Cellular communications - Revision history

Julian at 08:54, 11 September 2023

2023-09-11T08:54:19Z

← Older revision		Revision as of 08:54, 11 September 2023
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	Sometimes however, even in cases cellular communications are available, or have been partially restored, internet access itself is not available via mobile data routing. This is due to the 'backhaul' connections being broken or impaired. In both Haiti's 2010 earthquake and Eastern Japan's 2011 earthquake, submarine cables were severely damaged, cutting off large populations from the Internet<ref>https://journals.sagepub.com/doi/full/10.1177/1550147719829960#table1-1550147719829960</ref>. This serves as an example where the use of Internet-dependent remote 3rd party applications or services on phones is not always to be relied upon.		Sometimes however, even in cases cellular communications are available, or have been partially restored, internet access itself is not available via mobile data routing. This is due to the 'backhaul' connections being broken or impaired. In both Haiti's 2010 earthquake and Eastern Japan's 2011 earthquake, submarine cables were severely damaged, cutting off large populations from the Internet<ref>https://journals.sagepub.com/doi/full/10.1177/1550147719829960#table1-1550147719829960</ref>. This serves as an example where the use of Internet-dependent remote 3rd party applications or services on phones is not always to be relied upon.

			Fuel is often in short supply during disaster events. It is thus plausible that the large diesel tanks at the base of many large cell sites used for generating backup power may be drained to fuel vehicles or electricity generators for other needs.

	== Failure of mobile phones during disaster events ==		== Failure of mobile phones during disaster events ==

Julian: /* Use of cellular infrastructure in disasters */

2023-09-10T06:14:35Z

Use of cellular infrastructure in disasters

← Older revision		Revision as of 06:14, 10 September 2023
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	== Use of cellular infrastructure in disasters ==		== Use of cellular infrastructure in disasters ==

	As mobile phone adoption has rapidly increased, so has cellular communications infrastructure spread. In many parts of the developed world cell sites provide coverage across the majority of the landscape, whereas in economically poorer regions mobile data increasingly acts as the sole means of internet access in urban and rural areas.		As mobile phone adoption has rapidly increased, so has cellular communications infrastructure spread. In many parts of the developed world cell sites provide coverage across the majority of the landscape, whereas in economically poorer regions mobile data increasingly acts as the sole means of internet access in urban and rural areas. In 2021, 93% of the global population was covered by a mobile broadband network<ref>https://reliefweb.int/report/world/using-mobile-phone-technologies-disaster-risk-management-reflections-shear-june-2021</ref>.

	Due to this broad use, cellular communications are increasingly used as a broadcast medium for alerting as to a coming extreme environmental event. Further, during the preparation phase, the event phase and aftermath, cellular phones are often used to organise, stay in touch with loved ones and to give location and status updates to rescue teams. The use of realtime video and the sharing of photos and voice messages has proved vital for rescue efforts across many disaster events.		Due to this broad use, cellular communications are increasingly used as a broadcast medium for alerting as to a coming extreme environmental event. Further, during the preparation phase, the event phase and aftermath, cellular phones are often used to organise, stay in touch with loved ones and to give location and status updates to rescue teams. The use of realtime video and the sharing of photos and voice messages has proved vital for rescue efforts across many disaster events.

Julian: /* Failure of mobile phones during disaster events */

2023-09-10T06:13:15Z

Failure of mobile phones during disaster events

← Older revision		Revision as of 06:13, 10 September 2023
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	[[File:Nokia-phone.jpg\|thumb\|120px\|A Nokia GT-ET1200I 'dumbphone'.]]		[[File:Nokia-phone.jpg\|thumb\|120px\|A Nokia GT-ET1200I 'dumbphone'.]]

	While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications~~. A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible~~.		While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications.

	It is also good to have a fallback phone solely for texts and calls. This can be a very inexpensive 'dumbphone', many of which have battery life counted in several days, even weeks.		A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible. Pack a pre-charged 'power bank' and tested cable with which to charge your phone.

			It is also good to have a fallback phone solely for texts and calls. This can be a very inexpensive 'dumbphone', many of which have battery life counted in several days, even weeks. A simple pre-pay SIM card can be put into that phone with enough credit for calls and texts. Note that even a SIM without credit will function for emergency calls.

