Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/08—Arrangements for detecting or preventing errors in the information received by repeating transmission, e.g. Verdan system
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/0703—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation
  • G06F11/0751—Error or fault detection not based on redundancy
  • G06F11/0754—Error or fault detection not based on redundancy by exceeding limits
  • G06F11/076—Error or fault detection not based on redundancy by exceeding limits by exceeding a count or rate limit, e.g. word- or bit count limit
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/0703—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation
  • G06F11/0793—Remedial or corrective actions
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
  • G06Q20/00—Payment architectures, schemes or protocols
  • G06Q20/30—Payment architectures, schemes or protocols characterised by the use of specific devices or networks
  • G06Q20/32—Payment architectures, schemes or protocols characterised by the use of specific devices or networks using wireless devices
  • G06Q20/327—Short range or proximity payments by means of M-devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1867—Arrangements specially adapted for the transmitter end
  • H04L1/1887—Scheduling and prioritising arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
  • H04N19/164—Feedback from the receiver or from the transmission channel
  • H04N19/166—Feedback from the receiver or from the transmission channel concerning the amount of transmission errors, e.g. bit error rate [BER]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
  • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
  • H04N19/172—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a picture, frame or field
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/85—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression
  • H04N19/89—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving methods or arrangements for detection of transmission errors at the decoder

Definitions

• the present disclosure relates generally to electronic devices. More specifically, the present disclosure relates to systems and methods for mitigating effects of an unresponsive secure element (SE).
• SE secure element
• Some electronic devices transmit wireless signals.
• Wireless signals may, for example, be utilized to communicate with other electronic devices and, in some cases, convey information related to a secure transaction.
• Some electronic devices include one or more secure elements (SE) that store information for a secure transaction.
• SE secure elements
• an SE may become unresponsive while communicating with the electronic device. System and methods for mitigating effects of an unresponsive SE may be beneficial.
• a method includes counting a number of successive information frame (I-frame) retransmissions due to a guard timer expiring.
• a contactless front-end (CLF) transmits the I-frame to a secure element (SE) over a single wire protocol (SWP) interface.
• the method also includes discontinuing I-frame retransmission when the count equals a retransmission threshold.
• the method further includes deactivating the SWP interface.
• Counting the number of successive I-frame retransmissions may include incrementing the count for each successive I-frame retransmission. The count may be reset to zero when the SE acknowledges an I-frame.
• the retransmission threshold may be configurable.
• the guard timer may expire when the CLF fails to receive an I-frame acknowledgement from the SE within a guarding time.
• the I-frame may be sent over the SWP interface using simplified high level data link control (SHDLC) link layer control (LLC).
• SHDLC high level data link control
• LLC link layer control
• the method may also include triggering an interrupt of the CLF firmware.
• the method may further include notifying the CLF firmware of an unresponsive SE condition.
• the method may also include maintaining multiple counts associated with multiple I-frames that are transmitted by the CLF to the SE. Each I-frame may have a separate count for the number of successive I-frame retransmissions due to a guard timer expiring. The method may further include discontinuing I-frame retransmission and deactivating the SWP interface when at least one of the multiple counts equals the retransmission threshold. The method may also include resetting the multiple counts to zero when the SE acknowledges any one of the multiple I-frames.
• the electronic device includes a processor, memory in electronic communication with the processor, and instructions stored in the memory.
• the instructions are executable by the processor to maintain a counter that counts the number of successive I-frame retransmissions due to a guard timer expiring.
• a CLF transmits the I-frame to an SE over an SWP interface.
• the instructions are also executable to discontinue I-frame retransmission when the counter equals a retransmission threshold.
• the instructions are further executable to deactivate the SWP interface.
• the instructions executable to maintain the counter that counts the number of successive I-frame retransmissions may include instructions executable to increment the counter for each successive I-frame retransmission.
• the instructions may also be executable to reset the counter to zero when the SE acknowledges an I-frame.
• the apparatus includes means for counting the number of successive I-frame retransmissions due to a guard timer expiring.
• a CLF transmits the I-frame to an SE over an SWP interface.
• the apparatus also includes means for discontinuing I-frame retransmission when the count equals a retransmission threshold.
• the apparatus further includes means for deactivating the SWP interface.
