Patent Description:
The present disclosure relates generally to communication systems, and more particularly, to soft combining of decrypted packets.

A wireless personal area network (WPAN) is a personal, short-range wireless network for interconnecting devices centered around a specific distance from a user. WPANs have gained popularity because of the flexibility and convenience in connectivity that WPANs provide. WPANs, such as those based on short-range communication protocols (e.g., a Bluetooth® (BT) protocol, a Bluetooth® Low Energy (BLE) protocol, a Zigbee® protocol, etc.), provide wireless connectivity to peripheral devices by providing wireless links that allow connectivity within a specific distance (e.g., <NUM> meters, <NUM> meter, <NUM> meters, <NUM> meters, etc.).

BT is a short-range wireless communication protocol that supports a WPAN between a central device (e.g., a master device) and at least one peripheral device (e.g., a slave device). Power consumption associated with BT communications may render BT impractical in certain applications, such as applications in which an infrequent transfer of data occurs.

To address the power consumption issue associated with BT, BLE was developed and adopted in various applications in which an infrequent transfer of data occurs. BLE exploits the infrequent transfer of data by using a low duty cycle operation, and switching at least one of the central device and/or peripheral device(s) to a sleep mode in between data transmissions. A BLE communications link between two devices may be established using, e.g., hardware, firmware, host operating system, host software stacks, and/or host application support. Example applications that use BLE include battery-operated sensors and actuators in various medical, industrial, consumer, and fitness applications. BLE may be used to connect devices such as BLE enabled smart phones, tablets, and laptops. While traditional BLE offers certain advantages over BT, BLE and BT may not be able to validate the combination of decrypted data packets in an effort to decode the data error free. Transmitted and re-transmitted data packets may be encrypted using different encryption parameters, which may cause the re-transmitted data packets to appear as different data packets despite having the same payload.

There exists a need for an operation to validate the combination of decrypted data packets in wireless communications where a data packet and its retransmission may be sent using different encryption parameters. Document <CIT> discloses chase coding for error correction of encrypted packets with parity.

BLE was developed and adopted in various applications in which an infrequent transfer of data occurs. BLE exploits the infrequent transfer of data by using a low duty cycle operation, and switching at least one of the central device and/or peripheral device(s) to a sleep mode in between data transmissions. Example applications that use BLE include battery-operated sensors and actuators in various medical, industrial, consumer, and fitness applications. The BLE applications often connect to devices such as BLE enabled smart phones, tablets, and laptops.

While traditional BLE offers certain advantages, the traditional BLE protocol provides only for error detection in the payload of a data packet through the use of a cyclic redundancy check (CRC). Thus, according to the traditional BLE protocol, retransmission is the means by which errors in the payload may be "corrected," where correction via retransmission is different than the dynamic correction of the same data packet enabled through FEC. That is, FEC actually corrects the errors in the same data packet, while the retransmission corrects the errors of the current data packet by replacing the current data packet with another version of the data payload, which may or may not include errors.

Failing error correction in the traditional BLE protocol, an erroneous data packet may be replaced with a special packet that in effect defines silence or packet loss concealment. The silence packet and/or packet loss concealment may reduce communication quality because portions of the communication may be omitted (e.g., voice breaks during a voice call).

As many applications, such as wireless headsets used with cellular phones, require mostly error free (e.g., low error rate data streams) data to accurately reproduce a telephone conversation, uncorrected erroneous data packets may impact a perceived quality of a given application.

In addition, using the error correction techniques of traditional BLE may not only reduce the perceived audio quality of a given application, but may also limit a transmit power reduction of a BLE air interface packet due to a limited sensitivity at the receiving device. The receiving device sensitivity may be correlated with the lowest signal power level from which the receiving device may obtain information from a BLE air interface packet without meeting a Bit Error Rate (BER) threshold. Hence, the receiving device sensitivity may limit the transmit power reduction for a BLE air interface packet.

Validation of a correctly received packet may be done through the use of CRC. Incorrectly received packets may cause the packet to be retransmitted in response to a request for a new message sent to the transmitting device by the receiving device. The two or more packets may be combined until the receiving device can decode the message error free. Over the air bit errors may cause numerous retransmissions, but if the retransmitted packet is encrypted using different encryption parameters, such as but not limited to Nonce, then the retransmitted packet will appear to be different than the originally transmitted packet despite having the same payload.

There exists a need for an error correction technique to validate the combination of transmitted and retransmitted decrypted data packets in wireless communications (e.g., BLE) in situations where the transmitted and retransmitted packets are encrypted using different encryption parameters (e.g., nonce).

The error correction techniques of the present disclosure promote error-correction in communication systems that lack FEC or other embedded error correction mechanisms with respect to one or more portions of a data packet by decrypting the data packet to obtain a first payload, soft combining the decrypted first payload with a decrypted set of payloads, generating a CRC based on the soft combined decrypted payloads, and determining whether the generated CRC passes a CRC check against a first CRC. The techniques therefore provide error correction for the entire packet, including packet portions not protected by any embedded error correction mechanism. As a result, data communications over noisy communication mediums may be improved as the techniques may reduce bit error rates, and increase the sensitivity of the receiving device such that the transmission power of a data packet may be reduced. For data communications involving voice or other streaming audio data, the techniques promote increased audio quality over systems that do not employ the techniques described in the present disclosure.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may receive a first packet data unit (PDU) and a first CRC that is based on the first PDU. In one aspect, the first PDU may be encrypted based on a first nonce. The apparatus may decrypt the first PDU to obtain a first payload and a first cipher stream. The apparatus may soft combine the decrypted first payload with a decrypted set of payloads. In one aspect, the set of payload may be encrypted based on at least one nonce that is different than the first nonce. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. The apparatus may generate a second CRC based on the soft combined decrypted payloads and based on the first cipher stream. The apparatus may determine whether the generated second CRC for the soft combined decrypted payloads passes a CRC check against the first CRC.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may receive a first PDU and a first CRC that is based on the first PDU. In one aspect, the first PDU may be encrypted based on a first nonce. The apparatus may decrypt the first PDU to obtain a first payload. The apparatus may obtain an error bitmap by soft combining the decrypted first payload with a decrypted set of payloads. In one aspect, the set of payloads may be encrypted based on at least one nonce different than the first nonce. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. The apparatus may perform an Exclusive OR (XOR) operation on the received first PDU with the obtained error bitmap to obtain a soft combined encrypted payload. The apparatus may generate a second CRC based on the soft combined encrypted payload. The apparatus may determine whether the generated second CRC for the soft combined encrypted payload passes a CRC check against the first CRC.

<FIG> illustrates an example WPAN <NUM> in accordance with certain aspects of the disclosure. Within the WPAN <NUM>, a central device <NUM> may connect to and establish a BLE communication link <NUM> with one or more peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> using a BLE protocol or a modified BLE protocol. The BLE protocol is part of the BT core specification and enables radio frequency communication operating within the globally accepted <NUM> Industrial, Scientific & Medical (ISM) band.

The central device <NUM> may include suitable logic, circuitry, interfaces, processors, and/or code that may be used to communicate with one or more peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> using the BLE protocol or the modified BLE protocol as described below in connection with any of <FIG>. The central device <NUM> may operate as an initiator to request establishment of a link layer (LL) connection with an intended peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

A LL in the BLE protocol stack and/or modified BLE protocol stack (e.g., see <FIG>) provides, as compared to BT, ultra-low power idle mode operation, simple device discovery and reliable point-to-multipoint data transfer with advanced power-save and encryption functionalities. After a requested LL connection is established, the central device <NUM> may become a master device and the intended peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may become a slave device for the established LL connection. As a master device, the central device <NUM> may be capable of supporting multiple LL connections at a time with various peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> (slave devices). The central device <NUM> (master device) may be operable to manage various aspects of data packet communication in a LL connection with an associated peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> (slave device). For example, the central device <NUM> maybe operable to determine an operation schedule in the LL connection with a peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The central device <NUM> may be operable to initiate a LL protocol data unit (PDU) exchange sequence over the LL connection. LL connections may be configured to run periodic connection events in dedicated data channels. The exchange of LL data PDU transmissions between the central device <NUM> and one or more of the peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may take place within connection events.

In certain configurations, the central device <NUM> may be configured to transmit the first LL data PDU in each connection event to an intended peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. In certain other configurations, the central device <NUM> may utilize a polling scheme to poll the intended peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> for a LL data PDU transmission during a connection event. The intended peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may transmit a LL data PDU upon receipt of packet LL data PDU from the central device <NUM>. In certain other configurations, a peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may transmit a LL data PDU to the central device <NUM> without first receiving a LL data PDU from the central device <NUM>.

Examples of the central device <NUM> may include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a mobile station (STA), a laptop, a personal computer (PC), a desktop computer, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP<NUM> player), a camera, a game console, a tablet, a smart device, a wearable device (e.g., smart watch, wireless headphones, etc.), a vehicle, an electric meter, a gas pump, a toaster, a thermostat, a hearing aid, a blood glucose on-body unit, an Internet-of-Things (IoT) device, or any other similarly functioning device.

