5 E
`
`volution of Mobile Devices
`and Operating Systems
`
`Introduction
`5.1
`Mobile devices with wireless network interfaces have gone through a tremendous evolu-
`tion in recent years. From around 1992–2002, the main development goal was to make
`these devices smaller. While during that time the form factor of phones shrank con-
`siderably, voice telephony and SMS texting remained the main applications and overall
`functionality changed very little. By around 2002, technology had developed to a point
`where it became impractical to shrink phones any further from a usability point of view.
`The Panasonic GD55 is one of the smallest mobile phones ever produced, with a weight
`of just 65 g, and is smaller than a credit card [1]. To demonstrate the evolution that had
`taken place in only 10 years, Figure 5.1 shows one of the first GSM phones, the Siemens
`P1 of 1992.
`Once devices could not shrink, any further development has concentrated on adding
`additional multimedia functionality to mobile devices. At first, black and white displays
`were replaced by color displays, and display resolutions quickly rose from 100 × 64 pixels
`over 640 × 360 pixels to very high resolutions such as 960 × 640 pixels on 3.5–4 in.
`screens. Pixels thus have become so small that individual pixels cannot be seen anymore
`at a normal viewing distance. High-resolution color displays are a prerequisite for all
`other functionalities that have been added to mobile phones since. These functionalities
`include cameras, multimedia mobile e-mail and web browsing, video streaming, and social
`network interaction, just to name a few.
`High-resolution color displays, high processing power with low power consumption and
`an increase in available memory and storage space have given rise to a number of wireless
`mobile device categories, whose purpose and range of functionalities has extended and
`shifted over the years. Today, the most important ones are:
`• Smartphones — a smartphone can be defined as a combination of a mobile phone,
`what was formerly referred to as a (non-connected) Personal Digital Assistant (PDA),
`and an extension of previously desktop-based social media web services to the mobile
`world. Smartphones now usually include a high-resolution camera for taking pictures
`and videos, GPS and compass functionality as well as motion sensors, and various
`
`3G, 4G and Beyond–Bringing Networks, Devices and the Web Together, Second Edition. Martin Sauter.
`© 2013 John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd.
`
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`network interfaces such as high-speed cellular interfaces, Bluetooth, and Wi-Fi. These
`devices are usually shaped like mobile phones, but are slightly bigger to accommodate
`a larger screen and additional hardware.
`• Pads/tablets — over many years, the computing industry has been trying to scale down
`desktop PCs and make them mobile and portable by adding a touch-sensitive display
`and adapting the operating system to make its operation touch friendly. This device cat-
`egory did not become successful; however, until screen resolution, power consumption,
`and battery capacity enhancements were combined with the idea of adapting the user
`interface (UI) of touch-based smartphones for this type of device rather than using a
`desktop UI. With sufficient processing power for full-screen web browsers with similar
`functionality as is found in desktop and notebook PCs and web services adapted for
`touch-based input, tablets now fulfill many functionalities that were formerly only used
`with either a smartphone while being underway or with a PC when being at a desk.
`With cellular and Wi-Fi connectivity, tablets have become an ideal tool for multimedia
`consumption and for staying connected with friends via email, instant messaging, and
`web-based social networks without the need to sit at a desk.
`• Netbooks — formerly also referred to as ultramobile PCs, the idea behind this product
`category is to reduce the size of a typical notebook while keeping its main characteristics
`such as the use of a desktop operating system, near full size keyboard, and only a
`slightly reduced display resolution. Netbooks have a typical screen size of 10–11 in.
`and a power-efficient CPU, and the mainboard design enables long battery operation
`times at the expense of processing power. The first models were not very successful
`as storage and processor capacities were too small for the requirements of Microsoft’s
`Windows operating system. Asus was the first company that developed devices for this
`category [2]. Instead of using Windows, Asus initially used a Linux-based operating
`system, which is less resource hungry. Later versions then became powerful enough
`to host Microsoft’s Windows operating system. Even though those devices have been
`available for several years, the main means for connectivity is still the Wi-Fi interface.
