When Samsung announced its Galaxy S5 smartphone in February during the 2014 Mobile World Congress trade show, one of the device's highly touted features was the download booster, which bonds Wi-Fi and LTE simultaneously to accelerate the download of large files. However, the feature is absent from AT&T's (NYSE: T) recently released version of the device and is also not being offered in variants offered by Sprint (NYSE: S) or Verizon Wireless (NYSE: VZ).

Galaxy S5

AT&T's omission of the feature was first noted by Android Police, which said demo models of the S5 in AT&T stores lacked the download booster. The site said it delayed reporting the story until the feature's absence could be verified on an actual device that was sold to a customer.



In examining the SM-G900A AT&T variant of the S5, Android Police said a toggle for the download booster is completely missing, and there is nothing within any of the network settings allowing its use.



Sprint and Verizon are also following suit. Spokesmen for both Sprint and Verizon confirmed separately to FierceWirelessTech that those operators are not making the download booster available on their variants of the S5. They did not provide any reasons for the omission.

AT&T didn't immediately respond to questions on the topic. However, after this story was published, an AT&T spokesman told FierceWirelessTech: "We are evaluating Samsung's download booster feature. We thoroughly test new software, features and functionality to ensure that it meets our standards for a quality user experience."

That leaves T-Mobile US (NYSE: TMUS) as the only nationwide U.S. operator committed to offering the feature. In fact, T-Mobile highlighted the download booster in a Feb. 24 press release announcing that the S5 would be available from both T-Mobile and its MetroPCS business. T-Mobile also touts the feature on its S5 landing page.

According to Anandtech, Samsung's download booster uses HTTP range requests to divide files between Wi-Fi and LTE network links. Apps and functions that are supported by the feature include Google (NASDAQ: GOOG) Play Store, YouTube, Facebook photo and video downloads, Samsung apps and standard HTTP web browsing.

Anandtech reports that the download booster feature, "if enabled and under the right conditions," can be useful, though file downloads smaller than 30 MB won't trigger the function.

In addition, the download booster will not activate if one of the air interfaces is running substantially faster than the other. For example, ExtremeTech noted that "if you're downloading at 50 Mbps over Wi-Fi, it won't use your 5 Mbps LTE link."

The S5 supports Wi-Fi 802.11ac via Broadcom's 2x2 MIMO Wi-Fi chip, offering double the Wi-Fi performance of 802.11ac single-stream MIMO devices. The chip enables up to an 867 Mbps PHY rate and 80MHz channel bandwidth.

The Galaxy S5 also includes Qualcomm's Snapdragon 801 with integrated Category 4 (150/50 Mbps) LTE 9x25 modem core and can work across eight LTE bands in any given region. In addition, the smartphone supports LTE Advanced carrier aggregation.

For more:

- see this Android Police article

- see this AnandTech article

- see this ExtremeTech article

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Article updated on April 10, 2014, to include a comment from AT&T.