Examples of the one or more peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may include a cellular phone, a smart phone, a SIP phone, a STA, a laptop, a PC, a desktop computer, a PDA, a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP<NUM> player), a camera, a game console, a tablet, a smart device, a wearable device (e.g., smart watch, wireless headphones, etc.), a vehicle, an electric meter, a gas pump, a toaster, a thermostat, a hearing aid, a blood glucose on-body unit, an IoT device, or any other similarly functioning device. Although the central device <NUM> is illustrated in communication with six peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in the WPAN <NUM>, the central device <NUM> may communicate with more or fewer than six peripheral devices within the WPAN <NUM> without departing from the scope of the present disclosure.

Referring again to <FIG>, in certain aspects, the central device <NUM> and/or a peripheral device (e.g., peripheral device <NUM>) may be configured to perform a soft combine operation after the decryption of data packets if the transmission and the re-transmission of data packets are encrypted using different nonces (<NUM>), e.g., as described below in connection with any of <FIG>.

<FIG> is block diagram of a wireless device <NUM> in accordance with certain aspects of the disclosure. The wireless device <NUM> may correspond to, e.g., the central device <NUM>, and/or one of peripheral devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> described above in connection with <FIG>. In certain aspects, the wireless device <NUM> may be a BLE enabled device. However, the disclosure is not intended to be limited to the wireless device <NUM> being a BLE enabled device. In some aspects, the wireless device <NUM> may be a BT Classic enabled device, an <NUM>. <NUM> Zigbee enabled or any wireless device configured to communicate via short-range communication protocols.

As shown in <FIG>, the wireless device <NUM> may include a processing element, such as processor(s) <NUM>, which may execute program instructions for the wireless device <NUM>. The wireless device <NUM> may also include display circuitry <NUM> which may perform graphics processing and provide display signals to the display <NUM>. The processor(s) <NUM> may also be coupled to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and translate the addresses to address locations in memory (e.g., memory <NUM>, ROM <NUM>, Flash memory <NUM>) and/or to address locations in other circuits or devices, such as the display circuitry <NUM>, radio <NUM>, connector interface <NUM>, and/or display <NUM>. The MMU <NUM> may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU <NUM> may be included as a portion of the processor(s) <NUM>.

As shown, the processor(s) <NUM> may be coupled to various other circuits of the wireless device <NUM>. For example, the wireless device <NUM> may include various types of memory, a connector interface <NUM> (e.g., for coupling to the computer system), the display <NUM>, and wireless communication circuitry (e.g., for Wi-Fi, BT, BLE, cellular, etc.). The wireless device <NUM> may include a plurality of antennas 235a, 235b, 235c, 235d, for performing wireless communication with other BLE devices.

In certain aspects, the wireless device <NUM> may include hardware and software components (a processing element) configured to perform a soft combine operation after the decryption of data packets if the transmission and the re-transmission of data packets are encrypted using different nonces, e.g., using the techniques described below in connection with any <FIG>. The wireless device <NUM> may also comprise BLE firmware or other hardware / software for controlling BLE operations. In addition, the wireless device <NUM> may store and execute a wireless local area network (WLAN) software driver for controlling WLAN operations.

The wireless device <NUM> may be configured to implement part or all of the techniques described below in connection with any of <FIG>, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) and/or through hardware or firmware operation. In other embodiments, the techniques described below in connection with any of <FIG> may be at least partially implemented by a programmable hardware element, such as a field programmable gate array (FPGA), and/or an application specific integrated circuit (ASIC).

In certain aspects, radio <NUM> may include separate controllers configured to control communications for various respective radio access technology (RAT) protocols. For example, as shown in <FIG>, radio <NUM> may include a WLAN controller <NUM> configured to control WLAN communications and a short-range communications controller <NUM> configured to control short-range communications (e.g., BLE communications). A coexistence interface <NUM> (e.g., a wired interface) may be used for sending information between the WLAN controller <NUM> and the short-range communication controller <NUM>.

In some aspects, one or more of the WLAN controller <NUM> and/or the short-range communications controller <NUM> may be implemented as hardware, software, firmware or some combination thereof.

In certain aspects, the WLAN controller <NUM> may be configured to communicate with a second device using a WLAN link using all of the antennas 235a, 235b, 235c, 235d. In certain configurations, the short-range communication controller <NUM> may be configured to implement a BLE protocol stack (see <FIG>), and communicate with at least one second device using one or more of the antennas 235a, 235b, 235c, 235d. The short-range communication controller <NUM> may be configured to perform a soft combine operation after the decryption of data packets if the transmission and the re-transmission of data packets are encrypted using different nonces.

<FIG> illustrates a BLE protocol stack <NUM> that may be implemented in a BLE device in accordance with certain aspects of the present disclosure. For example, the BLE protocol stack <NUM> may be implemented by, e.g., one or more of processor(s) <NUM>, memory <NUM>, Flash memory <NUM>, ROM <NUM>, the radio <NUM>, and/or the short-range communication controller <NUM> illustrated in <FIG>.

Referring to <FIG>, the BLE protocol stack <NUM> may be organized into three blocks, namely, the Application block <NUM>, the Host block <NUM>, and the Controller block <NUM>. Application block <NUM> may be a user application which interfaces with the other blocks and/or layers of the BLE protocol stack <NUM>. The Host block <NUM> may include the upper layers of the BLE protocol stack <NUM>, and the Controller block <NUM> may include the lower layers of the modified BLE protocol stack <NUM>.

The Host block <NUM> may communicate with a BLE controller (e.g., short-range communication controller <NUM> in <FIG>) in a wireless device using a Host Controller Interface (HCI) (not shown in <FIG>). The HCI may also be used to interface the Controller block <NUM> with the Host block <NUM>. Interfacing the Controller block <NUM> and the Host block <NUM> may enable a wide range of Hosts to interface with the Controller block <NUM>.

The Application block <NUM> may include a higher-level Application Layer (App) <NUM>, and the BLE protocol stack <NUM> may run under the App <NUM>. The Host block <NUM> may include a Generic Access Profile (GAP) <NUM>, a Generic Attribute Protocol (GATT) <NUM>, a Security Manager (SM) <NUM>, an Attribute Protocol (ATT) <NUM>, and a Logical Link Control and Adaptation Protocol (L2CAP) <NUM>. The Controller block <NUM> may include a LL <NUM> and a Physical Layer (PHY) <NUM>.

The PHY <NUM> may define the mechanism for transmitting a bit stream over a physical link that connects BLE devices. The bit stream may be grouped into code words or symbols, and converted to a PDU that is transmitted over a transmission medium. The PHY <NUM> may provide an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequency band used for transmission, the modulation scheme, and similar low-level parameters may be specified by the PHY <NUM>.

The LL <NUM> may be responsible for low level communication over the PHY <NUM>. The LL <NUM> may manage the sequence and timing for transmitting and receiving data packets, and using a LL protocol, communicates with other devices regarding connection parameters and data flow control. The LL <NUM> may provide gate keeping functionality to limit exposure and data exchange with other devices. If filtering is configured, the LL <NUM> may maintain a list of allowed devices and ignore all requests for data exchange from devices not on the list. The LL <NUM> may also reduce power consumption. The LL <NUM> may use the HCI (not shown in <FIG>) to communicate with upper layers of the BLE protocol stack <NUM>. The LL <NUM> may include a third party's proprietary LL that may be used to discover peer devices (e.g., other devices associated with the third party), and establish a secure communication channel therewith.

In certain aspects, the LL <NUM> may be responsible for transporting data packets between devices in a WPAN. Each data packet may include a logical transport address LT_ADDR in a header field, which specifies the type of logical transport used to carry the data packet. Logical transports may exist between a master device and slave devices. Additionally, some logical transports may carry multiple logical links.

One type of logical transport is an ACL logical transport. The ACL logical transport may be used to carry data packets such as the data packet described below with reference to <FIG>. Each device may receive a default ACL logical transport when the device joins the WPAN. Each ACL logical transport may carry one or more ACL communication links, which are distinguished by a Logical Link ID (LLID) field of the header. Retransmitted data packets carried via an ACL communication link may be received automatically if unacknowledged by the receiver device, allowing for correction of a radio link that is subject to interference. The ACL logical transport may permit communication of data for time-sensitive or time-bounded applications, such as streaming services, voice applications including Voice over Internet Protocol (VoIP) and more standard, cellular telephone calls. Failing error correction, an erroneous data packet carried via an ACL communication link may be replaced with a special communication packet that in effect defines silence or packet loss concealment when the traditional BLE protocol is implemented. The special silence communication packet and/or packet loss concealment may reduce the communication quality experienced over ACL communication links because portions of the communications may be omitted (e.g., voice breaks during a voice call).

The L2CAP <NUM> may encapsulate multiple protocols from the upper layers into a data packet format (and vice versa). The L2CAP <NUM> may also break packets with a large data payload from the upper layers into multiple packets with the data payload segmented into smaller size data payloads that fit into a maximum payload size (e.g., <NUM> bytes) on the transmit side. Similarly, the L2CAP <NUM> may receive multiple data packets carrying a data payload that has been segmented, and the L2CAP <NUM> may combine the segmented data payload into a single data packet carrying the data payload that may be sent to the upper layers.