• Figure 1 is a block diagram illustrating one configuration of an electronic device in which systems and methods for mitigating effects of an unresponsive secure element (SE) may be implemented;
• Figure 2 is a flow diagram illustrating a method for mitigating effects of an unresponsive SE;
• FIG. 3 is a block diagram illustrating one configuration of a single wire protocol (SWP) interface
• Figure 4 is a flow diagram illustrating a detailed configuration of a method for mitigating effects of an unresponsive SE
• Figure 5 is a block diagram illustrating another configuration of an electronic device in which systems and methods for mitigating effects of an unresponsive SE may be implemented;
• Figure 7 is a block diagram illustrating another more specific configuration of an electronic device in which systems and methods for mitigating effects of an unresponsive SE may be implemented.
• Figure 8 illustrates various components that may be utilized in an electronic device.
• the systems and methods disclosed herein may be applied to communication devices that communicate wirelessly and/or that communicate using a wired connection or link. For example, some communication devices may communicate with other devices using an Ethernet protocol. In another example, some communication devices may communicate with other devices using wireless communication. In one configuration, the systems and methods disclosed herein may be applied to a communication device that communicates with another device using an induction-based communication technology.
• inductively coupled communication technology is near-field communication (NFC).
• An electronic device may include an NFC chip (also referred to as an NFC card, NFC controller chip, NFC controller, etc.).
• the direction for the data flow in the NFC communication standards is characterized by having a first device (also referred to as a poller, polling device, proximity coupling device (PCD) or initiator) provide an electromagnetic field (also referred to as an RF-field).
• a second device also referred to as a listener, listening device, proximity integrated circuit card (PICC) or target
• PICC proximity integrated circuit card
• an electronic device may perform contactless payment services.
• the electronic device may act as a credit card.
• This RF-based contactless payment approach may be appealing to users because of its ease of use. For example, users may benefit from increased speed, control of transactions and using the electronic device instead of cash.
• Multiple NFC applications may be supported by an electronic device. These NFC applications may include credit/debit payment, public transport ticketing, and loyalty and service initiation.
• NFC secure element
• the NFC chip may establish a communication interface with the SE to pass information from the SE to a remote device via the NFC chip or to be used within the electronic device itself.
• this interface may be a single wire protocol (SWP) interface.
• SWP single wire protocol
• the SE may become unresponsive. Therefore, systems and methods for mitigating effects of an unresponsive secure element (SE) may be beneficial.
• FIG. 1 is a block diagram illustrating one configuration of an electronic device 102 in which systems and methods for mitigating effects of an unresponsive secure element (SE) 106 may be implemented.
• electronic devices 102 include wireless communication devices, cellular phones, smartphones, tablet devices, voice recorders, digital cameras, still cameras, camcorders, gaming systems, laptop computers, etc.
• Each component of the electronic device 102 described herein may be implemented in hardware (e.g., circuitry) or a combination of hardware and software (e.g., a processor with executable instructions stored in memory).
• the electronic device 102 may include a contactless front-end (CLF) 104.
• the CLF 104 may be a near-field communication (NFC) chip.
• the CLF 104 may communicate with a remote device 128 via an antenna 126.
• the CLF 104 may perform inductively coupled communication with the remote device 128.
• the CLF 104 may establish an interface between a device host 130 (also referred to as an application processor).
• the interface between the device host 130 and the CLF 104 may be an NFC controller interface (NCI).
• NCI NFC controller interface
• the CLF 104 may establish a simplified high level data link control (SHDLC) link with the SE 106.
• the SHDLC layer is responsible for the error-free transmission of data between the CLF 104 and the SE 106.
• the CLF 104 and the SE 106 may exchange data payloads using the SHDLC link layer control (LLC).
• LLC SHDLC link layer control
• An I-frame 110 may carry upper-layer information and some control information. I-frame 110 functions may include sequencing, flow control, error detection and recovery. I-frames 110 may also carry send and receive sequence numbers. Both the S- frame and the U-frame may carry control information. Therefore, to exchange payload data (e.g., upper-layer information), the CLF 104 and the SE 106 may include the payload data in an I- frame 110.
• payload data e.g., upper-layer information
• a maximum of 29 bytes of payload may be included in an I-frame 110.
• the payload may be fragmented and sent over multiple I-frames 110.
• the payload may be in excess of 200 bytes, which may be split into 7 or more I-frames 110.
• an endpoint sends an I-frame 110
• the other endpoint should acknowledge the I- frame 110 within an acknowledge time 122 (Tl).
• Tl acknowledge time
• the guarding time 114 is 10 milliseconds (ms)
• the acknowledgment time 122 may be less than the guarding time 114 (e.g., Tl ⁇ T2) by at least 5 ms so the endpoint that sent the I- frame 110 should receive an acknowledgement 124 before the guard timer 112 expires.
