Mobile Hardware and Software Components: A Comprehensive Guide

Mobile phones are intricate devices built from both hardware and software components that work together to enable seamless functionality. Hardware components include the processor, memory, display, battery, and camera, each playing a vital role in a phone’s performance, durability, and usability.

On the software side, the operating system (OS) and various applications provide the interface and capabilities that users experience daily. Understanding these components helps us appreciate how modern mobile phones deliver powerful, high-speed performance while maintaining portability and convenience.

Mobile Phone Hardware Components

Figure depicts gsm mobile phone block diagram.

Typically, hardware components of a mobile phone include:

• Display (LCD, touch screen)
• Keypad
• Microphone
• Speaker
• SIM card
• Battery
• USB port
• Antenna
• Memory unit (RAM, ROM)
• Camera
• CODEC
• RF part
• DAC/ADC
• Baseband part (L1/Layer1/physical layer) running on DSP
• Application/protocol layers running on CPU
• ON/OFF switch
• Bluetooth/GPS features

Mobile Phone RF Transceiver

As shown in the figure, every mobile phone will have an RF part which consists of an RF frequency up-converter and RF frequency down-converter.

For the GSM system, the up-converter converts the modulated baseband signal (I and Q) either at zero IF (Intermediate frequency) or some IF to RF frequency (890-915 MHz).

The RF down-converter converts the RF signal (935 to 960 MHz) to the baseband signal (I and Q).

For GSM, GMSK modulation is used. There are two approaches employed in GSM Mobile phone receiver, i.e., heterodyne or homodyne. The basic component used for frequency conversion is the RF mixer.

Mobile Phone Antenna and Tx/Rx SW (Switch)

The antenna is the metallic object which converts the electromagnetic signal to an electric signal and vice versa.

Commonly used antennas in mobile phones are of various types such as helix type, planar inverted F type, whip, or patch type.

Microstrip-based patch-type antennas are popular among mobile phones due to their size, easy integration on the PCB, and multi-frequency band of operation.

Today’s mobile phones support various GSM bands and also various technologies such as CDMA, LTE, WiMAX, and also WLAN, Bluetooth, and so on. In these scenarios, this type of patch antenna does the job.

Tx/Rx Switch: As there is only one antenna used for both transmit and receive at different times, the Tx/Rx Switch is used to connect both the Tx path and Rx path with the antenna at different times.

The Tx/Rx Switch is controlled automatically by DSP based on the GSM frame structure with respect to the physical slot allocated for that particular GSM mobile phone in both downlink and uplink.

For FDD systems, a diplexer is used in place of a switch which acts as a filter to separate various frequency bands.

Mobile Phone Baseband Part

This part basically converts voice/data to be carried over the GSM air interface to the I/Q baseband signal.

This is the core part which changes modem to modem for various air interface standards viz. CDMA, Wimax, LTE, HSPA, and more.

It is often named as the physical layer or Layer 1 or L1. It is ported usually on DSP (Digital Signal Processor) to meet the latency and power requirements of the mobile phone.

For Speech/audio, a codec is used to compress and decompress the signal to match the data rate to the frame it has to fit in. The CODEC converts speech at an 8 KHz sampling rate to a 13 kbps rate for the full-rate speech traffic channel.

To do this, RELP (Residually Excited Linear Predictive coder) speech coder is used which packs 260 bits in 20 ms duration to achieve a 13 kbps rate.

The baseband or physical layer will add redundant bits to enable error detection as well as error correction. Error detection is obtained with CRC and error correction with forward error correction techniques such as convolutional encoder (used at the transmit part) and viterbi decoder (used at the receive part).

Other than this, interleaving is done for the data of one burst which helps in spreading the error over the time hence helps the receiver de-interleave and decode the frame (consecutively data burst) correctly.

ADC and DAC

ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) are used to convert analog speech signals to digital signals and vice versa in the mobile handset.

At the Transmit path, the ADC converted digital signal is given to the speech coder.

There are various ADCs available, among them the popular one is sigma delta type.

AGC (Automatic Gain Control) and AFC (Automatic Frequency Control) are used in the receiver path to control gain and frequency. AGC helps maintain the working of DAC satisfactorily, as it keeps the signal within the dynamic range of DAC. AFC keeps the frequency error within a limit to achieve better receiver performance.