The ATT <NUM> may be a client / server protocol based on attributes associated with a BLE device configured for a particular purpose (e.g., monitoring heart rate, monitoring temperature, broadcasting advertisements, etc.). The attributes may be discovered, read, and written by peer devices. The set of operations which are executed over ATT <NUM> may include, but are not limited to, error handling, server configuration, find information, read operations, write operations, queued writes, etc. The ATT <NUM> may form the basis of data exchange between BLE devices.

The SM <NUM> may be responsible for device pairing and key distribution. A security manager protocol implemented by the SM <NUM> may define how communications with the SM of a counterpart BLE deice are performed. The SM <NUM> may provide additional cryptographic functions that may be used by other components of the BLE protocol stack <NUM>. The architecture of the SM <NUM> used in BLE may be designed to minimize recourse requirements for peripheral devices by shifting work to an assumingly more powerful central device. BLE uses a pairing mechanism for key distribution. The SM <NUM> provides a mechanism to not only encrypt the data but also to provide data authentication.

The GATT <NUM> describes a service framework using the attribute protocol for discovering services, and for reading and writing characteristic values on a peer device. The GATT <NUM> interfaces with the App <NUM> through the App's profile. The App <NUM> profile defines the collection of attributes and any permission needed for the attributes to be used in BLE communications.

The GAP <NUM> may provide an interface for the App <NUM> to initiate, establish, and manage connection with counterpart BLE devices.

BLE provides for a method to transmit, and retransmit, a message until the receiving device decodes the message error free. Validation of a correctly received packet may be done through the use of CRC and/or Message Integrity Check (MIC). When packets are encrypted using AES-CCM, for example, the CRC is calculated on the encrypted packet. On the transmit side, when the CRC is generated and transmitted, the CRC is based on the encrypted data. In order for the CRC to be validated on the receive side, the encrypted data is analyzed by the receiver.

Incorrectly received packets may cause the packet to be retransmitted in response to a request for a new message (e.g., NACK) sent to the transmitting device by the receiving device. The transmitted packet and retransmitted packets may be soft combined until the receiving device can decode the message error free. However, if the same packet is encrypted using different cipher streams during the transmission and retransmission, then the retransmitted packet will not appear the same as the originally transmitted packet despite having the same payload.

For example, extended synchronous connection oriented (eSCO) packets are used for audio, and the eSCO packet transmission and each retransmission are each encrypted using a different nonce (e.g., counter). In addition, the cipher stream which encrypts the eSCO packet is also different. Soft combining is the process of combining received bits during different receptions in order to guess the correct bit. Soft combining eSCO packets will not work if the soft combining is performed before decryption because different nonces are used to encrypt the packet. If eSCO packets are soft combined after the packets are decrypted, then CRC validation cannot be performed directly on the corrected soft combined data because the CRC is calculated on the encrypted data. This thus presents the dilemma of how to validate the CRC. The packets have been decrypted to generate the corrected soft combined data, but validation of the CRC cannot be done on the decrypted data, validation of the CRC must occur on the encrypted data since the CRC has been calculated based on the encrypted data.

Thus, there exists a need for an error correction technique to validate the combination of transmitted and retransmitted decrypted data packets in BLE communications in situations where the transmitted and retransmitted packets are encrypted using different nonces and/or cipher streams.

The present disclosure provides an error correction technique to validate the combination of transmitted and retransmitted decrypted data packets that have been encrypted using different nonces and/or cipher streams. The error correction technique may be configured to validate the CRC (based on the encrypted data) against a CRC calculated on the data that has been decrypted and soft combined to generate the reconstructed data, but without re-encrypting the soft combined reconstructed data.

<FIG> illustrates a block diagram <NUM> illustrating a soft combining operation in accordance with certain aspects of the present disclosure. <FIG> is a block diagram <NUM> illustrating a header adjustment in accordance with certain aspects of the disclosure. The soft combining operation may occur in communications between a first device and second device in a WPAN in accordance with certain aspects of the disclosure. The first device may correspond to, e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>/<NUM>', or the mesh node <NUM>. The second device may correspond to, e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>/<NUM>', or the mesh node <NUM>.

As seen in <FIG>, the first device (e.g., transmitting device) may transmit encrypted data <NUM> to the second device (e.g., receiving device). The encrypted data <NUM> may include a first PDU and a first CRC that was calculated based on the encrypted first PDU. In some aspects, the first PDU may be encrypted based on a first nonce. The second device receives the encrypted data <NUM> provides the encrypted data <NUM> to the decryption block <NUM>. The decryption block <NUM> decrypts the encrypted data <NUM> and outputs decrypted data <NUM> (e.g., first payload) and a cipher stream <NUM>. The decryption block <NUM> is configured to generate the cipher stream <NUM> that was used to encrypt the encrypted data <NUM>. The cipher stream <NUM> may also be used to decrypt the data.

The decryption block <NUM> outputs the decrypted data <NUM> to the real time soft combining (RTSC) block <NUM>. In some aspects, the decrypted data <NUM> may be soft combined with a decrypted set of payloads at the RTSC block <NUM>. The decrypted set of payloads may be encrypted based on at least one nonce that is different than the first nonce used to encrypt the first PDU. However, in some aspects, the decrypted set of payloads may be encrypted based on a nonce that is the same as the first nonce. The decrypted set of payloads may be previously received data packets that may be stored within the RTSC block <NUM> or may be stored in a memory that is external to the RTSC block <NUM>. For example, the receiving device may receive a set of PDUs, prior to receiving the encrypted data <NUM>, and may attempt to decrypt each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads. The receiving device may be configured to transmit a negative acknowledgement (NACK) in the event that the receiving device fails to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. The transmission of the NACK from the receiving device to the transmitting device may indicate that the PDU was improperly received. In response to the NACK, the transmitting device sends another PDU to the receiving device. In some aspects, the retransmitted PDU may be the first PDU from the encrypted data <NUM>.

The RTSC block <NUM> may be configured to soft combine the decrypted data <NUM> with previously received data in an effort to correct previous corrupt reception or improper reception of the same packet. The RTSC block <NUM> cannot operate on encrypted data because the encryption (e.g., nonce) changes from packet to packet, whereas decrypting the encrypted data <NUM> allows the RTSC block <NUM> to generate soft combined decrypted data <NUM> to reconstruct the data. However, as discussed above, BLE specifications require the CRC to be calculated on the encrypted data, not the decrypted data. The reconstructed data (e.g., soft combined decrypted data <NUM>) generated by the RTSC block <NUM> is a combination of decrypted data, and a CRC calculated based on the decrypted data, alone, does not allow the first CRC based on the encrypted data to be validated. The first CRC based on the encrypted data needs to be validated to determine whether the soft combined decrypted data <NUM> has been properly received. Upon the determination that the soft combined decrypted data <NUM> has been properly received, the receiving device may send an acknowledgement (ACK) to the transmitting device. The ACK provides an indication to the transmitting device that the receiving device has properly received the PDU.

The RTSC block <NUM> outputs the soft combined decrypted data <NUM> to CRC generator <NUM>. The CRC generator <NUM> is configured to generate a CRC based on the soft combined decrypted data <NUM>. Although the CRC generated by the CRC generator <NUM> is a CRC based on decrypted data, this CRC may be utilized to calculate a CRC generated by the receiving device based on the reconstructed data without re-encrypting the reconstructed data. The CRC, generated by the CRC generator <NUM>, based on the decrypted data may be further processed in order for the CRC to mimic as if it was generated based on encrypted data.

While the decryption block <NUM> is decrypting the encrypted data <NUM>, the decryption block <NUM>, in parallel, will output the cipher stream <NUM>. The cipher stream <NUM> is outputted to the CRC generator <NUM>, and may be configured to generate a CRC of only the cipher stream <NUM>. The CRC of the cipher stream <NUM>, generated by the CRC generator <NUM>, may be used in conjunction with the CRC of the soft combined decrypted data <NUM>, generated by the CRC generator <NUM>, to generate a calculated CRC <NUM> which may then be used to validate the received CRC based on encrypted data (e.g., first CRC). The calculated CRC <NUM> may be based on the soft combined decrypted data <NUM> and based on the first cipher stream <NUM>.

The disclosure takes advantage of the linear properties of CRC polynomials to further process the CRC generated by the CRC generator <NUM>, based on the soft combined decrypted data, and to further process the CRC generated by the CRC generator <NUM>, based on the cipher stream, to validate the CRC based on encrypted data. For example: <MAT>.

If x is the unencrypted data, and y is the cipher stream used to encrypt the data, then it follows that the CRC of the encrypted data will be equal to the XOR of the individual CRC of the decrypted data and the cipher stream. Thus: <MAT>.