• an endpoint may not receive an acknowledgment 124 within the guarding time 114. In a first case, the sent I-frame 110 may be corrupted or lost and the other endpoint never received it properly.
• the other endpoint received the I-frame 110 properly and sent the corresponding acknowledgement 124 but the acknowledgement 124 got corrupted or lost over the SWP interface 108.
• the endpoint that sent the I-frame 110 may never receive a good acknowledgement 124 or anything at all.
• the receiving SE 106 may become unresponsive after receiving an I-frame 110 but before sending the acknowledgment 124.
• a removable SE 106 e.g., a SIM card or UICC card
• the SE 106 may be removed abruptly by the user after the SE 106 received the I-frame 110 but before it could send the acknowledgment 124.
• Most mobile phones have SIM slots designed such that the SIM card (i.e., the SE 106) can be pulled out while the phone is powered on.
• a user could potentially pull the SE 106 out after the CLF 104 sends an I- frame 110 and before the SE 106 gets a chance to respond with an acknowledgment 124.
• the CLF 104 has no way of detecting that the SE 106 on the other end has been disconnected.
• the SE 106 may become unresponsive by locking up. This may occur due to software or hardware failures. For example, I- frames 110 may get corrupted if the line is very noisy. The SE 106 may keep detecting noise, but may think the noise is an I-frame 110 and may never find an actual I-frame 110. The SE 106 may also lock up based on how good the SWP interface 108 line is. Therefore, the SE 106 may still be in the electronic device 102, but it may stop responding. In this scenario, the SE 106 may be considered as not present.
• the CLF 104 is supposed to retransmit the I-frame 110 after the guard timer 112 expires in order to retransmit the corresponding I-frame 110 so that the targeted endpoint receives it properly.
• ETSI European Telecommunications Standards Institute
• the electronic device 102 may maintain a counter 116 that counts the number of successive I-frame retransmissions 118 due to the guard timer 112 expiring.
• the counter 116 may be included in the CLF 104 (as shown) or may be included in another block or module of the electronic device 102.
• the guard timer 112 expires, the counter 116 may increment for each successive I- frame 110 retransmission. In one configuration, the counter 116 may increment before retransmitting the I-frame 110. In another configuration, the counter 116 may increment after retransmitting the I-frame 110. If the SE 106 acknowledges an I-frame 110, the counter 116 may be reset to zero.
• the retransmission threshold 120 may be configurable.
• the CLF 104 may retry the retransmission of an I-frame 110 pending acknowledgment 124 times, where n is any positive integer. Therefore, the value of the retransmission threshold 120 may be defined as n +1.
• the CLF 104 may deactivate the SWP interface 108 when the counter 116 equals the retransmission threshold 120. If the counter 116 reaches the retransmission threshold 120, this may indicate that the SE 106 has become unresponsive. In one configuration, the CLF 104 may interrupt the CLF firmware. The CLF 104 may notify the CLF firmware of an unresponsive SE condition. The CLF 104 may then deactivate the SWP interface 108.
• the systems and methods described herein will enable the CLF 104 to detect that the SE 106 on the other end is not replying after a few tries because the SE 106 may have been removed or is in a bad state.
• the described systems and methods provide a mechanism to avoid an infinite loop caused by an unresponsive SE 106. This may improve user experience.
• the described systems and methods may also save power by avoiding the infinite loop.
• FIG. 2 is a flow diagram illustrating a method 200 for mitigating effects of an unresponsive SE 106.
• the method 200 may be implemented by a contactless front-end (CLF) 104.
• the CLF 104 may be an NFC chip.
• the CLF 104 may activate 202 a single wire protocol (SWP) interface 108 with the SE 106.
• SWP single wire protocol
• the CLF 104 may then establish an SHDLC link with the SE 106.
• the CLF 104 may send one or more I-frames 110 to the SE 106.
• the I-frame 110 may carry payload data to the SE 106.
• the CLF 104 may start a guard timer 112.
• the guard timer 112 is disabled and reset when an acknowledgment 124 is received from the SE 106. If the I-frame 110 is not acknowledged within the guarding time 114, the CLF 104 may retransmit these I- frames 110.
• the guarding time 114 may be configurable.
