question: How does your mobile phone upload / send data to a cellphonetower or WiFi router?
comment: Big antennae allow for greater range of both sending and receiving radio signals. That's why you could, back in the day, get a big ol' antenna for your car that would boost the range that you could hear a radio station by for a bit. The antenna in your phone is large enough to receive and transmit back to the cell tower, but the cell tower's antenna is the major contributor to that situation; you'll notice that you need significantly larger and more exposed antenna in all but the most expensive walkie-talkies, which simply pick up and broadcast anything on a certain channel frequency, rather than use rotating code to tell a central controller/router what signals go to what devices.
passages: Cell site
  
  A cell site, cell tower, or cellular base station is a cellular-enabled mobile device site where antennae and electronic communications equipment are placed—typically on a radio mast, tower, or other raised structure—to create a cell (or adjacent cells) in a cellular network. The raised structure typically supports antenna and one or more sets of transmitter/receivers transceivers, digital signal processors, control electronics, a GPS receiver for timing (for CDMA2000/IS-95 or GSM systems), primary and backup electrical power sources, and sheltering.
   Typically, the way that a WISP operates is to order a fiber circuit to the center of the area they wish to serve. From there, the WISP will start building backhauls (gigabit wireless or fiber) to elevated points in the region, such as a radio towers, tall buildings, grain silos, or water towers. Those locations will have access points to provide service to individual customers or backhauls to other towers where they have more equipment. The WISP may also use gigabit wireless links to connect a PoP (Point of Presence) to several towers, reducing the need to pay for fiber circuits to the tower. For fixed wireless connections, a small dish or antenna is mounted to the roof of the customer's building and aligned to the WISP's nearest antenna site. When operating over the tightly limited range of the heavily populated 2.4 GHz band, as nearly all 802.11-based WiFi providers do, it is not uncommon to also see access points mounted on light posts and customer buildings.
   In wireless systems, WTCP is placed on a base station or intermediate gateway between a source host and a mobile (wireless) host. The base station is a wireless transmitter and receiver for the mobile host, and acts as a gateway to the internet for the host.
  
  The following is a highly simplified example of what happens when the mobile host and source host have a TCP connection with each other:
   Following the September 11 attacks on New York City in 2001, 36 cellular COWs were deployed by September 14, 2001 in Lower Manhattan to support the U.S. Federal Emergency Management Agency (FEMA) and provide critical phone service to rescue and recovery workers.
   Wireless data connections used in mobile computing take three general forms so. Cellular data service uses technologies GSM, CDMA or GPRS, 3G networks such as W-CDMA, EDGE or CDMA2000. and more recently 4G networks such as LTE, LTE-Advanced. These networks are usually available within range of commercial cell towers. Wi-Fi connections offer higher performance, may be either on a private business network or accessed through public hotspots, and have a typical range of 100 feet indoors and up to 1000 feet outdoors. Satellite Internet access covers areas where cellular and Wi-Fi are not available and may be set up anywhere the user has a line of sight to the satellite's location, which for satellites in geostationary orbit means having an unobstructed view of the southern sky. Some enterprise deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi and satellite. When using a mix of networks, a mobile virtual private network (mobile VPN) not only handles the security concerns, but also performs the multiple network logins automatically and keeps the application connections alive to prevent crashes or data loss during network transitions or coverage loss.
   Similarly, battery-powered routers may include a cellular Internet radio modem and Wi-Fi access point. When subscribed to a cellular data carrier, they allow nearby Wi-Fi stations to access the Internet over 2G, 3G, or 4G networks using the tethering technique. Many smartphones have a built-in capability of this sort, including those based on Android, BlackBerry, Bada, iOS (iPhone), Windows Phone and Symbian, though carriers often disable the feature, or charge a separate fee to enable it, especially for customers with unlimited data plans. "Internet packs" provide standalone facilities of this type as well, without use of a smartphone; examples include the MiFi- and WiBro-branded devices. Some laptops that have a cellular modem card can also act as mobile Internet Wi-Fi access points.
   A cellular network is a network of handheld mobile phones (cell phones) in which each phone communicates with the telephone network by radio waves through a local antenna at a cellular base station (cell site). The coverage area in which service is provided is divided into a mosaic of small geographical areas called "cells", each served by a separate low power multichannel transceiver and antenna at a base station. All the cell phones within a cell communicate with the system through that cell's antenna, on separate frequency channels assigned by the base station from a common pool of frequencies used by the system. 
   Section::::Technologies.:Wireless broadband access.:Wireless ISP.
  
