H04KSECRET COMMUNICATIONJAMMING OF COMMUNICATIONIn this subclass, the following expression is used with the meaning indicated: "secret communication" includes secret line and radiation transmission systems, i.e. those in which apparatus at the transmitting station modifies the signal in such a way that the information cannot be intelligibly received without corresponding modifying apparatus at the receiving station. H04K1/00 H04K1/00Secret communication H04K1/003by varying carrier frequency at or within predetermined or random intervals H04K1/04 takes precedence H04K1/006by varying or inverting the phase, at periodic or random intervals H04K1/02by adding a second signal to make the desired signal unintelligible H04K1/025using an analogue chaotic signal H04K1/04by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band H04K1/06by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards H04K1/08by varying the polarisation of transmitted waves H04K1/10by using two signals transmitted simultaneously or successively H04K3/00Jamming of communicationCounter-measures H04K3/20Countermeasures against jamming in radar G01S7/36; interference suppression in receivers H04B1/10 H04K3/22including jamming detection and monitoring H04K3/222wherein jamming detection includes detecting the absence or impossibility of intelligible communication on at least one channel H04K3/224with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer H04K3/226Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02 H04K3/228Elimination in the received signal of jamming or of data corrupted by jamming interference suppression in receivers H04B1/10 H04K3/25based on characteristics of target signal or of transmission as countermeasure against surveillance H04K3/827, e.g. using direct sequence spread spectrum or fast frequency hopping spread spectrum techniques H04B1/69 H04K3/255based on redundancy of transmitted data, transmission path or transmitting source H04K3/28with jamming and anti-jamming mechanisms both included in a same device or system, e.g. wherein anti-jamming includes prevention of undesired self-jamming resulting from jamming H04K3/40Jamming having variable characteristics H04K3/41characterized by the control of the jamming activation or deactivation time control of jamming activation and deactivation time only for the purpose of alternating between jamming mode and target monitoring mode H04K3/45 H04K3/415based on motion status or velocity, e.g. for disabling use of mobile phones in a vehicle H04K3/42characterized by the control of the jamming frequency or wavelength H04K3/43characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area H04K3/44characterized by the control of the jamming waveform or modulation type H04K3/45characterized by including monitoring of the target or target signal, e.g. in reactive jammers or follower jammers for example by means of an alternation of jamming phases and monitoring phases, called "look-through mode" H04K3/46characterized in that the jamming signal is produced by retransmitting a received signal, after delay or processing H04K3/60Jamming involving special techniques H04K3/62by exposing communication, processing or storing systems to electromagnetic wave radiation, e.g. causing disturbance, disruption or damage of electronic circuits, or causing external injection of faults in the information H04K3/65using deceptive jamming or spoofing, e.g. transmission of false signals for premature triggering of RCIED, for forced connection or disconnection to/from a network or for generation of dummy target signal H04K3/68using passive jamming, e.g. by shielding or reflection shielding of apparatus or components against electric or magnetic field H05K9/00 H04K3/80Jamming or countermeasure characterized by its function H04K3/82related to preventing surveillance, interception or detection H04K3/822by detecting the presence of a surveillance, interception or detection H04K3/825by jamming H04K3/827using characteristics of target signal or of transmission as countermeasure against jamming H04K3/25, e.g. using direct sequence spread spectrum or fast frequency hopping spread spectrum techniques H04B1/69 H04K3/84related to preventing electromagnetic interference in petrol station, hospital, plane or cinema H04K3/86related to preventing deceptive jamming or unauthorized interrogation or access, e.g. WLAN access or RFID reading record carriers with integrated circuit chips including means for preventing undesired reading or writing from or to record carriers by hindering electromagnetic reading or writing G06K19/07318; arrangements for sensing record carriers including arrangements for protecting the interrogation against piracy attacks G06K7/10257 H04K3/88related to allowing or preventing alarm transmission H04K3/90related to allowing or preventing navigation or positioning, e.g. GPS H04K3/92related to allowing or preventing remote control H04K3/94related to allowing or preventing testing or assessing H04K2203/00 H04K2203/00Jamming of communicationCountermeasures H04K2203/10Jamming or countermeasure used for a particular application H04K2203/12for acoustic communication H04K2203/14for the transfer of light or images, e.g. for video-surveillance, for television or from a computer screen H04K2203/16for telephony H04K2203/18for wireless local area networks or WLAN H04K2203/20for contactless carriers, e.g. RFID carriers record carriers with integrated circuit chips including means for preventing undesired reading or writing from or to record carriers by hindering electromagnetic reading or writing G06K19/07318; arrangements for sensing record carriers including arrangements for protecting the interrogation against piracy attacks G06K7/10257 H04K2203/22for communication related to vehicles H04K2203/24for communication related to weapons H04K2203/30Jamming or countermeasure characterized by the infrastructure components H04K2203/32including a particular configuration of antennas H04K2203/34involving multiple cooperating jammers H04K2203/36including means for exchanging jamming data between transmitter and receiver, e.g. in forward or backward direction