Why Network Clients Matter!

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It was clear from the beginning of the NWBr that the proper choice of client device makes all the difference in the complete system performance of a municipal wireless network ... and in particular the user experience. Cellular and pre-WiMax (and mobile WiMax when delivered) networks precisely specify the client and test its performance. These clients are much more rigorously controlled and, in general, have much high transmit power and better antennas with less noise than WiFi clients. In the process of the NWBR we have tested many client devices to see the effect of client devices on network performance - testing them in the same networks in the same locations, at the same time ... to more accurately assess the difference. We tested the following clients:
  1. Standard 802.11g laptop client - approximately 30 mW output power
  2. A high power 802.11g laptop client - approximately 200 mW output power
  3. A first generation 2x2 MIMO 802.11n client - approximately 30 mW output power. Current .11n clients should have even better performance.
  4. First generation iPhone smartphone WiFi client.
Let’s first examine the average performance of these clients across all the networks in which they were tested.
Client Delay (msec) Uplink (kbps) Downlink (kbps) Availability
Average Laptop 157 481 1030 64%
Average High Power 113 767 1286 85%
Average .11n 115 845 1712 82%
Average iPhone 422 231 810 45%
The clear performance advantage of the higher power client and for the 802.11n clients leaps out. Both deliver average megabit performance with approximately 85% outdoor availability - availability comparable to both the best of cellular and pre-WiMax with superior performance. The lower performance of both the standard laptop client and the iPhone client is understandable with the low power iPhone still showing a rather amazing 45% availability on average. The difference a good infrastructure network makes is clear when we look at the best performance by each of these clients. Our top three performing networks (Minneapolis, Toronto, and St. Cloud) all deliver outstanding performance but the single best performances were by the laptop, high power AND .11n clients in Minneapolis - delivering multimegabit performances that leave both cellular and pre-WiMax in the dust - while delivering avaiailability uniforming over 80% - including 100% for the high power client. The St. Cloud network delivered the best performance and availability combination for the iPhone client with 75%.
Client Delay (msec) Uplink (kbps) Downlink (kbps) Availability
Best Laptop (Minneapolis) 74 457 3090 80%
Best High Power (Minneapolis) 63 2062 2949 100%
Best .11n (Minneapolis) 77 1939 3237 82%
Best iPhone (St. Cloud) 415 158 831 75%
Some conclusions:
  1. A modern WiFi network designed with appropriate access node density ( greater than 40 nodes/mi^2) can deliver performance and coverage that outperforms cellular and pre-WiMax.
  2. The increasing usage of 802.11n in client devices will only improve the quality of already installed networks ... increasing performance, coverage and user satisfifaction.
  3. All the WiFi network infrastructure we tested was 802.11g compatible, often without diversity antennas for the uplink from clients. As infrastructure vendors move from .11g to MIMO .11n we can only expect these performance gains to increase even more.

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