In BLE unencrypted data is encrypted by using the cipher stream. For example, XORing the unencrypted data with the cipher stream yields the encrypted data. The cipher stream may also be used to decrypt encrypted data. For example, XORing the encrypted data with the same cipher stream will result in the decrypted data. For example, in the expression x ⊕ y = z where x is unencrypted data, y is a cipher stream, and z is encrypted data, the unencrypted data x is encrypted by the cipher stream y by XORing the cipher stream and the unencrypted data, and results in encrypted data z. The cipher stream may be used to encrypt and decrypt data, in instances where the same cipher stream is used to perform both. In such instances, XORing the encrypted data z and the same cipher stream y, used to encrypt the unencrypted data x, would result in the decrypted data x, or as stated as follows if x ⊕ y = z, then z ⊕ y = x.

A CRC may be initialized with a seed, and both the transmitting device and the receiving device need to know the initial seed in order for the CRC (e.g., calculated CRC <NUM>) to be correct. As such, the seed needs to be applied to one of the CRCs that is being generated by CRC generators <NUM>, <NUM> in order for the calculated CRC <NUM> to be correct. In addition, the header also needs to be adjusted in order for the calculated CRC <NUM> to be correct when the CRC based on the soft combined decrypted data <NUM> is XORed with the CRC based on the cipher stream <NUM>. In some aspects, a payload header <NUM> may be appended to the soft combined decrypted data <NUM> prior to the CRC generator <NUM> generating the CRC based on the soft combined decrypted data <NUM>. In some aspects, the cipher stream <NUM> maybe zero padded <NUM> prior to the CRC generator <NUM> generating the CRC based on the cipher stream <NUM>. In yet some aspects, the payload header <NUM> may be appended to the soft combined decrypted data <NUM>, and the first cipher stream <NUM> may be zero padded <NUM> prior to the calculated CRC <NUM> being generated. For example, as shown in <FIG>, the decrypted data <NUM> is soft combined to reconstruct the correct data as it goes through the RTSC block <NUM>, but the header does not run through the RTSC block <NUM>. Instead, the header is provided to the payload header <NUM> after the data is decrypted by the decryption block <NUM>. As the header portion is being processed by the decryption block <NUM>, a cipher stream portion corresponding to the header portion is not generated by the decryption block <NUM> since the header is not encrypted. The header is provided to the payload header <NUM>, and is provided to the CRC generator <NUM> prior to the soft combined decrypted data <NUM>. As the payload header <NUM> is being provided to the CRC generator <NUM>, the cipher stream <NUM> is not provided to the CRC generator <NUM>. Instead, a zero padding stream <NUM> is provided to the CRC generator <NUM> that may be configured to correspond with the payload header <NUM> provided to the CRC generator <NUM>. Once the payload header <NUM> has been fully received by the CRC generator <NUM>, then a first switch may be toggled to form a connection with the output of the RTSC Block <NUM> and allow the soft combined decrypted data <NUM> to be fed into the CRC generator <NUM>. Additionally, once the corresponding zero padding stream <NUM> has been fully received by the CRC generator <NUM>, a second switch may then be toggled to form a connection with an output of the decryption block <NUM> corresponding to the cipher stream <NUM>, to allow the cipher stream <NUM> to be fed into the CRC generator <NUM>.

The length of the zero padding stream <NUM> may be equal to the length of the payload header <NUM>. The length of the zero padding stream <NUM> may be equal to the length of the payload header <NUM> to ensure that when the generated CRC based on the soft combined decrypted data <NUM> is XORed with the generated CRC based on the cipher stream <NUM>, the payload header <NUM> is XORed with the zero padding stream <NUM>. Performing an XOR of the payload header <NUM> with the zero padding stream <NUM> will yield the payload header <NUM>, and essentially mimics the header being encrypted with a cipher stream of all zeros. This will assist in ensuring that the calculated CRC <NUM> includes the correct header information, so that when the calculated CRC <NUM> is checked against the received CRC, at <NUM>, the calculated CRC <NUM> can be validated. Validating the calculated CRC <NUM> indicates that the soft combined decrypted data <NUM> is correct, at which point, the receiving device may send an ACK back to the transmitting device.

At least one advantage of the disclosure is that the linear properties of CRC allows the header to be appended to either the soft combined decrypted data <NUM> or the cipher stream <NUM>. For example, in some aspects, the header may be appended to the cipher stream <NUM> instead of the soft combined decrypted data <NUM>. In such aspects, the header is provided to the CRC generator <NUM> prior to the cipher stream <NUM>, and the zero padding stream is provided to the CRC generator <NUM> prior to the soft combined decrypted data <NUM>. Once the header has been fully received by the CRC generator <NUM>, the cipher stream <NUM> may be fed into the CRC generator <NUM>. In addition, once the zero padding stream has been fully received by the CRC generator <NUM>, the soft combined decrypted data <NUM> may be fed into the CRC generator <NUM>. Prefixing the soft combined decrypted data <NUM> with the header before being fed into the CRC generator <NUM>, and similarly prefixing the cipher stream <NUM> with the zero padding stream for the length equal to the header length provides the header adjustment to ensure that the calculated CRC <NUM> can be properly validated against the received CRC.

Referring back to <FIG>, the CRC generator <NUM> outputs the generated CRC based on soft combined decrypted data <NUM> into the XOR block <NUM>, and the CRC generator <NUM> outputs the generated CRC based on the cipher stream <NUM> into the XOR block <NUM>. The result of the XOR between these two generated CRCs results in the calculated CRC <NUM>. The XOR between the CRC of the soft combined decrypted data <NUM> and the CRC of the cipher stream <NUM> produces the CRC of the encrypted data, as discussed above. Since the encrypted data is the result of the unencrypted data XOR with the cipher stream, then it follows that the CRC of the encrypted data is the result of the CRC of the decrypted data XOR with the CRC of the cipher stream, where the CRC of the decrypted data is calculated based on decrypted data (e.g., soft combined decrypted data <NUM>) which may be corrected decrypted data. Thus, XORing the CRC of the decrypted data and the CRC of the cipher stream may be configured to validate the calculated CRC <NUM> with the CRC of the encrypted data <NUM>.

The calculated CRC <NUM> is outputted to CRC check box <NUM>, where the calculated CRC <NUM> is compared against the received encrypted CRC (e.g., first CRC) to determine if the calculated CRC <NUM> passes a CRC check against the encrypted CRC. If the calculated CRC <NUM> passes a CRC check against the encrypted CRC (e.g., both being the same), then the encrypted data has been successfully combined such that the receiving device sends an ACK to the transmitting device. However, if the calculated CRC <NUM> is not the same as the encrypted CRC, then the encrypted data has not been successfully combined, and the receiving device may send a NACK to the transmitting device. At least one advantage of the disclosure is that the CRC of the soft combined decrypted data <NUM> may be utilized to validate the calculated CRC <NUM> without having to re-encrypt the data, which can enhance efficiency and reduce processing resources. At least another advantage of the disclosure is that if the encrypted data is not successfully combined and causes a NACK to be sent to the transmitting device, and another data packet being sent to the receiving device, the non-successfully combined data can be utilized by the RTSC block <NUM> to assist in generating the soft combined decrypted data <NUM>. As discussed above, the decrypted data <NUM> may be soft combined with the decrypted set of payloads at the RTSC block <NUM>. In some aspects, the decrypted set of payloads may be encrypted based on at least one nonce that is different than the first nonce used to encrypt the first PDU. However, in some aspects, the decrypted set of payloads may be encrypted based on a nonce that is the same as the first nonce. While in some aspects, the decrypted set of payloads may be previously received data packets.

<FIG> illustrates a block diagram <NUM> illustrating an aspect of a soft combining operation in accordance with certain aspects of the present disclosure. The aspect of <FIG> leverages the Advanced Encryption Standard (AES) encryption property that if some bits of an encrypted packet got flipped due to over-the-air corruption and if the corrupted packet is decrypted with the correct cipher stream, then the decrypted packet will have the same erroneous bits as the corrupted encrypted packet.

The soft combing operation of <FIG> may occur in communications between a first device and a second device in a WPAN in accordance with certain aspects of the disclosure. The first device may correspond to, e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>/<NUM>', or the mesh node <NUM>. The second device may correspond to, e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>/<NUM>', or the mesh node <NUM>.

With reference to <FIG>, the first device (e.g., transmitting device) may transmit encrypted data <NUM> to the second device (e.g., receiving device). The encrypted data <NUM> may be similar to encrypted data <NUM> of <FIG>. The encrypted data <NUM> may include a first PDU and a first CRC that was calculated based on the encrypted first PDU. In some aspects, the first PDU may be encrypted based on a first nonce. The second device receives the encrypted data <NUM> and the encrypted data <NUM> is provided to the decryption block <NUM>. The decryption block <NUM> may be configured in a manner similar to the decryption block <NUM> of <FIG>. The decryption block <NUM> decrypts the encrypted data <NUM> (e.g., first PDU) and outputs decrypted data <NUM> (e.g., first payload).