  Wireless Internet service providers (WISPs) operate independently of mobile phone operators. WISPs typically employ low-cost IEEE 802.11 Wi-Fi radio systems to link up remote locations over great distances (Long-range Wi-Fi), but may use other higher-power radio communications systems as well.
   A mobile phone, such as a smartphone, that connects to data or voice services without going through the cellular base station is not on the mobile Internet. A laptop with a broadband modem and a cellular service provider subscription, that is traveling on a bus through the city is on mobile Internet.
  
  A mobile broadband modem "tethers" the smartphone to one or more computers or other end-user devices to provide access to the Internet via the protocols that cellular telephone service providers may offer.
   Mobile broadband is the marketing term for wireless Internet access delivered through mobile phone towers to computers, mobile phones (called "cell phones" in North America and South Africa, and "hand phones" in Asia), and other digital devices using portable modems. Some mobile services allow more than one device to be connected to the Internet using a single cellular connection using a process called tethering. The modem may be built into laptop computers, tablets, mobile phones, and other devices, added to some devices using PC cards, USB modems, and USB sticks or dongles, or separate wireless modems can be used.
   BULLET::::- Sierra Wireless Overdrive (Note: 4G capable; available only in the United States through Sprint)
  
  BULLET::::- ZTE MF60, MF80
  
  BULLET::::- JioFi is a mobile router 4G (LTE) launched in India.
  
  BULLET::::- Rentafi is Singapore’s leading portable 4G WiFi rental service.
  
  Section::::Alternatives.
  
  Mobile phones with an Internet connection can often be turned into Wi-Fi hotspots using a process called "tethering", which is similar to using dedicated MiFi devices.
  
  The following phone families have built-in features to create Wi-Fi access point:
  
  BULLET::::- Android phones running Android 2.2 or later
  
  BULLET::::- BlackBerry devices running OS 7.1 or later
   Section::::Different kinds of mobile cell sites.:Cell on truck.
  
  A cell on truck is a particular kind of mobile cell site that is composed of mobile trucks with container and with self-mounting telescopic mast. They are portable structures that guarantee full operation in three hours and in restricted spaces.
   The exact details of the mobile system's move from one base station to the other vary considerably from system to system (see the example below for how a mobile phone network manages handover).
  
  Section::::Mobile phone network.
  
  The most common example of a cellular network is a mobile phone (cell phone) network. A mobile phone is a portable telephone which receives or makes calls through a cell site (base station) or transmitting tower. Radio waves are used to transfer signals to and from the cell phone.
   An Extended Service Set may be formed by deploying multiple access points that are configured with the same SSID and security settings. Wi-Fi client devices will typically connect to the access point that can provide the strongest signal within that service set.
  
  Section::::Network security.
   A wireless telephone base station communicates with a mobile or hand-held phone. For example, in a wireless telephone system, the signals from one or more mobile telephones in an area are received at a nearby base station, which then connects the call to the land-line network. Other equipment is involved depending on the system architecture. Mobile telephone provider networks, such as European GSM networks, may involve carrier, microwave radio, and switching facilities to connect the call. In the case of a portable phone such as a US cordless phone, the connection is directly connected to a wired land line.
   Mobile cell sites require neither civil works nor foundations, just minimal requirements like commercial power and grounding. The mobile units have been designed to be a temporary solution, but if requested, they can be transformed into a permanent station.
  
