Patent Grant
9515768
The present invention relates to a method of detecting a jamming transmitter affecting a communication user equipment according to the preamble part of claim 1. The present invention also relates to a device configured to execute said method and a system of the device with the user equipment with interfaces to the user equipment and with an application configured to execute said method.
Contemporary cellular radio networks known since many years are now meanwhile based on different technologies. The broadest coverage still is held by the global system for mobile communications according to the so-called GSM standard. A user equipment in such cellular network can move freely and may be handed over to various cells of the GSM networks as for instance described in GSM standard specification 3GPP ETSI TS 51.010 or the like.
Contemporary radio networks are based on a cellular code division multiple access CDMA as for instance realized in the universal mobile telecommunication system UMTS. Networks implementing these standards are increasingly important for security applications like camera systems or the like.
Generally, a user equipment in radio networks can be subject of being affected by a jamming transmitter—jamming in this context generally is performed by an instrument preventing a user equipment from receiving signals from its base station. In use the jammer effectively disables cellular phones mostly by broad frequency interference with communication frequencies of the user equipment at high power level. Whereas some jammer applications are meant to be legal for instances in places where phone call is to be suppressed due to silence conditions. Other jammers are applied during misuse for instances to interrupt security applications of user equipment or the like. Jammers are available for jamming GSM and also UMTS frequencies. However, jamming detecting and preventing solutions are known up to date basically only against GSM jammers. In this regard, it should be recognized that primary aim of an anti-jamming solution is to undoubtedly detect a jamming attack; however, it is also desirable to prevent the same.
In WO2005/112321 a method for jamming detection in a GSM mobile telecommunications network is described comprising the steps of, at a user equipment registered with the mobile telecommunications network: a) measuring a signal power level in at least one of a plurality of communication channels between the user equipment and a base station within a band of operation of the mobile telecommunications network; b) checking whether the signal power level in said at least one communication channel is greater than a threshold MNPL and, if so, attempting to decode a Base Station Identity Code BSIC broadcast by the base station in said communication channel; c) repeating steps a) and b) for a certain number of channels; d) signaling a jammed condition report JDR message to the base station if said BSIC cannot be decoded for said number DCMN of channels. This method suffers from the fact that usually a signaling of a jammed condition report JDR message to the base station is not possible due to the jammed condition; thus the jammed condition remains unanswered.
An anti-jamming solution is known from WO 2007/019814 which however also is restricted to the GSM standard. Therein a method for detecting a jamming transmitter affecting a communication terminal is described wherein receipt radio channel signal levels are evaluated at periodic intervals on a signaling channel. In the case that the communication terminal detects a radio channel signal level that exceeds a predefined threshold value in the signaling channel but is nevertheless unable to decode a message content of a message, then this state is interpreted as an interference state and an alarm signal is emitted. The problem related with this GSM anti-jamming solution is its fundament on a predefined threshold value in the signaling channel and the receipt of a message content. These features are somewhat specific for the GSM technology, however, less suited in the UMTS technology. More specifically it turns out that an anti jamming solution in the frame of a cellular code division multiple access based radio network is much more demanding. The state of dealing with disturbances in a communication frequency band of a user equipment is more or less a usual state of operation for a user equipment within a cellular code division multiple access based radio network. In particular, intracell and intercell interferences are generally accepted in a CDMA based radio network as long as a signal can be decoded. Thus, the state of operation naturally is permanently disturbed due to the CDMA based technology.
The specific reason is as follows. A communication user equipment UE and a number of base node stations BNS are the basic components of a CDMA based radio network. The radio network RN may work in either a frequency division duplex FDD or also a time division duplex TDD mode. Once a communication link in a serving cell coverage area is provided between the communication user equipment and a serving base node station sBNS a communication signal unit SU is correlated with a pseudonoise spread code SC in a serving cell coverage area CA of a serving base node station and transmitted as a pseudonoise chip CHI in a multiple shared communication frequency channel. Thus, interferences of multiple base node stations and user equipments in the communication frequency channel are spectrally located between an upper frequency and a lower frequency of a communication frequency band. Consequently, a broad band “jamming like” interference in the multiple shared communication frequency channel can not be considered as an extraordinary event but is on the contrary part of the usual state of operation. Such situation may also occur each time the number of users changes in said frequency band. The similar situation may also occur when a user equipment has a comparatively large or a comparatively small distance to a base node station. Also a similar situation may occur when a user equipment is in the reach of two base node stations in particular vice versa when two user equipments belong to the same or neighboring cells of the CDMA based radio network. In conclusion, an anti-jamming solution to be successfully implemented in a CDMA based radio network technology is more sophisticating.
In WO 00/62437 a concept for improving jammer detection sensitivity in a CDMA based communication network is provided wherein spectral analysis data are used to identify jamming signals having power spectral density characteristics which are distinguishable from those of legitimate subscriber transmissions in the wireless system's frequency band. By using several base stations located near the jamming transmitter, and by comparing the power spectral densities received at those base stations, the location of the jamming transmitter is estimated. Additionally, such spectral analysis data is used to detect aberrant receive spectrum characteristics which may indicate a hardware malfunction or failure. The spectral analysis uses a model of a real-input-data FFT and complex-input-data FFT for a CDMA signal bandwidth C of approximately 1.25 MHz and is based on the assumption that a jammer detection threshold will be set relative to a “noise floor”, and it can be concluded that the jammer detection threshold will be the same for the two cases of a FFT. The (in-band) power spectral density P will be the same for either technique, with the power spectral density equaling P/C. But because the jammer power divided equally between a I and a Q branch, the jammer power will be 3 dB less for the real-input-data FFT than in the case of the complex-input-data FFT.
