RF communication device for adaptive detection of further RF communication devices

Abstract

A radio frequency (RF) communication device for detecting a further RF communication device that is an active further RF communication device and / or a passive further RF communication device, the RF communication device comprising: i) an RF transmitting device configured to transmit an RF signal to be received by at least one further RF communication device; and ii) an adaptive detection device coupled to the RF transmitting device and configured to: iia) trigger transmission of a first RF signal, iib) trigger transmission of a second RF signal, and iic) detect an active further RF communication device based on the first RF signal and / or a passive further RF communication device based on the second RF signal; iii) wherein one of the first RF signal and the second RF signal is transmitted after the other RF signal, and iv) wherein a first energy level of the first RF signal is at least 25%, in particular at least 50%, in particular at least 90% higher than a second energy level of the second RF signal.

Description

Technical Field

[0001] The present disclosure relates to a radio frequency (RF) communication device having an RF transmitting device and an RF adaptive detection device. The present disclosure further relates to an RF communication system, the RF communication system comprising the RF communication device and another RF communication device, active and / or passive. The present disclosure also relates to a method of operating such an RF communication system. Therefore, the present disclosure may relate to the technical field of radio frequency devices, such as RFID and NFC communication applications. Background Art

[0002] Radio frequency (RF) transmitting and / or receiving devices are widely used to enable communication between electronic devices. Specific examples of radio devices may be RFIC devices and / or NFC devices. These devices are used in a variety of applications including, for example, smart cards or smart phones to establish radio communications with each other by touching them together or bringing them very close (e.g., within a short distance of, for example, a few meters or only a few centimeters). Applications include, in particular, simplified settings for contactless transactions, data exchange, and more complex communications such as Wi-Fi or Bluetooth. Some applications involving applications for identification products such as smart cards and tags are used in industries such as transportation (e.g., ticketing, road tolls, luggage tags), finance (e.g., debit and credit cards, electronic wallets, merchant cards), communications (e.g., SIM cards for GSM phones), and tracking (e.g., access control, inventory management, asset tracking).

[0003] In many RF (especially NFC) applications, a first RF device detects the presence of a second RF device. For this purpose, an RF signal is transmitted by the first RF device to be received by the second RF device. Thus, the second RF device can be an active device or a passive device. Conventionally, the transmitted RF signal is configured to detect an active RF device or is configured to detect a passive RF device.

[0004] Figure 6 A comparison between the ranging / detection distance (in cm) and the optimal energy level (here shown as transmitter voltage V) of an active further RF communication device 130 and a passive further RF communication device 140 is shown. Here, the devices 130 and 140 represent the above-mentioned second RF devices to be detected by the first RF device. It can be said that the longer the distance, the more effective the detection can be. Therefore, when searching for the presence of further RF communication devices by the RF communication device, it may be necessary to achieve a long detection distance. However, from Figure 6 As can be seen, the active further RF communication device 130 and the passive further RF communication device 140 are shown to behave exactly opposite to each other: when the optimum value (large detection distance) of the active RF communication device 130 is at a higher energy level, the optimum value of the passive RF communication device 140 is at a lower energy level.

[0005] In other words, state of the art low power card detection (LPCD) typically implements a low voltage for the transmitter driver. This not only saves current consumption, but also because the detection performance is not sacrificed due to passive (NFC) communication devices (e.g., PICC, mobile phone, etc.). However, active communication devices may implement active scanning functionality, which can sense the LPCD pulse from the detection device and generate its own pulse that matches the pulse generated by the detection device and causes detection. As in Figure 6 It can be seen that for detecting active scanning communication devices, the detection distance is much higher when the detection device uses a higher transmitter voltage. On the other hand, for passive communication devices, the detection distance is much higher when the detection device uses a lower transmitter voltage.

[0006] Figure 7 The behavior of the passive further RF communication device 140 at different magnetic field levels is shown. This is because the internal impedance of the pins of the antenna 141 of the proximity inductive coupling card (PICC) changes with different input currents (ie, the C and R values ​​of its equivalent circuit). Figure 7 The wake-up distance of a passive PICC static device (as a passive further RF communication device 140) is shown when different input impedances are implemented. In the shown figure, the behavior of the passive further RF communication device 140 at different magnetic field levels is simulated. In general, it can be observed that the detection distance increases with a higher resistance R. Therefore, the detection distance is affected by the input impedance of the antenna pin of the passive further RF communication device PICC. Summary of the invention

[0007] It may be desirable to provide detection of further RF communication devices, particularly active and / or passive further RF communication devices, in an efficient and reliable manner.