• the CLF 104 may count 204 the number of successive I-frame retransmissions due to the guard timer 112 expiring. For example, when the guard timer 112 expires, a counter 116 may increment. In other words, the number of successive I-frame retransmissions 118 may increase by one. If the SE 106 acknowledges an I-frame 110, the counter 116 may be reset to zero.
• the CLF 104 may discontinue 206 I-frame 110 retransmission when the count equals a retransmission threshold 120. For example, the CLF 104 may compare the number of successive I-frame retransmissions 118 (as indicated by the counter 116) to the retransmission threshold 120. If the number of successive I- frame retransmissions 118 is less than the retransmission threshold 120, the CLF 104 may continue to retransmit the I- frame 110, restart the guard timer 112 and wait for the guard timer 112 to expire. When the count reaches the retransmission threshold 120, the CLF 104 may stop retransmitting the I- frame 110.
• the retransmission threshold 120 may be configurable.
• the CLF 104 may retry the retransmission of an I-frame(s) 110 pending acknowledgment 124 times, where n is any positive integer. Therefore, the value of the retransmission threshold 120 may be defined as n +1.
• the CLF 104 may deactivate 208 the SWP interface 108 when the count equals the retransmission threshold 120. For example, if the counter 116 reaches the retransmission threshold 120, this may indicate that the SE 106 has become unresponsive. In one configuration, the CLF 104 may interrupt the CLF firmware. The CLF 104 may notify the CLF firmware of an unresponsive SE condition. The CLF 104 may then deactivate the SWP interface 108.
• FIG. 3 is a block diagram illustrating one configuration of a single wire protocol (SWP) interface 308.
• a CLF 304 may activate an SWP interface 308 with an SE 306.
• the SWP interface 308 may be a bit-oriented, point-to-point communication protocol between the CLF 304 and the SE 306.
• the CLF 304 may be the master and the SE 306 may be the slave.
• a signal S I 334 may be transmitted by a digital modulation (e.g., low (L) or high (H) electrical level) in the voltage domain.
• a signal S2 336 may be transmitted by a digital modulation (e.g., low or high electrical level) in the current domain.
• the SE 306 may either draw a current (state H) or not (state L) and thus transmit S2 336.
• pulse width modulation bit coding of S I 334 it is possible to transmit a transmission clock, as well as data in full duplex mode.
• FIG. 4 is a flow diagram illustrating a detailed configuration of a method 400 for mitigating effects of an unresponsive SE 106.
• the method 400 may be implemented by a contactless front-end (CLF) 104.
• the CLF 104 may be an NFC chip.
• the CLF 104 may activate 402 a single wire protocol (SWP) interface 108 with the SE 106.
• SWP single wire protocol
• the CLF 104 may then establish an SHDLC link with the SE 106.
• the CLF 104 may reset a counter 116 to zero.
• the counter 116 may count the number of successive I-frame retransmissions 118.
• the CLF 104 may send 404 an I-frame 110 to the SE 106.
• the I-frame 110 may carry payload data to the SE 106.
• the CLF 104 may reset 406 and start a guard timer 112.
• the guard timer 112 may be initialized with a guarding time 114.
• the CLF 104 may determine 408 whether an acknowledgement 124 has been received from the SE 106. If an acknowledgment 124 has not been received, then the CLF 104 may determine 410 whether the guard timer 112 has expired. If the guard timer 112 has not expired, the CLF 104 may continue to wait to receive an acknowledgment 124. If the CLF 104 determines 408 that it has received an acknowledgment 124, the CLF 104 may stop 412 the guard timer 112 and reset 414 the counter 116 (e.g., set the counter 116 to zero). The CLF 104 may then send 404 another I-frame 110 to the SE 106.
• the CLF 104 may increment the counter 116. For example, the SE 106 may become unresponsive due to being removed or locked up and the CLF 104 may not receive an acknowledgment 124.
• the counter 116 For a first I-frame retransmission, the counter 116 may be set to 1.
• the counter 116 For a second successive I-frame retransmission, the counter 116 may be set to 2, and so on.
• the CLF 104 may determine 418 whether the counter 116 equals a retransmission threshold 120.
• the retransmission threshold 120 may be a configurable integer value.
• the CLF 104 may compare the counter 116 with the retransmission threshold 120.
• the CLF 104 may retransmit 420 the I-frame 110 to the SE 106.
• the CLF 104 may then reset 406 and start the guard timer 112.
• the CLF 104 may wait for the guard timer 112 to expire and perform another iteration of incrementing 416 the counter 116 and retransmitting 420 the I- frame. If at any time the CLF 104 receives an acknowledgment 124, the CLF 104 may stop 412 the guard timer 112 and reset 414 the counter 116.