`Built-in cellular connectivity can only be found in a few models. This is mostly because
`of the additional price of the cellular network card, which would significantly increase
`the typical sales price of ¤250–300 or less. It has thus become quite common to use
`netbooks and notebooks with a cellular modem via the Universal Serial Bus (USB)
`port, often referred to as a “3G dongle,” or via Wi-Fi tethering to a mobile phone that
`acts as a Wi-Fi to cellular network bridge to the Internet. Today, netbooks compete
`with devices from the tablet category, and interest in them has diminished to some
`extent. While tablets are ideal for information and media consumption away from the
`desk, the strength of netbooks is their full keyboard integration and desktop operating
`system, which makes them preferable for many creative tasks that require text input.
`A significant part of this book, for example, was written on a netbook.
`• Ultrabooks — devices in this category are usually slightly larger than netbooks with a
`typical screen size of 13 in. but are significantly thinner and still very light in weight
`without compromising on battery operation time and processing capacity. This comes
`at the expense of a significantly higher sales price than netbooks, usually in the order
`of ¤800–1200. As with netbooks, USB modems or Wi-Fi tethering is used to connect
`to the Internet when not at home or at the office.
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`• Wireless computing equipment — a well-established trend for home and office net-
`works is to untether computer equipment such as printers and hard drives (or Network
`Attached Storage (NAS)) using Wi-Fi. With Wi-Fi chips having become a commod-
`ity, the additional price for consumers has dropped significantly and such devices are
`becoming more and more popular. This device category is different from those pre-
`viously mentioned because the aim of equipping them with wireless interfaces is not
`mobility but to reduce the amount of cables in home and office environments. A further
`advantage of having wireless access to such devices is that it also makes them usable
`from the mobile devices mentioned above.
`
`Most of the today’s connected devices except netbooks and ultrabooks are based on a
`chip with a processor design from ARM [3]. Although many companies such as Texas
`Instruments, Marvell, ST-Ericsson, and Qualcomm design and manufacture chips for small
`devices, most are based on a CPU core licensed from ARM. On the desktop, Intel’s x86
`design dominates in a similar way. With both architectures now targeting sophisticated
`mobile devices, these two worlds are about to collide.
`
`5.1.1 The ARM Architecture
`The ARM design was initially targeted at ultralow-power embedded devices. As technol-
`ogy evolved so did ARM’s processor design and it is estimated that an ARM processor
`
`Figure 5.1 The Siemens P1, one of the first GSM telephones in 1992.
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`core is used in 95% of mid- to high-end mobile devices today [4]. The current ARM-
`Cortex A9 and A15 platforms used in high-end smartphones and tablets is the result of a
`bottom-up approach, as it has evolved from earlier platforms for simpler devices. Today,
`all mobile devices of mobile giants such as Sony, Nokia, LG, Samsung, and Apple are
`ARM powered. This shows the flexibility of the ARM architecture since requirements
`range from voice telephony with very low power requirements to multimedia devices that
`trade in a higher power consumption for higher processing capabilities.
`Today, a lot of operating systems support the ARM architecture. Examples are fully
`embedded operating systems of low-end to mid-range mobile devices to operating systems
`for smartphones such as Symbian and Windows Phone. In addition, ARM processors are
`also used with operating systems that were initially developed for desktop computers
`such as Linux and Windows 8. Linux is a relatively new operating system for mobile
`devices as the first mass market device based on Linux was only shipped in 2008 as part
`of Google’s Android operating system [5]. The advantage of using Linux as an operating
`system for mobile devices is that a significant amount of code can be shared between the
`desktop and the mobile version of the operating system, as relatively little code directly
`deals with the differences of the x86 architecture found in the PC world and the ARM
`architecture found on mobile devices.
`It should also be noted at this point that unlike companies such as Intel or AMD, ARM
`does not produce processor chips themselves. Instead, ARM licenses its processor designs
`to other companies such as Qualcomm, Samsung, Mediatek, Marvell, Texas Instruments,
`and many others, which then include the processor designs in their own chip designs.
