measurements in an end-to-end environment with an integrated product that has a specific antenna sub-system. Allion leverages a unique solution that combines a large anechoic chamber (3m x 3m x 3.5m) coupled with inline programmable attenuation and butler matrix used to simulate the multi-path that is usually seen in an overthe-air environment. This environment provides the ability to test the performance of a wireless device in an ideal environment with consistent repeatable results, while at the same time keeping the Wireless Gateway intact as a final integrated solution. 4

5 The throughput measurements taken at each attenuation step are based on TCP (Transmission Control Protocol) results using a 30 second throughput test using Iperf*. Traffic direction is based on client receive throughput values at each attenuation point. Below are results from the testing against gateways used in Comcast, Verizon, & AT&T deployments. Range does NOT include the system path-loss of the test-bed; only that of the additional path-loss added to produce the above results Comparing the n-enabled gateways (Comcast and Verizon) vs. the bg-enabled gateway (AT&T) shows a large impact to the connection range of the gateway and overall performance the Comcast gateway is 6x faster than AT&T s gateway (~150Mbps vs. ~25Mbps) while showing a significantly better connection range of 13 db of attenuation. Verizon s gateway devices were over 3x faster than AT&T s gateway (~88Mbps vs. ~25Mbps) and evidenced similarly better connection range. When only comparing the n-enabled gateways: the 3x3 MIMO antennae gateway from Comcast vs. the 2x2 MIMO antennae solutions from Verizon show that the Comcast device benefits from the use of additional hardware by exhibiting almost 2x the peak performance of both Verizon gateways tested (~150Mbps vs. ~88Mbps). Both gateways exhibited essentially the same Comcast range in lab tests (with Comcast beating Verizon s model 2 by 2 db while Verizon s model 1 edged out Comcast by 1dB) 5

6 RSSI HEAT MAPS This test measures the gateway s ability to penetrate a coverage area, from a Receive Signal Strength Indication (RSSI) measured from a station, and provide a strong indication of the potential footprint of a residential gateway from a reference client connected to the gateway. While RSSI measurements alone do not guarantee good performance, they are useful as an indicator of the potential coverage footprint of a specific gateway. Allion uses a dedicated residential home in the Pacific Northwest as an OTA range to conduct the study. The site is comprised of a ~3,000 sq. ft., two-story residence with a combination of drywall, wood, glass, and brick as its main building material. While no OTA environment is an absolute indicator of another OTA environment because of the complexities of building structure & material, RF multi-path, etc., Allion s Wireless Test House helps provide a differentiation of gateway coverage. Below is the floor-plan of Allion s test environment: 6

7 Below are the measured client Received Signal Strength Indication (RSSI) values at each attenuation point measured in dbm Comcast / Cisco Verizon / Actiontec rev. G Verizon / Actiontec rev. I AT&T / 2Wire The results above support the results reported from the Rate vs. Range testing that using a gateway that leverages both the benefits of n and more advanced hardware (3x3 antennae configuration) also results in overall better coverage as compared to either legacy abg or lesser n technologies. The Comcast wireless gateway tested showed greater coverage in terms of client RSSI versus both Verizon and AT&T gateways tested. 7

8 Over-The-Air (OTA) Throughput This test measures the Wi-Fi throughput at different locations within the Allion house. As indicated earlier, no OTA environment is the same; hence, results may differ from one environment to another. However, the Allion test house helps quantify the performance of each gateway in a real world home (client test locations are marked in blue). The measurements taken at each location are similar to the Rate vs. Range test (TCP, 60 second duration, client receive direction). Test AP The results above once again support the results from the Rate vs. Range test as well as the RSSI Heat Map test. The Comcast wireless gateways showed superior performance over Verizon and AT&T gateways at all locations. 8

