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Bluetooth® Full Duplex Voice and Data Transmission

This model shows the full duplex communication between two Bluetooth® devices. Both data packets and voice packets can be transmitted between the two devices:

  • Supported voice packet types: HV1, HV2, HV3 and SCORT

  • Supported data packet types: DM1

A system parameters block configures the packet type, slot pair, and channel type. Stateflow® is used to implement the acknowledgement scheme for the data packets and the SCORT receiver state machine.

Structure of the Example

A Bluetooth core system consists of an RF transceiver, baseband, and protocol stack. The system offers services that enable the connection of devices and the exchange of a variety of classes of data between these devices. This example is focused on the simulation of a piconet consisting of a master, a slave, and a transmission channel.

This model includes CVSD speech coding, HEC, payload CRC for DM1, FEC, framing, GFSK Modulation, frequency hopping, hop sequence generation, an 802.11b interferer, wave file I/O, BER meters, spectrum, timing, and spectrogram plot.

You can set the system parameters by double-clicking the Model Parameters block in the top left. You can toggle instrumentation (spectrum, spectrogram, and timing diagram) by double-clicking the switch. The ARQN display for data transmission can be turned on or off.

Transmitter

The transmitter consists of:

  • The controller block (based on BT spec Part B 7.6 ARQ Scheme)

  • The payload and FEC block (based on BT spec Part B 7)

  • The framing block (based on BT spec Part B 6.1 6.4 and 7.3)

  • The radio block (based on BT spec Part A 3.1 Basic Rate)

Receiver

The receiver consists of:

  • The radio block (based on BT spec Part A 4.1 Basic Rate)

  • The deframing block (based on BT spec Part B 7)

  • The controller block(based on BT spec Part B 7)

Channel

The model makes use of configurable subsystems, swapping in and out the required components for the chosen parameters. The following configurable subsystems are constructed in the Bluetooth Full Duplex library:

  • AWGN Channel

  • AWGN Channel and 80211b interference

  • None (direct connection)

Communication Blocks Used

This model shows the use of the following Communications blocks:

  • The CPM Modulator Baseband block is used to implement the GFSK (Gaussian frequency shift keying). The Bluetooth radio module uses GFSK, where a binary one is represented by a positive frequency deviation and a binary zero by a negative frequency deviation.

  • The M-FSK Modulator Baseband block is used to implement the frequency hopping in Bluetooth Radio. The Bluetooth radio accomplishes spectrum spreading by using 79 frequency hops, each displaced by 1 MHz, starting at 2.402GHz and finishing at 2.480GHz.

  • The Free Space Path Loss block, together with the AWGN block and the 802.11b interference subsystem, shows the construction of a transmission channel.

  • The General CRC Generator block is used for transmitted data CRC calculation.

  • The use of the M-FSK Demodulator block, the General CRC Syndrome Detector block, and the implementation of rate 1/3 and rate 2/3 payload FEC are also included.

The model also uses Stateflow charts to implement:

  • The Transmitter Controller

  • The Receiver Controller, which decides on the successful reception of a packet by looking at the status of the access code, HEC and CRC

Signals Between the Two Devices

  • Tx_Raw_Bits1: The master device generates information data randomly, does CRC and FEC payload, and packs them according to the Bluetooth defined format (similarly, Tx_Raw_Bits2 is for the slave device).

  • Signal_Tx1: The master device takes Tx_Raw_Bits1 and modulates according to the Bluetooth standard. Signal_Tx1 will be transmitted through the channel (similarly, Signal_Tx2 is for the slave device).

  • Signal_Rx1: The raw received signal after AWGN and interference. Signal_Rx1 is fed to the master device for demodulation and detection (similarly, Signal_Rx2 is for the slave device).

  • Tx_Info_Bits1: The information data generated by the master with CRC payload but no FEC. Tx_Info_Bits1 is used for SCO BER check on the slave side (similarly, Tx_Info_Bits2 is for the master device).

  • Diagnostics2: A collection of frame and packet information for the ACL BER check on the master side (similarly, Diagnostics1 is for the slave device).

  • master_SCO: SCO BER information from the master device for display (similarly, slave_SCO is for the slave device).

  • master_ACL: ACL BER information from the master device for display (similarly, slave_ACL is for the slave device).

  • Interference: The interference signal generated from a 802.11b channel.

Results and Displays

The scope display includes:

  • The spectrogram of the channel

  • The timing diagram of the received signal

  • The received signal spectrum

The Master/Slave BER meters calculate:

  • The data BER

  • The data throughput

A succcessful system is decided by:

  • The ACL(Asynchronous connection-oriented) BER being zero.

  • The SCO (Synchronous connection-oriented) BER (which includes Raw BER, Residual BER, and FER) being within the specifications.

References

Standards can be found at: http://www.bluetooth.com/

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