Nevertheless, generally and as compared to the above mentioned GSM solution of WO 2007/019814 and WO2005/112321 a predefined threshold value for a signal level of a specific signalizing channel for a user equipment per se cannot be defined. Either the channel and/or the signal level is continuously changing depending on the surroundings of the network. Also, a message content as such can not be received unless a pseudonoise spread code is received by the communication user equipment. Consequently, without pseudonoise spread code neither transmission nor a content of a message is possible unless the pseudonoise spread code is known to the user equipment.
In 3GPP TS 25.133 in Chapter 422.1 a measurement and evaluation of cell selection criteria S of a serving cell is described, wherein the user equipment shall measure the CPICH Ec/Io and CPICH RSCP level of the serving cell and evaluate the cell selection criterion S defined in 3GPP TS 25.304 (“UE Procedures in Idle Mode and Procedures for Cell Reselection in Connected Mode”). After a certain period a user equipment is considered to be “out of service area” and shall perform actions according to 3GPP TS 25.331 (“RRC Protocol Specification”). On transition of the user equipment to another cell and if a user equipment cannot find a suitable UTRA cell, then it is considered to be “out of service area” and shall perform actions according to 3GPP TS 25.331. Thus, in principle, if no suitable cell according to its power level is found, the user equipment shall be considered to be out of service. This procedure demands for measuring one or more power levels.
Although a jamming-detection concept can be advantageously also be based identifying contents of messages or on measuring power levels, primarily it is desirable to have an anti-jamming concept which is less dependent on sophisticated measurement of signal strength or power and thus is more reliable. In particular in a CDMA based radio network decoding and dispreading procedures have to be taken into account when a comparison of power levels is taken as a basis for a jamming-detection and could be avoided. Also, all the above mentioned approaches suffer from the fact that a jamming situation can only be detected rather than prevented. However, jamming preventing solutions are highly desirable for UMTS standards. In this regard, it should be recognized that primary aim of an anti-jamming solution is to undoubtedly detect a jamming attack but nevertheless preventing the same shall be possible as well. At least a rather early detection of a jamming attack can help to prevent the same.
Usually, jamming results first in a user equipment losing traffic connection to the base station; thus user equipment falls back to idle mode. Thus, the mobile station is not able to make or receive a call. The above jamming approaches have the aim to detect a jamming situation only in the idle mode before the user equipment is unable to continue camping on the cell. It is known for instance that the idle mode still preserves certain operations as the user equipment is still registered in the radio network, that is when the user equipment (also referred to as a mobile station MS) is switched on but has no dedicated physical channel allocated. In particular certain idle mode tasks are still possible to provide a radio subsystem link control. As outlined above, a jamming detection in the idle mode is rather late and thus limits the chances to prevent a jamming situation.
This is where the invention comes in, the object of which is to provide an improved method of detecting a jamming transmitter affecting a communication user equipment wherein the communication user equipment and a number of base node stations are adapted to be components of a cellular code division multiple access based radio network like for instance frequency division duplex or time division duplex mode radio network. In particular it is an object of the invention to provide a method of detecting a jamming transmitter rather early, in particular prior that the user equipment falls back into the idle mode. A further object of the invention is to provide an improved communication module, in particular user equipment, adapted to execute the method of detecting a jamming transmitter affecting the communication user equipment, in particular to detect the jamming situation already whilst the communication user equipment is in a connected mode, in particular if the user equipment has a dedicated physical channel allocated; preferably before the connection breaks down. In particular the method and the communication module shall be adapted to detect a jamming warning before a jammed situation is to be accepted; in particular it shall be discriminated between an out of service state of the user equipment and a jamming warning situation. It is still another object of the invention to provide such method and device with a more elaborated anti-jamming concept allowing also detection of a jamming transmitter on a broad frequency range. In particular it is an object of the invention to provide an effective and reliable method and device for detecting a jamming transmitter affecting a communication user equipment and while nevertheless being less dependent on sophisticated measurement of signal strength or power.
As regards the method, the object is achieved by the invention with a method as claimed in claim 1.
As regards the device, the object is achieved by the invention with a device for a user equipment as claimed in claim 15.
As regards the device, the object is achieved by the invention with a system as claimed in claim 16.
Therein a communication user equipment UE is adapted for communication with a component of a cellular radio network RN having a number of user equipments UE and a number of base node stations BNS. Preferably the cellular radio network RN provides a synchronization channel SCH for synchronization of the user equipment UE to a cell of the cellular radio network RN, and wherein the detection device is provided in the neighborhood or part of the user equipment. Said communication user equipment UE and a number of base node stations BNS are components of a cellular code division multiple access CDMA based radio network RN, in particular in a frequency division duplex FDD or time division duplex TDD mode. Preferably a pseudonoise spread code SC is for spreading a communication signal unit SU and a synchronization of the user equipment UE to a cell of the cellular radio network RN is determined during a cell search from a synchronization channel.
