bluetooth architecture, General description

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Bluetooth wireless technology

  1. Basic Rate(BR)
    1. Enhanced Date Rate
    2. Alternertive Media Access Control (MAC)
    3. Physical(PHY) layer extensions
  2. Low Energy(LE)

Bluetooth Core System

  1. Host
  2. one or more Controller: primary Controllers and secondary Controllers
    BR/EDR controller:
    Radio,
    Baseband,
    Link Manager,
    HCI
    BLE Controller
    LE PHY
    Link Layer
    HCI

BR/EDR Overview

  1. Piconet
  2. Frequency hopping
  3. Physical channel: sub-divided into time units known as slots, TDD
    physical channel -> physical link -> logical transport -> logical link -> L2CAP channel

    The physical link is used as a transport for one or more logical links that support unicast synchronous, asynchronous and isochronous traffic, and broadcast traffic. Traffic on logical links is multiplexed onto the physical link by occupying slots assigned by a scheduling function in the resource manager.

  4. LMP,A control protocol for the baseband and physical layers is carried over logical links in addition to user data
  5. Connectionless Slave Broadcast devices

LE Overview

  1. PHY
    1M:
    1M Coded:
     coding scheme:(where S is the number of symbols per bit.)
     s=2: 2 symbols represent 1 bit, the speed is 500Kb/s
     s=8: 8 symbols represent 1 bit, the speed is 125Kb/s
    2M:
  2. 40 physical channel, 2M for 1 channel
  3. Events:The physical channel is sub-divided into time units known as events
    4 types events: Advertising, Extended Advertising, Periodic Advertising, and Connection events

    In connection events, channel hopping occurs at the start of each connection event. Within a connection event, the master and slave alternate sending data packets using the same data PHY channel. The master initiates the beginning of each connection event and can end each connection event at any time.

  4. Physical channel:

    The advertising and periodic physical links provide a unidirectional packet transport from the advertiser to a potentially unlimited number of scanners or initiators.

  5. Link Layer Protocol(LL), A control protocol for the link and physical layers is carried over logical links in addition to user data
  6. L2CAP:
    fregmentation and de-fregmentation
    multiplex and de-multiplex
    two Fixed channel: SMP and ATT.
  7. LE Radio: AoA, AoD

Question 1

Why the modem of BR is 1Mb/s, but the date rates is 721.2 kb/s?

The Basic Rate system offers synchronous and asynchronous connections with data rates of 721.2 kb/s for Basic Rate, 2.1 Mb/s for Enhanced Data Rate and high speed operation up to 54 Mb/s with the 802.11 AMP.
2DH5 / 6 slot
Question.2

Synchronization Train 是什么？

A series of packets transmitted on a set of fixed fre- quencies that deliver sufficient information for a receiv- ing device to start receiving corresponding Connectionless Slave Broadcast packets or to recover the current piconet clock after missing a Coarse Clock Adjust.