Mobile Phones - Base Station transmitter masts in Central London

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It is almost certain that any CyberPunk tourists to London will own one or more Mobile Phones.

Obviously these are now a core part of our modern communications society, but they are also increasingly being used for surveillance and snooping, by law enforcement and national security agencies, and by commercial vested interests, where they can get away with it.

GSM mobile phones (the vast majority, due to the relatively slow uptake of 3G PP
technology, the handsets for which in the UK are all also GSM capable) share out their government licensed radio frequency bands (900 Mhz and 1800 MHz for GSM and 2100MHz for 3G PP) by allocating a Network Provider, Base Station, Channel etc. "colours" " to each Mobile Phone Base Station transmitter, so that each "cell" around a particular transmitter does not interfere with its neighbouring cells.

In the sparsely populated open countryside or at sea, the cells cover approximately 35 kilometres (20 or so miles)

However within cities like London, the density of Base Stations and micro-cell transmitters is far greater than most people realise.

Here is an image published reluctantly by the UK Government agency which regulates the telecommunications and broadcasting industries and which allocates the radio frequency spectrum monopolies or licence free radio bands (such as it the 2.4GHz band used for WiFi and Bluetooth and some wireless CCTV cameras etc.). They deliberately make it hard to find from the front of their website and the data is out of date by up to 3 months, but it is still of interest: Ofcom Sitefinder website.


Mobile_Phone_Base_Station_masts_central_London_300.jpg

This map shows all the Mobile Phone Network Operators' Base Stations,- Vodafone, Orange, T-Mobile, O2,and Three - so any one individual phone will be handshaking with up to about a fifth of the total number in the area shown.

More on Location Based Services and Communications Traffic Data:mobile phone tracking:

Within each cell, the handsets are dynamically allocated a a Timing Advance Value (TADV) fiddle factor delay, depending on how far they are away from the Base Station, so that all the handsets in a Cell do not try to swamp the available transmission time slots at once. This fiddle factor is proportional to the speed of radio waves / light, and in large 35 Km Cells (TADV=63), equates to a distance between the handset and the Base Station accurate to about 550 metres.

However, in Central London, given that there could well be several Base Stations or micro-cells along the street where you and your handset are located, this accuracy could down to a metre or two, especially, where networks such as Orange, offer services such as Orange Location API which can triangulate your handset's position automatically, aided by recording which "o'clock" segment of a circular mobile phone Base Station transmitter array is being used, giving a rough direction, as well as the Cell ID, potentially giving an accuracy of a couple of metres or so to a location fix.

Each time you make or receive a mobile phone call, be it Voice or Data or an SMS text message, the data about which Mobile Phone Cell ID you start your call from, and the one which you finish it at is recorded n your Call Data Record (CDR) by the mobile phone network company. This also includes links to name and address data for billing purposes , financial records of credit card purchases of "anonymous" pre-paid airtime vouchers and top up cards etc.

Even if you do not make or receive any mobile phone calls etc, the network still has to get a periodic update of your position or transmission quality signal strength, in anticipation of when you do.

If you place your mobile phone near to your computer or hi fi speakers etc, you will hear the characteristic "handshake" bleeping every 5 to 10 minutes or so, as the handset checks its signal strength with the Base Station it last associated with,in order to decide whether to switch to a neighbouring cell within range (at a slightly different frequency), either because of radio wave propagation factors in an urban environment like absorption by damp concrete or reflection from metallised windows etc. or because your mobile phone is physically on the move. Obviously each time this "Handshake" happens, a record of the Cell and the signal strength derived TADV fiddle factor i.e. the distance from the Base Station, is recorded.

Therefore when travelling to , attending and travelling away from a meeting or social event, e.g. the William Gibson book signings, even if none of the participants make or receive mobile phone calls, they will have left a digital record of the fact that their mobile phones and probably therefore their owners, were physically associating with each other in a particular area.

Most of this data is used for billing and for network management, and is retained for a period of say 3 months to a year or more, depending on the business practices of the company. Then, according to the Data Protection Act, when there is no legitimate need for it to be retained, the data should be anonymised or destroyed.

Obviously, if there is an active Police investigation into a serious crime, then such data is handed over to the Police, for intelligence or legal evidence purposes.

However, as of September this year, along with most other European Union Countries, the UK Government is legally forcing telecomms companies to Retain such Communications Traffic Data , for at least a year, even after there is no business use for it any more, not just on criminal suspects, but on the 450 million innocent European Union citizens. See the Data Retention Is No Solution wiki for more details.

Private companies are also allowed to sell Location Based Services, which map this Cell Location Data onto a web map geographical information system, for a fee , supposedly only for registered mobile phones.

We are living in a surveillance police state "Spook Country"

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