The instant concept of jamming detection and/or warning according to the invention is based on providing the user equipment UE in a connected mode of a communication radiolink with the component of the radio network RN. According to the invention in the connected mode of said user equipment UE the steps are provided:
The cellular radio network RN provides a dedicated channel DPCH for a communication radiolink of the user equipment UE to a cell of the cellular radio network RN and the user equipment UE is in a connected mode of a communication radiolink via the dedicated channel DCH. The synchronization-indication is generated from power monitoring of the dedicated physical channel (DPCH). Advantageously the dedicated physical channel DPCH is a dedicated physical data channel DPDCH and/or dedicated physical control channel DPCCH.
Preferably said communication user equipment (UE) and a number of base node stations (BNS) are components of a cellular code division multiple access (CDMA) based radio network (RN), in particular in a frequency division duplex (FDD) or time division duplex (TDD) mode, wherein a pseudonoise spread code (SC) is for spreading a communication signal unit (SU) and a synchronization of the user equipment (UE) to a cell of the cellular radio network (RN) is determined during connected mode of a communication radiolink via the dedicated channel (DPCH), adapted to indicate, in particular to an application layer, that a jamming transmitter is affecting the communication user equipment.
The method and developed configurations thereof as outlined above may be implemented by digital circuits of any preferred kind, whereby the advantages associated with the digital circuits may be obtained. In particular one or more method steps or features of the method can be implemented by one or more means for functionally executing the method step. A single processor or other unit may fulfill the functions of several means recited in the claims—this in particular holds for a user equipment according to the concept of the invention. The concept also leads to a computer program product storable on a storage device and adapted for executing the method when executed on a device.
The invention starts from the consideration that the user equipment per se and without further measures cannot distinguish between a normal mode frequency disturbance due to interferences originating from the CDMA system as outlined in the introduction on the one hand and a loss of service availability due to external disturbing factors which in the specific situation usually cannot be fixed. Basically for detecting a jamming transmitter affecting a communication user equipment and while nevertheless being less dependent on sophisticated measurement or comparison of signal strength or power the invention provides an alternative concept for nevertheless actively and reliably detecting a jamming situation.
Further the invention starts from the consideration that instant approaches for detecting a jamming situation are based on measurements at a mobile station (user equipment UE) in the idle mode. The instant invention recognized that nevertheless it is also possible to find sufficient indication for a jamming situation when the user equipment is in a connected mode of a communication radiolink to a component of the radio network; thus in particular wherein during the connected mode the user equipment has a dedicated physical channel allocated. So to say, in particular the concept starts from the recognition that a jamming detection preferably is possible in a status where the mobile station has a dedicated physical channel allocated; thus is able to make or receive a call. Advantageously this approach allows for detecting a jamming attack even during a call or connection, i. e. an in-call/connection jamming detection concept is provided.
Consequently, the method is characterized by providing the user equipment in a connected mode of a communication radiolink to a component of the radio network. More precisely, the method provides a basis to observe the impact of the jammer, respectively jamming power, on an existing radiolink. Preferably the user-equipment indeed can be in an active-status, i.e. is switched on. Consequently, the method preferably further is characterized by providing the user equipment in an active-status, respectively switched on.
The concept of the invention thus has an advantage overcoming solutions wherein a jamming detection is possible only in the idle mode or even only in the out of service mode. Instantly, the concept provides a method for detecting a jamming situation in-call/connection, that is to say, already when a dedicated physical channel is allocated for the mobile station a jamming situation or an approach of a jamming situation can be detected. This has the advantage that a camera or other security systems can provide a better performance. An anti-jamming detection is rather quick and countermeasures can be provided in a broader and earlier range.
For instance according to a known approach, a jamming detection is based on detecting that no cell can be received (BCCH) although a high RSSI level is measured. But in a jamming situation a mobile station will at first lose the connected mode of a communication radiolink and will than fall back into the idle mode. Subsequently, the mobile station will have to provide a band or channel search and only in the case this search is not successful a jamming situation can be assumed. In this stadium the mobile station might already be in the out of service situation. This is disadvantageous as it takes time to identify a jamming situation. However time is a valuable parameter in security applications like camera systems or the like.
By generating a synchronization indication—in particular generating an out of synchronization (OUT-OF-SYNC) or in synchronization (IN-SYNC) status—from power monitoring—in the connected mode, i. e. an in-call connection, in the dedicated physical channel—and evaluating the synchronization indication, the concept of the invention is able to Indicate a jamming situation already when the user equipment still is functioning in a connected mode, although the radiolink in the connected mode is already endangered.
The concept provides also for measuring a further parameter at the dedicated physical channel (DPCH), namely a Layer-1 parameter. Preferably a Layer-1 parameter is any parameter, which is measurable directly at the dedicated physical channel (DPCH).
Preferred examples of a Layer-1 parameter are a value of a received signal code power (RSCP) value or a value of average energy per pseudonoise chip (PN) in the DPCH or a total transmit power spectral density. In particular preferred is a value of the ratio Ec/Io of the average transmit energy per PN chip for different fields or physical channels, in particular the DPCH, to the total transmit power spectral density. If one of these or other comparable Layer-1 parameters indicate a high energy in the DPCH in combination with a lasting situation of IN-SYNC status than a very reliable indication of a jamming detection can be given.
Also, alternatively or a value of a check sum, e.g. a hash value or the like control value transmitted with the data or provided for control or check of the transmission can be used. Once the transmitted control value—in particular the checksum—is correct this is an indication of a correct transmission; however a deviation indicates a disturbed transmission. Thus a deviating control value can be used as a further parameter at the dedicated channel in the Layer-1 to indicate a jamming situation.