• the CLF 104 may discontinue 422 I-frame 110 retransmission to the SE 106. If the counter 116 reaches the retransmission threshold 120, this may indicate that the SE 106 has become unresponsive.
• the CLF 104 may deactivate 424 the SWP interface 108.
• the CLF 104 may interrupt the CLF firmware.
• the CLF 104 may notify the CLF firmware of an unresponsive SE condition.
• the CLF 104 may then deactivate 424 the SWP interface 108.
• FIG. 5 is a block diagram illustrating another configuration of an electronic device 502 in which systems and methods for mitigating effects of an unresponsive secure element (SE) 506 may be implemented.
• the electronic device 502 may be implemented in accordance with the electronic device 102 described in connection with Figure 1.
• the electronic device 502 may include a near-field communication (NFC) chip 504.
• the NFC chip 504 is one example of the contactless front-end (CLF) 104 described in connection with Figure 1.
• the NFC chip may communicate with a remote device 528.
• the antenna 526a of the NFC chip 504 may be inductively coupled with an antenna 526b of the remote device 528.
• An example of NFC is described in connection with Figure 6.
• the NFC chip 504 may establish an interface between a device host 530 (also referred to as an application processor).
• the interface between the device host 530 and the NFC chip 504 may be an NFC controller interface (NCI) (also referred to as an NFC interface).
• NCI NFC controller interface
• the electronic device 502 includes at least two secure elements (SE) 506.
• a first secure element may be a universal integrated circuit card (UICC) 506a.
• the UICC 506a is an example of a removable SE 506.
• the UICC 506a may store subscriber details (e.g., credit card account numbers, transit accounts, and mobile phone details, etc.) and keeps these details separate and secure. Data is communicated between UICC 506a and the NFC chip 504 via a first SWP interface 508a.
• a second secure element may be an embedded SE 506b.
• the embedded SE 506b may be integrated into the electronic device 102 and is not removable by a user.
• the embedded SE 506b may communicate with the NFC chip 504 via a second SWP interface 508b. It should be noted that any number of secure elements may be included in the electronic device 502. Each of the secure elements may communicate with the NFC chip 504 via a separate SWP interface 508.
• the two SWP interfaces 508a-b may not share any configurations between them. Parameters like window size, re-transmission thresholds, guard timer values, etc. are independent of each other and could be different. In one case, only one SWP interface 508 is active. There may be two SWP interface controllers inside the NFC chip 504 that autonomously talk to the SE 506 they are connected to with no bearing on the other.
• the NFC chip 504 and SE 506 may exchange payload data using one or more I-frames 510.
• an I-Frame generator 527 may generate the one or more I-frames 510a-x to be transmitted to an SE 506.
• a maximum of 29 bytes of payload may be included in an I-frame 510.
• the payload may be fragmented and sent over multiple I-frames 510.
• a sliding window 550 is used to send multiple I- frames 510a-x before receiving a confirmation (i.e., acknowledgment 524a or 524b) that the first I-frame 510a has been received correctly. This means that data may continue to flow in situations where there may be long turnaround time lags without stopping to wait for an acknowledgement 524.
• the sliding window 550 size may be lower than a default value due to limited resources. Therefore, an endpoint may ask the other endpoint to lower the sliding window 550 size.
• the sliding window 550 size may be an x number of I-frames 510.
• the NFC chip 504 may have guard timers 512a-x associated with each of the I- frames 510 that are sent. Therefore, the number of guard timers 512 may correspond to the x number of I-frames 510 of the sliding window 550. Each I-frame 510 sent by the NFC chip 504 may have a separate guard timer 512.
• the guard timers 512a-x may each be set with guarding times 514a-x (e.g., T2).
• the guarding times 514a-x may be configurable. If an I-frame 510 is not acknowledged within the guarding time 514, the NFC chip 504 may retransmit these I-frames 510.
• the guarding time 514 defines the time to wait after sending an I-frame 510 and retransmitting the I-frame 510.
• the NFC chip 504 may wait to receive an acknowledgment 524 from the SE 506 before sending another I-frame 510.
• Each of the SEs 506a-b may be configured with an acknowledgment time 522a-b in which to send an acknowledgment 524a-b to the NFC chip 504.
• the NFC chip 504 may receive a single acknowledgment 524 for one, some or all of the I-frames 510.
