lar user’s field of vision and cognizance.
The opportunity to explore and learn
on one’s own has been correspondingly
limited and channeled, affecting both
self-realization and autonomy. 11 The
“tightness” of this Deleuzean feedback
loop—its bandwidth and precision—is
What it is about the cellular network
that makes it so surveillance friendly,
and a potential threat to the individual
user and to society? The answer lies
in a series of design choices, choices
made in an attempt to solve the problem of establishing and maintaining
contact with a mobile user. The details
have filled many books (see, for example, Etemad, 13 Holma and Toskala, 22
Kaarenenetal et al., 24 and Mouly and
Pautet. 30), but we need only trace the
path of a call that is incoming to a cellular user to see how personal data is being collected and put to use.
The coverage area of a cellular network is partitioned into relatively small
areas called cells, with each cell receiving a subset of the radio resources of
the overall network. Two cells may be
assigned identical spectral resources—
a process called frequency reuse—if
the cells are far enough apart to prevent
their radio transmissions from interfering with each other. A cell tower sits at
the center of each cell, establishing connections between mobile users and the
wired cellular infrastructure. Location
areas are defined to consist of one or a
small number of cells. As we will see, the
location area is the finest level of granularity used by the network in trying to
complete a call to a cellular platform.
We now consider an incoming call.
To complete an incoming call to a cellular phone, the network routes the call to
a mobile switching center (MSCt) that
is near the phone. Through a process
called paging, the MSC then causes the
called cellular phone to ring. When the
cellular user answers his or her phone,
the MSC completes the call and communication can commence.
t As space is limited and such details are not important to the theme of this article, I will not
attempt to track vocabulary distinctions between second-, third-, and fourth-generation
It remains possible,
In order to perform this routing and
paging process, the network must keep
track of the location of the cellular telephone. This is done through the registration process. All cellular telephones
that are powered on periodically transmit registration messages that are received by one or more nearby cell towers and then processed by the network.
The resulting location information
thus acquired is stored with varying levels of granularity in several databases.
The databases of interest to us here
are the Home Location Register (HLR)
and the Visitor Location Register (VLR).
The HLR is a centralized database that
contains a variety of subscriber information, including a relatively coarse
estimate of the subscriber’s current location. HLRs are generally quite large;
there need be only one per cellular network. VLRs, generally associated with
local switches, contain local registration data, including the identity of the
cell site through which registration
messages are received. There is typically one VLR per mobile switching center
(MSC) or equivalent.
The VLR stores the identification
number for the cell site through which
the registration message was received.
The identity of the MSC associated with
the VLR is forwarded to the Home Location Register (HLR) that maintains the
records for the registering platform.
We can now track the progress of
an incoming call in more detail. Calls
from outside the cellular network will
generally enter the network through a
gateway MSC. The gateway MSC will use
the called number to identify and query
the appropriate HLR to determine how
to route the call. The call is then forwarded to the MSC associated with the
last registration message, which in turn
queries the VLR to determine in which
location area to attempt to contact the
subscriber. The base station controller
associated with the location area then
causes a paging message to be sent to
the called cellular telephone, causing
it to ring. If the subscriber answers the
call, the MSC connects a pair of voice
channels (to and from the cellular platform), and completes call setup.
The HLR and VLRs (or equivalents)
are thus the sources of the historic
and prospective cell site data discussed earlier in the survey of telephone privacy law.