The concept of the invention also leads to a device for a user equipment, in particular a device reportingly connectable to an application layer, in particular configured to execute the method of detecting a jamming transmitter. According to the Invention the device is adapted to detect a jamming transmitter affecting the communication user equipment in a connected mode wherein the cellular radio network (RN) provides a dedicated channel (DPCH) for a communication radiolink of the user equipment (UE) to a cell of the cellular radio network (RN) and the user equipment (UE) is connectable in a connected mode of a communication radiolink via the dedicated channel (DPCH), wherein the detection device has
The concept of the invention also leads to system of the device and a communication user equipment (UE) adapted for communication with a component of a cellular code division multiple access (CDMA) based radio network (RN) having a number of user equipments (UE) and a number of base node stations (BNS), wherein the cellular radio network (RN) provides a dedicated channel (DPCH) for a communication radiolink of the user equipment (UE) to a cell of the cellular radio network (RN) and the user equipment (UE) is connectable in a connected mode of a communication radiolink via the dedicated channel (DPCH), wherein the synchronization-indication is generated from power monitoring of the dedicated physical channel (DPCH), preferably wherein the detection device is provided in the neighborhood or as part of the user equipment.
These aspects of the invention and further developments thereof are further outlined in the dependent claims. Thereby the mentioned advantages of the proposed concept are even more improved.
Generally existing synchronization primitives as described in TS 25.214 can be used to derive the synchronization-indication, in particular IN-SYNC and/or OUT-OF-SYNC.
Most preferably the synchronization-indication is generated by means of a transmission power control (TPC). Transmission power control (TPC) is defined in the standard 3GPP TS 25.101. The power control step is the change in the UE transmitter output power in response to a single TPC command, TPC_cmd, derived at the UE. The UE transmitter shall have the capability of changing the output power in each assigned carrier. Per TPC_cmd a certain transmitter power control range is defined as outlined in 6.42.1 of 3GPP TS 25.101. TPC can be set for uplink, downlink, minimum, maximum power in open-loop or closed-loop condition. A transmission power control error is already defined in the standard and thus can be used advantageously for jamming detection. Preferably a rate of transmission power control errors can be used. E.g. the synchronization-indication is generated in a cycle to provide a rate of synchronization-indication, in particular wherein a cycle has a periodicity, in particular in a periodicity on a millisecond (ms) timescale.
Out-of-synchronization handling of output power as described in 6.4.4 of 3GPP TS 25.101 comprises the receiver characteristics in as specified at the antenna connector of the UE. For UE(s) with an integral antenna only, a reference antenna with a gain of 0 dBi is assumed. UE with an integral antenna may be taken into account by converting these power levels into field strength requirements, assuming a 0 dBi gain antenna. For UEs with more than one receiver antenna connector the AWGN signals applied to each receiver antenna connector shall be uncorrelated. The levels of the test signal applied to each of the antenna connectors shall be as defined in section 6.4.4.2 of 3GPP TS 25.101. The UE shall monitor the DPCCH quality in order to detect a loss of the signal on Layer 1, as specified in 3GPP TS 25.214. The thresholds Qout and Qin specify at what DPCCH quality levels the UE shall shut its power off and when it shall turn its power on respectively. The thresholds are not defined explicitly, but are defined by the conditions under which the UE shall shut its transmitter off and turn it on. The DPCCH quality shall be monitored in the UE and compared to the thresholds Qout and Qin for the purpose of monitoring synchronization. The threshold Qout should correspond to a level of DPCCH quality where no reliable detection of the TPC commands transmitted on the downlink DPCCH can be made. This can be at a TPC command error ratio level of e.g. 30%. The threshold Qin should correspond to a level of DPCCH quality where detection of the TPC commands transmitted on the downlink DPCCH is significantly more reliable than at Qout. This can be at a TPC command error ratio level of e.g. 20%.
In a preferred embodiment the synchronization-indication is evaluated to a binary set of an in-synchronization state and an out-of-synchronization state. In particular then an out-of-synchronization state is used as a parameter to detect a jamming situation and/or an in-synchronization state is used as a parameter to detect a free-of-jamming situation.
Thus, particular preferred the jamming situation is detected only in dependence of a number of Layer-1 parameters. In particular only a Layer-1 parameter is selected from the group consisting of: one or more link power signals, one or more link quality signals, in particular an active set RSSI and/or a Ec/Io-signal, in-synchronization state, out-of-synchronization state.
Alternatively or additionally even more advantageous the synchronization-indication, i.e. most preferably a power monitor of the dedicated physical channel, is evaluated as function of time and/or amplitude, in particular according to one or more derivation of the function of time. Thus, the jamming situation is detected in dependence of a Layer-1 parameter and a Layer-2 parameter.
Thus, alternatively or additionally the synchronization-indication is evaluated as function of time and/or amplitude, in particular according to one or more derivation of the function. More precisely the synchronization-indication is evaluated by means of at least one amplitude measure for evaluating the amplitude behavior of the synchronization-indication, in particular wherein the amplitude of an out-of-synchronization state is evaluated to detect a jamming situation and/or the amplitude of an in-synchronization state is evaluated to detect a free-of-jamming situation. Alternatively or additionally more precisely the synchronization-indication is evaluated by means of at least one time measure for evaluating the time behavior of the synchronization-indication, in particular wherein the time span of an out-of-synchronization state is evaluated to detect a jamming situation and/or the time span of an in-synchronization state is evaluated to detect a free-of-jamming situation.