	== Community operated cellular infrastructure ==		== Community operated cellular infrastructure ==

Julian: Fixed Pink Cell Tower link

2023-09-10T06:10:08Z

Fixed Pink Cell Tower link

← Older revision		Revision as of 06:10, 10 September 2023
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	* Coaxial cable and connectors		* Coaxial cable and connectors

	A pre-packaged example implementation of this is Pink Cell Tower by technologist and artist Julian Oliver and contributor to this wiki<ref>https://julianoliver.com/projects/pink-cell-tower/<ref>. An entire pre-configured 'ISO' disk image can be downloaded and flashed onto an SDcard, for use on a Raspberry Pi minicomputer that is connected to a BlareRF SDR, in turn connected to directional antennae on its transmit (TX) and receive (RX) ports. Optionally running from a truck batteries powered by solar panels, the project can also serve a simple website on the Raspberry Pi 4's built-in WiFi device, whereby important information can be served to those physically proximate to the tower itself.		A pre-packaged example implementation of this is Pink Cell Tower by technologist and artist Julian Oliver and contributor to this wiki<ref>https://julianoliver.com/projects/pink-cell-tower/</ref>. An entire pre-configured 'ISO' disk image can be downloaded and flashed onto an SDcard, for use on a Raspberry Pi minicomputer that is connected to a BlareRF SDR, in turn connected to directional antennae on its transmit (TX) and receive (RX) ports. Optionally running from a truck batteries powered by solar panels, the project can also serve a simple website on the Raspberry Pi 4's built-in WiFi device, whereby important information can be served to those physically proximate to the tower itself.

	It is important to check your local jurisdiction before setting up a cell site, as doing so is often in breach of local radio frequency allocation and usage laws. In an emergency such strictures may matter very little.		It is important to check your local jurisdiction before setting up a cell site, as doing so is often in breach of local radio frequency allocation and usage laws. In an emergency such strictures may matter very little.

Julian: /* Anatomy of a cell tower */

2023-09-10T06:09:17Z

Anatomy of a cell tower

← Older revision		Revision as of 06:09, 10 September 2023
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	== Anatomy of a cell tower ==		== Anatomy of a cell tower ==

	[[File:Cell-tower2.jpeg\|thumb\|left\|Photo of a cell tower, or 'cell site'. One circular point-to-point remote radio head can be seen near image bottom. This microwave antenna connects one cell site to another. Image courtesy Petr Kratochvil, ~~licensed under Creative Commons~~ CC0 1.0 Public Domain.]]		[[File:Cell-tower2.jpeg\|thumb\|left\|Photo of a cell tower, or 'cell site'. One circular point-to-point remote radio head can be seen near image bottom. This microwave antenna connects one cell site to another. Image courtesy Petr Kratochvil, CC0 1.0 Public Domain.]]

	Antennae, and the equipment comprising a cellular base station, are typically mounted onto a radio mast, or other raised structure, like a building. Sometimes the structure is disguised as other things, like a tree, or as bricks, so as to blend in with the local environment.		Antennae, and the equipment comprising a cellular base station, are typically mounted onto a radio mast, or other raised structure, like a building. Sometimes the structure is disguised as other things, like a tree, or as bricks, so as to blend in with the local environment.

Julian: /* Failure of mobile phones during disaster events */

2023-09-10T06:08:51Z

Failure of mobile phones during disaster events

← Older revision		Revision as of 06:08, 10 September 2023
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	== Failure of mobile phones during disaster events ==		== Failure of mobile phones during disaster events ==

	[[File:Nokia-phone.jpg\|thumb\|~~200px~~\|A Nokia GT-ET1200I 'dumbphone'.]]		[[File:Nokia-phone.jpg\|thumb\|120px\|A Nokia GT-ET1200I 'dumbphone'.]]

	While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications. A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible.		While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications. A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible.

Julian: /* Community operated cellular infrastructure */

2023-09-10T06:08:24Z

Community operated cellular infrastructure

← Older revision		Revision as of 06:08, 10 September 2023
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	== Community operated cellular infrastructure ==		== Community operated cellular infrastructure ==

	[[File:Pink-cell-tower.jpg\|thumb\|Image of the Pink Cell Tower project, a cell site providing free voice and calls powered off a Rasberry Pi, BladeRF and the YateBTS GSM stack.]]		[[File:Pink-cell-tower.jpg\|thumb\|left\|240px\|Image of the Pink Cell Tower project, a cell site providing free voice and calls powered off a Rasberry Pi, BladeRF and the YateBTS GSM stack.]]