The decryption block <NUM> outputs the decrypted data <NUM> to a RTSC block <NUM>. In some aspects, the decryption block <NUM> may be configured to provide the decrypted data <NUM> to the RTSC block <NUM> in a packet of <NUM> bits. The RTSC block <NUM> may be configured in a manner similar to the RTSC block <NUM>. In some aspects, the decrypted data <NUM> may be soft combined with a decrypted set of payloads at the RSTC block <NUM>. In some aspects, the set of payloads have been encrypted based on at least one nonce that is different than the first nonce. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. In some aspects, the decrypted set of payloads may be previously received data packets that may be stored within the RTSC block <NUM> or may be stored in a memory that is external to the RTSC block <NUM>. For example, the receiving device may receive a set of PDUs, prior to receiving the encrypted data <NUM>, and may attempt to decrypt each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads. The receiving device may be configured to transmit a NACK in the event that the receiving device fails to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. The transmission of the NACK from the receiving device to the transmitting device may indicate that the PDU was improperly received. In response to the NACK, the transmitting device sends another PDU to the receiving device. In some aspects, the retransmitted PDU may be the first PDU from the encrypted data <NUM>.

The RTSC block <NUM> may be configured to soft combine the decrypted data <NUM> with the decrypted set of payload in order to reconstruct the data and generate an error bitmap <NUM>. In some aspects, additional information may be soft combined with the decrypted data <NUM>, such as but not limited to, previous corrupted receptions of the same packet and/or soft bit information from modem. The RTSC block <NUM> will output the reconstructed decrypted data along with the error bitmap <NUM> which may be a list of the bits which were erroneous e.g., bits that got flipped due to over-the-air corruption. In some aspects, the reconstructed data and/or the erroneous bitmap may be <NUM> bits long. The error bitmap may be arranged to track which bits may have flipped or are erroneous when the RTSC block <NUM> is soft combining the decrypted data <NUM>.

The RSTC block <NUM> outputs the error bitmap <NUM> to the XOR block <NUM>. The XOR block <NUM> also receives an input of the encrypted data <NUM>. The XOR block <NUM> XORs the encrypted data <NUM> (e.g., first PDU) with the generated error bitmap <NUM> to obtain a soft combined encrypted data <NUM>. A CRC is generated based on the soft combined encrypted data <NUM> and is then submitted to Check CRC box <NUM>. The Check CRC box <NUM> determines whether the CRC generated based on the soft combined encrypted data <NUM> passes a CRC check against the first CRC of the encrypted data <NUM>. If the CRCs match then the data after the soft combining is valid, and the receiving device sends an ACK to the transmitting device, indicating that the packet has been properly received. However, if the CRC based on the soft combined encrypted data <NUM> does not pass the CRC check at Check CRC box <NUM>, then the soft combined encrypted data <NUM> has not been successfully combined, and the receiving device may send a NACK to the transmitting device. At least one advantage of the disclosure is that the aspect of <FIG> generates a CRC based on the soft combined encrypted data <NUM>, which is consistent with the BLE requirements. Yet another advantage of the disclosure is that the aspect of <FIG> yields the same results as the aspect of <FIG>, because it is mathematically equivalent to the aspect of <FIG>.

<FIG> illustrates a block diagram <NUM> illustrating an aspect of a message integrity check (MIC) calculation operation in accordance with certain aspects of the present disclosure. A MIC includes information that may be used to authenticate a data packet. The MIC may be used by the receiving device to confirm that the received data came from a stated transmitting device (e.g., data packet authenticity), and to confirm that a payload has not been changed (e.g., data packet integrity). The MIC protects both payload integrity and the authenticity of the data packet by enabling a receiving device to detect any changes to the payload. The block diagram <NUM> is similar, in part, to the block diagram <NUM> of <FIG>, and has many similar components that operate in a manner similar to the corresponding components of <FIG>, such as but not limited to an RTSC block, a CRC generator that generates a CRC based on soft combined decrypted data, a CRC generator that generates a CRC based on the cipher stream, and that a calculated CRC is checked against the received CRC. However, the block diagram <NUM> may be configured to calculate the MIC based on the decrypted data and is validated against the received MIC included in the encrypted data <NUM>. A discussion of the similar components of block diagrams <NUM> and <NUM> is not included herein in an effort to reduce duplicative work. The discussion of <FIG> will be directed towards the additional components and/or features that are not present in the diagram <NUM> of <FIG>.

As shown in <FIG>, the transmitting device transmits the encrypted data <NUM> to the receiving device. The encrypted data <NUM> is provided to the decryption block <NUM>. The decryption block <NUM> may be configured to generate the decrypted data <NUM> from the encrypted data <NUM>. In some aspects, the decryption block <NUM> may comprise an AES decryption block <NUM> that generates the decrypted data <NUM> from the encrypted data <NUM>. The AES decryption block <NUM> receives the encrypted data <NUM> and generates the decrypted data <NUM>, which is outputted from the decryption block <NUM> into the RTSC block <NUM>. The disclosure is not intended to be limited to a decryption block comprising the AES decryption block. In some aspects, the decryption block <NUM> may be comprised of many different known encryption/decryption blocks. The RTSC block <NUM> may be configured in a manner similar to the RTSC block <NUM> of <FIG>. The RTSC block <NUM> receives the decrypted data <NUM> and may be soft combined with a decrypted set of payloads at the RTSC block <NUM>, in a manner similar to the RTSC block <NUM>. The decrypted set of payloads may be encrypted based on at least one nonce that is different than the first nonce used to encrypt the first PDU. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. The decrypted set of payloads may be previously received data packets that may be stored within the RTSC block <NUM> or may be stored in a memory that is external to the RTSC block <NUM>. For example, the receiving device may receive a set of PDUs, prior to receiving the encrypted data <NUM>, and may attempt to decrypt each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads.

The RTSC block <NUM> may be configured to soft combine the decrypted data <NUM> with previously received data in an effort to correct previous corrupt reception or improper reception of the same packet, similarly as discussed above for RTSC block <NUM>. The RTSC block <NUM> generates reconstructed data (e.g., soft combined decrypted data <NUM>) and output the soft combined decrypted data <NUM> to the CRC generator <NUM>, also in a manner similar to the RTSC block <NUM>. However, the RTSC block <NUM> further outputs the soft combined decrypted data <NUM> back to the decryption block <NUM> to calculate the MIC. In some aspects, the decryption block <NUM> may further comprise an AES MIC calculation block <NUM> for MIC calculation. The AES MIC calculation block <NUM> generates a calculated MIC <NUM> based on the corrected data (e.g., soft combined decrypted data <NUM>). The disclosure is not intended to be limited to a MIC calculation block comprising the AES MIC calculation block <NUM>. In some aspects, the MIC calculation block may be comprised of many different known MIC calculation blocks. At block <NUM>, the calculated MIC <NUM> is checked against the received MIC from within the encrypted data <NUM>. If the calculated MIC <NUM> is the same as the received MIC from the encrypted data <NUM>, then the soft combined decrypted data <NUM> is validated as being correct, such that the contents of the packet have not changed in the transmission from the transmitting device to the receiving device. However, if the calculated MIC <NUM> is not the same as the received MIC, then the soft combined decrypted data <NUM> may not be properly corrected by the RTSC block <NUM> and the calculated MIC <NUM> fails. In some aspects, if the calculated MIC fails, then something may have occurred with the link between the transmitting device and the receiving device resulting in one or more bits getting flipped.

The calculated MIC <NUM> may be configured to be validated in instances when the calculated CRC passes the CRC check against the CRC received from the transmitting device. Validating the calculated MIC <NUM> when the calculated CRC passes the CRC check ensures that the calculated MIC <NUM> is calculated based on corrected data (e.g., soft combined decrypted data) generated by the RTSC block. Thus, validating the calculated MIC <NUM> occurs after the calculated CRC has been validated.

<FIG> illustrates a block diagram <NUM> illustrating an aspect of a MIC calculation operation in accordance with certain aspects of the present disclosure. The block diagram <NUM> is similar, in part, to the block diagram <NUM> of <FIG>, and has many similar components that operate in a manner similar to the corresponding components of <FIG>, such as but not limited to an RTSC block that generates an error bitmap, an XOR block that XORs encrypted data and the error bitmap to generate a calculated CRC. The block diagram <NUM> maybe configured to calculate the MIC based on the decrypted data, similarly as the diagram <NUM> of <FIG>, and is validated against the received MIC included in the encrypted data <NUM>. A discussion of the similar components of block diagrams <NUM> and <NUM> is not included herein in an effort to reduce duplicative work. The discussion of <FIG> may be directed towards the additional components and/or features that are not present in the diagram <NUM>.

As shown in <FIG>, the transmitting device transmits the encrypted data <NUM> to the receiving device. The encrypted data <NUM> is provided to the decryption block <NUM>. The decryption block <NUM> may be configured to generate the decrypted data <NUM> from the encrypted data <NUM>. In some aspects, the decryption block <NUM> comprises an AES decryption block <NUM> that generates the decrypted data <NUM> from the encrypted data <NUM>. The AES decryption block <NUM> receives the encrypted data <NUM> and generates the decrypted data <NUM>, which is outputted from the decryption block <NUM> into the RTSC block <NUM>. The disclosure is not intended to be limited to a decryption block comprising the AES decryption block. In some aspects, the decryption block <NUM> may be comprised of many different known encryption/decryption blocks. The RTSC block <NUM> may be configured in a manner similar to the RTSC block <NUM> of <FIG>. The RTSC block <NUM> receives the decrypted data <NUM> and generates an error bitmap <NUM> that is provided to the XOR block <NUM> which generates a calculated CRC <NUM> based on the XOR of the error bitmap <NUM> and the encrypted data <NUM>.