`Companies such as Intel, however, go one step further and also design the chips that
`include their processor designs.
`ARM offers several types of licenses. The most basic license only offers the logic of
`a function block such as the CPU, a bus system, or the graphics chip for use with a chip
`design program such as Verilog. This is referred to as a soft-macro [6]. The licensees then
`use those function blocks with self-designed additional circuitry or function blocks bought
`from other companies and create a physical chip implementation, which is optimized for
`a certain production process, performance, power consumption, and die size. ARM also
`offers licenses that already include those steps. Such function blocks are then referred to
`as hard-macros. And finally, ARM also licenses the ARM architecture itself and allows
`companies to modify, design, and optimize their own CPU cores and other function blocks.
`ARM-compatible software still runs without modification on such modified processors but
`licensees have the opportunity to make enhancements to the architecture independently
`of ARM. Marvell and Qualcomm are companies that design their own ARM processors
`instead of buying a finished design.
`
`5.1.2 The x86 Architecture for Mobile Devices
`Intel is at the other end of the spectrum and is keen to play a major role in the mobile
`space with its x86 processor architecture. A few years ago Intel tried to get a foothold
`in the mobile space by licensing ARM technology and building a product line around
`that architecture. In the meantime, however, Intel has abandoned this approach and has
`been refining their x86 architecture for low power consumption and size for several years.
`In 2012, the size, processing speed, and power consumption of the chipset was for the
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`
`first time balanced enough for a smartphone-sized device. First prototypes were shown
`running an x86 version of Android on a form factor smartphone [7], and commercial
`products based on this design appeared shortly afterward on the market. This rather late
`competition to ARM’s dominance in the mobile space is the result of Intel’s approach that
`is directly the opposite of ARM’s as they had to streamline a powerful desktop processor
`architecture for smaller devices.
`Using an x86 platform for mobile devices has the advantage that even fewer adap-
`tations are required for operating systems such as Linux and Windows to use them on
`mobile devices compared to the ARM approach described above. In the case of Android,
`most applications are executed in a virtual machine based in Java and only compiled to
`native code at runtime, so the same executable runs without modification or the need for
`recompilation on both CPU architectures.
`At the time of publication, Intel and ARM have come quite close in terms of perfor-
`mance and power consumption and the two architectures are now competing for use in
`high-end mobile devices.
`
`5.1.3 Changing Worlds: Android on x86, Windows on ARM
`The significant advances in the mobile space in recent years and Intel’s inability to
`establish themselves with their x86 architecture in the mobile domain over many years
`have also had consequences for traditional alliances formed in the PC space.
`Over many years, Microsoft has only developed its Windows desktop operating system
`for x86-based architectures. With tablet devices having become attractive to end users
`starting from around 2011 and no company in sight to deliver power-efficient x86-based
`processors, Microsoft had to choose between extending their relatively novel Windows
`Phone operating system based on ARM to tablets or to scale down their Windows desktop
`operating system and adapt it to the ARM architecture. Microsoft chose to do the latter
`and has developed a new version of the Windows desktop operating system that can also
`be run on ARM-based devices such as tablets. Such a move would have been impossible
`only a few years earlier and demonstrates the significant increase in processing power
`that was achieved on the formerly low-cost low-processing power ARM architecture.
`A new UI was developed based on the Windows Phone smartphone UI to complement
`the existing desktop UI in an attempt to integrate the mobile and desktop computing worlds
`in a single Windows operating system. This demonstrates how the rise in computing
`power in mobile devices also has an effect on desktop computing and how the industry
`is integrating the formerly disparate worlds of low-power mobile devices and high-power
`desktop computing into a single space.
`New alliances are also formed on the x86 side with Android having been ported to
`the x86 architecture, as described in Section 5.1.2. This in effect enables Intel and other
`companies producing x86-based processors to move into the high-growth smartphone
`market, which further blurs the line between mobile and desktop computing.