[0008] Provided are an RF communication device, an RF communication system and a method.

[0009] According to one aspect of the present disclosure, a radio frequency (RF) communication device (e.g., a reader device) is described for detecting another RF communication device that is an active another RF communication device (e.g., a cell phone) and / or a passive another RF communication device (e.g., a tag), the RF communication device comprising:

[0010] i) an RF transmitting device (eg, an NFC antenna) configured to transmit an RF signal to be received by at least one further RF communication device; and

[0011] ii) an adaptive detection device (e.g., a processor, an integrated circuit, a control device), the adaptive detection device being coupled to the RF transmission device and configured to:

[0012] iia) triggering / controlling (RF transmitting device to execute) the transmission of a first RF signal (high energy signal),

[0013] iib) triggering / controlling (RF transmitting means to perform) the transmission of a second RF signal (low energy signal), and

[0014] iic) detecting the active further RF communication device based on the first RF signal and / or detecting the passive further RF communication device based on the second RF signal;

[0015] iii) wherein one of the first RF signal and the second RF signal is transmitted after the other RF signal (especially transmitted alternately), and

[0016] iv) wherein the first energy level of the first RF signal is at least 25%, in particular at least 50%, in particular at least 90%, more in particular at least 95%, more in particular at least 100% higher than the second energy level of the second RF signal.

[0017] According to a further aspect of the present disclosure, an RF communication system is described, the RF communication system comprising: the RF communication device as described above, and the at least one further RF communication device.

[0018] According to further aspects of the present disclosure, a method for operating a radio frequency (RF) communication system is described, the method comprising:

[0019] i) transmitting a first RF signal;

[0020] ii) transmitting a second RF signal; and

[0021] iii) detecting an active further RF communication device based on the first RF signal and / or detecting a passive further RF communication device based on the second RF signal;

[0022] a) wherein one of the first RF signal and the second RF signal is transmitted after the other RF signal, and

[0023] b) wherein a first energy level of the first RF signal is at least 25%, in particular at least 50%, in particular at least 95% higher than a second energy level of the second RF signal.

[0024] According to further aspects of the present disclosure, a use (method of use) of an RF signal sequence is described, wherein at least two RF pulses have different power levels in order to optimize detection of both active and passive further RF communication devices using the same RF pulse / signal sequence.

[0025] According to exemplary embodiments, the present disclosure may be based on the idea that detection of further RF communication devices (particularly active and / or passive further RF communication devices) may be performed by the RF communication device in an efficient and reliable manner when the RF communication device transmits at least two RF signals having different energy levels, wherein the high energy level RF signal is optimized for detecting active further RF communication devices and the low energy RF signal is optimized for detecting passive further RF communication devices.

[0026] Conventionally, RF detection devices are configured (optimized) to detect passive other devices using low energy signals, or to detect active other devices using high energy signals. As a result, RF detection devices cannot be used effectively, especially in low power card detection (LPCD) schemes.

[0027] However, the inventors of the present invention have discovered that surprisingly efficient and reliable detection of both active and passive devices can be achieved when two RF signals of different energy levels are applied within the same RF (pulse) sequence. In this way, operation in an LPCD scheme is possible, thereby saving energy and cost while achieving adaptive and optimized detection. In order to optimally adapt the detection, an average signal is not generated, but signals with significantly different energy levels can be applied within the same RF signal sequence.

[0028] The described adaptive (LPCD) method can be viewed as a method of having the (LPCD) signal / pulse have different voltage / power in low power mode. This can allow high performance for both passive and active (scanning) devices, and optimize current consumption. This can further increase the user experience over long distances, while power consumption can be reduced (battery life). Preferred applications can be seen in car access applications (e.g., with very small door handle antennas).

[0029] The aspects defined above and further aspects of the disclosure will be apparent from the examples of embodiment described hereinafter and are explained with reference to these examples of embodiment.The disclosure will be described in more detail hereinafter with reference to examples of embodiment but to which the disclosure is not limited.

[0030] Exemplary Embodiments

[0031] According to an embodiment, the RF communication device is configured as a radio frequency identification (RFID) device and / or a near field communication (NFC) device, and / or the RF signal is configured as an RFID and / or NFC signal. Thus, economically important and standardized applications can be directly addressed. Due to the large differences in power levels and limited space, the present disclosure may be particularly suitable for such applications.

