High-Speed Uplink Packet Access (HSUPA) is a mobile telephony protocol that belongs to the HSPA (high speed packet access) set of technologies.
HSUPA is designed for providing high uplink speeds. Current HSUPA devices feature uplink speeds of up to 5.7 Mbps.
Not all devices that support HSUPA have the same uplink speeds. For instance, Category 5 devices, like the Nokia N8, Nokia E72, BlackBerry Storm 9500, and Samsung Wave, can go up to 2 Mbps. But Category 6 devices, like the Apple iPhone 4 and Motorola Atrix 4G can go even faster; i.e., up to 5.7 Mbps.
There are actually two protocols under HSPA. The other one, known as HSDPA (where ‘D’ stands for Downlink), is focused more on providing higher downlink speeds. Because most HSPA users perform more downloads than uploads, HSUPA speeds are consequently slower.
The advantage of HSUPA comes into play when you need to upload a large email attachment via your mobile device. Otherwise, there isn’t as much use for it as compared to HSDPA.
Standards for HSUPA are being developed by the 3GPP, a group of telecommunications organizations whose focus is on evolved GSM core networks.