`A further positive effect of the competition between the ARM and the x86 architecture
`is likely to be further accelerated innovation and falling prices as mobile device manufac-
`turers can now choose between two camps with each one trying to stay ahead of the other
`with further innovations in the areas of power consumption, processing speed, graphical
`capabilities, and integration of other components into a single chip.
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`5.1.4 From Hardware to Software
`The following sections now take a look at how mobile device hardware has evolved over
`recent years and give an introduction to both hardware architectures mentioned above. Dif-
`ferent parts of the world use different frequency ranges for wireless communication. This
`chapter therefore takes a look at the global situation and describes the impact on mobile
`hardware design and global usability of devices. Adding a Wi-Fi interface to mobile
`devices has been another important step in the evolution of wireless communication and
`this chapter will discuss the profound impacts of this step on networks and applications.
`Finally, this chapter takes a look at the Android operating system for mobile devices.
`
`5.2 The System Architecture for Voice-Optimized Devices
`In the entry level segment, mobile phones are sold today both in developed markets and
`emerging economies that are optimized for voice communication. While the functionality
`of such phones has not changed much in the past decade, prices have been on a steady
`decline due to much higher production volumes and reducing the number of required
`chips and electronic components. This is referred to in the industry as reducing the Bill
`of Materials (BOMs). Figure 5.2 shows a block diagram of a typical voice-optimized
`mobile phone computing platform which is offered by many companies. The example in
`this book is based on Freescale Semiconductor’s GSM i.200-22 hardware platform [8],
`which is optimized for voice communication and even excludes functionalities such as
`basic General Packet Radio Service (GPRS).
`
`Power
`amplifier IC
`
`Front end IC
`(receiver,
`amplifier,
`mixers)
`
`Baseband
`processor
`chip
`
`FLASH RAM
`
`SIM card
`Display
`Keypad
`
`Data interfaces
`(e.g., RS-232, USB)
`
`Charger
`
`Battery
`
`External
`interfaces
`+ Power
`Management
`
`Loudspeaker
`Microphone
`Vibrator
`
`Figure 5.2 Block diagram of a voice-optimized mobile phone hardware platform. (Reproduced
`from Communication Systems for the Mobile Information Society, Martin Sauter, 2006, John Wiley
`and Sons, Ltd. Ref. [9].)
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`It contains a 32-bit
`is the baseband processor chip.
`this chipset
`The core of
`ARM7TDMI-S RISC (Reduced Instruction Set Computer) microprocessor but can be
`used with a 16- and 32-bit instruction set. While operations that can be performed with
`the 16-bit instruction set are not as versatile, only half the memory space is required for
`code compared with 32-bit instructions. Especially in memory-limited devices such as
`basic mobile phones, this is a big advantage. It is also possible to mix 16- and 32-bit
`instructions, which enables the software developers to compile their code into 16-bit
`instructions and profile-specific portions of the software by hand to use 32-bit instructions
`where more performance is required. The maximum clock speed of the ARM processor
`used in this chipset is 52 MHz. This is very low compared with processor speeds of
`2 GHz and beyond used in desktop systems today, but sufficient for this application.
`For more sophisticated devices more processing power is required. As will be discussed
`below, ARM thus offers several processor families and multimedia devices use ARM
`processor types that offer far better performance at the expense of higher production
`costs and power consumption. According to [10], power consumption at 52 MHz is
`between 1.5 and 3 mW. This is at least three orders of magnitude less than the power
`requirements for notebook processors.
`In addition, the baseband chip contains a Digital Signal Processor (DSP) of Motorola’s
`56x family, which is clocked at 130 MHz. DSP microprocessors are optimized for mathe-
`matical operations and run software which is usually designed for specific tasks. Figure 5.3
`shows how the RISC CPU and the DSP are used in combination in a mobile phone.
