[Here is a couple of interesting articles on evolving developments in 5G wireless space. 5G wireless networks use Open SIM for authentication, OpenFlow for VM routing and WiFi powered by renewable energy as the primary customer interface. It is an ideal technology for R&E networks and small ISPs to integrate with their fiber backbones. More details can be found at http://billstarnaud.blogspot.com/-- BSA]
Microsoft Wiffler lets smartphones use free WiFi from moving vehicles
Researchers from Microsoft and University of Massachusetts test a promising new protocol to offload 3G traffic to WiFi even from a moving vehicle.
Microsoft Researchers have been working on a technology that would let mobile phones and other 3G devices automatically switch to public WiFi even while the device is traveling in a vehicle. The technology is dubbed Wiffler and earlier this year, researchers took it for some test drives in Amherst, Mass, Seattle and San Francisco.
Mind you, WiFi was available only about 11 percent of the time for a mobile device in transit, the team discovered, compared to 87% of the time 3G was available. So it would stand to reason that, at best, the mobile device wouldn't only be able to use WiFi a tiny bit of the time. However, the Wiffler protocol allowed the device to offload nearly half of its data from 3G to WiFi.
How so? Wiffler is smart about when to send the packets. It doesn't replace 3G, it augments it and transmits over WiFi simultaneously, allowing users to set WiFi as the delivery method of choice when it is available -- and when an application can tolerate it.
"We try to ensure that application performance requirements are met. So, if some data needs to be transferred right away (e.g., VoIP) we do not wait for WiFi connectivity to appear. But if some data can wait for a few seconds, waiting for WiFi instead of transmitting right away on 3G, that can reduce 3G usage," Ratul Mahajan told me in an e-mail interview. Mahajan is a researcher with the Networking Research Group at Microsoft Research Redmond. Mahajan worked on the project with two teammates, Aruna Balasubramanian and Arun Venkataramani, both of whom are researchers at the University of Massachusetts Amherst.
"The second feature is that we may actually use both connections in parallel instead of using only one. So, if we deem that some data cannot be transferred using WiFi alone within its latency requirement, we will use both 3G and WiFi simultaneously. This parallel use is different from a handoff from one technology to the other, and it better balances the sometimes conflicting goals of reducing 3G usage and meeting application constraints," Mahajan explained.
The results of the test was presented in a paper, Augmenting Mobile 3G Using WiFi (PDF), presented in June 2010 at the eighth annual International Conference on Mobile Systems, Applications and Services.
The test consisted of running Wiffler units on 20 buses in Amherst, MA as well as in one car in Seattle and one in San Francisco at SFO. The Wiffler unit itself was a proxy device that included a small-from factor computer, similar to a car computer (no keyboard), an 802.11b radio, a 3G data modem, and a GPS unit. The 3G modem was using HSDPA-based service via AT&T.
"Today, the WiFi/3G combo management is highly suboptimal. Today, smart phones tend to use WiFi connectivity only when they are stationary and not use WiFi connectivity when they are on the move. At the same time, they experience poor application performance when the WiFi connectivity is poor because they happen to be far from the AP (access point) or because the WiFi network is congested. This experience occurs because the devices insist on using WiFi whenever they are connected, largely independent of the performance of WiFi. Our technology provides an automatic combo management that is aware of application performance," Mahajan says.
Next up, the crew plans to test the Wiffler protocol in other uses, including the 3G savings "in a setting when users have Wiffler running all the time rather than just driving. Another is to understand current smartphone traffic workloads to get a sense of how much traffic individual applications generate; this is important because data for some of the applications can be delayed and for some it cannot be delayed," Mahajan explains.
Solar Powered DIY Portable HotSpot
Ever wondered what it would be like to have your own hotspot no matter where you went? Well now you can with this portable solar powered Wi-Fi repeater.
This little mod is simply a wifi router connected to 5 AA batteries that is charged with the built in solar panel and all mounted into a little cigar box. I used this in the back window of my car and no matter where I am at I am able to surf the net and check email within 150 feet of my car.
Here is how it works:
First there is the solar panel. This panel puts out enough voltage and current to run the wireless router without the batteries. The batteries are simply there to act as a flywheel in case of clouds, shade, etc. The panel then recharges the 5 AA batteries which in turn supply the energy needed to run the router.
The router runs a custom firmware called dd-wrt that automatically scans for open hotspots and then connects to the strongest signal it finds automatically. It then repeats the signal locally so you can surf the net with a more reliable connection. No need to search for open hotspots, it finds em and connects to the strongest for you.
This comes in handy as one is at work and their car sits in the parking lot all day long. Then when I come out for lunch I am able to immediately login to my asus netbook and check email, etc.
Notes; This router (Linksys WRT54G v8) will run on up to 12 volts 1 amp or 12 volts 500ma or 6 volts 500ma. I know because I personally tested it with other wall warts of these voltages and amperages.
The solar panel puts out 7.5 volts @ 500 ma in direct sunlight. So no charging circuit was needed as the panel is unable to over charge the batteries due to the fact that the batteries voltage is too close to what the panel puts out in regards to voltage. Now you might be asking how can this router take such different voltages and amperages as stated…? Well, the router has a built in voltage regulator that takes care of any voltage ranging from 6v DC all the way up to 24 volts DC.
In further testing it did not seem to effect the unit in anyway if it was using 12 volts @ 1,000ma or 6 volts @500ma.
One might prefer to use the 12 volts 500ma instead simply due to the fact that a charge regulator is alot easier and cheaper to get for 12 volts then it is for 6 volts. The one below is one that I have that was less then $20 on ebay so I could use it for a larger 12 volt battery if I wanted to.
Bill St. Arnaud
- Bill St. Arnaud is a consultant and research engineer who works with clients around the world on a variety of subjects such as next generation Internet networks and developing practical solutions to reduce CO2 emissions such as free broadband and dynamic charging of eVehicles. He is an author of many papers and articles on these topics and is a frequent guest speaker. For more details on my research interests see https://www.researchgate.net/profile/Bill_Arnaud