System and method for detecting a cellular device
Methods and systems for cellular device detection are presented. A signal processing receiver operable to determine a plurality of uplink parameters according to a downlink broadcast message. The signal processing receiver is also configurable to receive an uplink message according to the plurality of uplink parameters, thereby determining a presence and/or an identity of a cellular device by decoding the uplink message.
1 . A system for detecting a cellular device comprising:
a plurality of signal processing receivers, wherein:
each signal processing receiver is operable to receive a plurality of samples from an uplink band used by a basestation,
each signal processing receiver is operable to measure a likelihood of a transmitted signal from the cellular device based on the plurality of samples from the uplink band, wherein the uplink band is determined according to an uplink parameter, and wherein the uplink parameter is determined according to decoding a downlink broadcast message received by at least one signal processing receiver of the plurality of signal processing receivers, and
a presence of the cellular device is determined according the aggregation and processing of the plurality of samples from more than one signal processing receiver.
2 . The system of claim 1 , wherein the uplink parameter is determined according to a downlink parameter stored in a database.
3 . The system of claim 1 , wherein the uplink parameter is accessed from a database of uplink parameters.
4 . The system of claim 1 , wherein the at least one signal processing receiver is operable to aggregate the likelihood measurements from the one or more signal processing receivers to locate the cellular device.
5 . The system of claim 1 , wherein the at least one signal processing receiver is operable to determine the identity of the cellular device according to an uplink message in the uplink band.
6 . A system for detecting a cellular device comprising:
a plurality of signal processing receivers, wherein:
each signal processing receiver is operable to decode a downlink broadcast message transmitted by a basestation;
each signal processing receiver is operable to determine at least one uplink parameter according to the decoded downlink broadcast message;
each signal processing receiver is operable to monitor an uplink band according to the at least one uplink parameter and to measure a likelihood of a transmitted signal from the cellular device; and
the system is operable to determine a presence of the cellular device according to aggregation of likelihood measurements from more than one signal processing receiver.
7 . The system of claim 6 , wherein the downlink broadcast message comprises system information defining an uplink frequency associated with the basestation.
8 . The system of claim 6 , wherein the uplink parameter comprises at least one of an uplink frequency, an uplink timing parameter, or an uplink access structure.
9 . The system of claim 6 , wherein the uplink parameter is stored in a network descriptor list accessible by the plurality of signal processing receivers.
10 . The system of claim 9 , wherein the network descriptor list is populated according to decoded downlink broadcast messages received from a plurality of basestations.
11 . The system of claim 6 , wherein measuring the likelihood of the transmitted signal comprises detecting a triggering event in the uplink band.
12 . The system of claim 11 , wherein the triggering event comprises detection of structured signal content indicative of a network access attempt by the cellular device.
13 . The system of claim 6 , wherein the aggregation of likelihood measurements comprises confirming detection when triggering events are detected by more than one signal processing receiver within a time interval.
14 . The system of claim 6 , wherein at least one signal processing receiver is operable to decode an uplink message transmitted by the cellular device.
15 . The system of claim 14 , wherein the decoded uplink message comprises an electronic identifier associated with the cellular device.
16 . The system of claim 6 , wherein received signal strength measurements derived from the uplink band are used to estimate proximity of the cellular device.
17 . The system of claim 6 , wherein the plurality of signal processing receivers are geographically distributed.