FAQ High Speed Downlink Packet Access (HSDPA)
By Zahid Ghadialy (zahidtg@yahoo.com)
QUESTIONS What does HSDPA stand for? So what exactly is HSDPA? Interesting! Is HSDPA part of 3G or will it be part of 4G? Why not similarly have HSUPA where U stands for uplink? Are HSDPA networks rolled out and can i buy HSDPA capable phones? Can existing 3G Networks be upgraded to support HSDPA with new Software release? What could be the possible uses of HSDPA? How did 3GPP manage to increase the speed of DL to over 10Mbps? Is HSDPA applicable for CS and PS RABs both? Is HSDPA applicable in CELL_FACH or CELL_DCH or both the UE states. Can you give comparison of HSDPA in FDD & TDD Mode? Where can i find basic tutorial on HSDPA? I would like to follow all HSDPA related News, which is the best place to look for? I am a researcher and i would like some references to read more on HSDPA.
What does HSDPA stand for?
HSDPA stands for High Speed
Downlink Packet Access
So what exactly is HSDPA?
HSDPA is an enhancement to the 3G
technology through which you can increase the DL data rates from 384Kbps
(theoretically 2Mbps) to 10Mbps (theoretically 14Mbps). Here Kbps stands for
Kilo bits per second and Mbps stands for Mega bits per second. HSDPA delivers
higher capacity through improved spectral effeciancy, which provides higher
data rates, shorter response times and better Qos (Quality of Service).
Interesting! Is HSDPA part of 3G
or will it be part of 4G?
HSDPA is part of 3G but people
also refer to it as 3.5G
Why not similarly have HSUPA
where U stands for uplink?
There is already a HSUPA.
Are HSDPA networks rolled out and
can i buy HSDPA capable phones?
In most of the countries, HSDPA
networks have already been rolled out and HSDPA phones are already available.
You can find the latest status of HSDPA capable networks in different
countries on the GSMA website here.
Can existing 3G Networks be
upgraded to support HSDPA with new Software release?
In theory they can be but it might
not always be the case. According to The Register HSDPA
is a power-hungry technology, and many of the base stations out there aren’t
up to the job. The key piece of technology is the power amplifier, which has
to be a full power, 45-watt model, to handle the extra data output. Having
said that, most of the new newly designed RNC and Node B's are now capable of
handling not just an upgrade from 3H to HSDPA and HSPA+ but also to LTE.
What could be the possible uses
of HSDPA?
The same use as that of Broadband
connections at home. It would be possible to watch extremely good quality
real time Videos, download complete song tracks in less than a minute. Do
real time video conferencing with more than one user using very high quality
video. Eventually the wireless operators plan that instead of having wired
broadband at home, people will move to wireless broadband. The list is non
exhaustive.
How did 3GPP manage to increase
the speed of DL speed to over 10Mbps?
To increase the data rates a new
channel called HS-DSCH (High speed downlink shared channel) was defined. This
was somewhat similar to the DSCH defined in the release 99 specs. This
channel maps to HS-PDSCH (high speed physical downlink shared channel). To
support this data channel a control channel HS-SCCH (High speed shared
control channels). The HS-DSCH is transmitted over the entire cell or over
only part of the cell using e.g. beam-forming antennas.
The increased data rates are supported
through the introduction of Fast and Complex channel-control mechanisms based
on a short fixed packet TTI (transmission time interval), AMC (adaptive
modulation and coding) and L1 HARQ (layer1 hybrid automatic repeat request).
Is HSDPA applicable for CS and PS
RABs both?
In release 5 HSDPA is only
applicable for PS streaming/interactive/background RABs. In release 6, HSDPA
will be used for Signalling Radio Bearers as well.
Is HSDPA applicable in CELL_FACH
or CELL_DCH or both the UE states.
HSDPA is only applicable to
CELL_DCH state.
Can you give comparison of HSDPA
in FDD & TDD Mode?
Where can i find basic tutorial
on HSDPA?
I am a researcher and i would
like some references to read more on HSDPA.
References as follows:
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