	Often it is victims of environmental and other disasters that are geographically closest to the damaged cellular communications infrastructure they depend upon, and yet even with sufficient knowledge at hand, civilians may not have the rights, credentials and rarefied tooling to attempt a repair that involves access to the base station component itself.		Often it is victims of environmental and other disasters that are geographically closest to the damaged cellular communications infrastructure they depend upon, and yet even with sufficient knowledge at hand, civilians may not have the rights, credentials and rarefied tooling to attempt a repair that involves access to the base station component itself.

Julian: /* Failure of mobile phones during disaster events */

2023-09-10T06:07:41Z

Failure of mobile phones during disaster events

← Older revision		Revision as of 06:07, 10 September 2023
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	== Failure of mobile phones during disaster events ==		== Failure of mobile phones during disaster events ==

	[[File:Nokia-phone.jpg\|thumb\|A Nokia GT-ET1200I 'dumbphone'.]]		[[File:Nokia-phone.jpg\|thumb\|200px\|A Nokia GT-ET1200I 'dumbphone'.]]

	While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications. A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible.		While modern smartphones provide many conveniences, much of their functionality is dependent on network connectivity. When mobile data or WiFi is unavailable, the device's use is limited to the on-phone features and applications that do not need Internet access. A common issue with smartphones in a disaster event is that they run out of battery, and so may not be usable into the 2nd day of an event. Another is that they suffer water or impact damage. For this reason it is wise to put your smartphone into low power mode early into a disaster event while disabling WiFi and any unnecessary idling applications. A ziplock bag can also protect your phone from water damage. When putting it into your go-bag, make sure it is easily accessible but also protected from impact damage where possible.

Julian: /* Anatomy of a cell tower */

2023-09-10T06:06:24Z

Anatomy of a cell tower

← Older revision		Revision as of 06:06, 10 September 2023
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	== Anatomy of a cell tower ==		== Anatomy of a cell tower ==

	[[File:Cell-tower2.jpeg\|thumb\|Photo of a cell tower, or 'cell site'. One circular point-to-point remote radio head can be seen near image bottom. This microwave antenna connects one cell site to another. Image courtesy Petr Kratochvil, licensed under Creative Commons CC0 1.0 Public Domain.]]		[[File:Cell-tower2.jpeg\|thumb\|left\|Photo of a cell tower, or 'cell site'. One circular point-to-point remote radio head can be seen near image bottom. This microwave antenna connects one cell site to another. Image courtesy Petr Kratochvil, licensed under Creative Commons CC0 1.0 Public Domain.]]

	Antennae, and the equipment comprising a cellular base station, are typically mounted onto a radio mast, or other raised structure, like a building. Sometimes the structure is disguised as other things, like a tree, or as bricks, so as to blend in with the local environment.		Antennae, and the equipment comprising a cellular base station, are typically mounted onto a radio mast, or other raised structure, like a building. Sometimes the structure is disguised as other things, like a tree, or as bricks, so as to blend in with the local environment.

	A cell tower acts as a single 'cell' within a network of other inter-connected cells, allowing for the seamless registration and migration of handsets (mobile phones) from cell to cell as they move across the geography. This inter-connection with neighbouring cell sites is done with the application of a dedicated point-to-point directional antenna (focused radio 'beams' transmit and receive along one direction) known as a ''remote radio head''. These special antenna typically transmit and receive on microwave (sub-millimeter ~~wavelenth~~ bands). The other directional antennae on a cell tower is typically of the flat-panel type, are for traffic to-and-fro handsets.		A cell tower acts as a single 'cell' within a network of other inter-connected cells, allowing for the seamless registration and migration of handsets (mobile phones) from cell to cell as they move across the geography. This inter-connection with neighbouring cell sites is done with the application of a dedicated point-to-point directional antenna (focused radio 'beams' transmit and receive along one direction) known as a ''remote radio head''. These special antenna typically transmit and receive on microwave (sub-millimeter wavelength bands). The other directional antennae on a cell tower is typically of the flat-panel type, are for traffic to-and-fro handsets.