The RSTC block <NUM> may be further configured to generate a soft combined decrypted data stream <NUM> that is fed back into the decryption block <NUM> to calculate the MIC. In some aspects, the decryption block <NUM> may further comprise an AES MIC calculation block <NUM> for MIC calculation. The AES MIC calculation block <NUM> generates a calculated MIC <NUM> based on the corrected data (e.g., soft combined decrypted data <NUM>). The disclosure is not intended to be limited to a MIC calculation block comprising the AES MIC calculation block <NUM>. In some aspects, the MIC calculation block may be comprised of many different known MIC calculation blocks. At block <NUM>, the calculated MIC <NUM> is checked against the received MIC from within the encrypted data <NUM>. If the calculated MIC <NUM> is the same as the received MIC from the encrypted data <NUM>, then the soft combined decrypted data <NUM> is validated as being correct, such that the contents of the packet have not changed in the transmission from the transmitting device to the receiving device. However, if the calculated MIC <NUM> is not the same as the received MIC, then the soft combined decrypted data <NUM> may not be properly corrected by the RTSC block <NUM> and the calculated MIC <NUM> fails. As in the diagram <NUM> of <FIG>, the calculated MIC <NUM> may be configured to be validated in instances when the calculated CRC passes the CRC check against the CRC received from the transmitting device. Validating the calculated MIC <NUM> when the calculated CRC passes the CRC check assists in ensuring that the calculated MIC <NUM> is calculated based on the corrected data (e.g., soft combined decrypted data <NUM>) generated by the RTSC block. As such, validation of the calculated MIC <NUM> occurs after the calculated CRC has been first validated.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a first device (e.g., the central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>/<NUM>') in communication with a second device (e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>). In <FIG>, optional operations are indicated with dashed lines.

Referring to <FIG>, at <NUM>, the first device may receive a set of PDUs, as discussed in reference to <FIG>, <FIG>, and <FIG>. At <NUM>, the first device may decrypt, at decryption block <NUM>, <NUM>, each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads, as discussed in reference to <FIG>, <FIG>, and <FIG>. At <NUM>, the first device may be configured to send a NACK after failing to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. In such aspects, the first device sending the NACK may indicate that the PDU was improperly received by the first device. In some aspects, a first PDU (e.g., encrypted data <NUM>, <NUM>) may be received based on the sent NACK.

At <NUM>, the first device may receive the first PDU (e.g., encrypted data <NUM>, <NUM>) and a first CRC that is based on the first PDU. In some aspects, as discussed in reference to <FIG>, <FIG> and <FIG>, the first PDU (e.g., encrypted data <NUM>, <NUM>) may be encrypted based on a first nonce.

At <NUM>, the first device may decrypt, at decryption block <NUM>, <NUM>, the first PDU (e.g., encrypted data <NUM>, <NUM>) to obtain a first payload (e.g., decrypted data <NUM>, <NUM>) and a first cipher stream (e.g., cipher stream <NUM>, <NUM>). For example, with reference to <FIG>, <FIG> and <FIG>, the decryption block <NUM>, <NUM> receives the encrypted data <NUM>, <NUM> and generates the decrypted data <NUM>, <NUM> and a cipher stream <NUM>, <NUM>. At <NUM>, the first device may be configured to decrypt the first PDU, at decryption block <NUM>, to obtain a first message integrity check (MIC).

At <NUM>, the first device may be configured to soft combine the decrypted first payload with a decrypted set of payloads. For example, the RTSC block <NUM>, <NUM> may be configured to real time soft combine the decrypted data <NUM>, <NUM> with a decrypted set of payloads. In some aspects, the decrypted set of payloads may comprise previously received decrypted data packets, as discussed above in reference to <NUM>. In some aspects, the set of payload may have been encrypted based on at least one nonce different than the first nonce. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. At <NUM>, the first device may be configured to append a payload header (e.g., payload header <NUM>) to the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>, <NUM>) and zero padding (e.g., zero padding stream <NUM>) the first cipher stream (e.g., cipher stream <NUM>, <NUM>) before generating a second CRC (e.g., calculated CRC <NUM>, <NUM>).

At <NUM>, the first device may be further configured to generate a second MIC (e.g., calculated MIC <NUM> of <FIG>) based on the soft combined decrypted payloads (e.g., soft combined decrypted payloads <NUM>).

At <NUM>, the first device may be configured to generate a second CRC (e.g., calculated CRC <NUM>, <NUM>) based on the soft combined decrypted payloads (e.g., soft combined decrypted payloads <NUM>, <NUM>) and based on the first cipher stream (e.g., cipher stream <NUM>, <NUM>). In some aspects, for example at <NUM>, to generate the second CRC (e.g., calculated CRC <NUM>, <NUM>) the first device may be configured to generate a third CRC, at CRC generator <NUM>, <NUM>, based on the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>, <NUM>). In some aspects, for example at <NUM>, the first device may be further configured to generate a fourth CRC, at CRC generator <NUM>, <NUM>, based on the first cipher stream (e.g., cipher stream <NUM>, <NUM>). In some aspects, for example at <NUM>, the first device may be configured to XOR, at XOR <NUM>, <NUM>, the third CRC and the fourth CRC to obtain the second CRC (e.g., calculated CRC <NUM>, <NUM>). In some aspects, the first device maybe configured to append a header (e.g., header payload <NUM>) to the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>, <NUM>) before generating the third CRC, at CRC generator <NUM>, and zero padding (e.g., zero padding stream <NUM>) the first cipher stream (e.g., cipher stream <NUM>, <NUM>) before generating the fourth CRC, at CRC generator <NUM>, <NUM>.

At <NUM>, the first device may determine whether the generated second CRC (e.g., calculated CRC <NUM>, <NUM>) for the soft combined decrypted payloads passes a CRC check (e.g., block <NUM>, <NUM>) against the first CRC. If the generated second CRC does not pass the CRC check, then at <NUM>, a NACK is sent by the first device to the second device, which results in a retransmission of the PDU and the process is repeated starting at <NUM>. If the generated second CRC does pass the CRC check, then at <NUM>, the first device may determine whether the generated second MIC (e.g., calculated MIC <NUM>) passes a MIC check (e.g., MIC check <NUM>) against the first MIC. If the generated second MIC does not pass the MIC check, then at <NUM>, a NACK is sent by the first device to the second device, which may result in the retransmission of the PDU and the process is repeated starting at <NUM>. If the generated second MIC does pass the MIC check, then at <NUM>, the first device may transmit an ACK to the second device. The transmission of an ACK to the second device indicates that the PDU was properly received, such that the soft combined decrypted data <NUM>, <NUM> was properly combined.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an exemplary apparatus <NUM>. The apparatus maybe a first device (e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>') in communication with a second device (e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>). The apparatus may include a reception component <NUM>, a decryption component <NUM>, a first CRC generator component <NUM>, a soft combine component <NUM>, a decrypted payloads component <NUM>, a second CRC generator component <NUM>, an XOR component <NUM>, a CRC check component <NUM>, and a broadcast component <NUM>.

The reception component <NUM> may be configured to receive a first PDU and a first CRC that is based on the first PDU from the second device <NUM>. In some aspects, the first PDU (e.g., encrypted data <NUM>) maybe encrypted based on a first nonce. In some aspects, the first device may receive a set of PDUs, and decrypt, at decryption block <NUM>, each PDU in the set of PDUs after the PDU is received to obtain a corresponding payload of the decrypted set of payloads, as discussed in reference to <FIG>, <FIG> and <FIG>. In some aspects, the first device may be configured to send a NACK after failing to properly validate, at block <NUM>, <NUM>, a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. In such aspects, the first device sending the NACK may indicate that the PDU was improperly received by the first device. In some aspects, the first PDU (e.g., encrypted data <NUM>, <NUM>) may be received based on the sent NACK.

The decryption component <NUM> may be configured to receive the encrypted data <NUM>, <NUM> (e.g., first PDU) from the reception component <NUM> and decrypt the first PDU to obtain a first payload and a first cipher stream. For example, with reference to <FIG>, <FIG>, and <FIG>, the decryption block <NUM>, <NUM> receives the encrypted data <NUM>, <NUM> and generates the decrypted data <NUM>, <NUM> and a cipher stream <NUM>, <NUM>. In some aspects, the decryption component <NUM> may be configured to decrypt the first PDU, by decryption block <NUM>, to obtain a first message integrity check (MIC). In some aspects, the decryption component <NUM> maybe configured to generate a second MIC (e.g., calculated MIC <NUM> of <FIG>) based on the soft combined decrypted payloads (e.g., soft combined decrypted payloads <NUM>).