`The DSP chip is responsible for decoding the received signal from the network and for
`encoding and decoding the voice signal. There are two main advantages of performing
`these tasks on the DSP and not on the main processor:
`
`DSP
`
`RISC
`
`Inter-
`leaver
`
`Cipherer
`
`Channel
`coder
`
`Signal
`decoding
`
`De-
`cipherer
`
`Deinter-
`leaver
`
`Channel
`decoder
`
`Speech
`encoder
`
`Speech
`decoder
`
`MMI
`
`GSM/GRPS
`control
`
`User
`programs
`
`External
`interfaces
`
`Operating system
`
`RS-232,
`USB
`
`Figure 5.3 Work split for voice telephony in a mobile phone. (Reproduced from Communica-
`tion Systems for the Mobile Information Society, Martin Sauter, 2006, John Wiley and Sons, Ltd.
`Ref. [9].)
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`• A DSP has an optimized instruction set for mathematical operations required for dealing
`with codecs and decoding analog radio signals that have been digitized by an analog-
`to-digital converter.
`• Encoding and decoding external signals is a continuous process and must not be inter-
`rupted by other activities such as reacting to user input or updating the display.
`
`A typical voice call is treated by the baseband chip as follows:
`• The analog input signal from the microphone is digitized and sent to the DSP chip.
`• The DSP applies speech coding and forwards the data to the ARM RISC CPU.
`• The ARM processor then packetizes the data stream, adds redundancy to the data
`(channel coding), changes the order of the bits so block errors can be more easily
`corrected on the other end (interleaving), encrypts the result and then sends the packet
`over the air interface.
`
`In the reverse direction, the same actions are performed in the reverse order. In addition,
`the DSP performs signal decoding. This is a complicated task since the signal sent by
`the base station is usually distorted by interference. To counter these effects, packets
`contain training bits (in the case of GSM) that are set to predefined values [9]. These
`are used by the DSP to build a mathematical model of how the signal was distorted. The
`mathematical model is then applied to the user data around the training bits to decrease
`the transmission error rate.
`In addition to the tasks above, the ARM CPU is responsible for interaction with the
`user (keyboard, display), to execute user programs such as Java applications, and to
`communicate with external devices (e.g., a computer) via interfaces such as USB. As all
`of these tasks have to run in parallel; a multitasking operating system is required that is
`able to give precedence to repetitive actions concerning communication with the network
`and assign the remaining time to less time critical tasks.
`For executing programs, about 250 kb of RAM is typically available on the base-
`band processor chip. In addition, about 1.7 Mb of nonvolatile memory (ROM, Read Only
`Memory) is available. If more memory is required, the chipset offers an external memory
`interface that can be used to connect additional RAM and ROM (e.g., flash memory).
`A 225-pin multiarray ball grid array connects the baseband chip via a 13 × 13 mm
`connection field to the other components of the device (cf. Figure 5.2). Other important
`components of the baseband chip are the module to access the Subscriber Identity Module
`(SIM) card and a display module for a monochrome or color display.
`In addition to the digital processing functionality of the baseband chip, other analog
`components such as power amplifiers, signal modulators, and functionalities to convert
`and control power for the device are required. These are implemented in separate chips
`as analog functionalities require a different manufacturing technology from the purely
`digital functions of the baseband chip.
`
`5.3 The System Architecture for Multimedia Devices
`The design intent for a voice centric mobile device chip set is to strip down the function-
`ality to the bare minimum to reduce the price as much as possible. For high-end wireless
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`mobile multimedia devices, however, the aim is to include as many functions as possible
`in the chipset. At the same time the device must consume as little power as possible in
`idle mode in order to achieve acceptable standby times. The chipset has to find a balance
`between power efficiency and performance while the user interacts with the device.
`There are three major building blocks of a high-end mobile chipset today. The first is
`the application processor unit, which usually consists of one or more CPU cores usually
`based on a 32-bit ARM architecture. Especially with the ARM Cortex CPU architecture
`introduced in 2005, ARM has increased performance by introducing a superscalar design
`that increases the number of execution units a machine instruction passes during its
`execution. This way, several machine instructions can be processed simultaneously as each
`can be in a different stage of execution. According to ARM, this increases the performance
`by a factor of 2–3 compared with the previous ARM processor generation at the same
`clock frequency. Performance gains for audio and video decoding are achieved with an
`extension referred to as NEON that allows application of the same operation with a single
`instruction to several variables simultaneously. This is used, for example, by Android’s
`WebM library to decode this type of video format [11]. Another feature now prevalent in
`mobile CPUs is a floating point unit to perform non-integer calculations in hardware.
