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Published: Wednesday, 11 May 2022 03:57
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Mobile communication:

Mobile communication refers to the tech used is cell phones to communicate with each other. Since this tech came into existence in 1980, it has gained immense popularity. It has undergone various generations with improving speeds.

Generations:

In the field of mobile communications, a "generation" generally refers to a change in the fundamental nature of the service, non-backwards-compatible transmission technology, higher peak bit rates, new frequency bands, wider channel frequency bandwidth in Hertz, and higher capacity for many simultaneous data transfers.

New mobile generations have appeared about every ten years since the one in 1981. Here's the wiki link: https://en.wikipedia.org/wiki/List_of_mobile_phone_generations

  • 1G: 1st generation, analog. Introduced in 1981. Not used anymore.
  • 2G: 2nd generation, digital. Introduced in 1992. 2G systems are significantly more efficient on the spectrum allowing for far greater cell phone penetration levels. 2G introduced data services for mobile, starting with SMS (Short Message Service) plain text-based messages, picture messages and MMS (Multimedia Message Service). GSM and IS-95 were the two most prevalent 2G mobile communication technologies in 2007. Even today as of 2022, 2G is still being used as a fallback service on all modern phones, as well as in rural areas.
    • GSM (Global System for Mobile Communications): This was more popular and had 80-85% market share. GSM uses TDMA (Time division multiple access) and FDMA (Frequency division multiple access) for user and cell separation. GSM phones used a SIM card, and so could be used internationally.
    • IS-95 (Interim Standard 95): This was the first ever CDMA-based digital cellular technology. It was developed by Qualcomm. It's proprietery name was CDMAone. This was less popular and had 10-15% market share. IS-95 uses CDMA (code division multiple access) for user and cell separation. IS-95 phones are generally unable to roam internationally, and are tied to a specific provider.
  • 3G: 3rd generation, introduced in 2001. multi-media support, spread spectrum transmission and a minimum peak bit rate of 144 kbit/s. Later 3G releases allowed max speed of Mbits, which made video calls, mobile internet access, mobile modems for laptops, etc possible. Most prevalent 3G standards are UMTS and CDMA2000 which are upgrades from GSM and IS-95 used in 2G. 3G is mostly dead, as newer generations use 2G as a fall back standard, instead of 3G.
    • UMTS (Universal Mobile Telecommunications System): Used in regions predominated by GSM 2G system infrastructure. The cell phones are typically UMTS and GSM hybrids. UMTS is a full revision from GSM in terms of encoding methods and hardware, although some GSM sites can be retrofitted to broadcast in the UMTS/W-CDMA format. W-CDMA is the most common deployment, commonly operated on the 2,100 MHz band. A few others use the 850, 900, and 1,900 MHz bands.
    • CDMA2000: This is used especially in North America and South Korea, sharing infrastructure with the IS-95 2G standard. The cell phones are typically CDMA2000 and IS-95 hybrids.
    • EDGE (Enhanced_Data_rates_for_GSM_Evolution): It's revision to the older 2G GSM based transmission methods, which utilizes the same switching nodes, base station sites, and frequencies as GPRS, but includes a new base station and cellphone RF circuits. It is based on the three times as efficient 8PSK modulation scheme as a supplement to the original GMSK modulation scheme. EDGE is still used extensively due to its ease of upgrade from existing 2G GSM infrastructure and cell phones.
  • 4G: 4th generation, introduced in 2011/2012, followed by "real" 4G, which refers to all-Internet protocol (IP) packet-switched networks giving mobile ultra-broadband (gigabit speed) access. 4G users get speeds of up to 100 Mbit/s, with Gbit/s speeds possible. Common standards supported are:
    • Mobile WiMAX: WiMAX added support for mobility, and thus came mobile WiMAX to be used for celular transmission. This is not widely used??
    • LTE (Long Term Evolution): It's commonly marketed as 4G-LTE. LTE is based on the GSM and UMTS standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE freq and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz and supports both FDD (Freq division duplexing) and TDD (time division duplexing).
  • 5G: 5th generation, introduced in 2021. Also known as 5G-NR (5G new radio). It supports data rates of several tens of megabits per second (Mbit/s) to tens of thousands of users, with speeds surpassing 10's of Gbit/s. 5G transmission is supported only on phones that have 5G chip on them, which are newer phones introduced in 2020. All these 5G phones also support 4G, since 5G isn't supported widely (as 5G transmission is expensive with all new equipment, etc needed). T-mobile USA was the 1st company in the world to launch a commercially available 5G NR Standalone network (others used 4G LTE network initially). The higher speeds in 5G are achieved partly by using additional higher-frequency radio waves, but they have a shorter useful physical range. 5G can be implemented in low, medium and high bands.
    • Low band: Low-band 5G uses a similar frequency range to 4G cellphones, 600–900 MHz, giving download speeds a little higher than 4G (25-250MBits/s). Low-band cell towers have a range and coverage area similar to 4G towers.
    • Mid band: Mid-band 5G uses microwaves of 1.7–4.7 GHz, allowing speeds of 100–900 Mbit/s, with each cell tower providing service up to several kilometers in radius. 
    • High band: High-band 5G uses frequencies of 24–47 GHz, near the bottom of the millimeter wave (mmWave) band, although higher frequencies may be used in the future. It often achieves download speeds in the Gbit/s range, comparable to cable internet. However, mmWave have a more limited range, requiring many small cells. They can be impeded or blocked by materials in walls or windows.

That's all the generations for cellular communication until new ones come up.