9 Dual-band Capability (2.4GHz + 5GHz) Wi-Fi can be deployed in 2 separate RF bands consisting of spectrum located in 2.4GHz and 5GHz spectrums. Many gateways default to 2.4GHz because of the legacy Wi-Fi support of b and g while at the same time easier to incorporate the aforementioned superior n in this same band on the same physical radio. Often times, because of additional cost, complexity to design, and a limited number of Wi-Fi clients supporting 5GHz, vendors have avoided adding support for 5 GHz. This line of reasoning is fast becoming an out of date strategy for ISP s providing gateways as a part of their deployment. Wi-Fi networks have long used 2.4GHz as its primary spectrum for delivering wireless connectivity; however this has become problematic as the rise of wireless use has caused an increase in both RF congestion and wireless bandwidth. There are two potential ways to mitigate these issues with existing technologies: 1. Availability of 5GHz bands more recent clients available in the market (i.e. iphone 5, ipad 4, Kindle Fire HD, various ultra-books, etc ) support 5GHz and if a gateway could leverage this capability it would allow the ability to off-load clients to an operating band that experiences significantly less interference with neighboring Wi-Fi networks 2. 20MHz vs. 40MHz channel width with the introduction of n, the potential to widen the bandwidth of a certain connection was created by doubling the amount of spectrum used for a single connection on a given Wi-Fi channel. Typical Wi-Fi channels operate on a 20MHz channel width, n allows the ability to double this channel width to 40MHz. However, this obvious advantage in bandwidth must also take into account overall available spectrum (2.4 GHz only has ~60 MHz of channel spectrum while 5GHz has over 400 MHz to available to utilize depending on the connection). In the following sections, we will explore the reasoning behind the pros and cons of different Wi-Fi strategies as it relates to current ISP deployments in the home. 9

10 Below are both spectral & related Wi-Fi networks examples of a typical office and home environment in terms of RF density in 2.4GHz. 2.4 GHz Office Environment (Spectrum Analysis) 2.4 GHz Home Environment (Spectrum Analysis) 10

11 2.4 GHz Office Environment (Wi-Fi Scan) Allion ISP Wireless Gateway Competitive Analysis 2.4 GHz Home Environment (Wi-Fi Scan) As the above charts highlight the 2.4GHz band not only has several AP s across the entire bands spectrum, but there is a measurable amount of RF noise generated. Performance of a gateway and its associated clients can be impacted because of Wi-Fi co-existence mechanisms and RF interference present in the environment. 11

12 Another important observation is the existence of networks operating at 40MHz as highlighted by the red circles and how they overlap with several other networks. While operating at 40MHz can increase throughput achieved, this illustrates how it is can be considered bad practice when operating in the 2.4GHz band. As a 40MHz connection effectively utilizes ~66% of available spectrum, it opens up further co-existence and interference issues. The potential increase of overlapping channels can have the inverse effect of lowering the performance vs. the desired result of an increase in throughput. In the next section, we will examine the same typical environment with a focus on the 5GHz. 12

13 Below are both spectral & related Wi-Fi networks examples of a typical office and home environment in terms of RF density in 5GHz. 5 GHz Office Environment (Spectrum Analysis) 5 GHz Home Environment (Spectrum Analysis) 13

14 5 GHz Office Environment (Wi-Fi Scan) Allion ISP Wireless Gateway Competitive Analysis 5 GHz Home Environment (Wi-Fi Scan) The first thing to note is the decrease in number of AP s across the 5GHz band in contrast to the 2.4GHz charts from the previous section. It s also important to note the amount of measurable RF noise is significant. These two observations point to the fact that the medium is not saturated with gateways, clients and other devices operating in the 5GHz band making it an ideal candidate for operating a Wi-Fi network. 14

15 Another benefit of the 5GHz band as defined for Wi-Fi are the operating channels are spread out so that if network operator chooses to deploy the 40MHz channel option, they can without huge risk of experiencing channel overlap and other RF detriments which could mitigate the performance benefits intended by using a 40MHz channel. The chart below illustrates this potential peak performance benefit when a 40MHz channel is used instead of a 20MHz channel. The Xfinity wireless gateway observed speeds over 270 Mbps when 40MHz was enabled vs. 150 Mbps with the standard 20MHz. Among the devices from Comcast, Verizon, & AT&T included in this study Comcast was the only ISP whose gateway supports both 2.4 GHz and 5 GHz. 15

16 Contact Information North America Contact TEL: Taka Watari Engineering Lead Chad Meyer Vice President Ryan Hoppes President