In particular the jamming situation is detected also in dependence of a number of further parameters—in particular a Layer-1 parameter and/or Layer-2 parameter and/or application layer parameter—wherein the further parameters are selected from the group consisting of: one or more good-reference parameters, one or more timers and/or counters, one or more cycles, in particular a periodicity.
Preferably the synchronization-indication is further evaluated by means of at least one time measure and the time measure has one or more start-triggers and/or stop-triggers and/or one or more timer- and/or counter-means. This can be used to increase reliability of a jamming detection and/or warning. More specifically preferred is a first timer- and/or counter-means starting from a begin-time (t3) of an OUT-OF-SYNC state, in particular for indicating a OUT-OF-SYNC error after expiration. Even more specifically preferred is a second timer- and/or counter-means starts from a time (t4) of an OUT-OF-SYNC state after a first timer- and/or counter-means, in particular for indicating a RADIO LINK failure. Even more specifically preferred is a third timer- and/or counter-means starts from a begin-time (t5) of an IN-SYNC state after a first timer- and/or counter-means, in particular for stopping a first and/or second timer- and/or counter-means, in particular for indicating an end-of-jamming situation. The timers can be set freely according to the situation and adapted to the demands of the technical application.
Preferably existing synchronization primitives can be used and evaluated as described in TS 25.331 to derive the synchronization-indication, in particular in accordance to evaluation methods used for deriving a radio link failure criteria, in particular at least one counter or one or more of a N313-value and/or a T313-value and/or a T315-value.
Even more advantageous, as exemplified in the drawing at
For a more complete understanding of the invention, the invention will now be described in detail with reference to the accompanying drawing. The detailed description will illustrate and describe what is considered as a preferred embodiment of the invention. It should of course be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention may not be limited to the exact form and detail shown and described herein, nor to anything less than the whole of the invention disclosed herein and as claimed hereinafter. Further the features described in the description, the drawing and the claims disclosing the invention may be essential for the invention considered alone or in combination. In particular, any reference signs in the claims shall not be construed as limiting the scope of the invention. The wording “comprising” does not exclude other elements or steps. The wording “a” or “an” does exclude a plurality.
In the drawing:
The communication link 1 is adapted for transmitting a signal comprising multiple communication signal units SU between the communication user equipment UE #1 and the serving base node station sBNS #1. As exemplified in
As a result, the pseudonoise chip CHI is transmitted in a multiple shared communication frequency channel as indicated in the communication link 1 of
The pseudonoise spread code SC is received by the communication user equipment UE #1 as a serving pseudonoise spread code sSC as shown in
As outlined in 3GPP ETSI TS25.214 during the cell search, a user equipment UE searches for a cell and determines the downlink spreading code and frame synchronization of that cell. The cell search is typically carried out in three steps:
Step 1: Slot synchronization
Step 2: Frame synchronization and code-group identification
Step 3: Spreading-code identification
During the third and last step of the cell search procedure, the UE determines the exact primary spreading code used by the found cell. The primary spreading code is typically identified through symbol-by-symbol correlation over the CPICH with all codes within the code group identified in the second step. After the primary spreading code has been identified, the Primary CCPCH can be detected. And the system- and cell specific BCH information can be read. If the user equipment UE has received information about which spreading codes to search for, steps 2 and 3 above can be simplified. Once the spreading code for a CPICH is known, the channel can be used for measurements of signal quality, usually with RSCP and Ec/I0 as will be shown below. Timing and phase estimations can also be made, providing a reference that helps to improve reliability when decoding other channels from the same Node B.
In the UMTS cellular communication system, received signal code power RSCP denotes the power measured by a receiver on a particular physical communication channel. It is used as an indication of signal strength, as a handover criterion, in downlink power control, and to calculate path loss. In CDMA systems, a physical channel corresponds to a particular spreading code, hence the same. While RSCP can be defined generally for any CDMA system, it is more specifically used in UMTS. Also, while RSCP can be measured in principle on the downlink as well as on the uplink, it is only defined for the downlink and thus presumed to be measured by the UE and reported to the Node B.
In the instant embodiment, a jammer affects the user equipment UE #1 by interfering with the multiple shared communication frequency channel as located in a communication frequency band. Frequency bands FBI to FBIXX are known, each having a bandwidth of approximately 60 MHz. Each frequency band comprises several communication frequency channels, each having a bandwidth of 5 MHz. For each frequency channel, therefore the noise floor of 110 dBm can be defined based on a relative noise of 174 dBm/Hz.
A staple power for an out of jamming region user equipment UE #10 is a piled up staple with a rather small amount of CPICH power, a larger amount of signal code power dedicated to the user equipment and a main portion of shared signal power. The latter is used by several user equipments in the same 5 MHz bandwidth of the communication frequency channel. Nevertheless, information can be retrieved for each user equipment according to the pseudonoise spread code provided by the serving base node station and also the further base node station to each of the user equipments.