The first CRC generator component <NUM> may be configured to receive the cipher stream <NUM>, <NUM> from the decryption component <NUM> and generate, at CRC generator <NUM>, <NUM>, a CRC based on the cipher stream <NUM>, <NUM>. The soft combine component <NUM> may be configured to soft combine, at RTSC block <NUM>, <NUM>, the decrypted first payload (e.g., decrypted data <NUM>, <NUM>) with a decrypted set of payloads. The decrypted payloads component <NUM> may be configured to store a set of payloads that have been encrypted based on at least one nonce different than the first nonce and provide the set of payloads to the soft combine component <NUM>. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. In some aspects, the decrypted set of payloads may comprise previously received decrypted data packets.

The second CRC generator component <NUM> may be configured to receive the soft combined decrypted data from the soft combine component and generate a CRC, at CRC generator <NUM>, <NUM>, based on the soft combined decrypted data <NUM>, <NUM>. The XOR component <NUM> may be configured to receive the CRC generated by the first CRC generator component <NUM> and the CRC generated by the second CRC generator component <NUM> to generate a second CRC (e.g., calculated CRC <NUM>, <NUM>) based on the soft combined decrypted payloads (e.g., soft combined decrypted payloads <NUM>,<NUM>) and based on the first cipher stream (e.g., cipher stream <NUM>, <NUM>). In some aspects, a payload header (e.g., payload header <NUM>) may be appended to the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>, <NUM>) and zero padding (e.g., zero padding stream <NUM>) may be appended to the first cipher stream (e.g., cipher stream <NUM>, <NUM>) before generating the second CRC (e.g., calculated CRC <NUM>, <NUM>).

The CRC check component <NUM> may be configured to determine whether the generated second CRC (e.g., calculated CRC <NUM>, <NUM>) for the soft combined decrypted payloads passes a CRC check (e.g., block <NUM>, <NUM>) against the first CRC. The MIC check component <NUM> may be configured to determine whether the calculated MIC (e.g., calculated MIC <NUM>) passes a MIC check (e.g., block <NUM>) against the first MIC. The broadcast component <NUM> may be configured to transmit an ACK or a NACK to the second device <NUM> based on whether the generated second CRC (e.g., calculated CRC <NUM>, <NUM>) for the soft combined decrypted payloads passes a CRC check and/or whether the calculated MIC <NUM> passes a MIC check against the MIC received with the encrypted data. For example, if the calculated CRC <NUM>, <NUM> passes the CRC check, then the broadcast component <NUM> may transmit an ACK to the second device <NUM> indicating that the PDU was properly received. In other aspects, if the calculated CRC <NUM> does not pass the CRC check, then the broadcast component <NUM> may transmit a NACK to the second device <NUM> indicating that the PDU was not properly received, and the second device <NUM> retransmits another PDU. In some aspects, if the calculated MIC <NUM> does not pass the MIC check, then the broadcast component <NUM> may transmit the NACK to the second device <NUM>, while in some aspects, if the calculated MIC <NUM> does pass the MIC check, then the broadcast component <NUM> may transmit the ACK to the second device <NUM> indicating that the PDU was properly received.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of <FIG>, <FIG>, and <FIG>. As such, each block in the aforementioned flowcharts of <FIG>, <FIG>, and <FIG> may be performed by a component and the apparatus may include one or more of those components.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system <NUM> may be coupled to a transceiver <NUM>. The transceiver <NUM> is coupled to one or more antennas <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. The transceiver <NUM> receives a signal from the one or more antennas <NUM>, extracts information from the received signal, and provides the extracted information to the processing system <NUM>, specifically the reception component <NUM>. In addition, the transceiver <NUM> receives information from the processing system <NUM>, specifically the broadcast component <NUM>, and based on the received information, generates a signal to be applied to the one or more antennas <NUM>. The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium / memory <NUM>. The processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium / memory <NUM>. The software, when executed by the processor <NUM>, causes the processing system <NUM> to perform the various functions described supra for any particular apparatus. The computer-readable medium / memory <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software. The processing system <NUM> further includes at least one of the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The components may be software components running in the processor <NUM>, resident/stored in the computer readable medium / memory <NUM>, one or more hardware components coupled to the processor <NUM>, or some combination thereof.

In certain configurations, the apparatus <NUM>/<NUM>' for wireless communication may include means for receiving a first packet data unit (PDU) and a first cyclic redundancy check (CRC) that is based on the first PDU, the first PDU being encrypted based on a first nonce, means for decrypting the first PDU to obtain a first payload and a first cipher stream, means for soft combining the decrypted first payload with a decrypted set of payloads, the set of payloads having been encrypted based on at least one nonce different than the first nonce, means for generating a second CRC based on the soft combined decrypted payloads and based on the first cipher stream, means for determining whether the generated second CRC for the soft combined decrypted payloads passes a CRC check against the first CRC, means for receiving a set of PDUs, means for decrypting each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads, means for sending a negative ACK (NACK), after failing to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data, indicating that the PDU was improperly received, means for wherein the first PDU is received based on the sent NACK, means for appending a payload header to the soft combined decrypted payloads and zero padding the first cipher stream before generating the second CRC, means for generating a third CRC based on the soft combined decrypted payloads, means for generating a fourth CRC based on the first cipher stream, means for XORing the generated third CRC and the generated fourth CRC to obtain the second CRC, means for appending a header to the soft combined decrypted payloads before generating the third CRC, means for zero padding the first cipher stream before generating the fourth CRC, wherein the first PDU is decrypted further to obtain a first message integrity check (MIC), further comprising means for generating a second MIC based on the soft combined decrypted payloads, further comprising means for determining whether the generated second MIC passes a MIC check against the first MIC. The aforementioned means may be one or more of the aforementioned processor(s) <NUM>, the short-range communications controller <NUM>, and/or radio <NUM> in <FIG>, components of apparatus <NUM>/<NUM>' configured to perform the functions recited by the aforementioned means.

Referring to <FIG>, at <NUM>, the first device may be configured to receive a set of PDUs, as discussed in reference to <FIG> and <FIG>. At <NUM>, the first device may decrypt, at decryption block <NUM>, <NUM>, each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads, as discussed in reference to <FIG> and <FIG>. At <NUM>, the first device may be configured to send a NACK after failing to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. In such aspects, the first device sending the NACK may indicate that the PDU was improperly received by the first device. In some aspects, a first PDU (e.g., encrypted data <NUM>, <NUM>) may be received by the first device based on the sent NACK.

At <NUM>, the first device may receive a first PDU (e.g., encrypted data <NUM>, <NUM>) and a first CRC that is based on the first PDU. In some aspects, as discussed in reference to <FIG> and <FIG>, the first PDU (e.g., encrypted data <NUM>, <NUM>) may be encrypted based on a first nonce.

At <NUM>, the first device may be configured to decrypt, at decryption block <NUM>, <NUM>, the first PDU (e.g., encrypted data <NUM>, <NUM>) to obtain a first payload (e.g., decrypted data <NUM>, <NUM>). For example, with reference to <FIG> and <FIG>, the decryption block <NUM>, <NUM> receives the encrypted data <NUM>, <NUM> and generates the decrypted data <NUM>, <NUM>. At <NUM>, the first device maybe configured to decrypt, at decryption block <NUM>, the first PDU (e.g., encrypted data <NUM>) to obtain a first MIC.

At <NUM>, the first device may be configured to soft combine, at RTSC block <NUM>, <NUM>, the decrypted first payload (e.g., decrypted data <NUM>, <NUM>) with a decrypted set of payloads to obtain an error bitmap <NUM>, <NUM>. In some aspects, the set of payloads have been encrypted based on at least one nonce different than the first nonce. However, in some aspects, the set of payloads may be encrypted based on a nonce that is the same as the first nonce. At <NUM>, the first device may be configured to generate a second MIC (e.g., calculated MIC <NUM>) based on the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>). For example, the decrypted data <NUM> is soft combined at the RTSC block <NUM> and the soft combined decrypted data <NUM> is outputted back to the decryption block <NUM>, so that that decryption block <NUM> can further decrypt the soft combined decrypted data <NUM> to obtain the second MIC (e.g., calculated MIC <NUM>). In some aspects, the decryption block <NUM> may comprise an AES block for MIC calculation <NUM>, which receives the soft combined decrypted data <NUM> and generates a calculated MIC <NUM> based on the soft combined decrypted data <NUM>.

At <NUM>, the first device may be configured to XOR, at XOR <NUM>, <NUM>, the received first PDU (e.g., encrypted data <NUM>, <NUM>) with the obtained error bitmap <NUM>, <NUM> to obtain a soft combined encrypted payload. At <NUM>, the first device may be configured to generate a second CRC (e.g., calculated CRC <NUM>) based on the soft combined encrypted payload <NUM> which is the result of the XOR of the received first PDU (e.g., encrypted data <NUM>, <NUM>) and the obtained error bitmap <NUM>, <NUM>.

