3G Technology Guide

HSPA &HSDPA Explained

The technology inside the GlobeSurfer range. HSDPA and HSPA+ were the 3G standards that turned mobile broadband from a corporate curiosity into a genuine home connectivity option.


The Basics

What Was 3G?

3G mobile networks launched in the UK with Three in March 2003. The underlying standard was UMTS (Universal Mobile Telecommunications System), built on WCDMA radio access. Early UMTS delivered around 384Kbps - faster than dial-up, slower than ADSL. The step change came with HSDPA.

HSDPA - High Speed Downlink Packet Access

HSDPA was a software upgrade to UMTS - no new towers required. It shortened the transmission time interval from 10ms to 2ms and added adaptive modulation and coding, delivering a five-fold throughput improvement on the same spectrum. The GlobeSurfer III used HSDPA Category 8 - 7.2Mbps theoretical. In UK conditions on Three or Vodafone, 2-4Mbps was typical in 2007 - better than average UK ADSL at the time.

HSPA+ - The Final Evolution

HSPA+ used 64-QAM modulation and MIMO techniques to push speeds to 21Mbps and with dual-carrier (DC-HSDPA) to 42Mbps. This is the technology inside the GlobeSurfer III+. Some operators marketed HSPA+ as "3.75G" - at 8-15Mbps real-world it was genuinely competitive with ADSL2+. For current multi-network SIM cards that use these bands as fallback, see multinetworksim.com.

3G Standards Hierarchy

UMTS / W-CDMAUp to 384 Kbps
HSDPA Cat 53.6 Mbps down
HSDPA Cat 87.2 Mbps (GlobeSurfer III)
HSUPA Cat 65.76 Mbps up
HSPA+ Cat 1421.1 Mbps (GlobeSurfer III+)
HSPA+ DC Cat 2442.2 Mbps down

UK HSPA Frequencies

Band 1 (B1)2100 MHz - primary 3G
Band 8 (B8)900 MHz - rural coverage
Channel Width5 MHz per carrier
DuplexFDD

What Replaced HSPA?

LTE (4G) launched in the UK with EE in October 2012 using OFDMA rather than WCDMA - fundamentally different radio access delivering 50-150Mbps from day one. See our 4G LTE guide.