• the corresponding guard timer(s) 512 are disabled and reset when an acknowledgment 524 is received from the SE 506.
• the electronic device 502 may maintain multiple counters 516a-x associated with the multiple I-frames 510a-x that are transmitted by the NFC chip 504 to the SE 506.
• Each I-frame 510 may be associated with a separate counter 516 that counts the number of successive I-frame 510 retransmissions due to a guard timer 512 expiring. When a guard timer 512 expires, the counter 516 associated with that guard timer 512 may increment. Therefore, the counter 516 may correspond to the number of successive I- frame retransmissions 518.
• the NFC chip 504 may have a first counter 516a that counts the number of successive I-frame retransmissions 518a due to the first guard timer 512a expiring.
• the NFC chip 504 may also have a second counter 516b that counts the number of successive I-frame retransmissions 518b due to the second guard timer 512b expiring.
• all of the multiple counters 516a-x may be reset to zero when the SE 506 acknowledges any one of the multiple I-frames 510.
• only the counter 516 associated with an acknowledged I- frame 510 may be reset to zero, while the counters 516 associated with unacknowledged I-frames 510 may not be reset. Both cases are possible depending on how many I-frames 510 are acknowledged by an acknowledgement frame sent by the SE 506.
• the acknowledgement frame has the number of the next I-frames 510 that it is ready to receive. Therefore, all frames before that may be considered acknowledged.
• the sliding window 550 size is four.
• the NFC chip 504 may stop sending I-frames 510 after sending four I-frames 510 (e.g., I-frames(0- 3)).
• the SE 506 may send an acknowledgment (e.g., an RR frame) after an acknowledge timeout and acknowledge all four I-frames 510.
• the SE 506 is indicating that it is ready to receive I-frame(4) and thus acknowledges I-frames(0-3) implicitly.
• all four guard timers 512 for I- frames(0-3) will be reset/stopped.
• the NFC chip 504 may compare the value of the counter 516 to a retransmission threshold 520. If the counter 516 is less than the retransmission threshold 520, the NFC chip 504 may continue to retransmit the corresponding I-frame. If the counter 516 equals the retransmission threshold 520, then the NFC chip 504 may discontinue I-frame 510 retransmission for each of the I-frames 510a-x. Therefore, the NFC chip 504 may discontinue I-frame 510 retransmission if at least one of the multiple counters 516 equals the retransmission threshold 520.
• the retransmission threshold 520 may be configurable.
• FIG. 6 is a block diagram illustrating one configuration of near-field communication (NFC) in a wireless communication system 600.
• a polling device 660 and a listening device 662 may operate according to NFC protocols.
• the polling device 660 and the listening device 662 may be implemented according to electronic device 102 described in connection with Figure 1. In other words, the electronic device 102 described in connection with Figure 1 may operate as either a polling device 660 a listening device 662 or both.
• Each device 660, 662 may include an antenna 626a-b connected to an electronic circuit 664a-b.
• the combination of two NFC devices i.e., the polling device 660 and listening device 662 may behave like a transformer.
• NFC is an inductive coupling communication technology.
• the two NFC-capable devices 660, 662 may be separated by a distance.
• An alternating current may pass through a primary coil (i.e., the polling device antenna 626a) and create an electromagnetic field 668 (which may also be referred to as a radio frequency (RF) field or radiated field).
• the electromagnetic field 668 may induce a current in the secondary coil (i.e., the listening device antenna 626b).
• the listening device 662 may use the electromagnetic field 668 transmitted by the polling device 660 to power itself.
• the configuration and tuning of both antennas 626a-b may determine the coupling efficiency from one device to the other device.
• the listening device 662 may function as a target, which is a role defined in the NFC standards.
• the NFC transmitter of one device and the NFC receiver of the other device are configured according to a mutual resonant relationship. When the resonant frequency of the NFC receiver and the resonant frequency of the NFC transmitter are very close, transmission losses between the NFC transmitter and the NFC receiver are minimal when the NFC receiver is located in the "near- field" of the radiated field.
• An NFC device may include an NFC loop antenna 626.
• the NFC loop antenna 626 may provide a means for energy transmission and reception. As stated, an efficient energy transfer may occur by coupling a large portion of the energy in the near-field of a transmitting antenna 626 to a receiving antenna 626 rather than propagating most of the energy in an electromagnetic wave to the far field.
• An NFC-capable device may obtain sufficient data 670 to allow for communications to be established.
• One form of communications that may be established is an international standards organization data exchange protocol (ISO-DEP) communication link.
