Week 3 - Mobile Device Components - The Basics Flashcards
What might you be able to find out about a device just by looking at it?
- Make, model, type (can look up spec on manufacturer websites & other open source)
- condition (any damage and unquie markings / damage or tarnished ports)
- age
- capabilities
- original service provider
- network type (GSM / 3G / 4G / 5G D2D etc)
What are the 3 main storage components that can exist on a GSM device?
- Mobile Device Internal Memory. Commonly large amount of data here.
- SIM / UICC (Subscriber Identity Module / Universal Intergrated Circuit Card)
Previously on old devices this was main storage area for user data because device memory was small & expensive. - Memory Card. Not all have this. May be micro SD or SD card.
Summarise the key points about Mobile Device Internal Memory
FLASH memory (2 types that can be used NAND and NOR)
FLASH memory is:
- Electrically erasible.
- Non volatile
- Varies in capacity
- Low power consumption
- Small physical dimensions
- Resiliant & robust storage capacity against physical & environment conditions.
- Available in different packages e.g TSOP (Thin Small Outline Packages or BGA ( Ball Grid Array)
- Uses different technologies (eMMC embedded Multi Media Card / eMCP embedded MultiChip Package / UFS universal Flash Storage
Summarise the key features of a SIM or UICC
Subscriber Identity Module / Universal Integrated Circuit Card
- Contains both user data and network specific data.
- User data can be PIN or PUK locked if SIM protection is enabled. Need PIN or PUK to access it.
- Limited memory capacity depending on SIM generation
- Can be standard size SIM, mini SIM, Micro SIM or Nano SIM (backward compatible)
- An embedded SIM also exists (instead of removeable) - used for machine to machine (end to end) communications. has featured in Amazon Kindle and other devices.
Summarise the key features of removeable media for mobile devices
- Capacity varies from Mb to multiple Gbs
- Typically a FAT file system format (so examination is relatively straightforward)
- Media can be locked / encrypted to the mobile device
- Can contain non standard mobile device data but typically contains larger data like media content or backup data from apps.
- Micro SD is the most common type
- Sony use M2 card
- Can be integrated within the device storage or as an add on dependin gon the device.
Summarise the key points about Operating Systems
Broad categories include:
- low end proprietary (manufacturer specific). Low cost. Can be problematic to examine. No standard.
- Sybian
- Windows Phone (MS)
- Blackberry
- iOS (proprietry to Apple products)
- Android (open source)
- Harmony /HongMeng
Market share is Android & iOS.
Common OS should help us in examining them, but because manufacturers can implenet their own features it is still difficult.
What should you consider around spyware?
- Remote monitoring software with different capabilities & functionality
- INHIBIT mobile network & WiFi connections.
- If believe it is installed then treat as HOSTILE & do not hold conversations in proximity of the device.
Summarise different types of non GSM Technologies
AMPS
- Analogue (discontinued)
D-AMPS / became known as ‘TDMA’ but not correct
- Digital 2G standard (2nd Ggeneration technology superceded by CDMA)
- Networks in North & South America (e.g. verizon)
CDMA (Code Division Multiple Access) Technologies
- May or may not require a SIM
- worldwide networks.
iDEN.
- Developed by Motorola
- networks in N & S AMerica & Asia.
Satellite Phones
- Global providers are Iridium, Globalstar & Immarsat
- regional providers also exist which have combined GSM/satphone functions (Thuraya)
- SIM cards can exist in them
GPS - Summary
- Most common system in use is US NAVSTAR Global Positioning System Network
- Network of 30+ satellites in Medium Earth Orbit (MEO) transmitting their location back to earth.
- 2 primary frequencies, First (L1) is SPS (Standard Positionaing Service) or Coarse Aquisition Code (C/A code). Second (L2) is PPS (Precise Position Service
- Signal is quite weak by the time it is recieved by GPS recievers on earth
- Multiple satellites provide coverage simultaneously
Usually at least 4 signals at any point on earth - 1 orbit every 12 hours
How does GPS Work?
- Uses Trilateration to determine location
- Uses timing difference on signal to determine distance from satellite. The difference in the time taken for the time stamped signal from the satellite, compared to the reference time on the GPS reciever clock indicates how long it has taken for the signal to be recieved. Distance = speed multipled by time means the distance can be calculated from the GPS reciever to the satellite.
- Performing the same technique from 3 satellites provides an accurate location to within 10 metres (2 Dimensional location)
- The distance calculated using the fourth satellite is used to validate the determind location (3 Dimmensional location)
What is aGPS (assisted GPS)?
aGPS (Assisted GPS). This assists with the acquiring a location on a mobile device
- when GPS is turned on for first time - Cold start TTFF - can take minutes to deterime location
- GPS is influenced by a number of factors e.g location (open skies = quicker fix), RF interference (around L1 & L2 frequencies), No. of satellites visible (min of 3 required)..
- aGPS uses addional technology (mobile network, WiFi).
- For example if in high rise building area and only 2 gps satellites are visible then other technologies can assist. WiFi can assist by providing approx location info. The vendor can compare the current WiFi access point and approximate the mobile device location.
- can be enabled or disabled on some devices.
- This speeds up acquisition time, reduces battery consumption, increases accuracy and may operate in non lines of sight conditions.
List some alternative global satellite navigation systems.
GLONAAS (Russia). 24 satellites. Slightly better accuracy than GPS. Covers Northern hemisphere better than southern
Galileo (EU)
Beidou Navigation Satellite Systam. BDS (China). regional to Asia / Pacific but over time will be global.
NavIC or IRNSS (India)
Quasi Zenith Satellite System QZSS (Japan)
Combining for example GPS and GLONAAS recievers in one device allows for better combined accuracy and uses more satellites. Common for mobile devices to use multiple types of recievers in the devices
GPS navigation devices
Combining Global Navigation Satellite System GNSS reciever with additional components such as touch screen and rechargeable battery provides portable navigation device.
These have FLASH memory or external media cards.
Various media content can be stored including user content.
Can include user data like routes, favourite routes, addressbook, home and work location and call registers.
GPS tracking devices
Various uses for tracking property / vehicles legitimately or covertly
Combines GPS reciever with a GSM module (that just requires power and a SIM) to report location data.
Reporting of the data from a tracking device can be to a server or to a mobile device or computer.
Some tracking devices can be interrogated locally by sending commands directly from a mobile device and an automatic response can be generted directly by SMS.
Some have variations of internal memory.
