My WiMAX Experiment - Part 4: VoIP Call Quality

Part 4 of my WiMAX Experiment deals with VoIP call quality while using the WiMAX Modem. I have placed a few calls to date and have had some great calls, but also some not-so-great calls. It seems to not only be dependant on my modem reception, but also some unknown factors which I could not quantify.

I thought that I would share recordings of some tests that I did to gauge the call quality relative to a cell phone. Note: they look like flash videos, but there is no video - only sound.

Call #1 - Cell phone call to a Vonage voice mail

• The purpose of this call was to baseline the VoIP call quality relative to a traditional cell call.

Call #2 - Gizmo call via WiMAX to a Vonage voice mail

• The proof is in the pudding, so-to-speak: my first documented test of a VoIP call with the WiMAX modem.

The VoIP call was a little unclear in spots, but I thought it was feasible, even with the latency and bandwidth I can attain with the WiMAX modem. Those initial tests gave me the courage to record a conversation with someone while connected via the WiMAX modem...

Call #3 - a real life Gizmo call to an InternetTabletTalk member via WiMAX!

• I cold-called ITT member, qwavel, by sending him a PM on Internet Tablet Talk. Since he had made some comments on my experiment, I wanted to see if he would be interested in participating in a VoIP call with me. He instantly agreed. Since I did not know of an easy way to record the call on the tablet using Gizmo, he offered to record the call on his end via his Nokia N95. Hats off to qwavel for his enthusiasm and helpful conversation!

The interesting observation I had after listening to this recording was that qwavel sounded pretty clear to me at the time of the call, but on the recording, I sounded distant and broken up frequently. If both voices were relaying through the WiMAX modem, why was there such a difference between my observation during the call, and the subsequent recording?

Stay tuned for Part 5 of my WiMAX Experiment, where I will take the show on the road - literally!

My WiMAX Experiment - Part 3: Speed Tests

As I mentioned in Part 2, the Portable Internet Basic I have from Rogers is slow, but usable. Slow is a relative thing. They advertise 512 Kbps download and 256 Kbps upload. I found it hard to get a reliable speed test using the WiMAX modem since many of the speed testing sites I would traditionally use on a DSL connection were too slow to load and relied heavily on flash.

I did find a mobile version on DSL Reports that was advertized for use with - ahem - the iPhone. Well, it turned out to be the most workable speed test site to use in this case.

http://i.dslr.net/tinyspeedtest.html

I found that the download speed was heavily dependant on the reception of the modem. Today, my reception ran anywhere from 1 bar to 3 bars of service. A little fiddling with the modem placement and orientation allowed me to gauge the speed of my connection as a function of the number of bars of reception I had.

Bars	Speed (avg – Kbps)
1	53.5
2	92
3	172.5

Table 1: Average Download Speeds as a Function of Reception

I wasn't expecting much of a correlation, but it seems relatively linear.

Most of the time, I was running at 3 bars of reception. The spread in my connection speed ran from 114-224 Kbps.

Figure 1: An Example Speed Test Result from http://i.dslr.net/tinyspeedtest.html

The spread in latency was large - ranging from 94 ms to just over 1000 ms. The IP for dslr.net is somewhere in the USA, and the domain is registered in New York. That level of latency is large for a server a few hundred kilometres from me!

Many of the mobile-optimized sites worked quite well, loading relatively fast. I tried out the following:

http://m.gmail.com
http://m.facebook.com
http://www.cbc.ca/mobile
http://internettablettalk.com/forums (using the Mobile II theme)

The mobile facebook site worked quite well, and allowed me to do all of the things I normally do on facebook. That mobile site, in my opinion, should be benchmarked by Google for their mobile optimized GMail. The mobile version of GMail had a pretty poor interface. The Inbox view is OK, but the Compose view isn't. The body of the message that you're typing is very narrow. There is an iPhone optimized GMail site, but it doen't work consistently on my N800, or at least, I could not get it to work consistently. I resorted to using the basic HTML view for GMail, and it didn't get bogged down by my WiMAX connection.

Stay Tuned for Part 4, where I will review the quality I get using VOIP - pumping the calls through WiMAX...