[0032] In the context of this document, the term "RFID" (radio frequency identification) may refer to a technology that uses electromagnetic fields (RF fields) to communicate over short distances, particularly 10 meters or less. The term "RFID device" may refer to any device having RFID functionality. An RFID device may include an antenna and an integrated circuit having a transmitter and a receiver. A typical RFID system may include an RFID reader and one or more RFID tags associated with one or more objects. In an example, a first RFID device includes a transmitter for transmitting an RF signal to a second RFID device, and a receiver for receiving modulated information from the second RFID device. Standard communications between RFID devices are specified in a protocol.

[0033] In the context of this document, the term "NFC" may refer to near field communication, which may be a short-range wireless technology (short range being a distance measured in centimeters). In order for two NFC devices to communicate, a user may bring the NFC devices close together or even touch them. NFC may be considered an established standard. In this document, the NFC standard may be considered a special form of RFID. In the context of this document, the term "NFC device" may refer to any device having NFC functionality as described above. NFC functionality may be implemented, for example, in a tag, a smart card, a card reader, or a mobile phone.

[0034] According to a further embodiment, the RF signal is configured as an RF pulse. Thus, the two energy levels can be effectively separated in time because they are implemented as different pulses. However, in an example, the two energy levels can also be combined into an extended pulse. In an exemplary example, the pulse of the first energy level can have 5 volts, and the pulse of the second energy level can have 1.5 volts. In a further exemplary example, the length of one pulse can be about 50 μs.

[0035] According to an embodiment, the adaptive detection device is additionally configured to:

[0036] The transmission of the RF signal sequence comprising the first RF signal and the second RF signal is triggered / controlled. Thus, the same sequence may be optimized for both detection of active and passive devices.

[0037] According to an embodiment, the plurality of first RF signals and the plurality of second RF signals are transmitted alternately in an RF sequence.Instead of a period of searching for active devices and a period of searching for passive devices, the described method enables in principle simultaneous searching / detection of two devices.

[0038] According to an embodiment, one first RF signal is transmitted alternately with one second RF signal. According to an embodiment, two or more first RF signals are transmitted alternately with two or more second RF signals. According to an embodiment, the first RF signal and the second RF signal are transmitted as extended pulses with different energy levels. Depending on the desired application, one sequence may be more suitable than the other.

[0039] According to an embodiment, the adaptive detection device is additionally configured to:

[0040] Calibration is performed for said first energy level of said first RF signal and said second energy level of said second RF signal. According to an embodiment, the adaptive detection device is further configured to derive a first reference value (refmax) for the first energy level and / or to derive a second reference value (refmin) for the second energy level. Depending on the RF power, an adaptive (LPCD) calibration may be used to optimize receiver settings. Figure 5 An exemplary embodiment is described in .

[0041] According to an embodiment, the at least one further RF communication device is configured as a passive device, in particular a passive smart card, more particularly a credit / debit card or tag. Such a small and simple device may not comprise its own energy source. Therefore, the detection depends on the energy provided by the RF communication device. However, if Figure 7 As shown in , for high performance detection, lower energy levels may be preferred.

[0042] According to an embodiment, the at least one further RF communication device is configured as an active device, in particular an active scanning device. For example, a mobile phone comprising its own energy source may be used. In particular, the active device itself may actively scan the RF communication device.

[0043] According to an embodiment, the first RF signal is optimized to detect an active device. According to an embodiment, the second RF signal is optimized to detect a passive device. According to an embodiment, the optimization refers to a detection distance. As described above, an optimal detection distance can be achieved by transmitting signals with different energy levels.

[0044] According to an embodiment, the further RF communication device is configured as at least one of the following: an RFID device, an NFC device, a tag, in particular an NFC tag or an RFID tag, a credit / debit card, a ticket, a point of sale (POS), a mobile phone, a proximity inductive coupling card (PICC). Thus, the described method can be directly implemented into economically important devices.

[0045] According to an embodiment, the method further comprises: receiving a first RF signal by the active RF communication device, and then initiating a first wake-up operation, and / or

[0046] The second RF signal is received by the passive RF communication device, and then a second wake-up operation is initiated. Thus, effective detection (polling) and activation can be achieved.

[0047] According to an embodiment, RF transmission is performed in a low power mode, in particular a low power communication mode, more particularly a low power card detection (LPCD) mode. Thus, energy resources and costs can be saved. LPCD is a mature standard, so that the present disclosure can be directly implemented in economically important measures.

[0048] According to an embodiment, the energy levels refer to RF power, in particular different transmitter voltage levels.

[0049] According to an embodiment of the method, a calibration is performed before starting the actual detection mode.