Once the number of user equipments changes in a coverage area CA1 of the service base node station 1 the shared signal power may vary rather often. However, as the serving pseudonoise spread code SSC is available for the user equipment UE #10 even upon variation of the shared signal power, user equipment UE #10 can uphold the communication link to the serving base node station sBNS #1. The reason for this is that even upon variation of the shared signal power nevertheless the CPICH power can be detected by the user equipment UE #10. The CPICH power normally is located not more than 24 dBm below the upper level of the staple power. Thus, due to the spread code gain value of instantly 24 dBm CPICH power and pseudonoise spread code SC can be detected by the user equipment UE #10 during normal operation.
In the case the distance between serving base node station sBNS #1 and user equipment UE #10 is diminished like for instance the distance between sBNS #1 and UE10 the cell selection criteria power parameters Ec/Io ratio—in the standard denoted as CPICH Ec/Io as well as the received signal code power CPICH RSCP will increase—thus overall the signal quality will increase. However, in the case the distance between UE #10 and sBNS #1 is enlarged—for instance by moving to UE #20—the biased parameter Ec/Io, i.e. ratio CPIHC Ec/Io and the received signal code power CPICH RSCP of the sBNS #1 will decrease but instead of those of the BNS #2 will increase. Thus, upon a situation, the soft-handover may occur between sBNS #1 and BNS #2 by moving UE #10 to UE #20. This situation is described for instance in 3GPP TS25.133.
Distinct from those normal operation interferences in the communication frequency channels is the situation shown in
The presence results in a user equipment UE #1 received staple power. Additional to the CPICH power the dedicated signal code and the shared signal power a large pile of jamming power on top of the staple power is detected by UE #1. The CPICH power therefore is not anymore in the spread code gain and consequently cannot be detected anymore. This situation is to be distinguished from the out of range situation as described in TS25.133 chapter 4.2.2.1. Namely, in the presently described situation of
In principle this situation can be used to detect a jamming transmitter affecting the user equipment UE #1 when also an unbiased received wideband power within the bandwidth of the communication user equipment receiver at the communication user equipment UE #1 antenna connector is measured. Upon verifying the condition that the biased parameters—namely the Ec/Io and RSCP—are not detectable and the unbiased parameter RSSI has increased a first indication of a jamming transmitter is given.
However, this demands for comparison of power levels of different points of time; namely before and after the jamming situation. However, due to the timespan in between the different points of time the user equipment UE #1 may have fallen back into the idle mode and thus loosing the communication link cannot be prevented anymore. According to the concept of the invention this situation can be used already to provide an effective concept of detecting a jamming transmitter affecting the user equipment UE #1 without detecting and comparing power levels.
In particular according to the concept of the invention detection of a jamming situation is possible in a connected mode of the user equipment, said communication user equipment UE is adapted for communication with a component of a cellular code division multiple access CDMA based radio network RN having a number of user equipments UE and a number of base node stations BNS. As a preferred prerequisite it can be made sure, that the user equipment indeed is in a UMTS communication modus and the received signal strength is a signal of a CDMA based radio network. Here it is verified whether a respective UMTS communication indicator is set. E. g. a UMTS communication indicator can be on hold by means of a binary value stored or some setting of a user equipment which is indicative that the user equipment is capable and in reach of a UMTS communication signal. More importantly, as described in 3GPP TS 25.124 Chapter 4.3. in detail for the dedicated physical channels DCH, synchronization primitives are used to indicate the synchronization status of radio links, both in uplink and downlink.
In detail for downlink synchronization primitives the criteria for reporting synchronization status are defined in two different phases. Each phase is performed by the UE for each individual downlink frequency associated with the activated uplink frequencies. The downlink synchronization primitives are also reported to higher layers for each individual downlink frequency associated with the activated uplink frequencies. The first phase starts when higher layers initiate dedicated physical channel establishment or whenever the UE initiates one of a number of existing synchronization procedures as described in section 4.3.2.1 and 4.3.2.3A of 3GPP TS 25.124 and lasts until 160 ms after the downlink dedicated physical channel is considered established by higher layers (which is a physical channel establishment as defined in 3GPP TS 25.331: “RRC Protocol Specification”). During this time out-of-sync shall not be reported and in-sync shall be reported if a certain Transmit power control (TPC) criterion is fulfilled. The second phase starts 160 ms after the downlink dedicated physical channel is considered established by higher layers. During this phase both out-of-sync and in-sync are reported. Out-of-sync shall be reported if another certain Transmit power control (TPC) criterion is fulfilled. In-sync shall be reported if another certain Transmit power control (TPC) criterion is fulfilled. How the primitives are used by higher layers is described in 3GPP TS 25.331. The above definitions may lead to radio frames where neither the in-sync nor the out-of-sync primitives are reported.
In detail for uplink synchronization primitives Layer-1 in the Node B shall every radio frame check synchronization status of all radio link sets. Synchronization status is indicated to the RL Failure/Restored triggering function using either a certain IN-SYNC-indication primitive or a certain OUT-OF-SYNC-indication primitive. Hence, only one synchronization status indication shall be given per radio link set. The exact criteria for indicating in-sync/out-of-sync is not subject of the standard, but could e.g. be based on received DPCCH quality or CRC checks. One example would be to have the same criteria as for the downlink synchronization status primitives.