  Section::::Different kinds of mobile cell sites.
  
  There are several different kinds of mobile cell sites, every one of which has different usage characteristics.
  
  Section::::Different kinds of mobile cell sites.:Rapid-deployment units (RDU).
  
  RDUs are mobile radio base stations transportable on trucks. Their use is strategic for the rapid expansion of cellular networks.
   Section::::History.:3G.
  
  3G networks have taken this approach to a higher level, using different underlying technology but the same principles. They routinely provide speeds over 300kbit/s. Due to the now increased internet speed, internet connection sharing via WLAN has become a workable reality. Devices which allow internet connection sharing or other types of routing on cellular networks are called also cellular routers.
   BULLET::::- Cell phone – a portable wireless telephone that is connected to the telephone network by radio signals exchanged with a local antenna at a cellular base station (cell tower). The service area covered by the provider is divided into small geographical areas called "cells", each served by a separate base station antenna and multichannel transceiver. All the cell phones in a cell communicate with this antenna on separate frequency channels, assigned from a common pool of frequencies.
   BULLET::::- Global System for Mobile Communications (GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.
   Cell site workers are called tower climbers or transmission tower workers. Transmission tower workers often work at heights of up to 1,500 feet (450 m), performing maintenance and repair work for cellular phone and other wireless communications companies.
  
  Section::::Employment.:Spy agency setup.
  
  According to documents leaked to Der Spiegel, the NSA sells a $40,000 "active GSM base station" to be used as a tool to mimic a mobile phone tower and thus monitor cell phones.
   Cell phones communicating with a single cell tower constitute a local subnetwork; the connection between the cell tower and the rest of the world begins with a backhaul link to the core of the Internet service provider's network (via a point of presence). A backhaul may include wired, fiber optic and wireless components. Wireless sections may include using microwave bands and mesh and edge network topologies that may use a high-capacity wireless channel to get packets to the microwave or fiber links.
   Hotspot 2.0 is based on the IEEE 802.11u standard, which is a set of protocols published in 2011 to enable cellular-like roaming. If the device supports 802.11u and is subscribed to a Hotspot 2.0 service it will automatically connect and roam.
  
  Section::::Types.:Hotspot 2.0.:Supported devices.
  
  BULLET::::- Some Chinese tablet computers
  
  BULLET::::- Some THL smartphones
  
  BULLET::::- Most Vivo smartphones
  
  BULLET::::- Apple mobile devices running iOS 7 and up
  
  BULLET::::- Some Samsung Galaxy smartphones
  
  BULLET::::- Huawei smartphones
  
  BULLET::::- Windows 10 devices have full support for network discovery and connection.
   Point-to-multipoint is the most popular approach for wireless communications that have a large number of nodes, end destinations or end users. Point to Multipoint generally assumes there is a central base station to which remote "subscriber units" or customer premises equipment (CPE) (a term that was originally used in the wired telephone industry) are connected over the wireless medium. Connections between the "base station" and "subscriber units" can be either line-of-sight or, for lower-frequency radio systems, non-line-of-sight where link budgets permit. Generally, lower frequencies can offer non-line-of-sight connections. Various software planning tools can be used to determine feasibility of potential connections using topographic data as well as link budget simulation. Often the point to multipoint links are installed to reduce the cost of infrastructure and increase the number of CPE's and connectivity.
   Section::::Summary.:Access.
  
  Users can auto-obtain wireless connectivity using Dynamic Host Configuration Protocol (DHCP)-IP addressing. Upon launching their Internet browser, subscribers are redirected to a captive portal homepage where they can either sign up or logon using an existing account.
  
  Section::::Summary.:Technology.
   Devices that can use Wi-Fi technologies include desktops and laptops, smartphones and tablets, smart TVs, printers, digital audio players, digital cameras, cars and drones. Compatible devices can connect to each other over Wi-Fi through a wireless access point as well as to connected Ethernet devices and may use it to access the Internet. Such an access point (or hotspot) has a range of about indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.
  