`After many years of refinement, Intel presented a design to enter the mobile chipset
`domain with its x86 architecture as well. Its platform, which is referred to as “Medfield,”
`seems for the first time be able to compete with the ARM design. A comparison between
`“Medfield” and current high-end ARM designs such as the ARM-Cortex-A9 and A15 can
`be found in [12]. In addition, Intel has ported the popular Android operating system to its
`x86 CPUs as well, which significantly helps to make future x86 platforms popular in the
`mobile domain if power consumption and processing speed develop along similar lines
`as those of the ARM architecture.
`The second major building block of a chipset is the graphics processing unit (GPU).
`This processing unit is specifically designed to efficiently handle 2D and 3D graphical
`operations and effects. The calculations required for rendering of web pages and graphical
`effects such as scrolling a web page and zooming into specific parts, blending screens
`when changing from one application to another, and rotating the screen when the user
`changes the orientation of the device are mostly performed in the GPU. Unlike CPUs,
`which are optimized for sequential program streams, the GPU is optimized to perform
`many similar operations that are not dependent on each other in parallel. The general
`functioning of a mobile GPU is the same as that of a GPU in the PC world but its power
`and processing capabilities are scaled down to adapt to the limited power availability on
`mobile platforms as well as the limitations imposed by passive (i.e., fan-less) cooling.
`Today, there are several companies whose GPUs are commonly used in practice. ARM
`has designed its own GPU, which it has named “Mali.” Nvidia, initially a graphics card
`manufacturer in the PC domain, has also developed a mobile GPU family, which it uses as
`part of its “Tegra” line of integrated chips for mobile devices. Imagination Technologies
`“PowerVR” is a division specifically focusing on mobile device GPUs, and its designs are
`also commonly found in mobile chipsets, with both ARM and Intel CPUs. And finally,
`Qualcomm also has its own GPU design referred to as “Adreno,” which is integrated into
`their line of “Snapdragon” chipsets. While ARM CPUs from different manufacturers all
`share the same instruction set, this is not the case for GPUs. To make application programs
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`compatible with different GPUs, a standardized Application Programming Interface (API)
`is required. This is discussed in more detail in Section 5.4.
`The third major building block in a mobile device is the cellular modem, sometimes
`also referred to as the “baseband” processor. It includes all digital components required
`to communicate with a cellular network. Analog parts such as power amplifiers, filters,
`and up- and downlink signal multiplexers are separate components on the motherboard
`as a different manufacturing process is required for such components. The baseband
`processor usually consists of an ARM-based processor and additional signal processing
`components such as a DSP, as described above for voice-optimized devices. While such
`low-end devices usually only include a GSM modem, baseband processors have signifi-
`cantly grown in complexity and processing power requirements as they now also include
`software and hardware to process much more complex radio signals than those of GSM,
`such as, for example, High-speed Packet Access (HSPA) and Long Term Evolution (LTE)
`(cf. Chapter 2). The baseband processor has its own operating system and communicates
`via a high-speed (HS) serial connection with the application processor unit on which
`operating systems such as Android, iOS, Symbian, Windows Phone, and so on are exe-
`cuted. The serial connection over which user data and modem commands are exchanged
`makes the baseband processor completely independent from the application processor
`block. When operating systems such as Android are used on the application processor, a
`modem driver software module simulates several serial connections, typically one for user
`data and one for modem control commands and feedback messages. Modem commands
`are, for example, the establishment of an Internet Protocol (IP) connection, and feedback
`messages contain information about signal strength and other frequently required network
`parameters. From a mobile operating system point of view, the cellular modem is thus
`used in a very similar way as a cellular USB dongle connected to a PC and allows the
`mobile operating system to be easily adapted to different baseband processor implemen-
`tations as the cellular modem driver module is the only piece of software affected when
`using different modems. Baseband processors are developed by several companies such
`as Qualcomm, ST-Ericsson, Marvell, Renesas, and Nvidia.