In particular, as will be described further, in a preferred embodiment a DPCCH or DPDCH can be used as part of a DPCH of a user equipment which exists for practical all operations, even when HSDPA/HSUPA operation is applied. A DPCH of a user equipment is needed as a reference in particular for a power control, preferably uplink and/or downlink power control. A Layer-1 information is given by a transmit power control TPC which can be used for addressing the state of the DPCH. In the case of jamming the transmit power control TPC is expected to be no more detectable and the user equipment stops transmitting as the transmit power control TPC, in particular the uplink (UL) transmit power control TPC is an important feature for the network. In this embodiment the power control is made on a received DPCCH whereas nevertheless any other DPCH could be used. But the DPCCH is part of the DPCH and is always existent even when HSDPA or HSUPA is made. 3GPP TS 25.101 explains in general certain Transmit power control (TPC) and tests in general and in Chapter 6 for a transmitter.
Thus, to the understanding here, generally power control, broadly speaking, is the intelligent selection of transmit power in a communication system to achieve good performance within the system. The notion of “good performance” can depend on context and may include optimizing metrics such as link data rate, network capacity, geographic coverage and range, and life of the network and network devices. Power control algorithms are used in many contexts including cellular networks. Transmit Power Control (TPC) is a technical mechanism used within some networking devices in order to prevent too much unwanted interference between different wireless networks (e.g. the owner's network and the neighbor's network). The network devices supporting this feature are e.g. IEEE 802.11h Wireless LAN devices in the 5 GHz band compliant to the IEEE 802.11a.
The idea of the mechanism is to automatically reduce the used transmission output power when other networks are within range. Reduced power means reduced interference problems and increased battery capacity. The power level of a single device can be reduced by 6 dB which should result in an accumulated power level reduction (the sum of radiated power of all devices currently transmitting) of at least 3 dB (which is half of the power).
The concept of the instant invention is based on detecting of an in-sync and/or out-of-sync behavior—the state, evolution and/or transient development—relative to the criteria of a threshold system; an example is given in
The embodiment of 3G in-call early jamming-detection is used to detect a jamming situation before a Radio link Failure is reported and before being out of service. The 3G in call early jamming detection is based on the Out-of-synchronization handling described in 3GPP TS 25.101. The UE shall monitor the DPCCH quality in order to detect a loss of the signal on Layer-1. The DPCCH quality is used in the UE for the purpose of monitoring synchronization.
The quality criterion is based in present example on measurement of the TPC command error ratio level, which is compared in the UE and to the thresholds Qout and Qin. These thresholds are used for decision if reliable detection of the TPC commands transmitted on the downlink DPCCH can be made.
The concept of the exemplifying approach as shown in
Those values TPC1 below the low threshold TPCeL label a first time span t1, t2 and a second time span t5, t6 which are assigned to an in-synchronization state IN-SYNC. Those values TPC3 however which exceed the high threshold TPCeH label a time span t3, t4 which is assigned to an out of synchronization state out of sync. The reason is that the thresholds TPCeL and TPCeH can be such that according to experienced values error rates TPC1 on the one hand can be assigned to an IN-SYNC state and error rates TPC3 can be assigned to a OUT-OF-SYNC state respectively.
TPC error rates TPC2 in between the thresholds TPCeL and TPCeH are considered to be not clearly assignable to one or the other binary state of IN-SYNC state and OUT-OF-SYNC state; thus a gap between thresholds TPCeL and TPCeH increases reliability of this embodiment. However, in a more simplified embodiment also a single threshold TPCeM, e.g. somewhere in between TPCeL and TPCeH as an example, can be used to distinguish between TPC1 and TPC3 values.
As will be clear from the further description further parameters can be used to also clarify assignability of TPC error rate values to either TPC1 or TPC3 like values if considered as useful. Here not only the amplitude of a TPC error rate can be used as a single parameter for generating the synchronization indication but also further parameters like those shown in
In detail,
A number of further parameters are shown in a group of optional selection in
A method as exemplified in flow chart of
In an even further embodiment additionally a counter N315 can be used which is triggered by an IN-SYNC state as generated and evaluated in steps S4 of
Further, in S6.3 a value of a control value e.g. a checksum, hash value or the like for a field of physical channel usually can be defined as a control value which is transmitted in the dedicated physical channel; once the transmitted control value—namely the checksum—is correct this is an indication of a correct transmission. However, if the checksum or the like control value is not correctly transmitted and/or not correctly confirmed—e.g. by comparing the transmitted control value and the recalculated control value of the transmitted data—than this is a valuable confirmation that the transmission is somewhat erroneous.
More specifically the RSCP value in Step S6.1 indeed can be more specifically provided as a CPICH_RSCP or DPICH_RSCP as outlined in Step 6.12.
More specifically the Ec/Io value as depicted in step S6.2 can be more specifically be provided as a CPICH Ec/Io, DPICH Ec/Io or active set Ec/Io value as shown in step S6.22.
More specifically the checksum shown in Step S6.3 can be formed as a CRC (Cyclic Redundance Control) value as is shown in step S6.32.
Execution of step S6.1, S6.2 or S6.3 and/or S6.12, 6.22 or S6.32, respectively the values shown therein, can be measured or determined alone or in combination for forming a Layer-1 parameter indication. In the case one or more of the Layer-1 parameters specifically shown in
Thus, somewhat the steps S5.1 and S5.2 correspond to the step S3 as depicted in
Additionally or alternatively depending on a synchronization status derived from S5.3 in step SM2′ a further more stringent jamming warning or a qualified indication of bad synchronization can be derived in the case the status is out-of-sync.
