Recently in LTE Category

Broadband Stimulus

There is a portion of the American Recovery And Reinvestment Act that will fund programs to accelerate the deployment and use of broadband in the United States. In particular, the NTIA's Broadband Technology Opportunities Program (BTOP) and the Department of Agriculture's Rural Utility Services (RUS) grants and loans will go to fund programs "in unserved, underserved, and rural areas and to strategic institutions that are likely to create jobs or provide significant public benefit". These programs are handing out billions of dollars in the next 18 months and will likely have thousands of applicants for the much needed stimulus money. How will these agencies do it? It is a daunting task and efforts are already underway. The first open public meeting was held earlier this week and two more will be held in the coming weeks. At this point there are more questions than answers. How are these agencies going to work together? Who is eligible to receive a grant? How will the success of the program be measured overall? What does "underserved" mean? For that matter - what does "broadband" mean? In the new era of transparency and accountability, grant applicants will have to explain how they are going to execute their program, deliver the claimed benefits, and measure the results. For the wireless broadband piece, this brings us right back to the basics. What are the technical requirements to support a given application - coverage, throughput, latency and overall system capacity? In order to support multiple different applications, what are the system level requirements? What performance is required to deliver an acceptable user experience? Perhaps it is time to dust off our Novarum lessons from the first round of Municipal Wireless. We can not afford to repeat those mistakes again.

Performance of Cellular Data Networks

| 0 Comments | 0 TrackBacks
We tested performance (delay, uplink throughput, downlink throughput) and availability (percentage of tested locations with service with the advertised service area) for ATT (Cingular), Sprint and Verizon cellular data networks in a number of North American cities during the NWBR. We tested one or more of these networks in these 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 tested twice to detect changes in traffic and improvements in network service. Great disparity of service was noted with several small towns (Galt CA and St. Cloud FL) having no 3G service at all (and hence barely averaging 100 kpbs of data service) from any service provider while larger, growing metro areas (Tempe AZ) had an abundance of high performance cellular data providers (with downlink service approaching 1000 kbps). When available, the three major cellular providers offered a similar grade of performance averaging about 200 kbps on the uplink and about 500 kpbs on the downlink. No measurements ever exceeded 1000 kbps.
Network Delay (msec) Uplink (kbps) Downlink (kbps) Total Availability 3G Availability
ATT (Cingular) 318 195 473 75% 59%
Sprint 330 215 559 96% 90%
Verizon 366 179 494 92% 70%
Average 340 195 507 89% 73%
On average, Sprint offered the highest performance with the greatest availability. ATT and Verizon both offered a slightly poorer grade of performance but the availability for these two networks is far more interesting. Cellular networks do not offer a single grade of service ... where available, 3G service is offered but when there is no 3G capacity left, the networks fall back to offering 2G service instead. This fallback results in an almost 3x decrease in upload performance and over a 5x decrease in download. For Sprint, almost all our testing locations offered 3G service and only in 6% of the those locations did the offered service fall back to 2G. For both ATT and Verizon, in about 25% of the locations with service - we could not get 3G service but rather fell back to 2G service. And in the case of ATT, this exacerbated the already poor availablity with only 75% of the tested locations could we get service at all! As we will see when we look at the results for WiFi networks, with the proper client modem selection, WiFi network uniformly outperform and can achieve availability of 85% - not dissimilar to the average availability of 89% for cellular data.

Novarum Wireless Broadband Review

| 0 Comments | 0 TrackBacks
We have been curious about how real wireless networks perform - both in the enterprise and in metropolitan areas. We have also been impressed by how few third party measurements at scale have been performaned for both applications of wireless networks. Most of our knowledge about how these networks really deliver service is either based on anecdotal reports or the marketing information from the service providers and equipment vendors. So we decided to test and obtain some real, non-partial information. We went out and tested over 136 wireless networks in 22 North American cities from July 2006 through early 2008. We devised an network independent testing regime that mimics the behaviour that ordinary users of these services would observe - testing packet delay, upload and download throughput (using industry standard tools) and percentage of the claimed service area in which we could actually get service. We tested in the following cities (some twice to reflect major changes in the networks between tests): Anaheim CA (2x), Brookline MA, Chico CA, Cuperino CA, Daytona FL, Eugene OR, Foster City CA, 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, Santa Clara CA, Sunnyvale CA, Tempe AZ, and Toronto ON (2x). Where we could find them, we tested cellular data networks from ATT (nee’ Cingular), Sprint and Verizon; pre-WiMax networks from ClearWire and WiFi networks from a variety of ISPs. The data clearly shows that all these technologies can deliver similar levels of service when properly built out. Subsequent blogs will address individual lessons learned for each of these network technologies.


| 0 Comments | 0 TrackBacks
This blog is the combined thoughts of Ken Biba and Phil Belanger ... two pioneers of wireless networking and arguably two of the co-inventors of the networking systems we think of as WiFi:
  1. Minimal licensing.
  2. Sharing of scarce radio spectrum.
  3. Robust technologies that survive (and often prosper) in a severe radio environment.
  4. Dirt cheap.
  5. Ubiquitous.
  6. High performance.
Look for us to be posting product critiques, technology thoughts and the results from our ongoing measurements of both enterprise and municipal networks. Over the last 18 months, we have done extensive studies of many of the foundation myths of deploying large scale wireless networks in both large enterprise and metropolitan environments. We will be reporting on those studies here and many of the implications of those studies on future use of unlicensed technology for providing mission critical network services. The Novarum Wireless Broadband Review surveyed and measured over 100 deployed municipal WiFi, cellular and pre-standard WiMax networks and comprises the largest available database of experience about these networks. We will be using this large experience base to inform our comments ... rather than mere opinion. We look forward to your comments.