	One way to tell the difference between phone-facing and cell-facing antennae in a dense urban environment is that the surface of the remote radio head is typically perpendicular to the ground (pointing to another cell site), whereas the directional antenna facing phones is angled slightly downward, for instance to a road or street. Remote radio heads are also often round, with a flat surface like a drum (as shown in this section's photograph). The antennae are all connected to their respective individual base stations, often housed inside rigid plastic weatherproof boxes, and connected to the local electricity grid. Sometimes the base stations are hidden within the tower structure, or in a dedicated structure built at its base.		One way to tell the difference between phone-facing and cell-facing antennae in a dense urban environment is that the surface of the remote radio head is typically perpendicular to the ground (pointing to another cell site), whereas the directional antenna facing phones is angled slightly downward, for instance to a road or street. Remote radio heads are also often round, with a flat surface like a drum (as shown in this section's photograph). The antennae are all connected to their respective individual base stations, often housed inside rigid plastic weatherproof boxes, and connected to the local electricity grid. Sometimes the base stations are hidden within the tower structure, or in a dedicated structure built at its base.
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	In some cases the cell tower will have redundant power supply in the form of a battery array or generator. Generators are often diesel, with a large tank of diesel supply.		In some cases the cell tower will have redundant power supply in the form of a battery array or generator. Generators are often diesel, with a large tank of diesel supply.

	Multiple providers will often mount their equipment to the same structure, sharing the rates and lease cost presiding over the structure.		Multiple providers will often mount their equipment to the same structure, sharing the rates and lease cost presiding over the structure.

	== Standards ==		== Standards ==

Julian: Added information on setting up a cell tower, referencing the Pink Cell Tower project.

2023-09-10T06:05:34Z

Added information on setting up a cell tower, referencing the Pink Cell Tower project.

← Older revision		Revision as of 06:05, 10 September 2023
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	== Community operated cellular infrastructure ==		== Community operated cellular infrastructure ==

			[[File:Pink-cell-tower.jpg\|thumb\|Image of the Pink Cell Tower project, a cell site providing free voice and calls powered off a Rasberry Pi, BladeRF and the YateBTS GSM stack.]]

	Often it is victims of environmental and other disasters that are geographically closest to the damaged cellular communications infrastructure they depend upon, and yet even with sufficient knowledge at hand, civilians may not have the rights, credentials and rarefied tooling to attempt a repair that involves access to the base station component itself.		Often it is victims of environmental and other disasters that are geographically closest to the damaged cellular communications infrastructure they depend upon, and yet even with sufficient knowledge at hand, civilians may not have the rights, credentials and rarefied tooling to attempt a repair that involves access to the base station component itself.

	It is here that community owned and operated cellular infrastructure presents an interesting fallback.		It is here that community owned and operated cellular infrastructure presents an interesting fallback where technical ability allows. A cell tower capable of providing voice and messaging for a remote or at risk community can be implemented using a [[Radio#Software_Defined_Radio\|Software Defined Radio (SDR)]], an open source software stack, a laptop or mini computer (like a Raspberry Pi) and flat panel directional antennae designed for a GSM band.

	* YateBTS		* YateBTS <ref>https://yatebts.com/</ref>
	* BladeRF		* BladeRF <ref>https://www.nuand.com/bladerf-1/</ref>
	* 2x GSM 900/1800 directional antennae		* 2x GSM 900 or GSM 1800 directional antennae
	* LNA		* LNA
			* Power amplifier
	* Coaxial cable and connectors		* Coaxial cable and connectors

			A pre-packaged example implementation of this is Pink Cell Tower by technologist and artist Julian Oliver and contributor to this wiki<ref>https://julianoliver.com/projects/pink-cell-tower/<ref>. An entire pre-configured 'ISO' disk image can be downloaded and flashed onto an SDcard, for use on a Raspberry Pi minicomputer that is connected to a BlareRF SDR, in turn connected to directional antennae on its transmit (TX) and receive (RX) ports. Optionally running from a truck batteries powered by solar panels, the project can also serve a simple website on the Raspberry Pi 4's built-in WiFi device, whereby important information can be served to those physically proximate to the tower itself.

			It is important to check your local jurisdiction before setting up a cell site, as doing so is often in breach of local radio frequency allocation and usage laws. In an emergency such strictures may matter very little.

	== Citations ==		== Citations ==

	<references />		<references />