`In the past, baseband processor, application processor, and graphics processor could
`often be found in dedicated chips. An example is the Nokia N8 that was released in 2010.
`It was built with a dedicated baseband processor chip of Texas Instruments, a dedicated
`application processor chip by Samsung based on an ARM11 core, a predecessor of the cur-
`rent ARM-Cortex platform, and a Broadcom graphics 3D processor chip. There is a strong
`trend, however, to combine all three components on a single System on a Chip (SoC)
`to save cost, reduce power consumption, and shrink the overall size of the circuit board.
`Table 5.1 shows examples of fully integrated systems on a chip and their manufacturers.
`It is interesting to note that none of the companies listed in the table develop complete
`mobile devices themselves and also do not develop other components required in a device
`such as touch screens, displays, batteries, casings, the scratch-resistant glass, camera
`modules, and so on. In other words, a mobile device contains components from many
`different manufacturers and the company owning a device and whose logo appears on
`it is mainly acting as an integrator of the different hardware and software components.
`When operating systems such as Android and Windows Phone are used, the companies
`are not even the developer of the operating system software, as that is again done by
`different companies such as Google and Microsoft.
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`Table 5.1 Examples of all-in-one system on chip manufacturers
`
`Manufacturer
`
`Platform name
`
`CPU
`
`GPU
`
`Baseband modem
`
`Qualcomm [13]
`
`Snapdragon
`
`ST-Ericsson [14, 15] NovaThor
`
`ARM, Qualcomm
`design, “Scorpion,”
`“Krait”
`ARM Cortex-A9
`
`Renesas [16]
`Nvidia [17]
`Mediatek [18]
`Intel [12]
`
`Renesas
`Tegra
`Mediatek
`Atom
`
`ARM Cortex-A9
`ARM Cortex A9
`ARM-Cortex-A9
`x86
`
`Qualcomm
`“Adreno”
`
`Qualcomm
`
`PowerVR and
`ARM “Mali”
`PowerVR
`ULP GeForce
`PowerVR
`PowerVR
`
`ST-Ericsson
`
`Renesas
`Nvidia (Icera)
`Mediatek
`Intel (Infineon)
`
`While CPU, GPU, and baseband modem are the most important components of a
`mobile chipset, they are by no means the only ones. A modern SoC has a variety of other
`special hardware units, which are either integrated into the SoC itself or are placed on the
`circuit board in chips of their own. An example of a possible configuration is shown in
`Figure 5.4. The example SoC contains two application processor CPUs, typically driven
`at clock rates of around 1.5 GHz today, the GPU, and the baseband processor on the main
`chip as discussed earlier.
`
`Cellular
`analog RF
`circuitry
`
`Wi-Fi
`bluetooth
`FM radio
`
`Motion
`sensor
`
`Flash
`memory
`
`SDRAM
`
`Camera
`module
`
`Baseband
`processor
`
`GPU
`
`ARM
`CPU
`
`ARM
`CPU
`
`Image
`processor
`
`Video
`en/decoder
`
`Shared memory controller
`
`Timers, interrupts, mailbox
`
`Front
`camera
`
`Battery charger
`
`Battery
`
`Voice codecs
`
`Microphone
`speaker
`
`USB transceiver
`
`USB port
`
`Keypad ctrl.
`
`Keypad
`
`GPS
`
`Secure ROM
`
`SoC
`
`SD card
`reader
`
`TV out
`(HDMI)
`
`TFT / OLED
`display
`
`Touch
`screen ctrl.
`
`Analog and
`power
`management
`chip
`
`Figure 5.4 Block diagram of a multimedia chipset for a mobile device.
`
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`3G, 4G and Beyond–Bringing Networks, Devices and the Web Together
`
`In addition, the SoC in this example contains an image processor unit that is used for
`processing the input stream delivered from external camera modules. Camera sensors with
`res