[0050] According to an embodiment, the method is applied to a vehicle-related application, in particular to an application related to the opening of a car door.

[0051] According to an exemplary embodiment, an optimized performance for an RF communication detection device with (true) low power optimization is described. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 An RF communication system according to an exemplary embodiment of the present disclosure is shown.

[0053] Figure 2 , 3 4 and 5 respectively show RF signal sequences according to an exemplary embodiment of the present disclosure.

[0054] Figure 5 A calibration method for an RF communication system according to an exemplary embodiment of the present disclosure is shown.

[0055] Figure 6 A comparison between detection distances and optimal energy levels of active and passive further communication devices according to an exemplary embodiment of the present disclosure is shown.

[0056] Figure 7 The behavior of a passive further communication device according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0057] The exemplary embodiments in the drawings are schematic.

[0058] Figure 1An RF communication system 150 according to an exemplary embodiment of the present disclosure is shown. The RF communication system 150 includes an RF communication device (detection device) 100 and two further RF communication devices 130, 140. While one further RF communication device 140 is configured as a passive device, such as a passive smart card, the other further RF communication device 130 is configured as an active device, here an active scanning device.

[0059] The RF communication device 100 comprises an RF transmission device (e.g., an antenna device) configured to transmit an RF signal sequence 101 to be received by another RF communication device 130, 140. The RF communication device 100 further comprises an adaptive detection device 120 (e.g., an IC and / or a processor) coupled to the RF transmission device 110. The adaptive detection device 120 is here configured to trigger the signal transmission of the RF transmission device 110. As will be described with respect to Figures 2 to 4 Described in detail, the RF signal sequence includes a plurality of first RF signals 111 and a plurality of second RF signals 112 that are transmitted one after another in a sequence 101 .

[0060] The adaptive detection device 120 is configured to detect the presence of (and induce wake-up of) an active further RF communication device 130 based on a first RF signal 111 optimized for a high energy level (with respect to detection distance). The adaptive detection device 120 is further configured to detect the presence of (and induce wake-up of) a passive further RF communication device 140 based on a second RF signal 112 optimized for a low energy level.

[0061] The RF communication device 100 is configured here as a near field communication (NFC) device, the RF signals 111, 112 are configured as NFC signals in this example, and the RF signals 111, 112 are configured as NFC pulses. NFC has a standardized frequency of 13.56 MHz.

[0062] Figure 2An RF signal sequence 101 according to an exemplary embodiment of the present disclosure is shown. The X-axis shows time (arbitrary units), and the Y-axis shows energy level as RF power (arbitrary units). In the sequence 101, a plurality of first RF signals 111 are transmitted alternately with a plurality of second RF signals 112, wherein exactly one first RF signal 111 is transmitted alternately with exactly one second RF signal 112; in other words, one after the other. It can be seen that the first energy level of the first RF signal 111 is 100% higher than the second energy level of the second RF signal 112, i.e., the second energy level is only half of the first energy level. It is obvious that the first RF signal 111 is optimized for detecting an active further RF communication device 130, and the second RF signal 112 is optimized for detecting a passive further RF communication device 140. In this example, each RF signal is configured as a pulse, wherein the duration between two pulses is 50 ms (as an exemplary time scheme).

[0063] Therefore, instead of a conventional static RF energy level (power), an adaptive detection profile is used. By doing so, both passive and active scanning of further RF communication devices 130, 140 can produce the highest possible wake-up distance with optimized low power current consumption. A sequence of changing energy / power level pings is used together with a dedicated detection sequence (two pulses).

[0064] Figure 3 A further RF signal sequence 101 according to an exemplary embodiment of the present disclosure is shown. The X-axis shows time (arbitrary units), and the Y-axis shows energy level as RF power (arbitrary units). In the sequence 101, a plurality of first RF signals 111 are transmitted alternately with a plurality of second RF signals 112, wherein two first RF signals 111 are transmitted alternately with two RF signals 112. It can be seen that the first energy level of the first RF signal 111 is 100% higher than the second energy level of the second RF signal 112, i.e., the second energy level is only half of the first energy level. The two first RF signals 111 are optimized for detecting an active further RF communication device 130, and the two second RF signals 112 are optimized for detecting a passive further RF communication device 140. In this example, each RF signal is configured as a pulse, wherein the duration between two pulses is 100 ms (as an exemplary time scheme.

