The invention relates to the field of radio communications and, particularly, to detection of intentional interference towards a cellular communication system.
Intentional radio interference also known as radio jamming is a potential indication of illegal activity, e.g. burglary or violence. Radio communications may be prevented in order to disable any type of alarming. Some radio devices are capable of detecting when they are being jammed but their communications capability to inform about the situation may be disabled by the jamming.
GB 2 435 987 discloses a mobile communication system includes an infrastructure including at least a first base transceiver station and a plurality of mobile stations, wherein each of the mobile stations is operable to detect interference by jamming to a signal sent on a downlink channel by the first base transceiver station and, when it determines that such interference exists, to send a notification message to the infrastructure.
EP 1 501 329 discloses a wireless communication system which comprises at least one wireless serving communication unit, e.g. base transceiver or transceiver station, serving a plurality of remote units with a communication resource. The at least one wireless serving communication unit detects non-availability of an one or more inbound communication resource(s) owing to interference or jamming and transmits a broadcast message on an outbound communication resource indicating a non-availability of the one or more inbound communication resource(s). Thus, by using a broadcast message of an uplink channel's non-availability, the impact of a third party transmitting a jamming/interfering signal to interfere with inbound signals to the serving unit is reduced.
According to an aspect of the invention, there is provided a method as specified in claim 1.
According to an aspect of the invention, there is provided an apparatus as specified in claim 14.
According to an aspect of the invention, there is provided a computer program product as specified in claim 15.
In an embodiment, there is provided an apparatus, comprising: at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to: acquire a message from a terminal device indicating communication quality below a determined threshold in a radio connection between a radio communication network infrastructure and the terminal device; detecting presence of an intentional radio interference source, wherein the detection is based on at least one measurement report received from the terminal device; and upon a result of said detection of the intentional radio interference source, causing transmission of a notification message to a determined target entity.
In an embodiment, the detection is based on analysing at least one metric derived from a signal strength of a downlink signal received by the terminal device wherein the at least one metric is comprised in the at least one measurement report received from the terminal device.
In an embodiment, the analysis comprises comparing the value of the at least one metric with a downlink signal quality reported by the terminal device and, upon determining that the at least one metric indicates downlink signal strength higher than what is proportional to the estimated path loss and transmission powers, determining that the terminal device is subject to the intentional radio interference.
In an embodiment, the at least one metric comprises at least one of the following: downlink signal quality, received signal strength, and path loss.
In an embodiment, the detection is based on analysing at least one metric derived from signal strengths of a plurality of downlink signals received by the terminal device from different base stations, wherein said at least one metric is comprised in the at least one measurement report received from the terminal device.
In an embodiment, the analysis comprises comparing said at least one metric with a determined threshold and determining, if a determined number of metrics exceed the determined threshold, that the terminal device is subject to the intentional radio interference.
In an embodiment, the terminal device is in a connected state with respect to the cellular communication network infrastructure at the time of launching the detection of the presence of the intentional radio interference source.
In an embodiment, said at least one measurement report comprises at least one measurement report received from the terminal device after launching the detection of the presence of the intentional radio interference source.
In an embodiment, the detection is based on analysis of measurement data history associated with the terminal device.
In an embodiment, the analysis of the measurement data history comprises searching for a rising edge in signal strength measurements and, upon detecting a rising edge, determining that the intentional radio interference source is present.
In an embodiment; the apparatus is further caused to, upon determining that the intentional radio interference source is present, determine a location of the terminal device and determining a context of the intentional radio interference on the basis of the determined location of the terminal device.
In an embodiment, the notification message triggers an alarm.
In an embodiment, the target entity comprises at least one of the following: an emergency centre, a security service entity, a public safety entity, and an insurance entity.
Some embodiments of the invention are defined in the dependent claims.
Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which
The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words “comprising” and “including” should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may contain also features/structures that have not been specifically mentioned.