At <NUM>, the first device may determine whether the generated second CRC (e.g., calculated CRC <NUM>) for the soft combined encrypted payload (e.g., soft combined encrypted data <NUM>) passes a CRC check, at CRC check <NUM>, <NUM>, against the first CRC based on the encrypted data <NUM>, <NUM>. If the generated second CRC does not pass the CRC check, the at <NUM>, a NACK is sent by the first device to the second device, which results in a retransmission of the PDU, and the process is repeated starting at <NUM>. If the generated second CRC does pass the CRC check, then at <NUM>, the first device may determine whether the generated second MIC (e.g., calculated MIC <NUM>) passes a MIC check (e.g., MIC check <NUM>) against the first MIC. If the generated second MIC does not pass the MIC check, then at <NUM>, a NACK is sent by the first device to the second device, which may result in the retransmission of the PDU and the process is repeated starting at <NUM>. If the generated second MIC does pass the MIC check, then at <NUM>, the first device may transmit an ACK to the second device. The transmission of an ACK to the second device indicates that the PDU was properly received, such that the soft combined decrypted data performed at RTSC block <NUM>, <NUM>, was properly combined.

In yet some aspects, an ACK may be sent by the first device when both the generated second CRC (e.g., calculated CRC <NUM>) passes the CRC check <NUM> against the first CRC and the generated second MIC (e.g., calculated MIC <NUM>) passes a MIC check <NUM> against the first MIC.

<FIG> is a conceptual data flow diagram <NUM> illustrating the data flow between different means/components in an exemplary apparatus <NUM>. The apparatus maybe a first device (e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>, the apparatus <NUM>') in communication with a second device (e.g., central device <NUM>, peripheral device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, wireless device <NUM>). The apparatus includes a reception component <NUM>, a decryption component <NUM>, a soft combine component <NUM>, a decrypted payloads component <NUM>, an XOR component <NUM>, a CRC generator component <NUM>, a CRC check component <NUM>, MIC check component <NUM>, and a broadcast component <NUM>.

The reception component <NUM> may be configured to receive a first PDU and a first CRC that is based on the first PDU from the second device <NUM>. In some aspects, the first PDU (e.g., encrypted data <NUM>, <NUM>) maybe encrypted based on a first nonce. In some aspects, the first device may receive a set of PDUs, and decrypt, at decryption block <NUM>, <NUM>, each PDU in the set of PDUs after the PDU is received to obtain a corresponding payload of the decrypted set of payloads, as discussed in reference to <FIG>, <FIG>. In some aspects, the first device may be configured to send a NACK after failing to properly validate, at block <NUM>, <NUM> a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data. In such aspects, the first device sending the NACK may indicate that the PDU (e.g., encrypted data <NUM>, <NUM>) was improperly received by the first device. In some aspects, the first PDU (e.g., encrypted data <NUM>, <NUM>) may be received based on the sent NACK.

The decryption component <NUM> may be configured to receive the encrypted data (e.g., first PDU) from the reception component <NUM> and decrypt, at decryption block <NUM>, <NUM>, the first PDU to obtain a first payload (e.g., decrypted data <NUM>, <NUM>). In some aspects, the first PDU may be decrypted further, at decryption block <NUM>, to obtain a first MIC corresponding to the first PDU (e.g., encrypted data <NUM>, <NUM>).

The soft combine component <NUM> may be configured to soft combine, at RTSC block <NUM>, <NUM>, the decrypted first payload (e.g., decrypted data <NUM>, <NUM>) with a decrypted set of payloads to obtain an error bitmap <NUM>. In some aspects, the set of payloads have been encrypted based on at least one nonce different than the first nonce. However, in some aspects, the set of payload may be encrypted based on a nonce that is the same as the first nonce. The MIC generator component <NUM> may be configured to generate a second MIC (e.g., calculated MIC <NUM>) based on the soft combined decrypted payloads (e.g., soft combined decrypted data <NUM>). For example, the decrypted data <NUM> is soft combined at the RTSC block <NUM> and the soft combined decrypted data <NUM> is outputted back to the decryption block <NUM>, so that that decryption block <NUM> can further decrypt the soft combined decrypted data <NUM> to obtain the second MIC (e.g., calculated MIC <NUM>). In some aspects, the decryption block <NUM> comprises an AES block for MIC calculation <NUM>, which receives the soft combined decrypted data <NUM> and generates a calculated MIC <NUM> based on the soft combined decrypted data <NUM>.

The XOR component <NUM> may be configured to receive the error bitmap <NUM> from the soft combine component <NUM> and receive the encrypted data <NUM> to perform an XOR operation between the error bitmap <NUM> and the encrypted data <NUM> to obtain a soft combined encrypted payload (e.g., soft combined encrypted data <NUM>). The CRC generator component <NUM> may receive the soft combined encrypted data from the XOR component <NUM> in order to generate a second CRC (e.g., calculated CRC <NUM>) based on the soft combined encrypted payload <NUM>. The CRC check component <NUM> may be configured to determine whether the generated second CRC (e.g., calculated CRC <NUM>) for the soft combined encrypted payload (e.g., soft combined encrypted data <NUM>) passes a CRC check, at CRC check <NUM>, against the first CRC based on the encrypted data <NUM>. The MIC check component <NUM> may be configured to determine whether the generated MIC (e.g., calculated MIC <NUM>) passes a MIC check (e.g., block <NUM>) against the first MIC based on the encrypted data. The broadcast component <NUM> may be configured to transmit an ACK when both the generated CRC (e.g., calculated CRC <NUM>) passes the CRC check <NUM> against the first CRC based on the first PDU, and when the generated second MIC (e.g., calculated MIC <NUM>) passes the MIC check <NUM> against the first MIC based on the first PDU. If the generated second CRC does not pass the CRC check then the broadcast component <NUM> may transmit a NACK to the second device, which may result in a retransmission of the PDU. If the generated second CRC does pass the CRC check, then the MIC check component <NUM> may determine whether the generated second MIC (e.g., calculated MIC <NUM>) passes the MIC check (e.g., MIC check <NUM>) against the first MIC. If the generated second MIC does not pass the MIC check, then the broadcast component <NUM> may send NACK to the second device, which may result in the retransmission of the PDU. If the generated second MIC does pass the MIC check, then the broadcast component <NUM> may transmit an ACK to the second device <NUM>. The transmission of an ACK to the second device <NUM> indicates that the PDU was properly received, such that the soft combined decrypted data performed at RTSC block <NUM>, <NUM>, was properly combined.

<FIG> is a diagram <NUM> illustrating an example of a hardware implementation for an apparatus <NUM>' employing a processing system <NUM>. The processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors and/or hardware components, represented by the processor <NUM>, the components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the computer-readable medium / memory <NUM>. The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

In certain configurations, the apparatus <NUM>/<NUM>' for wireless communication may include means for receiving a first packet data unit (PDU) and a first cyclic redundancy check (CRC) that is based on the first PDU, the first PDU being encrypted based on a first nonce, means for decrypting the first PDU to obtain a first payload, means for obtaining an error bitmap by soft combining the decrypted first payload with a decrypted set of payloads, the set of payloads having been encrypted based on at least one nonce different than the first nonce, means for XORing the received first PDU with the obtained error bitmap to obtain a soft combined encrypted payload, means for generating a second CRC based on the soft combined encrypted payload, means for determining whether the generated second CRC for the soft combined encrypted payload passes a CRC check against the first CRC, means for receiving a set of PDUs, means for decrypting each PDU in the set of PDUs after the PDU is received to obtain a corresponding decrypted payload of the decrypted set of payloads, means for sending a negative ACK (NACK), after failing to properly validate a received CRC, based on the encrypted data, against a calculated CRC, based on the soft combined data, indicating that the PDU was improperly received, wherein the first PDU is received based on the sent NACK, wherein the first PDU is decrypted further to obtain a first message integrity check (MIC), further comprising means for generating a second MIC based on the soft combined decrypted payloads, wherein the ACK is sent when both the generated second CRC passes the CRC check against the first CRC and the generated second MIC passes a MIC check against the first MIC. The aforementioned means may be one or more of the aforementioned processor(s) <NUM>, the short-range communications controller <NUM>, and/or radio <NUM> in <FIG>, components of apparatus <NUM>/<NUM>' configured to perform the functions recited by the aforementioned means.

Although the present disclosure discusses the scheme of validating the combination of decrypted data packets in relation to BLE technologies, it is understood that such scheme may also be applicable to BT technologies. In addition, the scheme may be applied to <NUM>. <NUM> based protocols, such as Zigbee, or any other wireless protocol wherein a packet and its retransmitted packets may be sent using different encryption parameters.

Claim 1:
A method (<NUM>) of wireless communication performed by a receiving device (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>, <NUM>'), comprising:
receiving (<NUM>, <NUM>) a first packet data unit, PDU, and a first cyclic redundancy check, CRC, that is based on the first PDU, the first PDU being encrypted based on a first cipher stream;
decrypting (<NUM>, <NUM>, <NUM>) the first PDU to obtain a first payload based on the first cipher stream;
soft combining (<NUM>, <NUM>, <NUM>) the decrypted first payload with a decrypted set of payloads, the set of payloads having been encrypted based on at least one cipher stream different than the first cipher stream;
generating (<NUM>, <NUM>, <NUM>) a second CRC based on the soft combined decrypted payloads and based on the first cipher stream; and
determining (<NUM>, <NUM>) whether the generated second CRC for the soft combined decrypted payloads passes a CRC check against the first CRC.