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Composition of Bluetooth BR/EDR Node

You can create Bluetooth Central and Peripheral basic rate/enhanced data rate (BR/EDR) nodes with Bluetooth® Toolbox by using the bluetoothNode object. These Bluetooth nodes contain a traffic manager and a protocol stack that comprises the baseband, and physical (PHY) layers, as illustrated in the figure. This topic outlines the functionalities implemented by the bluetoothNode object.

To use the bluetoothNode object, you must download the Communications Toolbox Wireless Network Simulation Library. For more information on installing add-ons, see Get and Manage Add-Ons.

Traffic Manager

The traffic manager uses the networkTrafficOnOff traffic pattern object from the Communications Toolbox™ Wireless Network Simulation Library to model real-world data traffic. This object generates a traffic pattern with two states: on or off. The object automatically configures default traffic settings when it establishes a synchronous connection-oriented (SCO) link.

Baseband Layer

The baseband layer of a BR/EDR node has these functionalities:

  • Decides whether to transmit asynchronous connection-less (ACL) or SCO packets.

  • Uses a scheduler at a Central node for ACL data transmission. You can use the configureScheduler object function to configure the scheduler. This object function employs round-robin strategy.

  • Uses the adaptive frequency hopping (AFH) technique when two devices connect. This changes the radio channel for packet communication at intervals.

  • Classifies a channel as used or unused, where used indicates a suitable channel for transmission and unused indicates a unsuitable channel for transmission. The updateChannelList object function updates the channel map for the physical link between the Bluetooth BR/EDR node and the specified destination node.

  • Supports a connection supervision timeout. The supervision timeout represents the maximum amount of time that can elapse without receiving any valid packets before the node consider the connection lost.

  • Packet reception management, which includes these operations.

    • Checks for duplicate packet receptions to prevent redundant processing, and acknowledges receipt of a data packet.

    • Forwards the received payload to higher layers for further processing.

  • Retransmits packets that previously failed to receive acknowledgment.

PHY Layer

The Bluetooth BR/EDR node supports full PHY processing. At the transmitter, the PHY layer involves these operations, as illustrated in this figure.

  • Generates packet headers using the control flag bits, computes a header error check (HEC) code, and attaches it to the header.

  • Generates the protocol data unit (PDU).

  • Whitens the data.

  • Applies forward error correction to the whitened data.

  • Modulates the whitened data using Gaussian frequency shift keying (GFSK) or differential phase shift keying (DPSK).

At the receiver, the PHY layer performs these operations, as illustrated in this figure.

  • Simulates interference effects on signals. Interference modeling offers these modes:

    • Overlapping adjacent channel — Considers any signal that overlaps in both time and frequency with the signal of interest as interference.

    • Non-overlapping adjacent channel — Regards signals as interference if they temporally overlap with the signal of interest and their frequencies lie within the range [f1 – fd, f2 + fd], where f1 and f2 denote the start and end frequencies of the signal of interest, respectively, and fd represents the maximum interference offset.

  • Applies a low-pass anti-aliasing filter to the received waveform.

  • Decodes the filtered waveform using these steps:

    • Separates the access code from the packet header.

    • Demodulates the initial segment of the received waveform to decode the access code.

    • Retrieves the lower address part (LAP) using the decoded access code.

    • If the packet header is present, perform data dewhitening on the header. Then, perform 1/3 rate repetitive decoding on the packet header."

    • Performs a header error check (HEC) on the packet header.

    • Demodulates the payload using the GFSK or DPSK technique.

    • Applies FEC decoding to the payload.

    • De-whitens the payload data.

    • Decodes the payload.

    • Performs a cyclic redundancy check (CRC).

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