My WiMAX Experiment - Part 2: Teething Pains & 'Mobile Setup'

As I mentioned in Part 1, my intended usage for the WiMAX modem is at my workplace, where I do not have WiFi.  One of my main concerns was with concealment of the modem/router package.  I solved this by strapping the router to the modem, and tucking it between my computer and the cubicle wall.  After work, I place the modem and router in my desk and lock it.

The first day brought to a light a few problems.  One was the choice of router.  That FON router would drop connections often.  I recalled that there was an issue with using this router and the NIT's, related to the power saving mode in the WiFi.  I bought a cheap D-Link router that night, and the router issue was solved.

The other problem I had was with the modem dropping connections sometimes.  It would go roaming for a signal, and take a few minutes to acquire it again.  Some twisting and shifting of the modem proved to be useful in securing a reliable spot to place it in.

Surfing on the first day was good.  I used the 'mobile' versions of most sites that I frequent.  Funnily enough, the ITT site was one of the hardest to switch to mobile since the option is in a drop box at the bottom of the page.  Loading the full site on the Basic connection I had was slow.  Gmail, Google, Wikipedia, CBC News, and more were very usable in their mobile forms, or basic HTML versions. 

I was chatting via GoogleTalk with some friends, and even placed a VOIP call via GoogleTalk.  The call was fairly clear, but would cut in and out frequently.  I need to do some more testing of the VOIP when connected via the WiMAX modem. 

The Portable Internet Basic I had was slow, no doubt about it.  But for access at a fixed remote location, and with the usage of mobile optimized sites, it proved to be very usable. 

Stay tuned for Part 3, where I will discuss actual speeds obtained from speed tests and load times of common mobile sites.

My WiMAX Experiment - Part 1: Background

I have been eagerly awaiting the N810 WiMAX Edition since news of it
surfaced last year. The N810WE would offer true mobility - a pocket
computer coupled with the excellent bandwidth that WiMAX delivers.
Canada is one of the few places in the world that has an existing WiMAX
network, albeit of the 'Pre-WiMAX' variety. Rogers and Bell offer
'Portable Internet' and 'Sympatico Un-Plugged', respectively. Both are
resellers of Inukshuk's WiMAX network.

After thinking about the N810WE more and more - a thought occured to
me. Did I really need to wait? My two main usage locations for my N800
are at home, where I have WiFi, and at work, where I don't. The reason
I wanted the N810WE was to be able to use it at my second location -
work. My company has a restrictive internet policy, and no WiFi.

Could I not then sign up for Rogers Portable Internet, and use that
service at work? Sure I could. I had my doubts - what would the
reception be like? What if I don't like the service? I don't really
want to spend $100 on a modem that I may not use for that long. How
would I hide a modem and WiFi router at work?

I found a used modem on craigslist - they were asking $50, but they
accepted my offer of $40. I was in business! That night, I spent about
20 minutes on the phone with the Rogers salesperson. They offered me a
deal on the Portable Internet Basic - $19.95/month and no activation.
The price was good for 12 months, and there was no contract. At the
most, I would be out one month of service, and would have to unload a
modem I bought for $40. Pretty low capital outlay for an experiment in
WiMAX. I had a spare FON router lying downstairs doing nothing useful -
time to put it to use and see what this WiMAX thing is all about.

Within 15-20 minutes, the modem had aquired its signal and registered
itself onto Rogers' network - a one time procedure for new modem
activations. The modem showed 3 bars of service, and I logged onto the
FON AP. I was in business!

Stay tuned for the second part of My WiMAX Experiment: First Days
Teething Pains and 'Mobile Setup'.

Welcome to Mobile Tablets!

Greetings fellow Internet Tablet users!

Welcome to Mobile Tablets, a blog aimed at sharing with you my experience of using an internet tablet in the daily grind. I intend to comment on my usage pattern, successes and frustrations with using my N800 at work and at home.

The idea for this blog came from the 'personal accounts' section of the internet tablet talk wiki.

Coming soon:

WiMAX, an experiment in mobile tabletting - it's not perfect, and certainly not for everyone.


Stay tuned and Enjoy!

EIPI