My experience with 3.5G mobile broadband

I've had 3.5G data access with a variety of data modems for almost a year now.

I started off early last year with a PCMCIA Vodafone-branded modem. I have since used a USB Huawei-branded modem before finally migrating to a 3.5G PDA, which I run as a tethered (or via Bluetooth) modem as necessary.

In Singapore, all three mobile operators are currently offering 3.5G data services. As you can imagine, the competition is intense. As of this month, two of them are now offering unlimited data downloads differentiated by speeds. The third operator is offering 50GB of free monthly data traffic on their highest end plans.

Depending on whether you sign on to mobile broadband part of a package, you can get unlimited 3.5G data services between about SG$22 (for 512Kbps speed) to about SG$72 (for 7.2Mbps speed) per month. This works out to be about US$15 to US$49 respectively.

At the moment, I'm on an unlimited 7.2Mbps/1.9Mbps data plan - which means I can theoretically download data at up to 7.2Mbps, and upload at a theoretical maximum of 1.9Mbps.

What is 3.5G?

3.5G, or High-Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. It's commonly abbreviated as 3.5G to denote the high speeds that they offer relative to standard 3G technologies.

Two standards, High-Speed Download Packet Access (HSDPA) and High-Speed Upload Packet Access (HSUPA), have been established at the moment. HSDPA gives download speed of up to 7.2Mbps.

Currently, most devices sold on the market are only capable of 3.6Mbps, though some are firmware upgradable to 7.2Mbps. The theoretical maximum speed for HSDPA clocks in at 14.4Mbps. HSUPA, on the other hand, specifies up to 1.9Mbps of upstream bandwidth. This is an enhancement compared to the default upstream of just 386kbps available with HSDPA.

HSPA for Microsoft Direct Push

I've been using Microsoft Direct Push first on a Windows Mobile 5 device and then on the newer Windows Mobile 6 operating system. Overall, it works very well, and both e-mails and file attachments get downloaded speedily. Because the data stream is separate from the voice stream, there's none of the abrupt suspension of data transfer that's part of GPRS whenever a call comes in.

A point of caution is that while HSDA is indeed fast, it's not the Holy Grail to all your problems.

For example, once a few months back I was out without my laptop but needed to check my mail. Knowing the particular folder that the mail was stored in, I foolishly selected it and tried to sync "All" my mails to my handheld. An hour or more of industrious (and continuous) synching later, I looked at the final bar of battery life - it was full earlier - and gave up the idea.

Also, there are instances when the data connection simply dies on my PDA. Voice still works and signal strength is reflected as acceptable -- yet no data connection can be established. I have eventually narrowed it down to a hardware issue - restarting the PDA once or thrice will resolve the issue. However, I wonder how many Pocket PC devices actually suffer from such problems, and if it could be due to the relatively youth of HSDA hardware and chipsets.

Instability on the data level is obviously detrimental to the continual function of push mail.


On the level of a handheld, it's a joy to have such high speed available in the form factor of a handheld device.

Upgrading or patching software installations (via CAB installers) poses no problem and is transparent for the most part. I have successfully upgraded my IM+ instant messaging software while on the road.

Even installing new PDA software that you chance upon - say at a Borders bookstore - is a simple matter of goggling for a CAB installer and then downloading it directly.

HSPA for data access

As mentioned earlier, I have taken to connecting to an O2 Atom Life Windows Mobile 6 PDA for data access. Yet, because the PDA only supports Bluetooth v1.2, my data access speed is limited by default to the 768kbps that version 1.2 of Bluetooth offers. I can circumvent that by connecting the PDA via a USB cable, but then I would still be limited by the 3.6Mbps/386Kbps speed of the hardware data modem in the Atom Life.

Surfing is adequate, and downloading moderate-sized files of up to a dozen megabytes is generally not an issue at all. However, Web pages have a tendency to time-out at times, requiring a refresh before they will load fully. I think this is a problem inherent to HSDA - I'll be writing more on that later.

Using a fully charged Atom Life as a data modem, I can squeeze about three to four hours of surfing via Bluetooth connection before the Atom Life runs out of juice.

I do have a dedicated E270 Huawei data modem that allows me to tap into the max speed. But since there is no observable difference in terms of speed, for convenience, I don't normally bother to bring it out.


Overall, this technology is speedy. There are some (minor) issues with latency and dropped connections though, resulting in having to reload Web pages at times.

After almost a full year of experiencing 3.5G, I regret to say that I would not rely exclusively on mobile broadband for my connectivity needs.


Paul Mah is a writer and blogger who lives in Singapore, where he has worked for a number of years in various capacities within the IT industry. Paul enjoys tinkering with tech gadgets, smartphones, and networking devices.