The terminal device 104 may operate in an idle mode in which it does not send or receive any data, and signalling with the bases stations is also reduced. The terminal device 104 may further operate in a connected mode in which it has established the radio connection with the base station, e.g. the base station 102, and transfer data with the base stations.
The cellular communication system may operate according to the specifications of a 2nd generation cellular communication system such as Global System for Mobile communications, 3rd generation cellular communication system such as Universal Mobile Telecommunication systems (UMTS) employing Wideband Code Division Multiple Access, or a 4th generation cellular communication system such as Long-Term Evolution (LTE) or LTE-Advanced of the UMTS.
In addition to the radio signals transmitted by the terminal device 104 and the base stations 100, 102, a radio interference source 106 is present in the vicinity of the terminal device. The radio interference source 106 is a source of intentional radio interference, and it is disposed in order to hinder or even prevent the communications of the terminal device 104. Such radio jammers may be used in connection with illegal activities such as burglaries or carjacking. The reason for using the radio jammers is to prevent emergency calls.
An embodiment of the invention provides the network infrastructure of the cellular communication system to detect the presence of the intentional radio interference by using existing control signals employed in the radio communications between the terminal device 104 and the base station(s) 100, 102. As a consequence, no dedicated control signals are needed for the detection of the intentional radio interference, although such dedicated signalling may be used in some embodiments. Referring to
Referring to
Upon determining as a result of said jammer detection procedure that the terminal device 104 is subject to the intentional radio interference or detection of the intentional radio interference source (block 206), the network element causes transmission of a notification message to a determined target entity (block 208).
In an embodiment, the target entity comprises at least one of the following: an emergency centre, a security service entity, a public safety entity, anti jamming function, jamming analysis function, O&M function, and an insurance entity.
Detection of the intentional radio interference in the network infrastructure provides an advantage that the radio interference may be detected in an element capable of conducting the emergency call or the alarm. In comparison, if the detection of the jamming is carried out in the terminal device, the terminal device may be in a situation in which it cannot send an alarm or emergency call even if it detects the presence of the jamming. As a consequence, the above-described embodiment provides an effective method for alarming the target entity of the intentional radio interference and appropriate countermeasures may be launched at an early phase.
In an embodiment, the network is configured to carry out the jammer detection procedure for terminal devices that are in the connected mode, e.g. have established a control channel connection with at least one base station of the cellular network infrastructure. In this embodiment, the jammer detection procedure may be disabled for the terminal devices that are not in the connected mode, e.g. for terminal devices that are in the idle mode.
In an embodiment, the uplink message is an uplink report indicating poor quality in a downlink connection. In another embodiment, the uplink message is a reference signal from which quality of an uplink connection may be determined.
In an embodiment, the network element uses, in the jammer detection procedure, measurement reports received from the terminal device.
While the RLF timer is counting, the terminal device may still send uplink measurement reports in step 308. The network element may use these measurement reports in the jammer detection procedure (block 310). Additionally or alternatively, the network element may use in block 310 measurement reports received before the downlink connection is lost or considered poor in quality. Embodiments of block 310 are described below. When the RLF time expires in block 312, an uplink connection with the terminal device may be disconnected, and the network element may not receive any further uplink measurement reports from the terminal device. Thereafter, the network element may use carry out the jammer detection procedure by using other means, e.g. previously received measurement reports and/or other measurements.
Let us now describe some embodiments for detecting the presence of the intentional interference in the jammer detection procedure with reference to
In an embodiment, the network element receives a channel quality indicator and a downlink signal strength metric (e.g. the path loss) from the terminal device and evaluates whether or not the downlink connection is interfered in the process of
In an embodiment, the network compares uplink quality with downlink quality and/or uplink signal strength with downlink signal strength and determines, on the basis of this comparison whether or not one of the uplink and downlink is interfered with intentional interference. For example, if the uplink quality is higher than the downlink quality by a determined amount, the network element may determine that the downlink is being interfered. On the other hand, if the downlink quality is higher than the uplink quality by a determined amount, the network element may determine that the uplink is being interfered. If the uplink signal strength is higher than the downlink signal strength by a determined amount, the network element may determine that the uplink is being interfered. On the other hand, if the uplink signal strength is lower than the downlink signal strength by a determined amount, the network element may determine that the downlink is being interfered.