Mobile Phone Software | Protocol stack

Other than the physical layer there are other layers involved in the GSM mobile phone to make it work with the GSM network/base station.

The entire protocol stack is ported on the CPU of ARM or of any other type of processor.

Application layer

It also runs on the CPU. Various applications run in GSM mobile phones. It includes audio, video, and image/graphics applications. It supports various audio formats such as MP3, MP4, WAV, rm. JPEG image formats are usually available.

It supports video formats e.g., MPEG-1 to MPEG-5. Mobile phones support CIF, and QCIF video standard resolutions.

Mobile Phone OS (Operating System)

Mobile phone operating systems (OSs) are the software platforms that enable smartphones to perform a wide range of tasks, from running apps to managing system resources.

The two most popular mobile OSs are Android and iOS. Android, developed by Google, is an open-source platform used by various manufacturers like Samsung, Google, and Xiaomi, providing extensive customization options and compatibility with numerous hardware configurations.

Apple’s iOS, on the other hand, is a proprietary OS exclusive to iPhone devices, known for its seamless integration with Apple’s ecosystem and a focus on security and user experience.

Mobile OSs rely on powerful CPUs to handle complex processes, multitasking, and high-performance applications. Android devices typically run on CPUs like Qualcomm’s Snapdragon, Samsung’s Exynos, and MediaTek’s Dimensity series, all designed for optimized speed, graphics, and power efficiency. iPhones, meanwhile, run exclusively on Apple’s A-series Bionic chips, such as the A17 Bionic, which deliver industry-leading performance tailored to iOS.

These processors enable mobile OSs to provide smooth experiences in gaming, multimedia, and productivity tasks.

Battery

It is the only major source of power to make/to keep the mobile phone functional.

There are various types of batteries made of Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH), based on lithium, Li-ion, and so on.

The major factors for designers are to reduce battery size, last for more talk time, and increase battery life.

The battery comes usually with 3.6 or 3.7 voltage and 600mAh or 960 mAh ratings.

A Battery Charger is usually provided with the mobile phone to charge the mobile phone battery. The Battery charger is an AC to DC converter.

Connectivity

To make data transfer fast enough between the mobile phone and other computing devices (laptop, desktop, tablet) or between mobile and mobile, various technologies have evolved which include WLAN, Bluetooth, USB, etc.

GPS (global positioning system) is used for location assistance and will enable google maps to work efficiently.

Microphone and Speaker

Microphone: A microphone or mic converts air pressure variations (result of our speech) to an electrical signal to couple on the PCB for further processing. Usually, in mobile phones, mics of types condenser, dynamic, carbon, or ribbon are used.

Speaker: It converts the electrical signal to an audible signal (pressure vibrations) for human beings to hear. This is often coupled with an audio amplifier to get the required amplification of the audio signal.

It is also tied with a volume control circuit to change (increase or decrease) the amplitude of the audio signal.

Camera

Now-a-days with almost all the mobile phone camera feature is available for one to click pictures at various occasions. It is the major specification in increasing the cost of a mobile phone.

There are various mega pixel cameras for mobile phones available such as 12 mega pixels, 14 mega pixels, and even 41 mega pixels available in smartphones. This has become evident because of advancements in sensor technology. If one wants to buy a low-cost mobile phone, they usually go for a non-camera mobile phone.

Display and Keypad

Display: There are various display devices used in mobile phones such as LCD (liquid crystal display), TFT (Thin-film transistor) screen, OLED (organic light emitting diode), TFD (thin film diode), touch screen of capacitive and resistive type, etc.

Keypad: Earlier days keypad was simple matrix type keypad which contains numeric digits (0 to 9), alphabets (a to z), special characters and specific function keys. These has been designed for various applications such as accepting call,rejecting call,cursor movement(left,right,top,down) dialling number, typing name/sms/mms and so on.

Now-a-days keypad has been removed from the phone design and it has become part of mobile phone software. It pops on the display screen itself which can be operated by user using touch of a finger tip.

Conclusion

In today’s mobile phones, hardware and software components are meticulously designed to provide fast processing, vivid displays, long battery life, and extensive functionality. The integration of powerful hardware with optimized software enables mobile phones to serve as versatile tools for communication, productivity, and entertainment. As technology advances, mobile hardware and software will continue to evolve, pushing the boundaries of what’s possible in our pocket-sized devices.