Two important issues in large-scale municipal wireless have been: (1) can a given technology provide a usable data communications service and (2) how much does it cost to deploy such a service?
A useful network service provided at an affordable price is a necessary condition for a successful network offering. Many of the early muni Wi-Fi networks were hampered by poor service AND a higher cost to deploy than expected.
In seeking to answer these questions, Novarum structured its Wireless Broadband Review to provide information on the performance of Wi-Fi, cellular and pre-WiMAX networks.
During 2007 and early 2008, we tested cellular, Wi-Fi and pre-WiMax networks in the following cities: Anaheim CA (2x), Brookline MA, Chico CA, Cupertino CA, Daytona FL, Eugene OR, Galt CA, Longmont CO, Madison WI, Minneapolis MN, Mountain View CA (2x), Palo Alto CA, Philadelphia PA (2x), Portland OR (2x), Raleigh NC, Rochelle IL, St. Cloud FL (2x), Santa Clara CA, Sunnyvale CA, and Tempe AZ (2x). In several cities we conducted the tests twice to detect changes in traffic and improvements in network service over time.
We discovered that, on the average, all of these networks have substantial performance and coverage. But the best Wi-Fi networks substantially outperformed the best of the cellular AND pre-WiMax networks.
Our test was an “apples-to-apples” comparison of performance (delay, uplink throughput, downlink throughput) and availability (percentage of tested locations with service within an advertised service area) for all of the major network technologies:
- ATT (Cingular), Sprint and Verizon cellular data networks;
- A number of metro WiFi networks using equipment by BelAir, SkyPilot, Strix, Tropos; and
- Four of ClearWire’s pre-WiMax networks.
We tested outdoor coverage in an average of 20 locations per city, testing all networks with the same traffic load and in the same location and time. One of the important determinants of good performance is a good client modem, and indeed we tested a variety of these modems.
We took standard USB external modems for each of the cellular data networks, a higher power Wi-Fi modem (noting that current 802.11n modems appear to perform on par with these higher power clients), and a desktop directional CPE for the pre-WiMax ClearWire networks (no portable device was available at the time). We expected the WiMax modem (AC powered, directional antenna) to have the advantage in performance.
To our surprise, using similar client modems, averaged over good and bad networks, Wi-Fi networks delivered almost three times better performance than cellular networks and materially better performance than pre-WiMax networks – with similar levels of availability of service over the promised coverage area for all three network technologies.
If we look at the best and most recently deployed Wi-Fi networks, we see performance and availability superior to the best of the cellular data networks and pre-WiMAX networks – by a factor of 3!
The measured performance demonstrates that Wi-Fi networks materially outperform cellular data networks AND pre-WiMax networks – and do it over similar service area coverage, and likely lower deployment costs.
These network technologies are still evolving and we can expect improved performance and availability from cellular networks (with more extensive tower deployments and eventual migration to LTE from the CDMA and HSPA measured in these cities); from WiMax, as it moves from pre-WiMax OFDM systems measured here to standardized mobile WiMax; and from Wi-Fi as we begin to see the deployment of Wi-Fi metro networks based on IEEE 802.11n.
About the author
Ken Biba is a co-Founder and Chief Technical Officer of Novarum, an advisory firm specializing in wireless data networks. Ken has over 30 years experience in the network information systems industry combining a background of general management with a strong product and marketing focus in network systems and information security. Ken was an early engineer of the Internet in 1975. He has co-founded and managed four notable networking companies-Sytek, which was focused on cable TV-based local and metropolitan data networks, Agilis which delivered the first wireless handheld computers, Xircom, which pioneered local area networks for mobile computing, and Vivato, which was focused on scaling Wi-Fi infrastructure to cover campuses and metropolitan areas. Ken’s perspective as CEO, board member of public and private companies, and as a technologist brings unique insight to the business, market and technology of bringing useful wireless solutions to users. Ken has a Bachelor of Science in Physics (Magna Cum Laude, Tau Beta Pi) and a Master of Science in Computer Science from Case Western Reserve University.
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