High Speed Packet Access is an amalgamation of two mobile telephony protocols, High Speed
Downlink Packet Access and High Speed Uplink Packet Access, that extends and improves the
performance of existing 3rd generation mobile telecommunication networks utilizing the WCDMA
protocols. A further improved 3GPP standard, Evolved HSPA, was released late in 2008 with
subsequent worldwide adoption beginning in 2010. The newer standard allows bit-rates
to reach as high as 337 Mbit/s in the downlink and 34 Mbit/s in the uplink. However, these
speeds are rarely achieved in practice.
Overview The first HSPA specifications supported increased
peak data rates of up to 14 Mbit/s in the downlink and 5.76 Mbit/s in the uplink. It
also reduced latency and provided up to five times more system capacity in the downlink
and up to twice as much system capacity in the uplink compared with original WCDMA protocol.
High Speed Downlink Packet Access
The first step required to upgrade WCDMA to HSPA is to improve the downlink by introducing
HSDPA. The improved downlink provides up to 14 Mbit/s with significantly reduced latency.
The improvement in speed and latency reduces the cost per bit and enhances support for
high-performance packet data applications. HSDPA is based on shared channel transmission
and its key features are shared channel and multi-code transmission, higher-order modulation,
short transmission time interval, fast link adaptation and scheduling along with fast
hybrid automatic repeat request. The upgrade to HSDPA is often just a software update for
most WCDMA networks, and as of May 2008 90 percent of WCDMA networks had been upgraded
to HSDPA. Voice calls are usually prioritized over data transfer. Singapore's three network
providers M1, StarHub and SingTel provide up to 28 Mbit/s throughout the entire island.
The Australian provider Telstra provides up to 14.4 Mbit/s nationwide and up to 42Mbit/s
in selected areas. The Croatian VIPnet network supports a downlink speed of 7.2 Mbit/s,
as does Rogers Wireless in Canada which also supports 21 Mbit/s in the Toronto area. In
South Korea, a nationwide 7.2 Mbit/s coverage is now established by SK Telecom and KTF.
In Hong Kong, PCCW, CSL and Hutchinson 3 provide 21 Mbit/s coverage and in India BPL, MTS
and Tata DoCoMo provide speed of 21.1 Mbit/s nationwide while Reliance ADAE provides speeds
up to 28.8 Mbit/s nationwide. Sri Lankan companies like Mobitel, Etisalat provides
up to 42 Mbit/s and Dialog, Airtel and Hutch provides 7.2 Mbit/s. In Nepal, HSPA is in
a rush. Ncell Currently Provides 42.2 Mbit/s and Nepal Telecom Provides 5.2 Mbit/s. HSPA
is Currently replaced by HSPA+ in Nepal. High Speed Uplink Packet Access
The second major step in the WCDMA upgrade process is to upgrade the uplink, which is
introduced in 3GPP Release 6. Upgrading to HSUPA is usually only a software update. Enhanced
Uplink adds a new transport channel to WCDMA, called the Enhanced Dedicated Channel. An
enhanced uplink creates opportunities for a number of new applications including VoIP,
uploading pictures and sending large e-mail messages. The enhanced uplink increases the
data rate, the capacity, and also reduces latency. The enhanced uplink features several
improvements similar to those of HSDPA, including multi-code transmission, short Transmission
Time Interval, fast scheduling and fast Hybrid Automatic Repeat reQuest.
In Singapore, Starhub announced a 1.9 Mbit/s HSUPA Service as part of its new MaxMobile
plan on 1 August 2007. In Finland, Elisa announced on 30 August 2007, 1.4 Mbit/s HSUPA to most
large cities with plans to add the service to its whole 3G network within months.. 3
Italia and Ericsson announced on 16 July 2008, the successful tests of HSUPA 5.8 Mbit/s
in the live network of 3 Italia. In Haiti, NATCOM, the former public company now operated
by Viettel from Vietnam, offers up to 7.2 Mbit/s nationwide.
Evolved High Speed Packet Access
Evolved HSPA is a wireless broadband standard defined in 3GPP release 7 and 8 of the WCDMA
specification. It provides extensions to the existing HSPA definitions and is therefore
backward-compatible all the way to the original Release 99 WCDMA network releases. Evolved
HSPA provides data rates up to 84 Mbit/s in the downlink and 10.8 Mbit/s in the uplink
with multiple input, multiple output technologies and higher order modulation. With Dual Cell
technology, these can be doubled. Since 2011, HSPA+ has been very widely deployed
amongst WCDMA operators with nearly 200 commitments. Dual-carrier HSDPA
Dual-Carrier HSDPA, part of 3GPP Release 8, is the natural evolution of HSPA by allowing
a user to connect to two cells at once, thereby theoretically doubling the connection speeds
for the user. An HSPA+ network can theoretically support up to 28 Mbit/s and 42 Mbit/s with
a single cell, although real speeds are far lower. Besides the throughput gain from doubling
the number of cells to be used, some diversity and joint scheduling gains can also be achieved.
Dual-cell can particularly improve the QoS for end users in poor radio reception where
they cannot benefit from the other WCDMA capacity improvements due to poor radio signal quality.
From Release 9 onwards it will be possible to use DC-HSDPA in combination with MIMO.
The support of MIMO in combination with DC-HSDPA will allow operators even more capacity improvements
within their network. Dual-carrier HSUPA
Similar enhancements as introduced with DC-HSDPA in the downlink for UMTS Release 8 are being
standardized for UMTS Release 9 in the uplink, called Dual-Cell HSUPA. applied to HSUPA UL
physical channels and DPCCH. The standardisation of Release 9 was completed in December 2009.
Multi-carrier HSPA The aggregation of more than two carriers
has been studied and 3GPP Release 11 is scheduled to include 4-carrier HSPA. The standard is
scheduled to be finalised in Q3 2012 and first chipsets supporting MC-HSPA in late
2013. Release 11 specifies 8-carrier HSPA allowed in non-contiguous bands with 4 × 4 MIMO
offering peak transfer rates up to 672 Mbit/s. See also
Broadband Internet access Global mobile Suppliers Association
Mobile broadband Mobile broadband modem
3GPP Long Term Evolution References
Further reading Martin Sauter: Communication Systems for the
Mobile Information Society, John Wiley, September 2006, ISBN 0-470-02676-6
External links GSMworld.com, Official HSPA website
Linkedin.com, Public HSPA Discussion Forum 3.5G drivin), ericsson.com
Dual carrier HSPA: DC-HSPA, DC-HSPDA, radio-electronics.com