In an embodiment the network uses transmitter powers of base station and terminal device together with the received signal strengths of both uplink and downlink for comparing path losses in order to detect if the terminal is interfered.
Furthermore, if signal strengths of one of or both the uplink and downlink are above a maximum signal level threshold, the network element may determine that intentional interference is present. The maximum signal level threshold may be selected to be so high that a false alarm is not triggered in the presence of only signal(s) transmitted by the terminal device or the base station even when superimposed with unintentional interference from neighbouring cells etc. An appropriate level may be derived on the basis of measurements and testing.
The process of
In the embodiment of
In an embodiment, the network element may compare the signal strengths of different cells or base stations with each other. If a plurality of cells or base stations are associated with approximately the same signal strength (within a determined tolerance), the network element may determine that the interference buries the signals transmitted by the base stations and that the intentional interference is present. This may enable the detection of broadband interference.
In the embodiment of
In an embodiment, the network element attempts to detect the context of the intentional interference upon detecting the presence of the intentional interference.
As a consequence, on the basis of the detection of the intentional interference and the determined location of the terminal device, the network element may in block 806 determine the possible context of the intentional interference and send the notification signal to a target entity associated with the determined context, e.g. an emergency centre, a security service, etc.
In summary, a jamming situation may be detected in the network infrastructure as a signature from measurement report(s) even before the connection with the, terminal device is lost. Indicators of the jamming may comprise: reported signal levels of serving cell and/or neighbour cell(s) are high and possibly approximately equal indicating use of broadband jammer; reception quality reported by the terminal device is poor or weak related to a signal level of a serving cell reported by the terminal device; earlier measurements may show a rapid trend from earlier non jammed situation (the rising edge).
Similar interference detection features may be implemented in the terminal device. A network infrastructure, e.g. the network element, may provide the terminal device with interference detection parameters enabling the terminal device to cope with different radio conditions. The parameters may be provided dynamically and/or at least some of the parameters may be static.
A result of one or more of the circuitries 54 to 58 may be output to the target entity in the notification message through an input/output (I/O) interface 62. The I/O interface 62 may provide a connection to other elements of the network infrastructure and, in some embodiments, to the terminal device. The I/O interface 62 may support one or more communication protocols comprising wired and/or wireless protocols. The I/O interface 62 may comprise circuitries and components necessary for providing the apparatus with communication capability. Such components may comprise modulation and/or coding circuitries, amplifiers, filters, frequency converters, etc.
As used in this application, the term ‘circuitry’ refers to all of the following: (a) hardware-only circuit implementations such as implementations in only analog and/or digital circuitry; (b) combinations of circuits and software and/or firmware, such as (as applicable): (i) a combination of processor(s) or processor cores; or (ii) portions of processor(s)/software including digital signal processor(s), software, and at least one memory that work together to cause an apparatus to perform specific functions; and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.
This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, the term “circuitry” would also cover an implementation of merely a processor (or multiple processors) or portion of a processor, e.g. one core of a multi-core processor, and its (or their) accompanying software and/or firmware. The term “circuitry” would also cover, for example and if applicable to the particular. element, a baseband integrated circuit, an application-specific integrated circuit (ASIC), and/or a field-programmable grid array (FPGA) circuit for the apparatus according to an embodiment of the invention.
The processes or methods described in connection with
The present invention is applicable to cellular or mobile communication systems defined above but also to other suitable communication systems. The protocols used, the specifications of such communication systems, their network elements and terminal devices, develop rapidly. Such development may require extra changes to the described embodiments. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
Number | Date | Country | Kind |
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EP13169348 | May 2013 | EP | regional |