Speed technologies in your phone explained

From 4G-faker HSPA+ to dual-core, dual-channel silicon

LG Optimus 2X

This article is brought to you in association with LG Optimus 2X

Today's smartphones feature some of the most advanced technology on the planet and they're getting smarter and faster all the time.

We're watching a technology race unfold as handsets evolve from 3G/HSDPA to 4G/LTE and from single-core processors to multi-core chips.

Time to slice through the mobile phone jargon and acronyms with a TechRadar knife…


When Three rolled out the UK's first 3G/UMTS network in 2003, it offered a serious upgrade from sluggish GPRS/EDGE data connectivity. Admittedly, 3G got off to a forgettable start with phones like the god-awful NEC e606. But it's now a standard feature on most new handsets, enabling faster downloads, music streaming and video chat.

Eight years on and 3G is now where GPRS/EDGE was before it. Faster technologies like HSPA+, WiMAX and Long Term Evolution (LTE) are queuing up to replace it, promising another jump in downlink performance. But don't hold your breath. The 4G spectrum auction won't take place until 2012 in the UK, so these new services won't be launched until 2013 at the earliest.


While we twiddle our thumbs waiting for next-generation 4G phone networks, High-Speed Downlink Packet Access (HSDPA) provides a handy speed-boost. Often called 3.5G or 3G+, the technology improves UMTS downloads.

Existing HSDPA deployments support 1.8, 3.6, 7.2 and 14.4Mbps downlink speeds. But again, take these numbers with a pinch of salt. You'll rarely get anywhere near the theoretical top-speeds.


As its name suggests, High-Speed Uplink Packet Access lights a fire under conventional 3G upload speeds and rockets them from 384Kbps to 5.76Mbps. Unfortunately, it's not available everywhere. For example, while HSDPA coverage extends right across the UK, HSUPA isn't as widespread.


High Speed Packet Access is a next-gen mix of High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA). It's a catch-all term that defines any network that uses both 3.5G technologies to boost network speeds to 14.4Mbps (downlink) and 5.76Mbps (uplink).


Evolved HSPA or HSPA+ is being badged as 4G in the US by T-Mobile and AT&T but, technically speaking, it's still a 3G standard. Support for HSPA+ is just starting to appear in next-gen phones like the Samsung Galaxy S II and the Motorola Atrix 4G.

Downlink speeds of up to 42Mbps can be achieved thanks to the same MIMO technologies that have revolutionised Wi-Fi. Future dual carrier or dual cell technologies will effective double this, hence the 4G tag.


Long Term Evolution is a true 4G network solution. Using TCP/IP protocols and OFDM (Orthoganal Frequency Division Multiplexing), downlink speeds in excess of 100Mbps should be possible. In a Nokia trial, LTE set a cellular data record of 173Mbps in 2008.

But hold your horses… Real-world tests on the Verizon network in the US suggest that LTE delivers an average downlink speed of between 8-10Mbps. Of course, that's still 3-4 times faster than 3G.


Based on the 802.16e wireless networking standard, WiMAX offers a 4G alternative to Long Term Evolution (LTE). The current version of the technology (802.16e) supports downlink speeds of up to 40Mbps, which compares well to HSPA+. The next version of WiMAX (802.16m) could boost this to a more impressive 1Gbps. Sprint has rolled out a WiMAX network in the US.


A CPU with two processing cores.


System on a chip. The process of integrating the CPU and GPU into a single processor die.


Look closely enough and you'll see the ARM A9 MPCore architecture everywhere: NVidia's Tegra platform; Apple's A5 (which appears in the iPad 2); Samsung's Exynos; and the OMAP4 chips designed by Texas Instruments. While current implementations use dual-core designs, the A9 specification can support up to 4 cores and speeds between 800MHz and 2GHz.

Nvidia Tegra

We got our first taste of a dual-core mobile phone in 2010 in the shape of LG's Optimus 2X. But the Nvidia Tegra 250 silicon inside it actually got its first outing a year earlier in the US-only release of the Zune HD.

Making both fly is a system-on-a-chip that blends a dual-core ARM Cortex A9 CPU with an Ultra Low Power (ULP) GeForce GPU. You'll now find NVidia's handiwork in everything from the Motorola Atrix to the Samsung Galaxy Tab 10.1.

Samsung Exynos

Formerly known by its codename, Orion, you'll find the brand-spanking new Exynos processor inside the fantastic Samsung Galaxy S II. It pairs ARM's dual-core A9 CPU with ARM's Mali-400 GPU for some great performance. The name is a mish-mash of two Greek words – 'exypnos' (smart) and 'prasinos' (green). Hmm. We preferred the codename…

Apple A5

As the follow-up to the single-core A4 chip that powers the iPhone 4, the superior A5 uses ARM's 1GHz dual-core A9 silicon in partnership with a dual-corePowerVR SGX543MP2GPU. The A5 debuted in the iPad 2 and is expected to power the iPhone 5.


This next-gen Texas Instruments chip is less popular than its rivals, but you'll be able to spot it in the Blackberry PlayBook and the LG Optimus 3D. Like the other chips in this list, it puts its faith in ARM's dual-core A9 CPU and pairs it with a PowerVR SGX540 GPU. Crucially, it delivers a speed boost via its dual-channel LPDDR2 memory controller.


Think the ARM A9 designs we've mentioned here are fast? There's already a successor to the A9 called the A15 (codenamed 'Eagle'), which will feature 1-4 cores, hit clock speeds up to 2.5GHz and support up to 1TB of memory.

"It is expected that mobile configurations of the Cortex-A15 MPCore processor will deliver over five times the performance of today's advanced smartphones," claims ARM. In a word: 'wow'. Expect to see the first A15 silicon in TI's forthcoming OMAP5 processor and then everywhere else in 2012/2013.

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