• ISO-DEP international standards organization data exchange protocol
• Communications between the NFC devices may be enabled over a variety of NFC radio frequency (RF) technologies, including but not limited to, NFC-A, NFC-B, etc.
• RF radio frequency
• Figure 7 is a block diagram illustrating another more specific configuration of an electronic device 702 in which systems and methods for mitigating effects of an unresponsive secure element (SE) 706 may be implemented.
• SE unresponsive secure element
• the components included within the electronic device 702 may be examples of corresponding components described above in connection with one or more of Figures 1, 3, 5 and 6.
• the electronic device 702 includes a receiver 776 that receives a signal from, for instance, a receive antenna (not shown), performs typical actions on (e.g., filters, amplifies, downconverts, etc.) the received signal, and digitizes the conditioned signal to obtain samples.
• the receiver 776 can comprise a demodulator 778 that can demodulate received symbols and provide them to a processor 703 for channel estimation.
• the processor 703 can be a processor dedicated to analyzing information received by the receiver 776 and/or generating information for transmission by the transmitter 784, a processor that controls one or more components of the electronic device 702, and/or a processor that analyzes information received by the receiver 776, generates information for transmission by the transmitter 784 and controls one or more components of the electronic device 702. Further, signals may be prepared for transmission by the transmitter 784 through the modulator 782, which may modulate the signals processed by the processor 703.
• the electronic device 702 can additionally comprise memory 705 that is operatively coupled to the processor 703 and that can store data to be transmitted, received data, information related to available channels, transmission control protocol (TCP) flows, data associated with analyzed signal and/or interference strength, information related to an assigned channel, power, rate or the like, and any other suitable information for estimating a channel and communicating via the channel.
• TCP transmission control protocol
• the processor 703, receiver 776, transmitter 784, NFC controller 704, and/or the device host 730 may perform one or more of the functions described above in connection with Figures 1-6.
• the data store e.g., memory 705
• nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), or flash memory.
• Volatile memory can include random access memory (RAM), which acts as external cache memory.
• RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).
• SRAM synchronous RAM
• DRAM dynamic RAM
• SDRAM synchronous DRAM
• DDR SDRAM double data rate SDRAM
• ESDRAM enhanced SDRAM
• SLDRAM Synchlink DRAM
• DRRAM direct Rambus RAM
• the memory 705 of the subject systems and methods may comprise, without being limited to, these and any other suitable types of memory.
• the electronic device 702 may include an NFC controller interface (NCI) 774.
• NCI NFC controller interface
• the NCI 774 may be operable to enable communications between the device host 730 and the NFC controller 704.
• the electronic device 702 may include an NFC controller 704.
• the NFC controller 704 is one example of a contactless front-end (CLF) 104, as described in connection with Figure 1.
• the NFC controller 704 may communicate with one or more secure elements (SEs) 706.
• SEs secure elements
• the NFC controller 704 may include one or more counters 716 that counts the number of successive I- frame retransmissions in order to discontinue I- frame retransmission and deactivate an SWP interface 108 with an unresponsive SE 706.
• the NFC controller 704 may be operable to obtain, through the NCI 774, information from other devices, such as a remote NFC device 528.
• the NFC controller 704 may operate using a frame RF interface or an ISO- DEP interface. When operating using the ISO-DEP interface, the NFC controller 704 may be operable to change various parameters associated with communications between the device host 730 and a remote NFC device 528 using a data exchange change module.
• the NFC controller 704 may act as a relay and communicate messages between the device host 730 and a remote NFC device 528.
• the device host 730 may extract data from messages exchanged with the remote NFC device 528. Communications may prompt the NFC controller 704 to change various data.
• the NFC controller 704 may update received parameters and/or may store parameters in memory.
• Figure 8 illustrates various components that may be utilized in an electronic device 802.
• the illustrated components may be located within the same physical structure or in separate housings or structures.
• the electronic device 802 described in connection with Figure 8 may be implemented in accordance with one or more of the electronic devices 102, 502 described herein.
• the electronic device 802 includes a processor 803.
• the processor 803 may be a general purpose single- or multi-chip microprocessor (e.g., an advanced RISC machine (ARM)), a special purpose microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc.
• the processor 803 may be referred to as a central processing unit (CPU).
• CPU central processing unit
• a combination of processors 803 e.g., an ARM and DSP
• the electronic device 802 also includes memory 805 in electronic communication with the processor 803. That is, the processor 803 may read information from and/or write information to the memory 805.