[0065] Figure 4 Another RF signal sequence 101 according to an exemplary embodiment of the present disclosure is shown. The X-axis shows time (arbitrary units), and the Y-axis shows energy level as RF power (arbitrary units). In the sequence 101, a first RF signal 111 and a second RF signal 112 are transmitted together as an extended pulse including two different energy levels (combining the two pulses into an extended pulse with different power levels).

[0066] Figure 5 A calibration method for an RF communication system 150 according to an exemplary embodiment of the present disclosure is shown. The adaptive detection device 120 is configured to perform calibration for a first energy level of a first RF signal 111 and a second energy level of a second RF signal 112, and derive a first reference value (refmax) of the first energy level and / or derive a second reference value (refmin) of the second energy level.

[0067] In all three examples (see above Figures 2 to 4 ), two different transmitter voltage levels (energy levels) are used, and thus a dedicated calibration can be performed for each voltage level. In general, calibration is performed to derive reference values ​​for LPCD measurement parameters (e.g., RSSI, I, Q). Calibration is then performed before entering LPCD mode (actual detection). If during LPCD mode, the measured LPCD parameter is higher or lower than the reference value by a specified threshold, wake-up will be triggered. Therefore, calibration and derivation of reference values ​​for two voltage levels used during LPCD mode are performed.

[0068] Reference numeral 100: Radio frequency (RF) communication device

[0069] 101 RF signal sequence

[0070] 110 RF transmitter

[0071] 111 First RF signal

[0072] 112 Second RF signal

[0073] 120 Adaptive detection device

[0074] 130 Active additional RF communication device 131 Active antenna

[0075] 132 Active scanning 140 Passive additional RF communication device 141 Passive antenna 150 RF communication system.

Claims

1. A radio frequency (RF) communication device (100), characterized in that: The RF communication device (100) is used to detect at least one further RF communication device (130, 140) that is at least one of: an active further RF communication device (130), passive additional RF communication means (140), The RF communication device (100) comprises: an RF transmitting device (110) configured to transmit an RF signal to be received by the at least one further RF communication device (130, 140); and An adaptive detection device (120) is coupled to the RF transmission device (110) and is configured to: triggering the transmission of a first RF signal (111), triggering transmission of a second RF signal (112), and Perform at least one of the following tests: detecting the active further RF communication device (130) based on the first RF signal (111), detecting the passive additional RF communication device (140) based on the second RF signal (112); wherein one of the first RF signal (111) and the second RF signal (112) is transmitted after the other RF signal, and The first energy level of the first RF signal (111) is at least 25% higher than the second energy level of the second RF signal (112).

2. The RF communication device (100) according to claim 1, It is characterized in that The RF communication device (100) is configured as a near field communication (NFC) device, and The RF signals (111, 112) are configured as NFC signals.

3. The RF communication device (100) according to any one of the preceding claims, It is characterized in that The RF signals (111, 112) are configured as RF pulses.

4. The RF communication device (100) according to any of the preceding claims, characterized in that The adaptive detection device (120) is further configured to: The transmission of an RF signal sequence (101) comprising the first RF signal (111) and the second RF signal (112) is triggered.

5. The RF communication device (100) according to claim 4, It is characterized in that A plurality of first RF signals (111) and a plurality of second RF signals (112) are transmitted alternately in the RF sequence (101).

6. The RF communication device (100) according to claim 4 or 5, characterized in that: Includes at least one of the following features: A first RF signal (111) and a second RF signal (112) are transmitted alternately; Two or more first RF signals (111) and two or more second RF signals (112) are transmitted alternately.

7. The RF communication device (100) according to any one of the preceding claims, It is characterized in that The first RF signal (111) and the second RF signal (112) are transmitted as extended pulses having different energy levels.

8. The RF communication device (100) according to any of the preceding claims, characterized in that The adaptive detection device (120) is further configured to: Calibration is performed on the first energy level of the first RF signal (111) and the second energy level of the second RF signal (112).

9. An RF communication system (150), characterized in that: include: The RF communication device (100) according to any one of claims 1 to 8; and The at least one further RF communication device (130, 140).

10. A method for operating a radio frequency (RF) communication system (150), characterized in that: The method comprises: Transmitting a first RF signal (111); transmitting a second RF signal (112); and Perform at least one of the following tests: detecting an active further RF communication device (130) based on the first RF signal (111), detecting a passive additional RF communication device (140) based on the second RF signal (112); wherein one of the first RF signal (111) and the second RF signal (112) is transmitted after the other RF signal, and The first energy level of the first RF signal (111) is at least 25% higher than the second energy level of the second RF signal (112).

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