3G HSUPA - High Speed Uplink Packet Access
- a tutorial, description or information about the basics of HSUPA, High
Speed Uplink Packet Access, the enhancement to the UMTS / WCDMA standard for 3G
cellular telecommunications
Work is now staring on developing the standards for High
Speed Uplink Packet Access ( HSUPA ) to improve the data rates on the 3G W-CDMA
mobile or cell phone standard. With the cellular telecommunications standards
established and work progressing to introduce the equipment for High Speed
Downlink Packet Access ( HSDPA ), the standards are now starting to be developed
to enable the uplink from the mobile handset or User Equipment (UE) to the base
station (Node B) to be able to handle data at similar speeds. This is known as
HSUPA and it will enable new features including full video conferencing to be
introduced.
For most applications including internet surfing, emails,
video downloads and the like, data flowing in the downlink is far greater than
the uplink. However for applications such as video conferencing, data flows
equally in both directions. It is anticipated that video conferencing will
become an increasing requirement, and a significant revenue generator for the
operators in the near future. To enable high quality video to be passed, it is
therefore essential to ensure that the uplink performs as fast as the downlink.
Although it is very early days for the standards, work on
HSUPA has already started under the auspices of 3GPP, the body that controls the
Wideband CDMA (W-CDMA) standards.
Technologies used for HSUPA
It is anticipated that many of the same techniques used in
HSDPA will be used for HSUPA, but these still need to be formalised. Accordingly
it is expected that adaptive modulation, along with HARQ (hybrid automatic
repeat request) will be used. Improvements in the base station similar to those
employed on HSDPA are also likely.
Originally W-CDMA had used only QPSK as the modulation
scheme, however under the new HSUPA system,16-QAM which can carry a higher data
rate, but is less resilient to noise is also used when the link is sufficiently
robust. The robustness of the channel and its suitability to use 16-QAM instead
of QPSK is determined by analysing information fed back about a variety of
parameters. These include details of the channel physical layer conditions,
power control, Quality of Service (QoS), and information specific to HSDPA.
Fast HARQ (hybrid automatic repeat request), has also been
implemented along with multi-code operation and this eliminates the need for a
variable spreading factor. By using these approaches all users, whether near or
far from the base station are able to receive the optimum available data rate.
It is also likely that within the HSUPA upgrades there will
be an additional uplink data channel introduced comparable to that in the
downlink.
The future
Many manufacturers are working on implementing HSDPA, with
initial equipment deliveries anticipated in 2005. Now with HSUPA in people's
sights this should be implemented in the following years, making a far faster 3G
system than is currently available
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