• the memory 805 may be any electronic component capable of storing electronic information.
• the memory 805 may be random access memory (RAM), read-only memory (ROM), magnetic disk storage media, optical storage media, flash memory devices in RAM, on-board memory included with the processor 803, programmable read-only memory (PROM), erasable programmable readonly memory (EPROM), electrically erasable PROM (EEPROM), registers, and so forth, including combinations thereof.
• RAM random access memory
• ROM read-only memory
• EPROM erasable programmable readonly memory
• EEPROM electrically erasable PROM
• Data 809a and instructions 807a may be stored in the memory 805.
• the instructions 807a may include one or more programs, routines, sub-routines, functions, procedures, etc.
• the instructions may include a single computer-readable statement or many computer-readable statements.
• the instructions 807a may be executable by the processor 803 to implement one or more of the methods, functions and procedures described above. Executing the instructions may involve the use of the data 809a that is stored in the memory 805.
• Figure 8 shows some instructions 807b and data 809b being loaded into the processor 803 (which may come from instructions 807a and data 809a that are stored in the memory 805).
• the electronic device 802 may also include one or more communication interfaces 811 for communicating with other electronic devices.
• the communication interfaces 811 may be based on wired communication technology, wireless communication technology, or both. Examples of different types of communication interfaces 811 include a serial port, a parallel port, a Universal Serial Bus (USB), an Ethernet adapter, an Institute of Electrical and Electronics Engineers (IEEE) 1394 bus interface, a near-field communication (NFC) transceiver, a small computer system interface (SCSI) bus interface, an infrared (IR) communication port, a Bluetooth wireless communication adapter, a 3rd Generation Partnership Project (3GPP) transceiver, an IEEE 802.11 (“Wi-Fi”) transceiver and so forth.
• the communication interface 811 may be coupled to one or more antennas (not shown) for transmitting and receiving wireless signals.
• a speaker 819 may be a transducer that converts electrical or electronic signals into acoustic signals.
• One specific type of output device 817 that may be typically included in an electronic device 802 is a display 821 device.
• Display 821 devices used with configurations disclosed herein may utilize any suitable image projection technology, such as a cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), gas plasma, electroluminescence, or the like.
• a display controller 823 may also be provided, for converting data stored in the memory 805 into text, graphics, and/or moving images (as appropriate) shown on the display 821 device.
• the various components of the electronic device 802 may be coupled together by one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc.
• buses may include a power bus, a control signal bus, a status signal bus, a data bus, etc.
• the various buses are illustrated in Figure 8 as a bus system 825. It should be noted that Figure 8 illustrates only one possible configuration of an electronic device 802. Various other architectures and components may be utilized.
• determining encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing and the like.
• memory should be interpreted broadly to encompass any electronic component capable of storing electronic information.
• the term memory may refer to various types of processor-readable media such as random access memory (RAM), readonly memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable PROM (EEPROM), flash memory, magnetic or optical data storage, registers, etc.
• RAM random access memory
• ROM readonly memory
• NVRAM non-volatile random access memory
• PROM programmable read-only memory
• EPROM erasable programmable read-only memory
• EEPROM electrically erasable PROM
• flash memory magnetic or optical data storage, registers, etc.
• instructions and “code” should be interpreted broadly to include any type of computer-readable statement(s).
• the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc.
• “Instructions” and “code” may comprise a single computer-readable statement or many computer-readable statements.
• the functions described herein may be implemented in software or firmware being executed by hardware.
• the functions may be stored as one or more instructions on a computer-readable medium.
• computer-readable medium or “computer- program product” refers to any tangible storage medium that can be accessed by a computer or a processor.
• a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
• the methods disclosed herein comprise one or more steps or actions for achieving the described method.
• the method steps and/or actions may be interchanged with one another without departing from the scope of the claims.
• the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.
• modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a device.
• a device may be coupled to a server to facilitate the transfer of means for performing the methods described herein.
• various methods described herein can be provided via a storage means (e.g., random access memory (RAM), read only memory (ROM), a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a device may obtain the various methods upon coupling or providing the storage means to the device.
• RAM random access memory
• ROM read only memory
• CD compact disc
• floppy disk floppy disk

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• 2014
  • 2014-10-15 US US14/515,319 patent/US9647802B2/en not_active Expired - Fee Related
• 2015
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  • 2015-09-17 JP JP2017519869A patent/JP2017539112A/ja active Pending
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