In particular, a jamming detection message corresponding to message SM3 shown in
One or the other possibility of step S5.5 and step S5.6 can be derived from the evaluation thereof according to a standardized procedure shown in technical specification 25.331 and as depicted in step S5.4. Here, certain counters N313, T313 and N315 are provided for determining the time of an out-of-sync status and compare to a time of in-sync status. Depending on the outbalance of the competing counters either indication of an out-of-sync error or a radio link failure is possible. A detailed exemplifying description of the counters follows. Irrespective of these standard related counters, other counters can alternatively be implemented that lead to an earlier or later indication of an out of sync situation.
I. The layer-1 sync measurements are used to derive the Radio link failure criteria which is described in 25.331. In CELL_DCH State, after receiving N313 consecutive “out of sync” indications from layer-1 for the established DPCCH or F-DPCH physical channel in FDD the UE shall:
Periods in time where neither “in sync” nor “out of sync” is reported by Layer-1 do not affect the evaluation of the number of consecutive (resp. successive) “in sync” or “out of sync” indications.
II. The 3G in call early Jamming Detection is triggered by the handling of the “in sync” and “out of sync” indications from layer-1.
It uses two phases.
In the pre out-of-sync phase during accumulation of N313 out of sync indications a jamming detection is triggered by each out-of-sync.
In the out of sync phase jamming detection is triggered in each frame when T313 increments and in addition if N315 increments due to “in sync” indication.
With each trigger the power parameters like Ec/Io and RSCP of the active set are used for the jamming decision.
In addition the in-sync indications may be used to derive the reference values for the jamming decision.
A more complicated situation is depicted in
The alternative situation is shown in
Thus, in
These embodiments are further illustrated with regard to the following examples. Further, a measuring example 2 for a jamming situation is given and a measuring example 3 for a shielding situation is given respectively.
1.
CELL_DPCH state:
N313 consecutive “out of sync” indications from Layer-1=>Start T313
a) N315 successive “in sync” indications from Layer-1=>Stop+reset T313
b) T313 Expiry=>“Radio link failure”
=>Early Jamming detection can be triggered by the N313 and T313 counters.
The values of the sync timers and constants depend on the network.
These parameters are sent to the UE in the UTRAN MOBILITY INFORMATION message (25.331 chapter 8.3.3.3).
The values are transferred in the information element “UE Timers and Constants in connected mode” (25.331 chapter 10.3.3.43).
The ranges are:
T313: 0 . . . 15 seconds. Default value is 3.
N313: Integer 1, 2, 4, 10, 20, 50, 100, 200. Default value is 20.
N315: Integer 1, 2, 4, 10, 20, 50, 100, 200, 400, 600, 800, 1000. Default value is 1.
N313, T313 and N315 are part of the standard protocol stack.
The “in sync” and “out of sync” indications from L1 are evaluated each 10 ms frame for control of these timers and counters.
This is used to trigger collection of the Radio Link Quality data needed for early Jamming Detection. Therefore a set of Radio Link Quality data for early jamming detection is available every 10 ms.
2.
When radio link conditions are good N313 is 0 and T313 is not activated.
The Radio Link Quality data can be used as “Good Reference” by the JD.
When radio link conditions get worse e.g. due to Jamming during the phase preceding a Radio Link Failure, the counters/timers N313 and T313 start to count.
The set of data is used for Jamming Decision.
If a “Good Reference” is available, then the accuracy of the Jamming Decision increases. The decision “High Jamming Likelihood”/“Low Jamming Likelihood” can be made every 10 ms by evaluation of the data collected when N313 is incremented or T313 is active. The accuracy of the decision increases with each new set of jamming detection data.
3.
The principle is demonstrated below.
The example implementation uses a new 3G In Call jamming detection URC (lsta,12).
The URC displays the data used to trigger the JD.
Description of the 3G In Call jamming detection URC:
+CIEV: lsta,12,<parameters>
Parameters:
| Number | Date | Country | Kind |
|---|---|---|---|
| 12167935 | May 2012 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2013/059373 | 5/6/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/171085 | 11/21/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20080123585 | Granzow | May 2008 | A1 |
| 20080267165 | Bertrand | Oct 2008 | A1 |
| 20110151795 | D'Avello | Jun 2011 | A1 |
| 20110170420 | Xi | Jul 2011 | A1 |
| 20110223851 | Stoddard | Sep 2011 | A1 |
| 20120170754 | Girard et al. | Jul 2012 | A1 |
| 20120327801 | Seo | Dec 2012 | A1 |
| 20130034092 | Lampinen | Feb 2013 | A1 |
| 20150030033 | Vasseur | Jan 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 2 918 828 | Jan 2009 | FR |
| 5-284100 | Oct 1993 | JP |
| WO 0062437 | Oct 2000 | WO |
| WO 2005112321 | Nov 2005 | WO |
| WO 2007019814 | Feb 2007 | WO |
| Entry |
|---|
| International Search Report (PCT/ISA/210) mailed on Jun. 6, 2013, by the European Patent Office as the International Searching Authority for International Application No. PCT/EP2013/059373. |
| Written Opinion (PCT/ISA/237) mailed on Jun. 6, 2013, by the European Patent Office as the International Searching Authority for International Application No. PCT/EP2013/059373. |
| Number | Date | Country | |
|---|---|---|---|
| 20150126181 A1 | May 2015 | US |
